     1                                  ; ****************************************************************************
     2                                  ; UNIX386.ASM (RETRO UNIX 386 Kernel) - v0.2.1.2
     3                                  ; ----------------------------------------------------------------------------
     4                                  ; NASM version 2.15 (unix386.s)
     5                                  ;
     6                                  ; RETRO UNIX 386 (Retro Unix == Turkish Rational Unix)
     7                                  ; Operating System Project (v0.2) by ERDOGAN TAN (Beginning: 24/12/2013)
     8                                  ;
     9                                  ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
    10                                  ; (v0.1 - Beginning: 11/07/2012)
    11                                  ;
    12                                  ; [ Last Modification: 04/02/2016 (v0.2.1.0) ]
    13                                  ;	 31/12/2021 - BugFix and Code Optimization (v0.2.1.1)
    14                                  ;	 03/03/2022 - Code Optimization and BugFix (v0.2.1.2) - 02/01/2022
    15                                  ;
    16                                  ; Derived from UNIX Operating System (v1.0 for PDP-11) 
    17                                  ; (Original) Source Code by Ken Thompson (1971-1972)
    18                                  ; <Bell Laboratories (17/3/1972)>
    19                                  ; <Preliminary Release of UNIX Implementation Document>
    20                                  ;
    21                                  ; Derived from 'UNIX v7/x86' source code by Robert Nordier (1999)
    22                                  ; UNIX V7/x86 source code: see www.nordier.com/v7x86 for details.
    23                                  ;
    24                                  ; ****************************************************************************
    25                                  ; 31/12/2021 - 03/03/2022
    26                                  ; nasm unix386.s -l unix386.txt -o unix386 -Z error.txt
    27                                  ; ('unixcopy' utility is used for updating retro unix kernel on runix fs disk)
    28                                  
    29                                  ; 02/01/2022 - Code Optimization
    30                                  ; Runix Kernel v0.2.1.2
    31                                  ; 24/12/2021 - BugFix and Code Optimization
    32                                  ; Runix Kernel v0.2.1.1 
    33                                  
    34                                  ; 24/12/2013
    35                                  
    36                                  ; Entering protected mode:
    37                                  ; Derived from 'simple_asm.txt' source code file and 
    38                                  ; 'The world of Protected mode' tutorial/article by Gregor Brunmar (2003)
    39                                  ; (gregor.brunmar@home.se)
    40                                  ; http://www.osdever.net/tutorials/view/the-world-of-protected-mode
    41                                  ;
    42                                  
    43                                  ; "The Real, Protected, Long mode assembly tutorial for PCs" 
    44                                  ; by Michael Chourdakis (2009) 
    45                                  ; http://www.codeproject.com/Articles/45788/
    46                                  ; http://www.michaelchourdakis.com
    47                                  ;
    48                                  
    49                                  ; Global Descriptor Table:
    50                                  ; Derived from 'head.s" source code of Linux v1.0 kernel
    51                                  ; by Linus Torvalds (1991-1992)
    52                                  ;
    53                                  
    54                                  KLOAD	equ 10000h ; Kernel loading address
    55                                  	; NOTE: Retro UNIX 8086 v1 /boot code loads kernel at 1000h:0000h
    56                                  KCODE	equ 08h	; Code segment descriptor (ring 0)
    57                                  KDATA	equ 10h	; Data segment descriptor (ring 0)
    58                                  ; 19/03/2015
    59                                  UCODE	equ 1Bh ; 18h + 3h  (ring 3)
    60                                  UDATA	equ 23h ; 20h + 3h  (ring 3)
    61                                  ; 24/03/2015
    62                                  TSS	equ 28h	; Task state segment descriptor (ring 0)
    63                                  ; 19/03/2015
    64                                  CORE	equ 400000h  ; Start of USER's virtual/linear address space 
    65                                  		     ; (at the end of the 1st 4MB)
    66                                  ECORE	equ 0FFC00000h ; End of USER's virtual address space (4GB - 4MB)
    67                                  		     ; ULIMIT = (ECORE/4096) - 1 = 0FFBFFh (in GDT)
    68                                  
    69                                  ; 02/01/2022 (Retro UNIX 386 v1.1, Runix Kernel v0.2.1.2)
    70                                  ;; 27/12/2013
    71                                  ;KEND	equ KLOAD + 65536 ; (28/12/2013) (end of kernel space)
    72                                  
    73                                  ; IBM PC/AT BIOS ----- 10/06/85 (postequ.inc)
    74                                  ;--------- CMOS TABLE LOCATION ADDRESS'S -------------------------------------
    75                                  CMOS_SECONDS	EQU	00H		; SECONDS (BCD)
    76                                  CMOS_MINUTES	EQU	02H		; MINUTES (BCD)	
    77                                  CMOS_HOURS	EQU	04H		; HOURS (BCD)
    78                                  CMOS_DAY_WEEK	EQU	06H		; DAY OF THE WEEK  (BCD)
    79                                  CMOS_DAY_MONTH	EQU	07H		; DAY OF THE MONTH (BCD) 
    80                                  CMOS_MONTH	EQU	08H		; MONTH (BCD)
    81                                  CMOS_YEAR	EQU	09H		; YEAR (TWO DIGITS) (BCD)
    82                                  CMOS_CENTURY	EQU	32H		; DATE CENTURY BYTE (BCD)
    83                                  CMOS_REG_A	EQU	0AH		; STATUS REGISTER A
    84                                  CMOS_REG_B	EQU	00BH		; STATUS REGISTER B  ALARM
    85                                  CMOS_REG_C	EQU	00CH		; STATUS REGISTER C  FLAGS
    86                                  CMOS_REG_D	EQU	0DH		; STATUS REGISTER D  BATTERY
    87                                  CMOS_SHUT_DOWN	EQU	0FH		; SHUTDOWN STATUS COMMAND BYTE
    88                                  ;----------------------------------------
    89                                  ;	CMOS EQUATES FOR THIS SYSTEM	;
    90                                  ;-----------------------------------------------------------------------------
    91                                  CMOS_PORT	EQU	070H		; I/O ADDRESS OF CMOS ADDRESS PORT
    92                                  CMOS_DATA	EQU	071H		; I/O ADDRESS OF CMOS DATA PORT
    93                                  NMI		EQU	10000000B	; DISABLE NMI INTERRUPTS MASK -
    94                                  					; HIGH BIT OF CMOS LOCATION ADDRESS
    95                                  
    96                                  ; Memory Allocation Table Address
    97                                  ; 05/11/2014
    98                                  ; 31/10/2014
    99                                  MEM_ALLOC_TBL	equ	100000h		; Memory Allocation Table at the end of
   100                                  					; the 1st 1 MB memory space.
   101                                  					; (This address must be aligned
   102                                  					;  on 128 KB boundary, if it will be
   103                                  					;  changed later.)
   104                                  					; ((lower 17 bits of 32 bit M.A.T.
   105                                  					;   address must be ZERO)).
   106                                  					; ((((Reason: 32 bit allocation 
   107                                  					;     instructions, dword steps)))
   108                                  					; (((byte >> 12 --> page >> 5)))  
   109                                  ;04/11/2014	
   110                                  PDE_A_PRESENT	equ	1		; Present flag for PDE
   111                                  PDE_A_WRITE	equ 	2		; Writable (write permission) flag
   112                                  PDE_A_USER	equ	4		; User (non-system/kernel) page flag
   113                                  ;
   114                                  PTE_A_PRESENT	equ	1		; Present flag for PTE (bit 0)
   115                                  PTE_A_WRITE	equ 	2		; Writable (write permission) flag (bit 1)
   116                                  PTE_A_USER	equ	4		; User (non-system/kernel) page flag (bit 2)
   117                                  PTE_A_ACCESS    equ	32		; Accessed flag (bit 5) ; 09/03/2015
   118                                  
   119                                  ; 17/02/2015 (unix386.s)
   120                                  ; 10/12/2014 - 30/12/2014 (0B000h -> 9000h) (dsectrm2.s)
   121                                  DPT_SEGM equ 09000h  ; FDPT segment (EDD v1.1, EDD v3)
   122                                  ;
   123                                  HD0_DPT	 equ 0	    ; Disk parameter table address for hd0
   124                                  HD1_DPT	 equ 32	    ; Disk parameter table address for hd1
   125                                  HD2_DPT	 equ 64	    ; Disk parameter table address for hd2
   126                                  HD3_DPT	 equ 96	    ; Disk parameter table address for hd3
   127                                  
   128                                  
   129                                  ; FDPT (Phoenix, Enhanced Disk Drive Specification v1.1, v3.0)
   130                                  ;      (HDPT: Programmer's Guide to the AMIBIOS, 1993)
   131                                  ;
   132                                  FDPT_CYLS	equ 0 ; 1 word, number of cylinders
   133                                  FDPT_HDS	equ 2 ; 1 byte, number of heads
   134                                  FDPT_TT		equ 3 ; 1 byte, A0h = translated FDPT with logical values
   135                                  		      ; otherwise it is standard FDPT with physical values 	
   136                                  FDPT_PCMP	equ 5 ; 1 word, starting write precompensation cylinder
   137                                  		      ; (obsolete for IDE/ATA drives)
   138                                  FDPT_CB		equ 8 ; 1 byte, drive control byte
   139                                  			; Bits 7-6 : Enable or disable retries (00h = enable)
   140                                  			; Bit 5	: 1 = Defect map is located at last cyl. + 1
   141                                  			; Bit 4 : Reserved. Always 0
   142                                  			; Bit 3 : Set to 1 if more than 8 heads
   143                                  			; Bit 2-0 : Reserved. Alsways 0
   144                                  FDPT_LZ		equ 12 ; 1 word, landing zone (obsolete for IDE/ATA drives)
   145                                  FDPT_SPT	equ 14 ; 1 byte, sectors per track
   146                                  
   147                                  ; Floppy Drive Parameters Table (Programmer's Guide to the AMIBIOS, 1993)
   148                                  ; (11 bytes long) will be used by diskette handler/bios
   149                                  ; which is derived from IBM PC-AT BIOS (DISKETTE.ASM, 21/04/1986).						 	  		 	  
   150                                  
   151                                  [BITS 16]       ; We need 16-bit intructions for Real mode
   152                                  
   153                                  [ORG 0]
   154                                  
   155                                  KSTART: ; 01/01/2022
   156                                   
   157                                  	; 12/11/2014
   158                                  	; Save boot drive number (that is default root drive)
   159 00000000 8816[CA65]              	mov	[boot_drv], dl ; physical drv number
   160                                  
   161                                  	; Determine installed memory
   162                                  	; 31/10/2014
   163                                  	;
   164 00000004 B801E8                  	mov	ax, 0E801h ; Get memory size 
   165 00000007 CD15                    	int	15h	   ; for large configurations
   166 00000009 7308                    	jnc	short chk_ms
   167 0000000B B488                    	mov	ah, 88h    ; Get extended memory size 
   168 0000000D CD15                    	int	15h
   169                                  	;	   
   170                                  	;mov	al, 17h	; Extended memory (1K blocks) low byte
   171                                  	;out	70h, al ; select CMOS register
   172                                  	;in	al, 71h ; read data (1 byte)
   173                                  	;mov	cl, al
   174                                  	;mov	al, 18h ; Extended memory (1K blocks) high byte
   175                                  	;out	70h, al ; select CMOS register
   176                                  	;in	al, 71h ; read data (1 byte)
   177                                  	;mov	ch, al
   178                                   	;      
   179 0000000F 89C1                    	mov	cx, ax
   180 00000011 31D2                    	xor	dx, dx
   181                                  chk_ms:
   182 00000013 890E[6468]              	mov	[mem_1m_1k], cx
   183 00000017 8916[6868]              	mov	[mem_16m_64k], dx
   184                                  	; 05/11/2014
   185                                  	;and	dx, dx
   186                                  	;jz	short L2
   187 0000001B 81F90004                        cmp     cx, 1024
   188 0000001F 7351                    	jnb	short L0
   189                                  		 ; insufficient memory_error	
   190                                  		 ; Minimum 2 MB memory is needed... 
   191                                  	; 05/11/2014
   192                                  	; (real mode error printing)
   193 00000021 FB                      	sti
   194 00000022 BE[3600]                	mov	si, msg_out_of_memory
   195 00000025 BB0700                  	mov	bx, 7
   196 00000028 B40E                    	mov	ah, 0Eh	; write tty
   197                                  oom_1:
   198 0000002A AC                      	lodsb
   199 0000002B 08C0                    	or	al, al
   200 0000002D 7404                    	jz	short oom_2
   201 0000002F CD10                    	int	10h
   202 00000031 EBF7                    	jmp	short oom_1
   203                                  oom_2:
   204 00000033 F4                              hlt
   205 00000034 EBFD                    	jmp	short oom_2
   206                                  
   207                                  ; 02/01/2022
   208                                  ; 05/11/2014
   209                                  msg_out_of_memory:
   210 00000036 070D0A                  	db 	07h, 0Dh, 0Ah
   211 00000039 496E73756666696369-             db      'Insufficient memory !'
   211 00000042 656E74206D656D6F72-
   211 0000004B 792021             
   212 0000004E 0D0A                    	db	0Dh, 0Ah
   213                                  _int13h_48h_buffer: ; 02/01/2022 (Runix Kernel v0.2.1.2, 'diskinit.inc')
   214 00000050 284D696E696D756D20-     	db	'(Minimum 2MB memory is needed.)'
   214 00000059 324D42206D656D6F72-
   214 00000062 79206973206E656564-
   214 0000006B 65642E29           
   215 0000006F 0D0A00                   	db	0Dh, 0Ah, 0
   216                                  
   217                                  L0:
   218                                  %include 'diskinit.inc' ; 07/03/2015
   219                              <1> ; Retro UNIX 386 v1 Kernel - DISKINIT.INC
   220                              <1> ; Last Modification: 02/01/2022
   221                              <1> 
   222                              <1> ; DISK I/O SYSTEM INITIALIZATION - Erdogan Tan (Retro UNIX 386 v1 project)
   223                              <1> 
   224                              <1> ; ///////// DISK I/O SYSTEM STRUCTURE INITIALIZATION ///////////////
   225                              <1> 
   226                              <1> 	; 02/01/2022 (Retro UNIX 386 v1.1, Runix Kernel v0.2.1.2)
   227                              <1> 	; 10/12/2014 - 02/02/2015 - dsectrm2.s
   228                              <1> ;L0:
   229                              <1> 	; 12/11/2014 (Retro UNIX 386 v1 - beginning)
   230                              <1> 	; Detecting disk drives... (by help of ROM-BIOS)
   231 00000072 BA7F00              <1> 	mov	dx, 7Fh
   232                              <1> L1:	
   233 00000075 FEC2                <1> 	inc	dl
   234 00000077 B441                <1> 	mov	ah, 41h ; Check extensions present
   235                              <1> 			; Phoenix EDD v1.1 - EDD v3
   236 00000079 BBAA55              <1> 	mov	bx, 55AAh
   237 0000007C CD13                <1> 	int 	13h
   238 0000007E 721A                <1> 	jc	short L2
   239                              <1> 
   240 00000080 81FB55AA            <1> 	cmp	bx, 0AA55h
   241 00000084 7514                <1> 	jne	short L2
   242 00000086 FE06[CD65]          <1> 	inc	byte [hdc]	; count of hard disks (EDD present)
   243 0000008A 8816[CC65]          <1>         mov     [last_drv], dl  ; last hard disk number
   244 0000008E BB[5065]            <1> 	mov	bx, hd0_type - 80h
   245 00000091 01D3                <1> 	add	bx, dx	 
   246 00000093 880F                <1> 	mov	[bx], cl ; Interface support bit map in CX
   247                              <1> 			 ; Bit 0 - 1, Fixed disk access subset ready
   248                              <1> 			 ; Bit 1 - 1, Drv locking and ejecting ready
   249                              <1> 			 ; Bit 2 - 1, Enhanced Disk Drive Support
   250                              <1>                          ;            (EDD) ready (DPTE ready)
   251                              <1> 			 ; Bit 3 - 1, 64bit extensions are present
   252                              <1>                          ;            (EDD-3)
   253                              <1> 			 ; Bit 4 to 15 - 0, Reserved
   254 00000095 80FA83              <1> 	cmp	dl, 83h	 ; drive number < 83h
   255 00000098 72DB                <1> 	jb	short L1
   256                              <1> L2:
   257                              <1> 	; 23/11/2014
   258                              <1> 	; 19/11/2014
   259 0000009A 30D2                <1> 	xor	dl, dl  ; 0
   260                              <1> 	; 04/02/2016 (esi -> si)
   261 0000009C BE[CE65]            <1> 	mov	si, fd0_type
   262                              <1> L3:
   263                              <1> 	; 14/01/2015
   264 0000009F 8816[CB65]          <1> 	mov	[drv], dl
   265                              <1> 	;
   266 000000A3 B408                <1> 	mov 	ah, 08h ; Return drive parameters
   267 000000A5 CD13                <1> 	int	13h	
   268 000000A7 7210                <1> 	jc	short L4
   269                              <1> 		; BL = drive type (for floppy drives)
   270                              <1> 		; DL = number of floppy drives
   271                              <1> 		;		
   272                              <1> 		; ES:DI = Address of DPT from BIOS
   273                              <1> 		;
   274 000000A9 881C                <1> 	mov	[si], bl ;  Drive type
   275                              <1> 			; 4 = 1.44 MB, 80 track, 3 1/2"
   276                              <1> 	; 14/01/2015
   277 000000AB E8BB01              <1> 	call	set_disk_parms
   278                              <1> 	; 10/12/2014
   279 000000AE 81FE[CE65]          <1> 	cmp	si, fd0_type
   280 000000B2 7705                <1> 	ja	short L4
   281 000000B4 46                  <1> 	inc	si ; fd1_type
   282 000000B5 B201                <1> 	mov	dl, 1
   283 000000B7 EBE6                <1> 	jmp	short L3
   284                              <1> L4:
   285                              <1> 	; Older BIOS (INT 13h, AH = 48h is not available)
   286 000000B9 B27F                <1> 	mov	dl, 7Fh
   287                              <1> 	; 24/12/2014 (Temporary)
   288 000000BB 803E[CD65]00        <1> 	cmp	byte [hdc], 0 ; EDD present or not ?	
   289                              <1> 	;ja	L10       ; yes, all fixed disk operations
   290                              <1> 			  ; will be performed according to
   291                              <1> 			  ; present EDD specification
   292                              <1> 	; 02/01/2022
   293 000000C0 7603                <1> 	jna	short L5
   294 000000C2 E99100              <1> 	jmp	L10
   295                              <1> L5:
   296 000000C5 FEC2                <1> 	inc 	dl
   297 000000C7 8816[CB65]          <1>         mov     [drv], dl
   298 000000CB 8816[CC65]          <1>         mov     [last_drv], dl ; 14/01/2015
   299 000000CF B408                <1> 	mov 	ah, 08h ; Return drive parameters
   300 000000D1 CD13                <1> 	int	13h	; (conventional function)
   301                              <1> 	;jc	L13	; fixed disk drive not ready
   302                              <1> 	; 02/01/2022
   303 000000D3 7303                <1> 	jnc	short L6
   304 000000D5 E98301              <1> 	jmp	L13
   305                              <1> L6:
   306 000000D8 8816[CD65]          <1>         mov     [hdc], dl ; number of drives
   307                              <1> 	;; 14/01/2013
   308                              <1> 	;;push	cx
   309 000000DC E88A01              <1> 	call	set_disk_parms
   310                              <1> 	;;pop	cx
   311                              <1> 	;
   312                              <1> 	;;and	cl, 3Fh	 ; sectors per track (bits 0-6)
   313 000000DF 8A16[CB65]          <1>         mov     dl, [drv]
   314 000000E3 BB0401              <1> 	mov	bx, 65*4 ; hd0 parameters table (INT 41h)	
   315 000000E6 80FA80              <1> 	cmp	dl, 80h
   316 000000E9 7603                <1> 	jna	short L7
   317 000000EB 83C314              <1> 	add	bx, 5*4	 ; hd1 parameters table (INT 46h)
   318                              <1> L7:	
   319 000000EE 31C0                <1> 	xor	ax, ax
   320 000000F0 8ED8                <1> 	mov	ds, ax
   321 000000F2 8B37                <1>         mov     si, [bx]
   322 000000F4 8B4702              <1>         mov     ax, [bx+2] 
   323 000000F7 8ED8                <1> 	mov	ds, ax
   324 000000F9 3A4C0E              <1>         cmp     cl, [si+FDPT_SPT] ; sectors per track 
   325                              <1> 	;jne	L12 ; invalid FDPT
   326                              <1> 	; 02/01/2022
   327 000000FC 7403                <1> 	je	short L7_8
   328 000000FE E95601              <1> 	jmp	L12
   329                              <1> L7_8:
   330 00000101 BF0000              <1> 	mov	di, HD0_DPT
   331 00000104 80FA80              <1> 	cmp	dl, 80h
   332 00000107 7603                <1> 	jna	short L8
   333 00000109 BF2000              <1> 	mov	di, HD1_DPT 
   334                              <1> L8:
   335                              <1> 	; 30/12/2014
   336 0000010C B80090              <1> 	mov	ax, DPT_SEGM
   337 0000010F 8EC0                <1> 	mov	es, ax
   338                              <1> 	; 24/12/2014
   339 00000111 B90800              <1> 	mov	cx, 8
   340 00000114 F3A5                <1> 	rep	movsw  ; copy 16 bytes to the kernel's DPT location
   341 00000116 8CC8                <1> 	mov	ax, cs
   342 00000118 8ED8                <1> 	mov	ds, ax
   343                              <1> 	; 02/02/2015
   344 0000011A 8A0E[CB65]          <1>         mov     cl, [drv]
   345 0000011E 88CB                <1> 	mov	bl, cl
   346 00000120 B8F001              <1> 	mov	ax, 1F0h
   347 00000123 80E301              <1> 	and	bl, 1
   348 00000126 7406                <1> 	jz	short L9
   349 00000128 C0E304              <1> 	shl	bl, 4
   350 0000012B 2D8000              <1> 	sub	ax, 1F0h-170h
   351                              <1> L9:
   352 0000012E AB                  <1> 	stosw	; I/O PORT Base Address (1F0h, 170h)
   353 0000012F 050602              <1> 	add	ax, 206h
   354 00000132 AB                  <1> 	stosw	; CONTROL PORT Address (3F6h, 376h)	
   355 00000133 88D8                <1> 	mov	al, bl
   356 00000135 04A0                <1> 	add	al, 0A0h
   357 00000137 AA                  <1> 	stosb	; Device/Head Register upper nibble
   358                              <1> 	;
   359 00000138 FE06[CB65]          <1> 	inc	byte [drv]
   360 0000013C BB[5065]            <1> 	mov	bx, hd0_type - 80h
   361 0000013F 01CB                <1> 	add	bx, cx
   362 00000141 800F80              <1>         or      byte [bx], 80h  ; present sign (when lower nibble is 0)
   363 00000144 A0[CD65]            <1> 	mov	al, [hdc]
   364 00000147 FEC8                <1> 	dec	al
   365                              <1> 	;jz	L13
   366                              <1> 	; 02/01/2022
   367 00000149 7408                <1> 	jz	short L9_10
   368 0000014B 80FA80              <1> 	cmp	dl, 80h
   369                              <1>         ;jna	L5
   370                              <1> 	;jmp	L13
   371                              <1> 	; 02/01/2022
   372 0000014E 7703                <1> 	ja	short L9_10
   373 00000150 E972FF              <1> 	jmp	L5
   374                              <1> L9_10:
   375 00000153 E90501              <1>         jmp     L13
   376                              <1> L10:
   377 00000156 FEC2                <1> 	inc 	dl
   378                              <1> 	; 25/12/2014
   379 00000158 8816[CB65]          <1> 	mov	[drv], dl
   380 0000015C B408                <1> 	mov 	ah, 08h ; Return drive parameters
   381 0000015E CD13                <1> 	int	13h	; (conventional function)
   382                              <1> 	;jc	L13
   383                              <1> 	; 02/01/2022
   384 00000160 72F1                <1> 	jc	short L9_10
   385                              <1> 	; 14/01/2015
   386 00000162 8A16[CB65]          <1> 	mov	dl, [drv]
   387 00000166 52                  <1> 	push	dx
   388 00000167 51                  <1> 	push	cx
   389 00000168 E8FE00              <1> 	call	set_disk_parms
   390 0000016B 59                  <1> 	pop	cx
   391 0000016C 5A                  <1> 	pop	dx
   392                              <1> 	; 02/01/2022 - Retro UNIX 386 v1.1 (Runix Kernel v0.2.1.2)
   393                              <1> 	; 04/02/2016 (esi -> si)
   394                              <1> 	;mov	si, _end ; 30 byte temporary buffer address
   395                              <1> 	;		 ; at the '_end' of kernel.
   396                              <1> 	;mov	word [si], 30
   397                              <1> 	; 06/07/2016
   398 0000016D BE[5000]            <1> 	mov	si, _int13h_48h_buffer
   399                              <1> 	; 09/07/2016
   400 00000170 B81E00              <1> 	mov	ax, 001Eh
   401 00000173 8824                <1> 	mov	[si], ah ; 0
   402 00000175 46                  <1> 	inc	si
   403 00000176 8904                <1> 	mov	word [si], ax
   404                              <1>  	; word [si] = 30
   405                              <1> 	;
   406 00000178 B448                <1> 	mov	ah, 48h	 ; Get drive parameters (EDD function)
   407 0000017A CD13                <1> 	int	13h
   408                              <1>         ;jc	L13
   409                              <1> 	; 02/01/2022
   410 0000017C 72D5                <1> 	jc	short L9_10
   411                              <1> 	; 04/02/2016 (ebx -> bx)
   412                              <1> 	; 14/01/2015
   413                              <1> 	;sub	bx, bx
   414 0000017E 28FF                <1> 	sub	bh, bh ; 02/01/2022
   415 00000180 88D3                <1> 	mov	bl, dl
   416 00000182 80EB80              <1> 	sub	bl, 80h
   417 00000185 81C3[D065]          <1> 	add	bx, hd0_type
   418 00000189 8A07                <1> 	mov 	al, [bx]
   419 0000018B 0C80                <1> 	or	al, 80h
   420 0000018D 8807                <1> 	mov 	[bx], al	
   421 0000018F 81EB[CE65]          <1> 	sub	bx, hd0_type - 2 ; 15/01/2015
   422 00000193 81C3[1A66]          <1> 	add	bx, drv.status
   423 00000197 8807                <1> 	mov	[bx], al
   424                              <1> 	; 04/02/2016 (eax -> ax)
   425 00000199 8B4410              <1> 	mov	ax, [si+16]
   426 0000019C 854412              <1> 	test	ax, [si+18]
   427 0000019F 7413                <1> 	jz	short L10_A0h 
   428                              <1> 			; 'CHS only' disks on EDD system 
   429                              <1> 			;  are reported with ZERO disk size
   430 000001A1 81EB[1A66]          <1> 	sub	bx, drv.status
   431 000001A5 C1E302              <1> 	shl	bx, 2
   432 000001A8 81C3[FE65]          <1> 	add	bx, drv.size ; disk size (in sectors)
   433 000001AC 8907                <1> 	mov	[bx], ax
   434 000001AE 8B4412              <1> 	mov	ax, [si+18]
   435                              <1> 	;mov	[bx], ax
   436                              <1> 	; 02/01/2022 (BugFix)
   437 000001B1 894702              <1> 	mov	[bx+2], ax
   438                              <1> 
   439                              <1> L10_A0h: ; Jump here to fix a ZERO (LBA) disk size problem 
   440                              <1> 	 ; for CHS disks (28/02/2015)
   441                              <1> 	; 30/12/2014
   442 000001B4 BF0000              <1> 	mov	di, HD0_DPT
   443 000001B7 88D0                <1> 	mov	al, dl
   444 000001B9 83E003              <1> 	and 	ax, 3
   445 000001BC C0E005              <1> 	shl	al, 5 ; *32
   446 000001BF 01C7                <1> 	add 	di, ax
   447 000001C1 B80090              <1> 	mov	ax, DPT_SEGM
   448 000001C4 8EC0                <1> 	mov	es, ax
   449                              <1> 	;
   450 000001C6 88E8                <1> 	mov	al, ch	; max. cylinder number (bits 0-7)
   451 000001C8 88CC                <1> 	mov	ah, cl	
   452 000001CA C0EC06              <1> 	shr	ah, 6	; max. cylinder number (bits 8-9)
   453 000001CD 40                  <1>  	inc	ax	; logical cylinders (limit 1024)
   454 000001CE AB                  <1> 	stosw		
   455 000001CF 88F0                <1> 	mov	al, dh	; max. head number
   456 000001D1 FEC0                <1> 	inc	al
   457 000001D3 AA                  <1> 	stosb		; logical heads (limits 256)
   458 000001D4 B0A0                <1> 	mov	al, 0A0h ; Indicates translated table
   459 000001D6 AA                  <1> 	stosb
   460 000001D7 8A440C              <1> 	mov	al, [si+12]
   461 000001DA AA                  <1> 	stosb		 ; physical sectors per track
   462 000001DB 31C0                <1>  	xor	ax, ax
   463                              <1> 	;dec	ax	 ; 02/01/2015 
   464 000001DD AB                  <1> 	stosw		 ; precompensation (obsolete)
   465                              <1> 	;xor	al, al	 ; 02/01/2015	
   466 000001DE AA                  <1> 	stosb		 ; reserved
   467 000001DF B008                <1> 	mov	al, 8	 ; drive control byte
   468                              <1> 		         ; (do not disable retries, 
   469                              <1> 			 ; more than 8 heads)
   470 000001E1 AA                  <1> 	stosb
   471 000001E2 8B4404              <1> 	mov	ax, [si+4]
   472 000001E5 AB                  <1> 	stosw		 ; physical number of cylinders	
   473                              <1> 	;push	ax	 ; 02/01/2015
   474 000001E6 8A4408              <1> 	mov	al, [si+8]
   475 000001E9 AA                  <1> 	stosb		 ; physical num. of heads (limit 16)
   476 000001EA 29C0                <1> 	sub 	ax, ax
   477                              <1> 	;pop	ax	 ; 02/01/2015	
   478 000001EC AB                  <1> 	stosw		 ; landing zone (obsolete)
   479 000001ED 88C8                <1> 	mov	al, cl	 ; logical sectors per track (limit 63)
   480 000001EF 243F                <1> 	and 	al, 3Fh	
   481 000001F1 AA                  <1> 	stosb
   482                              <1> 	;sub	al, al	 ; checksum
   483                              <1> 	;stosb
   484                              <1> 	;
   485 000001F2 83C61A              <1> 	add	si, 26   ; (BIOS) DPTE address pointer
   486 000001F5 AD                  <1> 	lodsw
   487 000001F6 50                  <1> 	push	ax	 ; (BIOS) DPTE offset
   488 000001F7 AD                  <1> 	lodsw
   489 000001F8 50                  <1> 	push	ax	 ; (BIOS) DPTE segment
   490                              <1> 	;
   491                              <1> 	; checksum calculation
   492 000001F9 89FE                <1> 	mov	si, di
   493 000001FB 06                  <1> 	push	es
   494 000001FC 1F                  <1> 	pop	ds
   495                              <1> 	;mov	cx, 16
   496 000001FD B90F00              <1> 	mov 	cx, 15
   497 00000200 29CE                <1> 	sub	si, cx
   498 00000202 30E4                <1> 	xor	ah, ah
   499                              <1> 	;del	cl
   500                              <1> L11:		
   501 00000204 AC                  <1> 	lodsb
   502 00000205 00C4                <1> 	add	ah, al
   503 00000207 E2FB                <1> 	loop	L11
   504                              <1> 	;
   505 00000209 88E0                <1> 	mov	al, ah
   506 0000020B F6D8                <1> 	neg	al	; -x+x = 0
   507 0000020D AA                  <1> 	stosb		; put checksum in byte 15 of the tbl
   508                              <1> 	;
   509 0000020E 1F                  <1> 	pop	ds	; (BIOS) DPTE segment
   510 0000020F 5E                  <1> 	pop	si	; (BIOS) DPTE offset	
   511                              <1> 	;
   512                              <1> 	; 23/02/2015
   513 00000210 57                  <1> 	push	di
   514                              <1> 	; ES:DI points to DPTE (FDPTE) location
   515                              <1> 	;mov	cx, 8
   516 00000211 B108                <1> 	mov	cl, 8
   517 00000213 F3A5                <1> 	rep	movsw	
   518                              <1> 	;
   519                              <1> 	; 23/02/2015
   520                              <1> 	; (P)ATA drive and LBA validation
   521                              <1> 	; (invalidating SATA drives and setting
   522                              <1> 	; CHS type I/O for old type fixed disks)
   523 00000215 5B                  <1> 	pop	bx
   524 00000216 8CC8                <1> 	mov	ax, cs
   525 00000218 8ED8                <1> 	mov	ds, ax
   526 0000021A 268B07              <1> 	mov	ax, [es:bx]
   527 0000021D 3DF001              <1> 	cmp	ax, 1F0h
   528 00000220 7418                <1> 	je	short L11a
   529 00000222 3D7001              <1> 	cmp	ax, 170h
   530 00000225 7413                <1> 	je	short L11a
   531                              <1> 	; invalidation 
   532                              <1> 	; (because base port address is not 1F0h or 170h)
   533 00000227 30FF                <1> 	xor	bh, bh
   534 00000229 88D3                <1> 	mov	bl, dl
   535 0000022B 80EB80              <1> 	sub	bl, 80h
   536 0000022E C687[D065]00        <1> 	mov	byte [bx+hd0_type], 0 ; not a valid disk drive !		
   537 00000233 808F[1C66]F0        <1>         or      byte [bx+drv.status+2], 0F0h ; (failure sign)
   538 00000238 EB14                <1> 	jmp	short L11b
   539                              <1> L11a:	
   540                              <1> 	; LBA validation
   541 0000023A 268A4704            <1> 	mov	al, [es:bx+4] ; Head register upper nibble
   542 0000023E A840                <1> 	test	al, 40h ; LBA bit (bit 6)
   543 00000240 750C                <1> 	jnz	short L11b ; LBA type I/O is OK! (E0h or F0h)
   544                              <1> 	; force CHS type I/O for this drive (A0h or B0h)
   545 00000242 28FF                <1> 	sub	bh, bh
   546 00000244 88D3                <1> 	mov	bl, dl
   547 00000246 80EB80              <1> 	sub	bl, 80h ; 26/02/2015
   548 00000249 80A7[1C66]FE        <1>         and     byte [bx+drv.status+2], 0FEh ; clear bit 0
   549                              <1> 				; bit 0 = LBA ready bit
   550                              <1> 	; 'diskio' procedure will check this bit !
   551                              <1> L11b:
   552 0000024E 3A16[CC65]          <1> 	cmp	dl, [last_drv] ; 25/12/2014
   553 00000252 7307                <1>         jnb     short L13
   554 00000254 E9FFFE              <1>         jmp     L10
   555                              <1> L12:
   556                              <1> 	; Restore data registers
   557 00000257 8CC8                <1> 	mov	ax, cs
   558 00000259 8ED8                <1> 	mov	ds, ax	
   559                              <1> L13:
   560                              <1> 	; 13/12/2014
   561 0000025B 0E                  <1> 	push	cs
   562 0000025C 07                  <1> 	pop	es
   563                              <1> L14:
   564 0000025D B411                <1> 	mov 	ah, 11h
   565 0000025F CD16                <1> 	int 	16h
   566                              <1> 	;jz 	short L15 ; no keys in keyboard buffer
   567                              <1> 	; 02/01/2022
   568 00000261 7466                <1> 	jz	short L16
   569 00000263 B010                <1> 	mov	al, 10h
   570 00000265 CD16                <1> 	int 	16h
   571 00000267 EBF4                <1> 	jmp 	short L14
   572                              <1> L15:
   573                              <1> 
   574                              <1> ; //////
   575                              <1> 
   576                              <1> ; 02/01/2022 - Retro UNIX 386 v1.1 (Runix Kernel v0.2.1.2)
   577                              <1> %if 0
   578                              <1> 	; 24/11/2014
   579                              <1> 	; 19/11/2014
   580                              <1> 	; 14/11/2014
   581                              <1> 	; Temporary code for disk searching code check
   582                              <1> 	;
   583                              <1> 	; This code will show existing (usable) drives and also
   584                              <1> 	; will show EDD interface support status for hard disks		
   585                              <1> 	; (If status bit 7 is 1, Identify Device info is ready,
   586                              <1> 	; no need to get it again in protected mode...) 
   587                              <1> 	;	
   588                              <1> 	; 13/11/2014
   589                              <1> 	mov	bx, 7
   590                              <1> 	mov	ah, 0Eh
   591                              <1> 	mov	al, [fd0_type]
   592                              <1> 	and	al, al
   593                              <1> 	jz	short L15a
   594                              <1> 	mov	dl, al
   595                              <1> 	mov	al, 'F'
   596                              <1> 	int 	10h
   597                              <1> 	mov	al, 'D'
   598                              <1> 	int 	10h
   599                              <1> 	mov	al, '0'
   600                              <1> 	int 	10h
   601                              <1> 	mov	al, ' '
   602                              <1> 	int	10h
   603                              <1> 	call	L15c
   604                              <1> 	mov	al, ' '
   605                              <1> 	int	10h
   606                              <1> 	;
   607                              <1> 	mov	al, [fd1_type]
   608                              <1> 	and	al, al
   609                              <1> 	jz	short L15a
   610                              <1> 	mov	dl, al
   611                              <1> 	mov	al, 'F'
   612                              <1> 	int 	10h
   613                              <1> 	mov	al, 'D'
   614                              <1> 	int 	10h
   615                              <1> 	mov	al, '1'
   616                              <1> 	int 	10h
   617                              <1> 	mov	al, ' '
   618                              <1> 	int	10h
   619                              <1> 	call	L15c
   620                              <1> 	mov	al, ' '
   621                              <1> 	int	10h
   622                              <1> 	mov	al, ' '
   623                              <1> 	int	10h
   624                              <1> L15a:
   625                              <1> 	mov	al, [hd0_type]
   626                              <1> 	and	al, al
   627                              <1> 	jz	short L15b
   628                              <1> 	mov	dl, al
   629                              <1> 	mov	al, 'H'
   630                              <1> 	int 	10h
   631                              <1> 	mov	al, 'D'
   632                              <1> 	int 	10h
   633                              <1> 	mov	al, '0'
   634                              <1> 	int 	10h
   635                              <1> 	mov	al, ' '
   636                              <1> 	int 	10h
   637                              <1> 	call	L15c
   638                              <1> 	mov	al, ' '
   639                              <1> 	int	10h
   640                              <1> 	;
   641                              <1> 	mov	al, [hd1_type]
   642                              <1> 	and	al, al
   643                              <1> 	jz	short L15b
   644                              <1> 	mov	dl, al
   645                              <1> 	mov	al, 'H'
   646                              <1> 	int 	10h
   647                              <1> 	mov	al, 'D'
   648                              <1> 	int 	10h
   649                              <1> 	mov	al, '1'
   650                              <1> 	int 	10h
   651                              <1> 	mov	al, ' '
   652                              <1> 	int 	10h
   653                              <1> 	call	L15c
   654                              <1> 	mov	al, ' '
   655                              <1> 	int	10h
   656                              <1> 	;
   657                              <1> 	mov	al, [hd2_type]
   658                              <1> 	and	al, al
   659                              <1> 	jz	short L15b
   660                              <1> 	mov	dl, al
   661                              <1> 	mov	al, 'H'
   662                              <1> 	int 	10h
   663                              <1> 	mov	al, 'D'
   664                              <1> 	int 	10h
   665                              <1> 	mov	al, '2'
   666                              <1> 	int 	10h
   667                              <1> 	mov	al, ' '
   668                              <1> 	int 	10h
   669                              <1> 	call	L15c
   670                              <1> 	mov	al, ' '
   671                              <1> 	int	10h
   672                              <1> 	;
   673                              <1> 	mov	al, [hd3_type]
   674                              <1> 	and	al, al
   675                              <1> 	jz	short L15b
   676                              <1> 	mov	dl, al
   677                              <1> 	mov	al, 'H'
   678                              <1> 	int 	10h
   679                              <1> 	mov	al, 'D'
   680                              <1> 	int 	10h
   681                              <1> 	mov	al, '3'
   682                              <1> 	int 	10h
   683                              <1> 	mov	al, ' '
   684                              <1> 	int 	10h
   685                              <1> 	call	L15c
   686                              <1> 	mov	al, ' '
   687                              <1> 	int	10h
   688                              <1> 	;
   689                              <1> L15b:
   690                              <1> 	mov	al, 0Dh
   691                              <1> 	int 	10h	
   692                              <1> 	mov	al, 0Ah
   693                              <1> 	int 	10h
   694                              <1> 	;;xor	ah, ah
   695                              <1> 	;;int 	16h	
   696                              <1> 	;
   697                              <1>         ;jmp	L16  ; jmp short L16
   698                              <1>         ; 02/01/2022
   699                              <1> 	jmp	short L16
   700                              <1> 	;
   701                              <1> L15c:
   702                              <1> 	mov	dh, dl
   703                              <1> 	shr	dh, 4
   704                              <1> 	add	dh, 30h
   705                              <1> 	and	dl, 15
   706                              <1> 	add	dl, 30h
   707                              <1> 	mov	al, dh
   708                              <1> 	int	10h
   709                              <1> 	mov	al, dl
   710                              <1> 	int	10h
   711                              <1> 	retn
   712                              <1> 	;
   713                              <1> 	; end of temporary code for disk searching code check
   714                              <1> 
   715                              <1> %endif
   716                              <1> 
   717                              <1> ; //////
   718                              <1> 
   719                              <1> set_disk_parms:
   720                              <1> 	; 04/02/2016 (ebx -> bx)
   721                              <1> 	; 10/07/2015
   722                              <1> 	; 14/01/2015
   723                              <1> 	;push	bx
   724 00000269 28FF                <1> 	sub	bh, bh
   725 0000026B 8A1E[CB65]          <1> 	mov	bl, [drv]
   726 0000026F 80FB80              <1> 	cmp	bl, 80h
   727 00000272 7203                <1> 	jb	short sdp0
   728 00000274 80EB7E              <1> 	sub	bl, 7Eh
   729                              <1> sdp0:	
   730 00000277 81C3[1A66]          <1> 	add	bx, drv.status
   731 0000027B C60780              <1>   	mov	byte [bx], 80h ; 'Present' flag
   732                              <1> 	;
   733 0000027E 88E8                <1> 	mov	al, ch ; last cylinder (bits 0-7)
   734 00000280 88CC                <1> 	mov	ah, cl ; 
   735 00000282 C0EC06              <1> 	shr	ah, 6  ; last cylinder (bits 8-9)
   736 00000285 81EB[1A66]          <1> 	sub	bx, drv.status
   737 00000289 D0E3                <1> 	shl	bl, 1
   738 0000028B 81C3[D465]          <1> 	add	bx, drv.cylinders
   739 0000028F 40                  <1> 	inc	ax  ; convert max. cyl number to cyl count		
   740 00000290 8907                <1> 	mov	[bx], ax
   741 00000292 50                  <1> 	push	ax ; ** cylinders
   742 00000293 81EB[D465]          <1> 	sub	bx, drv.cylinders
   743 00000297 81C3[E265]          <1> 	add	bx, drv.heads
   744 0000029B 30E4                <1> 	xor	ah, ah
   745 0000029D 88F0                <1> 	mov	al, dh ; heads
   746 0000029F 40                  <1> 	inc	ax
   747 000002A0 8907                <1> 	mov	[bx], ax
   748 000002A2 81EB[E265]          <1>         sub     bx, drv.heads
   749 000002A6 81C3[F065]          <1>         add     bx, drv.spt
   750 000002AA 30ED                <1> 	xor	ch, ch
   751 000002AC 80E13F              <1> 	and	cl, 3Fh	; sectors (bits 0-6)
   752 000002AF 890F                <1> 	mov	[bx], cx
   753 000002B1 81EB[F065]          <1>         sub     bx, drv.spt
   754 000002B5 D1E3                <1> 	shl	bx, 1
   755 000002B7 81C3[FE65]          <1> 	add	bx, drv.size ; disk size (in sectors)
   756                              <1> 	; LBA size = cylinders * heads * secpertrack
   757 000002BB F7E1                <1> 	mul	cx 
   758 000002BD 89C2                <1> 	mov	dx, ax	; heads*spt					
   759 000002BF 58                  <1> 	pop	ax ; ** cylinders
   760 000002C0 48                  <1> 	dec	ax ; 1 cylinder reserved (!?)
   761 000002C1 F7E2                <1> 	mul	dx ; cylinders * (heads*spt)		
   762 000002C3 8907                <1> 	mov	[bx], ax
   763 000002C5 895702              <1> 	mov	[bx+2], dx
   764                              <1> 	;
   765                              <1> 	;pop	bx
   766 000002C8 C3                  <1> 	retn
   767                              <1> 
   768                              <1> ;align 2
   769                              <1> 
   770                              <1> ;cylinders :  dw 0, 0, 0, 0, 0, 0
   771                              <1> ;heads	  :  dw 0, 0, 0, 0, 0, 0
   772                              <1> ;spt	  :  dw 0, 0, 0, 0, 0, 0
   773                              <1> ;disk_size :  dd 0, 0, 0, 0, 0, 0
   774                              <1> 
   775                              <1> ;last_drv:
   776                              <1> ;	db  0
   777                              <1> ;drv_status:
   778                              <1> ;	db  0,0,0,0,0,0
   779                              <1> ;	db 0
   780                              <1> 
   781                              <1> ; End Of DISK I/O SYSTEM STRUCTURE INITIALIZATION /// 06/02/2015
   782                              <1> 
   783                              <1> L16:
   219                                  
   220                                  	; 10/11/2014
   221 000002C9 FA                           	cli	; Disable interrupts (clear interrupt flag)
   222                                  		; Reset Interrupt MASK Registers (Master&Slave)
   223                                  	;mov	al, 0FFh	; mask off all interrupts
   224                                  	;out	21h, al		; on master PIC (8259)
   225                                  	;jmp 	$+2  ; (delay)
   226                                  	;out	0A1h, al	; on slave PIC (8259)
   227                                  	;
   228                                  	; Disable NMI 
   229 000002CA B080                    	mov   	al, 80h 
   230 000002CC E670                    	out   	70h, al		; set bit 7 to 1 for disabling NMI
   231                                  	;23/02/2015
   232 000002CE 90                      	nop			;
   233                                  	;in	al, 71h		; read in 71h just after writing out to 70h
   234                                  				; for preventing unknown state (!?)
   235                                  
   236                                  	; 02/01/2022
   237                                  	%define KERNELFSIZE KEND-KSTART 
   238                                  	;
   239                                   	; 20/08/2014
   240                                  	; Moving the kernel 64 KB back (to physical address 0)
   241                                  	; DS = CS = 1000h
   242                                  	; 05/11/2014
   243 000002CF 31C0                    	xor	ax, ax
   244 000002D1 8EC0                    	mov	es, ax ; ES = 0
   245                                  	;
   246                                  	;;mov	cx, (KEND - KLOAD)/4
   247                                  	;mov	cx, (KERNELFSIZE+3)/4 ; 02/01/2022
   248 000002D3 B93634                  	mov	cx, (KERNELFSIZE+1)/2 ; 02/01/2022
   249 000002D6 31F6                    	xor	si, si
   250 000002D8 31FF                    	xor	di, di
   251                                  	;rep	movsd
   252 000002DA F3A5                    	rep	movsw ; 02/01/2022
   253                                  	;
   254 000002DC 06                      	push	es ; 0
   255 000002DD 68[E102]                	push	L17
   256 000002E0 CB                      	retf
   257                                  	;
   258                                  L17:
   259                                  	; Turn off the floppy drive motor
   260 000002E1 BAF203                          mov     dx, 3F2h
   261 000002E4 EE                              out     dx, al ; 0 ; 31/12/2013
   262                                  
   263                                  	; Enable access to memory above one megabyte
   264                                  L18:
   265 000002E5 E464                    	in	al, 64h
   266 000002E7 A802                    	test	al, 2
   267 000002E9 75FA                            jnz     short L18
   268 000002EB B0D1                    	mov	al, 0D1h	; Write output port
   269 000002ED E664                    	out	64h, al
   270                                  L19:
   271 000002EF E464                    	in	al, 64h
   272 000002F1 A802                    	test	al, 2
   273 000002F3 75FA                            jnz     short L19
   274 000002F5 B0DF                    	mov	al, 0DFh	; Enable A20 line
   275 000002F7 E660                    	out	60h, al
   276                                  ;L20:
   277                                  	;
   278                                  	; Load global descriptor table register
   279                                  
   280                                          ;mov     ax, cs
   281                                          ;mov     ds, ax
   282                                  
   283 000002F9 2E0F0116[F062]                  lgdt    [cs:gdtd]
   284                                  
   285 000002FF 0F20C0                          mov     eax, cr0
   286                                  	; or 	eax, 1
   287 00000302 40                      	inc     ax
   288 00000303 0F22C0                  	mov     cr0, eax
   289                                  
   290                                  	; Jump to 32 bit code
   291                                  	
   292 00000306 66                      	db 66h 			; Prefix for 32-bit
   293 00000307 EA                      	db 0EAh 		; Opcode for far jump
   294 00000308 [0E030000]              	dd StartPM 		; Offset to start, 32-bit
   295                                  				; (1000h:StartPM = StartPM + 10000h)
   296 0000030C 0800                    	dw KCODE		; This is the selector for CODE32_DESCRIPTOR,
   297                                  				; assuming that StartPM resides in code32
   298                                  
   299                                  [BITS 32] 
   300                                  
   301                                  StartPM:
   302                                  	; Kernel Base Address = 0 ; 30/12/2013
   303 0000030E 66B81000                	mov ax, KDATA           ; Save data segment identifier
   304 00000312 8ED8                            mov ds, ax              ; Move a valid data segment into DS register
   305 00000314 8EC0                           	mov es, ax              ; Move data segment into ES register
   306 00000316 8EE0                           	mov fs, ax              ; Move data segment into FS register
   307 00000318 8EE8                          	mov gs, ax              ; Move data segment into GS register
   308 0000031A 8ED0                            mov ss, ax              ; Move data segment into SS register
   309 0000031C BC00000900                      mov esp, 90000h         ; Move the stack pointer to 090000h
   310                                  
   311                                  clear_bss: ; Clear uninitialized data area
   312                                  	; 11/03/2015
   313 00000321 31C0                    	xor	eax, eax ; 0
   314                                  	;mov	ecx, (bss_end - bss_start)/4
   315                                  	;;shr	ecx, 2 ; bss section is already aligned for double words
   316                                  	; 02/01/2022
   317 00000323 B9BC050000              	mov	ecx, BSS_SIZE/4
   318 00000328 BF[70680000]            	mov	edi, bss_start
   319 0000032D F3AB                    	rep	stosd  		
   320                                  
   321                                  memory_init:
   322                                  	; Initialize memory allocation table and page tables
   323                                  	;
   324                                  	; 02/01/2022 (Retro UNIX 386 v1.1, Runix Kernel v0.2.1.2)
   325                                  	; 16/11/2014
   326                                  	; 15/11/2014
   327                                  	; 07/11/2014
   328                                  	; 06/11/2014
   329                                  	; 05/11/2014
   330                                  	; 04/11/2014
   331                                  	; 31/10/2014 (Retro UNIX 386 v1 - Beginning) 
   332                                  	;
   333                                  ;	xor	eax, eax
   334                                  ;	xor 	ecx, ecx
   335 0000032F B108                    	mov	cl, 8
   336 00000331 BF00001000              	mov	edi, MEM_ALLOC_TBL	
   337 00000336 F3AB                    	rep	stosd		   ; clear Memory Allocation Table
   338                                  				   ; for the first 1 MB memory
   339                                  	;
   340 00000338 8B0D[64680000]          	mov	ecx, [mem_1m_1k]   ; 02/01/2022	
   341                                  	;mov	cx, [mem_1m_1k]	   ; Number of contiguous KB between
   342                                  				   ; 1 and 16 MB, max. 3C00h = 15 MB.
   343                                  	;shr	cx, 2		   ; convert 1 KB count to 4 KB count
   344 0000033E C1E902                  	shr	ecx, 2	; 02/01/2022
   345 00000341 890D[E06A0000]          	mov	[free_pages], ecx
   346 00000347 8B15[68680000]          	mov	edx, [mem_16m_64k] ; 02/01/2022
   347                                  	;mov	dx, [mem_16m_64k]  ; Number of contiguous 64 KB blocks
   348                                  				   ; between 16 MB and 4 GB.
   349                                  	;or	dx, dx
   350 0000034D 09D2                    	or	edx, edx ; 02/01/2022
   351 0000034F 7412                    	jz	short mi_0
   352                                  	;
   353                                  	;mov	ax, dx
   354 00000351 89D0                    	mov	eax, edx ; 02/01/2022
   355 00000353 C1E004                  	shl	eax, 4		   ; 64 KB -> 4 KB (page count)
   356 00000356 0105[E06A0000]          	add	[free_pages], eax
   357 0000035C 0500100000              	add	eax, 4096	   ; 16 MB = 4096 pages
   358 00000361 EB06                    	jmp	short mi_1
   359                                  mi_0:
   360                                  	;mov	ax, cx
   361 00000363 89C8                    	mov	eax, ecx ; 02/01/2022	 
   362 00000365 66050001                	add	ax, 256		   ; add 256 pages for the first 1 MB
   363                                  mi_1:
   364 00000369 A3[DC6A0000]            	mov	[memory_size], eax ; Total available memory in pages
   365                                  				   ; 1 alloc. tbl. bit = 1 memory page
   366                                  				   ; 32 allocation bits = 32 mem. pages
   367                                  	;
   368 0000036E 05FF7F0000              	add	eax, 32767	   ; 32768 memory pages per 1 M.A.T. page
   369 00000373 C1E80F                  	shr	eax, 15		   ; ((32768 * x) + y) pages (y < 32768)
   370                                  				   ;  --> x + 1 M.A.T. pages, if y > 0
   371                                  				   ;  --> x M.A.T. pages, if y = 0
   372                                  	;mov	[mat_size], ax	   ; Memory Alloc. Table Size in pages
   373 00000376 A3[F06A0000]            	mov	[mat_size], eax ; 02/01/2022
   374 0000037B C1E00C                  	shl	eax, 12		   ; 1 M.A.T. page = 4096 bytes
   375                                  	;			   ; Max. 32 M.A.T. pages (4 GB memory)
   376 0000037E 89C3                    	mov	ebx, eax	   ; M.A.T. size in bytes
   377                                  	; Set/Calculate Kernel's Page Directory Address
   378 00000380 81C300001000            	add	ebx, MEM_ALLOC_TBL
   379 00000386 891D[D86A0000]          	mov	[k_page_dir], ebx  ; Kernel's Page Directory address
   380                                  				   ; just after the last M.A.T. page
   381                                  	;
   382 0000038C 83E804                  	sub	eax, 4		   ; convert M.A.T. size to offset value
   383 0000038F A3[E86A0000]            	mov	[last_page], eax   ; last page ofset in the M.A.T.
   384                                  	;			   ; (allocation status search must be
   385                                  				   ; stopped after here)
   386 00000394 31C0                    	xor	eax, eax
   387 00000396 48                      	dec	eax		   ; FFFFFFFFh (set all bits to 1)
   388                                  	;push	cx
   389 00000397 51                      	push	ecx ; 02/01/2022 
   390 00000398 C1E905                  	shr	ecx, 5		   ; convert 1 - 16 MB page count to
   391                                  				   ; count of 32 allocation bits
   392 0000039B F3AB                    	rep	stosd
   393                                  	;pop	cx
   394 0000039D 59                      	pop	ecx ; 02/01/2022
   395 0000039E 40                      	inc	eax		   ; 0
   396 0000039F 80E11F                  	and	cl, 31		   ; remain bits
   397 000003A2 7412                    	jz	short mi_4
   398 000003A4 8907                    	mov	[edi], eax	   ; reset
   399                                  mi_2:
   400 000003A6 0FAB07                  	bts	[edi], eax	   ; 06/11/2014
   401 000003A9 FEC9                    	dec	cl
   402 000003AB 7404                    	jz	short mi_3
   403 000003AD FEC0                    	inc	al
   404 000003AF EBF5                    	jmp	short mi_2
   405                                  mi_3:
   406 000003B1 28C0                    	sub	al, al	   	   ; 0
   407 000003B3 83C704                  	add	edi, 4		   ; 15/11/2014
   408                                  mi_4:
   409 000003B6 09D2                    	or	edx, edx ; 02/01/2022
   410                                  	;or	dx, dx		  ; check 16M to 4G memory space
   411 000003B8 741F                    	jz	short mi_6	  ; max. 16 MB memory, no more...
   412                                  	;	
   413 000003BA B900021000              	mov	ecx, MEM_ALLOC_TBL + 512 ; End of first 16 MB memory
   414                                  	;	
   415 000003BF 29F9                    	sub	ecx, edi	  ; displacement (to end of 16 MB)
   416 000003C1 7405                    	jz	short mi_5	  ; jump if EDI points to 
   417                                  				  ;         end of first 16 MB	
   418                                  	;shr	ecx, 1		  ; convert to dword count
   419                                  	;shr	ecx, 1		  ; (shift 2 bits right) 
   420 000003C3 C1E902                  	shr	ecx, 2	; 02/01/2022
   421 000003C6 F3AB                    	rep 	stosd		  ; reset all bits for reserved pages
   422                                  				  ; (memory hole under 16 MB)
   423                                  mi_5:
   424 000003C8 89D1                    	mov	ecx, edx ; 02/01/2022
   425                                  	;mov	cx, dx		  ; count of 64 KB memory blocks
   426 000003CA D1E9                    	shr	ecx, 1		  ; 1 alloc. dword per 128 KB memory
   427 000003CC 9C                      	pushf			  ; 16/11/2014		
   428 000003CD 48                      	dec	eax		  ; FFFFFFFFh (set all bits to 1)
   429 000003CE F3AB                    	rep	stosd
   430 000003D0 40                      	inc	eax		  ; 0
   431 000003D1 9D                      	popf			  ; 16/11/2014
   432 000003D2 7305                    	jnc	short mi_6
   433 000003D4 6648                    	dec	ax		  ; eax = 0000FFFFh
   434 000003D6 AB                      	stosd
   435 000003D7 6640                    	inc	ax		  ; 0		
   436                                  mi_6:
   437 000003D9 39DF                    	cmp	edi, ebx	  ; check if EDI points to 	
   438 000003DB 7309                    	jnb	short mi_7	  ; end of memory allocation table
   439                                  	;			  ; (>= MEM_ALLOC_TBL + 4906) 
   440 000003DD 89D9                    	mov	ecx, ebx	  ; end of memory allocation table
   441 000003DF 29F9                    	sub	ecx, edi	  ; convert displacement/offset
   442                                  	;shr	ecx, 1		  ; to dword count
   443                                  	;shr	ecx, 1		  ; (shift 2 bits right) 
   444 000003E1 C1E902                  	shr	ecx, 2 ; 02/01/2022	
   445 000003E4 F3AB                    	rep 	stosd		  ; reset all remain M.A.T. bits
   446                                  mi_7:
   447                                  	; Reset M.A.T. bits in M.A.T. (allocate M.A.T. pages)
   448 000003E6 BA00001000              	mov	edx, MEM_ALLOC_TBL
   449                                  	;sub	ebx, edx	  ; Mem. Alloc. Tbl. size in bytes
   450                                  	;shr	ebx, 12		  ; Mem. Alloc. Tbl. size in pages	
   451 000003EB 8B0D[F06A0000]          	mov	ecx, [mat_size] ; 02/01/2022
   452                                  	;mov	cx, [mat_size]	  ; Mem. Alloc. Tbl. size in pages
   453 000003F1 89D7                    	mov	edi, edx
   454 000003F3 C1EF0F                  	shr	edi, 15		  ; convert M.A.T. address to
   455                                  				  ; byte offset in M.A.T.
   456                                  				  ; (1 M.A.T. byte points to 
   457                                  				  ;	      32768 bytes)
   458                                  				  ; Note: MEM_ALLOC_TBL address 
   459                                  				  ; must be aligned on 128 KB 
   460                                  				  ; boundary!
   461 000003F6 01D7                    	add	edi, edx	  ; points to M.A.T.'s itself	
   462                                  	; eax = 0
   463 000003F8 290D[E06A0000]          	sub	[free_pages], ecx ; 07/11/2014
   464                                  mi_8:
   465 000003FE 0FB307                  	btr	[edi], eax	  ; clear bit 0 to bit x (1 to 31)
   466                                  	;dec	bl
   467 00000401 FEC9                    	dec	cl
   468 00000403 7404                    	jz	short mi_9
   469 00000405 FEC0                    	inc	al
   470 00000407 EBF5                    	jmp	short mi_8
   471                                  mi_9:
   472                                  	;
   473                                  	; Reset Kernel's Page Dir. and Page Table bits in M.A.T.
   474                                  	;		(allocate pages for system page tables)
   475                                  
   476                                  	; edx = MEM_ALLOC_TBL
   477 00000409 8B0D[DC6A0000]          	mov	ecx, [memory_size] ; memory size in pages (PTEs)
   478 0000040F 81C1FF030000            	add	ecx, 1023	 ; round up (1024 PTEs per table)
   479 00000415 C1E90A                  	shr	ecx, 10		 ; convert memory page count to 
   480                                  				 ; page table count (PDE count)
   481                                  	;
   482 00000418 51                      	push	ecx		 ; (**) PDE count (<= 1024)
   483                                  	;
   484 00000419 41                      	inc	ecx		 ; +1 for kernel page directory	
   485                                  	;
   486 0000041A 290D[E06A0000]          	sub	[free_pages], ecx ; 07/11/2014
   487                                  	;
   488 00000420 8B35[D86A0000]          	mov	esi, [k_page_dir] ; Kernel's Page Directory address
   489 00000426 C1EE0C                  	shr	esi, 12		 ; convert to page number
   490                                  mi_10:
   491 00000429 89F0                    	mov	eax, esi	 ; allocation bit offset
   492 0000042B 89C3                    	mov	ebx, eax
   493 0000042D C1EB03                  	shr	ebx, 3		 ; convert to alloc. byte offset
   494 00000430 80E3FC                  	and	bl,  0FCh	 ; clear bit 0 and bit 1
   495                                  				 ;   to align on dword boundary
   496 00000433 83E01F                  	and	eax, 31		 ; set allocation bit position 
   497                                  				 ;  (bit 0 to bit 31)
   498                                  	;
   499 00000436 01D3                    	add	ebx, edx	 ; offset in M.A.T. + M.A.T. address 
   500                                  	;
   501 00000438 0FB303                  	btr 	[ebx], eax	 ; reset relevant bit (0 to 31)
   502                                  	;
   503 0000043B 46                      	inc	esi		 ; next page table
   504 0000043C E2EB                    	loop	mi_10		 ; allocate next kernel page table 
   505                                  				 ; (ecx = page table count + 1)
   506                                  	;
   507 0000043E 59                      	pop	ecx		 ; (**) PDE count (= pg. tbl. count)
   508                                  	;
   509                                  	; Initialize Kernel Page Directory and Kernel Page Tables
   510                                  	;
   511                                  	; Initialize Kernel's Page Directory
   512 0000043F 8B3D[D86A0000]          	mov	edi, [k_page_dir]
   513 00000445 89F8                    	mov	eax, edi
   514 00000447 0C03                    	or	al, PDE_A_PRESENT + PDE_A_WRITE
   515                                  		     	      ; supervisor + read&write + present
   516 00000449 89CA                    	mov	edx, ecx 	; (**) PDE count (= pg. tbl. count)
   517                                  mi_11:
   518 0000044B 0500100000              	add	eax, 4096	; Add page size (PGSZ)
   519                                  			        ; EAX points to next page table
   520 00000450 AB                      	stosd
   521 00000451 E2F8                    	loop	mi_11
   522 00000453 29C0                    	sub	eax, eax	; Empty PDE
   523                                  	;mov	cx, 1024	; Entry count (PGSZ/4)
   524                                  	; 02/01/2022
   525 00000455 B504                    	mov	ch, 4 ; cx = 4*256 = 1024
   526 00000457 29D1                    	sub	ecx, edx
   527 00000459 7402                    	jz	short mi_12
   528 0000045B F3AB                    	rep	stosd 		; clear remain (empty) PDEs
   529                                  	;
   530                                  	; Initialization of Kernel's Page Directory is OK, here.
   531                                  mi_12:
   532                                  	; Initialize Kernel's Page Tables
   533                                  	;
   534                                  	; (EDI points to address of page table 0)
   535                                  	; eax = 0
   536 0000045D 8B0D[DC6A0000]          	mov	ecx, [memory_size] ; memory size in pages
   537 00000463 89CA                    	mov	edx, ecx	; (***)
   538 00000465 B003                    	mov	al, PTE_A_PRESENT + PTE_A_WRITE
   539                                  			     ; supervisor + read&write + present
   540                                  mi_13:
   541 00000467 AB                      	stosd
   542 00000468 0500100000              	add	eax, 4096	
   543 0000046D E2F8                    	loop	mi_13
   544                                  	; 02/01/2022
   545 0000046F 66B9FF03                	mov	cx, 1023
   546 00000473 21CA                    	and	edx, ecx
   547                                  	;and	dx, 1023	; (***)
   548 00000475 7407                    	jz	short mi_14
   549                                  	;mov	cx, 1024	
   550                                  	; 02/01/2022
   551                                  	;mov	ch, 4 ; cx = 4*256 = 1024
   552 00000477 41                      	inc	ecx ; ecx = 1024
   553 00000478 29D1                    	sub	ecx, edx
   554                                  	;sub	cx, dx		; from dx (<= 1023) to 1024
   555 0000047A 31C0                    	xor	eax, eax
   556 0000047C F3AB                    	rep	stosd		; clear remain (empty) PTEs 
   557                                  				; of the last page table
   558                                  mi_14:
   559                                  	;  Initialization of Kernel's Page Tables is OK, here.
   560                                  	;
   561 0000047E 89F8                    	mov	eax, edi	; end of the last page table page
   562                                  			        ; (beginging of user space pages)
   563 00000480 C1E80F                  	shr	eax, 15		; convert to M.A.T. byte offset
   564 00000483 24FC                    	and	al, 0FCh	; clear bit 0 and bit 1 for
   565                                  				; aligning on dword boundary
   566                                  	 
   567 00000485 A3[EC6A0000]            	mov	[first_page], eax
   568 0000048A A3[E46A0000]            	mov	[next_page], eax ; The first free page pointer
   569                                  				 ; for user programs
   570                                  				 ; (Offset in Mem. Alloc. Tbl.)	
   571                                  	;
   572                                  	; Linear/FLAT (1 to 1) memory paging for the kernel is OK, here.
   573                                  	;
   574                                  	
   575                                  	; Enable paging
   576                                  	;
   577 0000048F A1[D86A0000]                    mov     eax, [k_page_dir]
   578 00000494 0F22D8                  	mov	cr3, eax
   579 00000497 0F20C0                  	mov	eax, cr0
   580 0000049A 0D00000080              	or	eax, 80000000h	; set paging bit (bit 31)
   581 0000049F 0F22C0                  	mov	cr0, eax
   582                                          ;jmp    KCODE:StartPMP
   583                                  
   584 000004A2 EA                      	db 0EAh 		; Opcode for far jump
   585 000004A3 [A9040000]                      dd StartPMP		; 32 bit offset
   586 000004A7 0800                    	dw KCODE		; kernel code segment descriptor
   587                                  
   588                                  StartPMP:
   589                                  	; 06/11//2014
   590                                  	; Clear video page 0
   591                                  	;
   592                                  	; Temporary Code
   593                                  	;
   594                                  	;mov	ecx, 80*25/2
   595 000004A9 66B9E803                	mov	cx, (80*25)/2 ; 02/01/2022
   596 000004AD BF00800B00              	mov	edi, 0B8000h
   597 000004B2 57                      	push	edi ; * ; 02/01/2022
   598 000004B3 31C0                    	xor	eax, eax	; black background, black fore color
   599 000004B5 F3AB                    	rep	stosd
   600                                  	
   601                                  	; 19/08/2014
   602                                  	; Kernel Base Address = 0
   603                                  	; It is mapped to (physically) 0 in the page table.
   604                                  	; So, here is exactly 'StartPMP' address.
   605                                  	;
   606                                  	;;mov	ah, 4Eh	; Red background, yellow forecolor
   607                                  	;;mov	esi, msgPM
   608                                  	;; 14/08/2015 (kernel version message will appear
   609                                  	;;	       when protected mode and paging is enabled)
   610 000004B7 B40B                    	mov	ah, 0Bh ; Black background, light cyan forecolor
   611 000004B9 BE[30660000]            	mov	esi, msgKVER
   612 000004BE 5F                      	pop	edi ; * ; 02/01/2022
   613                                  	;mov	edi, 0B8000h ; 27/08/2014
   614                                  	; 20/08/2014
   615 000004BF E892010000              	call	printk
   616                                  
   617                                  	; 'UNIX v7/x86' source code by Robert Nordier (1999)
   618                                  	; // Set IRQ offsets
   619                                  	;
   620                                  	;  Linux (v0.12) source code by Linus Torvalds (1991)
   621                                  	;
   622                                  					;; ICW1
   623 000004C4 B011                    	mov	al, 11h			; Initialization sequence
   624 000004C6 E620                    	out	20h, al			; 	8259A-1
   625                                  	; jmp 	$+2
   626 000004C8 E6A0                    	out	0A0h, al		; 	8259A-2
   627                                  					;; ICW2
   628 000004CA B020                    	mov	al, 20h			; Start of hardware ints (20h)
   629 000004CC E621                    	out	21h, al			;	for 8259A-1
   630                                  	; jmp 	$+2
   631 000004CE B028                    	mov	al, 28h			; Start of hardware ints (28h)
   632 000004D0 E6A1                    	out	0A1h, al		; 	for 8259A-2
   633                                  					;
   634 000004D2 B004                    	mov	al, 04h			;; ICW3
   635 000004D4 E621                    	out	21h, al			; 	IRQ2 of 8259A-1 (master)
   636                                  	; jmp 	$+2
   637 000004D6 B002                    	mov	al, 02h			; 	is 8259A-2 (slave)
   638 000004D8 E6A1                    	out	0A1h, al		;
   639                                  					;; ICW4
   640 000004DA B001                    	mov	al, 01h	 		;
   641 000004DC E621                    	out	21h, al			; 	8086 mode, normal EOI	
   642                                  	; jmp 	$+2
   643 000004DE E6A1                    	out	0A1h, al		;	for both chips.
   644                                  
   645                                  	;mov	al, 0FFh	; mask off all interrupts for now
   646                                  	;out	21h, al
   647                                  	;; jmp 	$+2
   648                                  	;out	0A1h, al
   649                                  
   650                                  	; 02/04/2015
   651                                  	; 26/03/2015 System call (INT 30h) modification
   652                                  	;  DPL = 3 (Interrupt service routine can be called from user mode)			
   653                                  	;
   654                                  	;; Linux (v0.12) source code by Linus Torvalds (1991)
   655                                  	;  setup_idt:
   656                                  	;
   657                                          ;; 16/02/2015
   658                                  	;;mov	dword [DISKETTE_INT], fdc_int ; IRQ 6 handler
   659                                  	; 21/08/2014 (timer_int)
   660 000004E0 BE[FC620000]            	mov	esi, ilist
   661 000004E5 8D3D[70680000]          	lea	edi, [idt]
   662                                  	; 26/03/2015
   663 000004EB B930000000              	mov	ecx, 48		; 48 hardware interrupts (INT 0 to INT 2Fh)
   664                                  	; 02/04/2015
   665 000004F0 BB00000800              	mov	ebx,  80000h
   666                                  rp_sidt1:
   667 000004F5 AD                      	lodsd
   668 000004F6 89C2                    	mov	edx, eax
   669 000004F8 66BA008E                	mov	dx, 8E00h
   670 000004FC 6689C3                  	mov	bx, ax
   671 000004FF 89D8                    	mov	eax, ebx	; /* selector = 0x0008 = cs */
   672                                         			        ; /* interrupt gate - dpl=0, present */
   673 00000501 AB                      	stosd	; selector & offset bits 0-15 	
   674 00000502 89D0                    	mov	eax, edx
   675 00000504 AB                      	stosd	; attributes & offset bits 16-23
   676 00000505 E2EE                    	loop	rp_sidt1
   677 00000507 B110                    	mov	cl, 16        ; 16 software interrupts (INT 30h to INT 3Fh)
   678                                  rp_sidt2:
   679 00000509 AD                      	lodsd
   680 0000050A 21C0                    	and	eax, eax
   681 0000050C 7413                    	jz	short rp_sidt3
   682 0000050E 89C2                    	mov	edx, eax
   683 00000510 66BA00EE                	mov	dx, 0EE00h	; P=1b/DPL=11b/01110b
   684 00000514 6689C3                  	mov	bx, ax
   685 00000517 89D8                    	mov	eax, ebx	; selector & offset bits 0-15 	
   686 00000519 AB                      	stosd
   687 0000051A 89D0                    	mov	eax, edx
   688 0000051C AB                      	stosd
   689 0000051D E2EA                    	loop	rp_sidt2
   690 0000051F EB16                    	jmp	short sidt_OK
   691                                  rp_sidt3:
   692 00000521 B8[7A090000]            	mov	eax, ignore_int
   693 00000526 89C2                    	mov	edx, eax
   694 00000528 66BA00EE                	mov	dx, 0EE00h	; P=1b/DPL=11b/01110b
   695 0000052C 6689C3                  	mov	bx, ax
   696 0000052F 89D8                    	mov	eax, ebx	; selector & offset bits 0-15 	
   697                                  rp_sidt4:
   698 00000531 AB                      	stosd
   699 00000532 92                      	xchg	eax, edx
   700 00000533 AB                      	stosd
   701 00000534 92                      	xchg	edx, eax
   702 00000535 E2FA                    	loop	rp_sidt4
   703                                  sidt_OK: 
   704 00000537 0F011D[F6620000]        	lidt 	[idtd]
   705                                  	;
   706                                  	; TSS descriptor setup ; 24/03/2015
   707 0000053E B8[706A0000]            	mov	eax, task_state_segment
   708 00000543 66A3[EA620000]          	mov	[gdt_tss0], ax
   709 00000549 C1C010                  	rol	eax, 16
   710 0000054C A2[EC620000]            	mov	[gdt_tss1], al
   711 00000551 8825[EF620000]          	mov	[gdt_tss2], ah
   712 00000557 66C705[D66A0000]68-     	mov	word [tss.IOPB], tss_end - task_state_segment
   712 0000055F 00                 
   713                                  		; 
   714                                  		; IO Map Base address (When this address points
   715                                  		; to end of the TSS, CPU does not use IO port 
   716                                  		; permission bit map for RING 3 IO permissions, 
   717                                  		; access to any IO ports in ring 3 will be forbidden.)
   718                                   		;
   719                                  	;mov	[tss.esp0], esp ; TSS offset 4
   720                                  	;mov	word [tss.ss0], KDATA ; TSS offset 8 (SS)
   721 00000560 66B82800                   	mov	ax, TSS  ; It is needed when an interrupt 
   722                                  			 ; occurs (or a system call -software INT- is requested)
   723                                  			 ; while cpu running in ring 3 (in user mode).				
   724                                  			 ; (Kernel stack pointer and segment will be loaded
   725                                  			 ; from offset 4 and 8 of the TSS, by the CPU.)	 
   726 00000564 0F00D8                  	ltr	ax  ; Load task register
   727                                  	;
   728                                  esp0_set0:
   729                                  	; 30/07/2015
   730 00000567 8B0D[DC6A0000]          	mov 	ecx, [memory_size] ; memory size in pages
   731 0000056D C1E10C                  	shl 	ecx, 12 ; convert page count to byte count
   732 00000570 81F900004000            	cmp	ecx, CORE ; beginning of user's memory space (400000h)
   733                                  			  ; (kernel mode virtual address)
   734 00000576 7605                    	jna	short esp0_set1
   735                                  	;
   736                                  	; If available memory > CORE (end of the 1st 4 MB)
   737                                  	; set stack pointer to CORE
   738                                  	;(Because, PDE 0 is reserved for kernel space in user's page directory)
   739                                  	;(PDE 0 points to page table of the 1st 4 MB virtual address space)
   740 00000578 B900004000              	mov	ecx, CORE
   741                                  esp0_set1:
   742 0000057D 89CC                    	mov	esp, ecx ; top of kernel stack (**tss.esp0**)
   743                                  esp0_set_ok:
   744                                  	; 30/07/2015 (**tss.esp0**) 
   745 0000057F 8925[746A0000]          	mov	[tss.esp0], esp
   746 00000585 66C705[786A0000]10-             mov     word [tss.ss0], KDATA
   746 0000058D 00                 
   747                                  	; 14/08/2015
   748                                  	; 10/11/2014 (Retro UNIX 386 v1 - Erdogan Tan)
   749                                  	;
   750                                  	;cli	; Disable interrupts (for CPU)
   751                                  	;    (CPU will not handle hardware interrupts, except NMI!)
   752                                  	;
   753 0000058E 30C0                    	xor	al, al		; Enable all hardware interrupts!
   754 00000590 E621                    	out	21h, al		; (IBM PC-AT compatibility)
   755 00000592 EB00                    	jmp 	$+2		; (All conventional PC-AT hardware
   756 00000594 E6A1                    	out	0A1h, al	;  interrupts will be in use.)	
   757                                  				; (Even if related hardware component
   758                                  				;  does not exist!)
   759                                  	; Enable NMI 
   760 00000596 B07F                    	mov	al, 7Fh		; Clear bit 7 to enable NMI (again)
   761 00000598 E670                    	out  	70h, al
   762                                  	; 23/02/2015
   763 0000059A 90                      	nop
   764 0000059B E471                    	in	al, 71h		; read in 71h just after writing out to 70h
   765                                  				; for preventing unknown state (!?)
   766                                  	;
   767                                  	; Only a NMI can occur here... (Before a 'STI' instruction)
   768                                  	;
   769                                  	; 02/09/2014
   770                                  	;xor	bx, bx
   771                                  	;mov	dx, 0200h	; Row 2, column 0  ; 07/03/2015
   772                                  	; 27/02/2022	
   773 0000059D 31DB                    	xor	ebx, ebx
   774 0000059F 31D2                    	xor	edx, edx
   775 000005A1 B602                    	mov	dh, 2
   776 000005A3 E8280F0000              	call	set_cpos
   777                                  	;
   778                                  	; 06/11/2014
   779                                  	; Temporary Code
   780                                  	;
   781 000005A8 E8A1100000              	call	memory_info
   782                                  	; 14/08/2015
   783                                  	;call getch ; 28/02/2015
   784                                  drv_init:
   785 000005AD FB                      	sti	; Enable Interrupts 
   786                                  	; 06/02/2015
   787 000005AE 8B15[D0650000]          	mov	edx, [hd0_type] ; hd0, hd1, hd2, hd3
   788 000005B4 668B1D[CE650000]        	mov	bx, [fd0_type] ; fd0, fd1
   789                                  	; 22/02/2015
   790 000005BB 6621DB                  	and	bx, bx
   791 000005BE 751B                    	jnz	short di1
   792                                  	;
   793 000005C0 09D2                    	or 	edx, edx
   794 000005C2 7529                    	jnz	short di2
   795                                  	;
   796                                  setup_error:
   797 000005C4 BE[19670000]            	mov 	esi, setup_error_msg
   798                                  psem:	
   799 000005C9 AC                      	lodsb
   800 000005CA 08C0                    	or	al, al
   801                                  	;jz	short haltx ; 22/02/2015
   802 000005CC 7426                    	jz	short di3
   803 000005CE 56                      	push	esi
   804 000005CF 31DB                    	xor	ebx, ebx ; 0
   805                                  			; Video page 0 (bl=0)
   806 000005D1 B407                    	mov	ah, 07h ; Black background, 
   807                                  			; light gray forecolor
   808 000005D3 E8EE0D0000              	call	write_tty
   809 000005D8 5E                      	pop	esi
   810 000005D9 EBEE                    	jmp	short psem
   811                                  
   812                                  di1:
   813                                  	; supress 'jmp short T6'
   814                                  	;  (activate fdc motor control code)
   815 000005DB 66C705[D7060000]90-     	mov	word [T5], 9090h ; nop
   815 000005E3 90                 
   816                                  	;
   817                                  	;mov	ax, int_0Eh	; IRQ 6 handler
   818                                  	;mov	di, 0Eh*4	; IRQ 6 vector
   819                                  	;stosw
   820                                  	;mov 	ax, cs
   821                                  	;stosw
   822                                  	;; 16/02/2015
   823                                          ;;mov	dword [DISKETTE_INT], fdc_int ; IRQ 6 handler
   824                                  	;
   825 000005E4 E8761F0000              	CALL	DSKETTE_SETUP	; Initialize Floppy Disks
   826                                  	;
   827 000005E9 09D2                    	or	edx, edx
   828 000005EB 7407                            jz      short di3
   829                                  di2:
   830 000005ED E8B21F0000              	call   	DISK_SETUP	; Initialize Fixed Disks
   831 000005F2 72D0                            jc      short setup_error
   832                                  di3:
   833 000005F4 E829100000              	call	setup_rtc_int	; 22/05/2015 (dsectrpm.s)
   834                                  	;
   835 000005F9 E81B5C0000              	call	display_disks ; 07/03/2015  (Temporary)
   836                                  ;haltx:
   837                                  	; 14/08/2015
   838                                  	;call	getch ; 22/02/2015
   839 000005FE FB                      	sti	; Enable interrupts (for CPU)
   840                                  	; 14/08/2015
   841                                  	;mov 	ecx, 0FFFFFFFh
   842                                  	; 24/12/2021
   843 000005FF B9FFFF2F00              	mov 	ecx, 02FFFFFh
   844                                  md_info_msg_wait:
   845 00000604 51                      	push 	ecx
   846 00000605 B001                    	mov	al, 1
   847 00000607 8A25[066B0000]          	mov 	ah, [ptty] ; active (current) video page
   848 0000060D E866590000              	call	getc_n
   849 00000612 59                      	pop	ecx
   850 00000613 7502                    	jnz	short md_info_msg_ok
   851 00000615 E2ED                    	loop	md_info_msg_wait
   852                                  md_info_msg_ok:
   853                                  	; 30/06/2015
   854 00000617 E8932C0000              	call	sys_init
   855                                  	;
   856                                  	;jmp 	cpu_reset ; 22/02/2015
   857                                  hang:
   858                                  	; 24/12/2021
   859 0000061C 29C0                    	sub	eax, eax
   860                                  _hang:	
   861                                  	; 23/02/2015
   862                                  	;sti			; Enable interrupts
   863 0000061E F4                      	hlt
   864                                  	;
   865                                  	;nop
   866                                  	;; 03/12/2014
   867                                  	;; 28/08/2014
   868                                  	;mov	ah, 11h
   869                                  	;call	getc
   870                                  	;jz      _c8
   871                                  	;
   872                                  	; 23/02/2015
   873                                  	; 06/02/2015
   874                                  	; 07/09/2014
   875 0000061F 31DB                    	xor	ebx, ebx
   876 00000621 8A1D[066B0000]          	mov	bl, [ptty]	; active_page
   877 00000627 89DE                    	mov	esi, ebx
   878 00000629 66D1E6                  	shl 	si, 1
   879 0000062C 81C6[086B0000]          	add	esi, ttychr
   880 00000632 668B06                  	mov	ax, [esi]
   881                                  	;and	ax, ax
   882                                  	;;jz	short _c8
   883                                  	;jz	short hang
   884                                  	; 24/12/2021
   885 00000635 21C0                    	and	eax, eax
   886 00000637 74E5                    	jz	short _hang
   887 00000639 66C7060000              	mov	word [esi], 0
   888 0000063E 80FB03                  	cmp	bl, 3		; Video page 3
   889                                  	;jb	short _c8
   890 00000641 72D9                    	jb	short hang
   891                                  	;	
   892                                  	; 02/09/2014
   893 00000643 B40E                    	mov	ah, 0Eh		; Yellow character 
   894                                  				; on black background
   895                                  	; 24/12/2021 (32 bit reg push-pop)
   896                                  	; 07/09/2014
   897                                  nxtl:
   898 00000645 53                      	push	ebx
   899                                  	;
   900                                  	;xor	ebx, ebx	; bl = 0 (video page 0)
   901                                  				; bh = 0 (video mode)
   902                                  				; Retro UNIX 386 v1 - Video Mode 0
   903                                  				; (PC/AT Video Mode 3 - 80x25 Alpha.)
   904 00000646 50                      	push	eax
   905 00000647 E87A0D0000              	call 	write_tty
   906 0000064C 58                      	pop	eax
   907                                  	;pop	bx
   908 0000064D 5B                      	pop	ebx
   909 0000064E 3C0D                    	cmp	al, 0Dh		; carriage return (enter)
   910                                  	;jne	short _c8
   911 00000650 75CA                    	jne	short hang
   912 00000652 B00A                    	mov	al, 0Ah		; next line
   913 00000654 EBEF                    	jmp	short nxtl
   914                                  	
   915                                  ;_c8:
   916                                  ;	; 25/08/2014
   917                                  ;	cli			; Disable interrupts
   918                                  ;	mov	al, [scounter + 1]
   919                                  ;	and	al, al
   920                                  ;	jnz	hang
   921                                  ;	call	rtc_p
   922                                  ;	jmp     hang
   923                                  
   924                                  
   925                                  	; 27/08/2014
   926                                  	; 20/08/2014
   927                                  printk:
   928                                          ;mov    edi, [scr_row]
   929                                  pkl:
   930 00000656 AC                      	lodsb
   931 00000657 08C0                    	or 	al, al
   932 00000659 7404                    	jz	short pkr
   933 0000065B 66AB                    	stosw
   934 0000065D EBF7                    	jmp	short pkl
   935                                  pkr:
   936 0000065F C3                      	retn
   937                                  
   938                                  ; 25/07/2015
   939                                  ; 14/05/2015 (multi tasking -time sharing- 'clock', x_timer)
   940                                  ; 17/02/2015
   941                                  ; 06/02/2015 (unix386.s)
   942                                  ; 11/12/2014 - 22/12/2014 (dsectrm2.s) 
   943                                  ;
   944                                  ; IBM PC-XT Model 286 Source Code - BIOS2.ASM (06/10/85)
   945                                  ;
   946                                  ;-- HARDWARE INT  08 H - ( IRQ LEVEL 0 ) ---------------------------------------
   947                                  ;	THIS ROUTINE HANDLES THE TIMER INTERRUPT FROM FROM CHANNEL 0 OF        :
   948                                  ;	THE 8254 TIMER.  INPUT FREQUENCY IS 1.19318 MHZ AND THE DIVISOR        :
   949                                  ;	IS 65536, RESULTING IN APPROXIMATELY 18.2 INTERRUPTS EVERY SECOND.     :
   950                                  ;									       :
   951                                  ;	THE INTERRUPT HANDLER MAINTAINS A COUNT (40:6C) OF INTERRUPTS SINCE    :
   952                                  ;	POWER ON TIME, WHICH MAY BE USED TO ESTABLISH TIME OF DAY.	       :
   953                                  ;	THE INTERRUPT HANDLER ALSO DECREMENTS THE MOTOR CONTROL COUNT (40:40)  :
   954                                  ;	OF THE DISKETTE, AND WHEN IT EXPIRES, WILL TURN OFF THE 	       :
   955                                  ;	DISKETTE MOTOR(s), AND RESET THE MOTOR RUNNING FLAGS.		       :
   956                                  ;	THE INTERRUPT HANDLER WILL ALSO INVOKE A USER ROUTINE THROUGH	       :
   957                                  ;	INTERRUPT 1CH AT EVERY TIME TICK.  THE USER MUST CODE A 	       :
   958                                  ;	ROUTINE AND PLACE THE CORRECT ADDRESS IN THE VECTOR TABLE.	       :
   959                                  ;-------------------------------------------------------------------------------
   960                                  ;
   961                                  
   962                                  timer_int:	; IRQ 0
   963                                  ;int_08h:	; Timer
   964                                  	; 14/10/2015
   965                                  	; Here, we are simulating system call entry (for task switch)
   966                                  	; (If multitasking is enabled, 
   967                                  	; 'clock' procedure may jump to 'sysrelease')
   968 00000660 1E                      	push	ds
   969 00000661 06                      	push	es
   970 00000662 0FA0                    	push	fs
   971 00000664 0FA8                    	push	gs
   972 00000666 60                      	pushad  ; eax, ecx, edx, ebx, esp -before pushad-, ebp, esi, edi
   973 00000667 66B91000                	mov     cx, KDATA
   974 0000066B 8ED9                            mov     ds, cx
   975 0000066D 8EC1                            mov     es, cx
   976 0000066F 8EE1                            mov     fs, cx
   977 00000671 8EE9                            mov     gs, cx
   978                                  	;
   979 00000673 0F20D9                  	mov	ecx, cr3
   980 00000676 890D[19070000]          	mov	[cr3reg], ecx ; save current cr3 register value/content
   981                                  	;
   982 0000067C 3B0D[D86A0000]          	cmp 	ecx, [k_page_dir]
   983 00000682 741F                    	je	short T3
   984                                  	;
   985                                  	; timer interrupt has been occurred while OS is in user mode
   986 00000684 A3[986E0000]            	mov 	[u.r0], eax
   987 00000689 89E1                    	mov	ecx, esp
   988 0000068B 83C130                  	add	ecx, ESPACE ; 4 * 12 (stack frame)	
   989 0000068E 890D[906E0000]          	mov	[u.sp], ecx ; kernel stack pointer at the start of interrupt
   990 00000694 8925[946E0000]          	mov	[u.usp], esp ; kernel stack points to user's registers   
   991                                  	;
   992 0000069A 8B0D[D86A0000]          	mov	ecx, [k_page_dir]
   993 000006A0 0F22D9                  	mov	cr3, ecx
   994                                  T3:
   995 000006A3 FB                      	sti				; INTERRUPTS BACK ON
   996 000006A4 66FF05[546B0000]        	INC	word [TIMER_LOW]	; INCREMENT TIME
   997 000006AB 7507                    	JNZ	short T4		; GO TO TEST_DAY
   998 000006AD 66FF05[566B0000]        	INC	word [TIMER_HIGH]	; INCREMENT HIGH WORD OF TIME
   999                                  T4:					; TEST_DAY
  1000 000006B4 66833D[566B0000]18      	CMP	word [TIMER_HIGH],018H	; TEST FOR COUNT EQUALING 24 HOURS
  1001 000006BC 7519                    	JNZ	short T5		; GO TO DISKETTE_CTL
  1002 000006BE 66813D[546B0000]B0-     	CMP	word [TIMER_LOW],0B0H
  1002 000006C6 00                 
  1003 000006C7 750E                    	JNZ	short T5		; GO TO DISKETTE_CTL
  1004                                  
  1005                                  ;-----	TIMER HAS GONE 24 HOURS
  1006                                  	;;SUB	AX,AX
  1007                                  	;MOV	[TIMER_HIGH],AX
  1008                                  	;MOV	[TIMER_LOW],AX
  1009 000006C9 29C0                    	sub	eax, eax
  1010 000006CB A3[546B0000]            	mov	[TIMER_LH], eax
  1011                                  	;	
  1012 000006D0 C605[586B0000]01        	MOV	byte [TIMER_OFL],1
  1013                                  
  1014                                  ;-----	TEST FOR DISKETTE TIME OUT
  1015                                  
  1016                                  T5:
  1017                                  	; 23/12/2014
  1018 000006D7 EB1D                    	jmp	short T6		; will be replaced with nop, nop
  1019                                  					; (9090h) if a floppy disk
  1020                                  					; is detected.
  1021                                  	;mov	al,[CS:MOTOR_COUNT]
  1022 000006D9 A0[5B6B0000]            	mov	al, [MOTOR_COUNT]
  1023 000006DE FEC8                    	dec	al
  1024                                  	;mov	[CS:MOTOR_COUNT], al	; DECREMENT DISKETTE MOTOR CONTROL
  1025 000006E0 A2[5B6B0000]            	mov	[MOTOR_COUNT], al
  1026                                  	;mov	[ORG_MOTOR_COUNT], al
  1027 000006E5 750F                    	JNZ	short T6		; RETURN IF COUNT NOT OUT
  1028 000006E7 B0F0                    	mov 	al,0F0h
  1029                                  	;AND	[CS:MOTOR_STATUS],al 	; TURN OFF MOTOR RUNNING BITS
  1030 000006E9 2005[5A6B0000]          	and	[MOTOR_STATUS], al
  1031                                  	;and	[ORG_MOTOR_STATUS], al
  1032 000006EF B00C                    	MOV	AL,0CH			; bit 3 = enable IRQ & DMA, 
  1033                                  					; bit 2 = enable controller
  1034                                  					;	1 = normal operation
  1035                                  					;	0 = reset	
  1036                                  					; bit 0, 1 = drive select
  1037                                  					; bit 4-7 = motor running bits 
  1038 000006F1 66BAF203                	MOV	DX,03F2H		; FDC CTL PORT
  1039 000006F5 EE                      	OUT	DX,AL			; TURN OFF THE MOTOR
  1040                                  T6:	
  1041                                  	;inc	word [CS:wait_count]	; 22/12/2014 (byte -> word)
  1042                                  					; TIMER TICK INTERRUPT
  1043                                  	;;inc	word [wait_count] ;;27/02/2015
  1044                                  	;INT	1CH			; TRANSFER CONTROL TO A USER ROUTINE
  1045                                  	;;;;cli
  1046                                  	;call 	u_timer			; TRANSFER CONTROL TO A USER ROUTINE
  1047 000006F6 FF15[11070000]          	call	[x_timer] ; 14/05/2015
  1048                                  T7:
  1049                                  	; 14/10/2015
  1050 000006FC B020                    	MOV	AL,EOI			; GET END OF INTERRUPT MASK
  1051 000006FE FA                      	CLI				; DISABLE INTERRUPTS TILL STACK CLEARED
  1052 000006FF E620                    	OUT	INTA00,AL		; END OF INTERRUPT TO 8259 - 1	
  1053                                  	;
  1054 00000701 A1[19070000]            	mov 	eax, [cr3reg] 		; previous value/content of cr3 register
  1055 00000706 0F22D8                   	mov	cr3, eax  ; restore cr3 register content
  1056                                  	;
  1057 00000709 61                      	popad ; edi, esi, ebp, temp (icrement esp by 4), ebx, edx, ecx, eax
  1058                                  	;
  1059 0000070A 0FA9                    	pop	gs
  1060 0000070C 0FA1                    	pop	fs
  1061 0000070E 07                      	pop	es
  1062 0000070F 1F                      	pop	ds
  1063 00000710 CF                      	iretd	; return from interrupt
  1064                                  
  1065                                  
  1066                                  ; ////////////////
  1067                                  
  1068                                  ; 14/05/2015 - Multi tasking 'clock' procedure (sys emt)
  1069                                  x_timer:
  1070 00000711 [1D070000]              	dd 	u_timer			; 14/05/2015
  1071                                  	;dd	clock
  1072                                  
  1073                                  ; 26/02/2022 - Real time clock (digital) output demo (sys emt)
  1074                                  x_rtci:
  1075 00000715 [530A0000]              	dd	rtc_p	; (temporary demo code)	; 26/02/2022
  1076                                  
  1077                                  ; 14/10/2015
  1078 00000719 00000000                cr3reg: dd 0
  1079                                  
  1080                                  	; 24/12/2021 - Retro UNIX 386 v1.1
  1081                                  	; 06/02/2015
  1082                                  	; 07/09/2014
  1083                                  	; 21/08/2014
  1084                                  u_timer:
  1085                                  ;timer_int:	; IRQ 0
  1086                                  	; 06/02/2015
  1087                                  	;push	eax
  1088                                  	;push	edx
  1089                                  	;push	ecx
  1090                                  	;push	ebx
  1091                                  	;push	ds
  1092                                  	;push	es
  1093                                  	;mov	eax, KDATA
  1094                                  	;mov	ds, ax
  1095                                  	;mov	es, ax
  1096 0000071D FF05[1C6B0000]          	inc	dword [tcount]
  1097 00000723 BB[A2660000]            	mov	ebx, tcountstr + 4
  1098                                  	;mov	ax, [tcount]
  1099                                  	; 24/12/2021
  1100 00000728 A1[1C6B0000]            	mov	eax, [tcount]
  1101 0000072D B90A000000              	mov	ecx, 10
  1102                                  rp_divtcnt:
  1103 00000732 31D2                    	xor	edx, edx
  1104 00000734 F7F1                    	div	ecx
  1105 00000736 80C230                  	add	dl, 30h
  1106 00000739 8813                    	mov	[ebx], dl
  1107                                  	;or	ax, ax
  1108                                  	; 24/12/2021
  1109 0000073B 09C0                    	or	eax, eax
  1110 0000073D 7403                    	jz	short print_lzero
  1111 0000073F 4B                      	dec	ebx
  1112 00000740 EBF0                    	jmp	short rp_divtcnt
  1113                                  print_lzero:
  1114 00000742 81FB[9E660000]          	cmp	ebx, tcountstr
  1115 00000748 7606                    	jna	short print_tcount
  1116 0000074A 4B                      	dec	ebx
  1117 0000074B C60330                   	mov	byte [ebx], 30h
  1118 0000074E EBF2                    	jmp	short print_lzero
  1119                                  print_tcount:
  1120 00000750 56                      	push	esi
  1121 00000751 57                      	push	edi
  1122 00000752 BE[7A660000]            	mov	esi, timer_msg ; Timer interrupt message
  1123                                  	; 07/09/2014
  1124                                  	;mov	bx, 1	; Video page 1
  1125                                  	; 24/12/2021
  1126 00000757 29DB                    	sub	ebx, ebx
  1127                                  	;inc	bl ; ebx = 1
  1128                                  	; 02/01/2022
  1129 00000759 B306                    	mov	bl, 6	; Video page 6
  1130                                  ptmsg:
  1131 0000075B AC                      	lodsb
  1132 0000075C 08C0                    	or	al, al
  1133 0000075E 740D                    	jz	short ptmsg_ok
  1134 00000760 56                      	push	esi
  1135                                  	;push	bx
  1136                                  	; 24/12/2021
  1137 00000761 53                              push	ebx
  1138 00000762 B42F                    	mov     ah, 2Fh ; Green background, white forecolor
  1139 00000764 E85D0C0000              	call 	write_tty
  1140                                  	;pop	bx
  1141                                  	; 24/12/2021
  1142 00000769 5B                      	pop	ebx
  1143 0000076A 5E                      	pop	esi
  1144 0000076B EBEE                    	jmp	short ptmsg
  1145                                  	;; 27/08/2014
  1146                                  	;mov	edi, 0B8000h + 0A0h ; Row 1
  1147                                  	;call	printk
  1148                                  	;
  1149                                  ptmsg_ok:
  1150                                  	; 07/09/2014
  1151                                  	;xor	dx, dx		; column 0, row 0
  1152                                  	; 24/12/2021
  1153 0000076D 31D2                    	xor	edx, edx
  1154 0000076F E85C0D0000              	call	set_cpos	; set cursor position to 0,0 
  1155                                  	; 23/02/2015
  1156                                  	; 25/08/2014
  1157                                  	;mov	ebx, scounter		; (seconds counter)
  1158                                  	;dec	byte [ebx+1]		; (for reading real time clock)
  1159                                  ;	dec	byte [scounter+1]
  1160                                  ;;	jns	short timer_eoi		; 0 -> 0FFh ?
  1161                                  ;	jns	short u_timer_retn
  1162                                  	; 26/02/2015
  1163                                  ;	call	rtc_p
  1164                                  ;	mov	ebx, scounter		; (seconds counter)
  1165                                  ;	mov	byte [ebx+1], 18	; (18.2 timer ticks per second)
  1166                                  ;	dec 	byte [ebx]		; 19+18+18+18+18 (5)	
  1167                                  ;	jnz	short timer_eoi		; (109 timer ticks in 5 seconds)
  1168                                  ;	jnz	short u_timer_retn ; 06/02/2015
  1169                                  ;	mov	byte [ebx], 5
  1170                                  ;	inc	byte [ebx+1] ; 19
  1171                                  ;;timer_eoi:
  1172                                  ;;	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1173                                  ;;	out	20h, al	; 8259 PORT
  1174                                  	;
  1175                                  ;u_timer_retn:  ; 06/02/2015
  1176 00000774 5F                      	pop	edi
  1177 00000775 5E                      	pop	esi
  1178                                  	;pop	es
  1179                                  	;pop	ds
  1180                                  	;pop	ebx
  1181                                  	;pop	ecx
  1182                                  	;pop	edx
  1183                                  	;pop	eax
  1184                                  	;iret
  1185 00000776 C3                      	retn	; 06/02/2015
  1186                                  
  1187                                  	; 28/08/2014
  1188                                  irq0:
  1189 00000777 6A00                            push 	dword 0
  1190 00000779 EB48                    	jmp	short which_irq
  1191                                  irq1:
  1192 0000077B 6A01                            push 	dword 1
  1193 0000077D EB44                    	jmp	short which_irq
  1194                                  irq2:
  1195 0000077F 6A02                            push 	dword 2
  1196 00000781 EB40                    	jmp	short which_irq
  1197                                  irq3:
  1198                                  	; 20/11/2015
  1199                                  	; 24/10/2015
  1200 00000783 2EFF15[D5390000]        	call	dword [cs:com2_irq3]
  1201 0000078A 6A03                    	push 	dword 3
  1202 0000078C EB35                    	jmp	short which_irq
  1203                                  irq4:
  1204                                  	; 20/11/2015
  1205                                  	; 24/10/2015
  1206 0000078E 2EFF15[D1390000]        	call	dword [cs:com1_irq4]
  1207 00000795 6A04                            push 	dword 4
  1208 00000797 EB2A                    	jmp	short which_irq
  1209                                  irq5:
  1210 00000799 6A05                            push 	dword 5
  1211 0000079B EB26                    	jmp	short which_irq
  1212                                  irq6:
  1213 0000079D 6A06                            push 	dword 6
  1214 0000079F EB22                    	jmp	short which_irq
  1215                                  irq7:
  1216 000007A1 6A07                            push 	dword 7
  1217 000007A3 EB1E                    	jmp	short which_irq
  1218                                  irq8:
  1219 000007A5 6A08                            push 	dword 8
  1220 000007A7 EB1A                    	jmp	short which_irq
  1221                                  irq9:
  1222 000007A9 6A09                            push 	dword 9
  1223 000007AB EB16                    	jmp	short which_irq
  1224                                  irq10:
  1225 000007AD 6A0A                            push 	dword 10
  1226 000007AF EB12                    	jmp	short which_irq
  1227                                  irq11:
  1228 000007B1 6A0B                            push 	dword 11
  1229 000007B3 EB0E                    	jmp	short which_irq
  1230                                  irq12:
  1231 000007B5 6A0C                            push 	dword 12
  1232 000007B7 EB0A                    	jmp	short which_irq
  1233                                  irq13:
  1234 000007B9 6A0D                            push 	dword 13
  1235 000007BB EB06                    	jmp	short which_irq
  1236                                  irq14:
  1237 000007BD 6A0E                            push 	dword 14
  1238 000007BF EB02                    	jmp	short which_irq
  1239                                  irq15:
  1240 000007C1 6A0F                            push 	dword 15
  1241                                  	;jmp	short which_irq
  1242                                  
  1243                                  	; 19/10/2015
  1244                                  	; 29/08/2014
  1245                                  	; 21/08/2014
  1246                                  which_irq:
  1247 000007C3 870424                  	xchg	eax, [esp]  ; 28/08/2014
  1248 000007C6 53                      	push	ebx
  1249 000007C7 56                      	push	esi
  1250 000007C8 57                      	push	edi
  1251 000007C9 1E                      	push 	ds
  1252 000007CA 06                      	push 	es
  1253                                  	;
  1254 000007CB 88C3                    	mov	bl, al
  1255                                  	;
  1256 000007CD B810000000              	mov	eax, KDATA
  1257 000007D2 8ED8                    	mov	ds, ax
  1258 000007D4 8EC0                    	mov	es, ax
  1259                                  	; 19/10/2015
  1260 000007D6 FC                      	cld
  1261                                          ; 27/08/2014
  1262 000007D7 8105[28660000]A000-             add     dword [scr_row], 0A0h
  1262 000007DF 0000               
  1263                                  	;
  1264 000007E1 B417                    	mov	ah, 17h	; blue (1) background, 
  1265                                  			; light gray (7) forecolor
  1266 000007E3 8B3D[28660000]                  mov     edi, [scr_row]
  1267 000007E9 B049                    	mov	al, 'I'
  1268 000007EB 66AB                    	stosw
  1269 000007ED B052                    	mov	al, 'R'
  1270 000007EF 66AB                    	stosw
  1271 000007F1 B051                    	mov	al, 'Q'
  1272 000007F3 66AB                    	stosw
  1273 000007F5 B020                    	mov	al, ' '
  1274 000007F7 66AB                    	stosw
  1275 000007F9 88D8                    	mov	al, bl
  1276 000007FB 3C0A                    	cmp	al, 10
  1277 000007FD 7208                    	jb	short iix
  1278 000007FF B031                    	mov	al, '1'
  1279 00000801 66AB                    	stosw
  1280 00000803 88D8                    	mov	al, bl
  1281 00000805 2C0A                    	sub	al, 10
  1282                                  iix:
  1283 00000807 0430                    	add	al, '0'
  1284 00000809 66AB                    	stosw
  1285 0000080B B020                    	mov	al, ' '
  1286 0000080D 66AB                    	stosw
  1287 0000080F B021                    	mov	al, '!'
  1288 00000811 66AB                    	stosw
  1289 00000813 B020                    	mov	al, ' '
  1290 00000815 66AB                    	stosw
  1291                                  	; 23/02/2015
  1292 00000817 80FB07                  	cmp	bl, 7 ; check for IRQ 8 to IRQ 15 
  1293                                  	;jna	iiret
  1294                                  	; 02/01/2022
  1295 0000081A 7604                    	jna	short iiz
  1296                                  iiy:
  1297 0000081C B020                    	mov	al, 20h  ; END OF INTERRUPT COMMAND TO
  1298 0000081E E6A0                    	out	0A0h, al ; the 2nd 8259
  1299                                  iiz:
  1300 00000820 E983010000              	jmp     iiret
  1301                                  	;
  1302                                  	; 22/08/2014
  1303                                  	;mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1304                                  	;out	20h, al	; 8259 PORT
  1305                                  	;
  1306                                  	;pop	es
  1307                                  	;pop	ds
  1308                                  	;pop	edi
  1309                                  	;pop	esi
  1310                                  	;pop	ebx
  1311                                  	;pop 	eax
  1312                                  	;iret
  1313                                  
  1314                                  	; 02/04/2015
  1315                                  	; 25/08/2014
  1316                                  exc0:
  1317 00000825 6A00                            push 	dword 0
  1318 00000827 E990000000                      jmp     cpu_except
  1319                                  exc1:
  1320 0000082C 6A01                            push 	dword 1
  1321 0000082E E989000000                      jmp     cpu_except
  1322                                  exc2:
  1323 00000833 6A02                            push 	dword 2
  1324 00000835 E982000000                      jmp     cpu_except
  1325                                  exc3:
  1326 0000083A 6A03                            push 	dword 3
  1327 0000083C EB7E                            jmp     cpu_except
  1328                                  exc4:
  1329 0000083E 6A04                            push 	dword 4
  1330 00000840 EB7A                            jmp     cpu_except
  1331                                  exc5:
  1332 00000842 6A05                            push 	dword 5
  1333 00000844 EB76                            jmp     cpu_except
  1334                                  exc6:
  1335 00000846 6A06                            push 	dword 6
  1336 00000848 EB72                            jmp     cpu_except
  1337                                  exc7:
  1338 0000084A 6A07                            push 	dword 7
  1339 0000084C EB6E                            jmp     cpu_except
  1340                                  exc8:
  1341                                  	; [esp] = Error code
  1342 0000084E 6A08                            push 	dword 8
  1343 00000850 EB5C                            jmp     cpu_except_en
  1344                                  exc9:
  1345 00000852 6A09                            push 	dword 9
  1346 00000854 EB66                            jmp     cpu_except
  1347                                  exc10:
  1348                                  	; [esp] = Error code
  1349 00000856 6A0A                            push 	dword 10
  1350 00000858 EB54                            jmp     cpu_except_en
  1351                                  exc11:
  1352                                  	; [esp] = Error code
  1353 0000085A 6A0B                            push 	dword 11
  1354 0000085C EB50                            jmp     cpu_except_en
  1355                                  exc12:
  1356                                  	; [esp] = Error code
  1357 0000085E 6A0C                            push 	dword 12
  1358 00000860 EB4C                            jmp     cpu_except_en
  1359                                  exc13:
  1360                                  	; [esp] = Error code
  1361 00000862 6A0D                            push 	dword 13
  1362 00000864 EB48                            jmp     cpu_except_en
  1363                                  exc14:
  1364                                  	; [esp] = Error code
  1365 00000866 6A0E                            push 	dword 14
  1366 00000868 EB44                    	jmp	short cpu_except_en
  1367                                  exc15:
  1368 0000086A 6A0F                            push 	dword 15
  1369 0000086C EB4E                            jmp     cpu_except
  1370                                  exc16:
  1371 0000086E 6A10                            push 	dword 16
  1372 00000870 EB4A                            jmp     cpu_except
  1373                                  exc17:
  1374                                  	; [esp] = Error code
  1375 00000872 6A11                            push 	dword 17
  1376 00000874 EB38                    	jmp	short cpu_except_en
  1377                                  exc18:
  1378 00000876 6A12                            push 	dword 18
  1379 00000878 EB42                    	jmp	short cpu_except
  1380                                  exc19:
  1381 0000087A 6A13                            push 	dword 19
  1382 0000087C EB3E                    	jmp	short cpu_except
  1383                                  exc20:
  1384 0000087E 6A14                            push 	dword 20
  1385 00000880 EB3A                    	jmp	short cpu_except
  1386                                  exc21:
  1387 00000882 6A15                            push 	dword 21
  1388 00000884 EB36                    	jmp	short cpu_except
  1389                                  exc22:
  1390 00000886 6A16                            push 	dword 22
  1391 00000888 EB32                    	jmp	short cpu_except
  1392                                  exc23:
  1393 0000088A 6A17                            push 	dword 23
  1394 0000088C EB2E                    	jmp	short cpu_except
  1395                                  exc24:
  1396 0000088E 6A18                            push 	dword 24
  1397 00000890 EB2A                    	jmp	short cpu_except
  1398                                  exc25:
  1399 00000892 6A19                            push 	dword 25
  1400 00000894 EB26                    	jmp	short cpu_except
  1401                                  exc26:
  1402 00000896 6A1A                            push 	dword 26
  1403 00000898 EB22                    	jmp	short cpu_except
  1404                                  exc27:
  1405 0000089A 6A1B                            push 	dword 27
  1406 0000089C EB1E                    	jmp	short cpu_except
  1407                                  exc28:
  1408 0000089E 6A1C                            push 	dword 28
  1409 000008A0 EB1A                    	jmp	short cpu_except
  1410                                  exc29:
  1411 000008A2 6A1D                            push 	dword 29
  1412 000008A4 EB16                    	jmp	short cpu_except
  1413                                  exc30:
  1414 000008A6 6A1E                            push 	dword 30
  1415 000008A8 EB04                    	jmp	short cpu_except_en
  1416                                  exc31:
  1417 000008AA 6A1F                            push 	dword 31
  1418 000008AC EB0E                            jmp     short cpu_except
  1419                                  
  1420                                  	; 02/01/2022
  1421                                  	; 19/10/2015
  1422                                  	; 19/09/2015
  1423                                  	; 01/09/2015
  1424                                  	; 28/08/2015
  1425                                  	; 28/08/2014
  1426                                  cpu_except_en:
  1427 000008AE 87442404                	xchg	eax, [esp+4] ; Error code
  1428 000008B2 36A3[886B0000]          	mov	[ss:error_code], eax
  1429 000008B8 58                      	pop	eax  ; Exception number
  1430 000008B9 870424                  	xchg	eax, [esp]
  1431                                  		; eax = eax before exception
  1432                                  		; [esp] -> exception number
  1433                                  		; [esp+4] -> EIP to return
  1434                                  	; 19/10/2015
  1435                                  	; 19/09/2015
  1436                                  	; 01/09/2015
  1437                                  	; 28/08/2015
  1438                                  	; 29/08/2014
  1439                                  	; 28/08/2014
  1440                                  	; 25/08/2014
  1441                                  	; 21/08/2014
  1442                                  cpu_except:	; CPU Exceptions
  1443 000008BC FC                      	cld
  1444 000008BD 870424                  	xchg	eax, [esp] 
  1445                                  		; eax = Exception number
  1446                                  		; [esp] = eax (before exception)
  1447 000008C0 53                      	push	ebx
  1448 000008C1 56                      	push	esi
  1449 000008C2 57                      	push	edi
  1450 000008C3 1E                      	push 	ds
  1451 000008C4 06                      	push 	es
  1452                                  	; 28/08/2015
  1453 000008C5 66BB1000                	mov	bx, KDATA
  1454 000008C9 8EDB                    	mov	ds, bx
  1455 000008CB 8EC3                    	mov	es, bx
  1456 000008CD 0F20DB                  	mov	ebx, cr3
  1457 000008D0 53                      	push	ebx ; (*) page directory
  1458                                  	; 19/10/2015
  1459 000008D1 FC                      	cld
  1460                                  	; 25/03/2015
  1461 000008D2 8B1D[D86A0000]          	mov	ebx, [k_page_dir]
  1462 000008D8 0F22DB                  	mov	cr3, ebx
  1463                                  	; 28/08/2015
  1464 000008DB 83F80E                  	cmp	eax, 0Eh ; 14, PAGE FAULT
  1465 000008DE 7513                    	jne	short cpu_except_nfp
  1466 000008E0 E884270000              	call	page_fault_handler
  1467 000008E5 21C0                    	and 	eax, eax
  1468                                  	;jz	iiretp ; 01/09/2015
  1469                                  	; 02/01/2022
  1470 000008E7 7505                    	jnz	short cpu_except_pf
  1471 000008E9 E9B6000000              	jmp	iiretp
  1472                                  cpu_except_pf:
  1473 000008EE B80E000000              	mov	eax, 0Eh ; 14
  1474                                  cpu_except_nfp:
  1475                                  	; 02/04/2015
  1476 000008F3 BB[1C060000]            	mov	ebx, hang
  1477 000008F8 875C241C                	xchg	ebx, [esp+28]
  1478                                  		; EIP (points to instruction which faults)
  1479                                  	  	; New EIP (hang)
  1480 000008FC 891D[8C6B0000]          	mov	[FaultOffset], ebx
  1481 00000902 C744242008000000        	mov	dword [esp+32], KCODE ; kernel's code segment
  1482 0000090A 814C242400020000        	or	dword [esp+36], 200h ; enable interrupts (set IF)
  1483                                  	;
  1484 00000912 88C4                    	mov	ah, al
  1485 00000914 240F                    	and	al, 0Fh
  1486 00000916 3C09                    	cmp	al, 9
  1487 00000918 7602                    	jna	short h1ok
  1488 0000091A 0407                    	add	al, 'A'-':'
  1489                                  h1ok:
  1490 0000091C D0EC                    	shr	ah, 1
  1491 0000091E D0EC                    	shr	ah, 1
  1492 00000920 D0EC                    	shr	ah, 1
  1493 00000922 D0EC                    	shr	ah, 1
  1494 00000924 80FC09                  	cmp	ah, 9
  1495 00000927 7603                    	jna	short h2ok
  1496 00000929 80C407                  	add	ah, 'A'-':'
  1497                                  h2ok:	
  1498 0000092C 86E0                    	xchg 	ah, al	
  1499 0000092E 66053030                	add	ax, '00'
  1500 00000932 66A3[B6660000]          	mov	[excnstr], ax
  1501                                  	;
  1502                                  	; 29/08/2014
  1503 00000938 A1[8C6B0000]            	mov	eax, [FaultOffset]
  1504 0000093D 51                      	push	ecx
  1505 0000093E 52                      	push	edx
  1506 0000093F 89E3                    	mov	ebx, esp
  1507                                  	; 28/08/2015
  1508 00000941 B910000000              	mov	ecx, 16	  ; divisor value to convert binary number
  1509                                  			  ; to hexadecimal string
  1510                                  	;mov	ecx, 10	    ; divisor to convert
  1511                                  			    ; binary number to decimal string
  1512                                  b2d1:
  1513 00000946 31D2                    	xor	edx, edx
  1514 00000948 F7F1                    	div	ecx
  1515                                  	;push	dx
  1516                                  	; 02/01/2022
  1517 0000094A 52                      	push	edx
  1518 0000094B 39C8                    	cmp	eax, ecx
  1519 0000094D 73F7                    	jnb	short b2d1
  1520 0000094F BF[C1660000]            	mov	edi, EIPstr ; EIP value
  1521                                  			    ; points to instruction which faults
  1522                                  	; 28/08/2015
  1523 00000954 89C2                    	mov	edx, eax
  1524                                  b2d2:
  1525                                  	;add	al, '0'
  1526 00000956 8A82[06170000]          	mov	al, [edx+hexchrs]
  1527 0000095C AA                      	stosb		    ; write hexadecimal digit to its place
  1528 0000095D 39E3                    	cmp	ebx, esp
  1529 0000095F 7605                    	jna	short b2d3
  1530                                  	; 02/01/2022
  1531 00000961 58                      	pop	eax
  1532                                  	;pop	ax
  1533 00000962 88C2                    	mov	dl, al
  1534 00000964 EBF0                    	jmp	short b2d2
  1535                                  b2d3:
  1536 00000966 B068                    	mov 	al, 'h' ; 28/08/2015
  1537 00000968 AA                      	stosb
  1538 00000969 B020                    	mov	al, 20h	    ; space
  1539 0000096B AA                      	stosb
  1540 0000096C 30C0                    	xor	al, al	    ; to do it an ASCIIZ string	
  1541 0000096E AA                      	stosb
  1542                                  	;
  1543 0000096F 5A                      	pop	edx
  1544 00000970 59                      	pop	ecx
  1545                                  	;
  1546 00000971 B44F                    	mov	ah, 4Fh	; red (4) background, 
  1547                                  			; white (F) forecolor
  1548 00000973 BE[A6660000]            	mov	esi, exc_msg ; message offset
  1549                                  	;
  1550 00000978 EB11                    	jmp	short piemsg
  1551                                  	;
  1552                                          ;add    dword [scr_row], 0A0h
  1553                                          ;mov    edi, [scr_row]
  1554                                          ;
  1555                                  	;call 	printk
  1556                                  	;
  1557                                  	;mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1558                                  	;out	20h, al	; 8259 PORT
  1559                                  	;
  1560                                  	;pop	es
  1561                                  	;pop	ds
  1562                                  	;pop	edi
  1563                                  	;pop	esi
  1564                                  	;pop 	eax
  1565                                  	;iret
  1566                                  	
  1567                                  	; 28/08/2015
  1568                                  	; 23/02/2015
  1569                                  	; 20/08/2014
  1570                                  ignore_int:
  1571 0000097A 50                      	push	eax
  1572 0000097B 53                      	push	ebx ; 23/02/2015
  1573 0000097C 56                      	push	esi
  1574 0000097D 57                      	push	edi
  1575 0000097E 1E                      	push 	ds
  1576 0000097F 06                      	push 	es
  1577                                  	; 28/08/2015
  1578 00000980 0F20D8                  	mov	eax, cr3
  1579 00000983 50                      	push	eax ; (*) page directory
  1580                                  	;
  1581 00000984 B467                    	mov	ah, 67h	; brown (6) background, 
  1582                                  			; light gray (7) forecolor
  1583 00000986 BE[64660000]            	mov	esi, int_msg ; message offset
  1584                                  piemsg:
  1585                                          ; 27/08/2014
  1586 0000098B 8105[28660000]A000-             add     dword [scr_row], 0A0h
  1586 00000993 0000               
  1587 00000995 8B3D[28660000]                  mov     edi, [scr_row]
  1588                                          ;
  1589 0000099B E8B6FCFFFF              	call 	printk
  1590                                  	;
  1591                                  	; 23/02/2015
  1592 000009A0 B020                    	mov	al, 20h  ; END OF INTERRUPT COMMAND TO
  1593 000009A2 E6A0                    	out	0A0h, al ; the 2nd 8259
  1594                                  iiretp: ; 01/09/2015
  1595                                  	; 28/08/2015
  1596 000009A4 58                      	pop	eax ; (*) page directory
  1597 000009A5 0F22D8                  	mov	cr3, eax
  1598                                  	;
  1599                                  iiret:
  1600                                  	; 22/08/2014
  1601 000009A8 B020                    	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1602 000009AA E620                    	out	20h, al	; 8259 PORT
  1603                                  	;
  1604 000009AC 07                      	pop	es
  1605 000009AD 1F                      	pop	ds
  1606 000009AE 5F                      	pop	edi
  1607 000009AF 5E                      	pop	esi
  1608 000009B0 5B                      	pop	ebx ; 29/08/2014
  1609 000009B1 58                      	pop 	eax
  1610 000009B2 CF                      	iretd
  1611                                  
  1612                                  	; 26/02/2022
  1613                                  	; 26/02/2015
  1614                                  	; 07/09/2014
  1615                                  	; 25/08/2014
  1616                                  rtc_int:       ; Real Time Clock Interrupt (IRQ 8)
  1617                                  	; 22/08/2014
  1618 000009B3 50                      	push	eax
  1619 000009B4 53                      	push	ebx ; 29/08/2014
  1620 000009B5 56                      	push	esi
  1621 000009B6 57                      	push	edi
  1622 000009B7 1E                      	push 	ds
  1623 000009B8 06                      	push 	es
  1624                                  	;
  1625 000009B9 B810000000              	mov	eax, KDATA
  1626 000009BE 8ED8                    	mov	ds, ax
  1627 000009C0 8EC0                    	mov	es, ax
  1628                                  	;
  1629                                  	; 25/08/2014
  1630                                  	;call	rtc_p
  1631                                  	; 26/02/2022
  1632 000009C2 FF15[15070000]          	call	[x_rtci]
  1633                                  	;
  1634                                  	; 22/02/2015 - dsectpm.s
  1635                                  	; [ source: http://wiki.osdev.org/RTC ]
  1636                                  	; read status register C to complete procedure
  1637                                  	;(it is needed to get a next IRQ 8) 
  1638 000009C8 B00C                    	mov	al, 0Ch ; 
  1639 000009CA E670                    	out	70h, al ; select register C
  1640 000009CC 90                      	nop
  1641 000009CD E471                    	in	al, 71h ; just throw away contents
  1642                                  	; 22/02/2015
  1643 000009CF B020                    	MOV	AL,EOI		; END OF INTERRUPT
  1644 000009D1 E6A0                    	OUT	INTB00,AL	; FOR CONTROLLER #2
  1645                                  	;
  1646 000009D3 EBD3                    	jmp	short iiret	
  1647                                  
  1648                                  	; 22/08/2014
  1649                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (bios.asm)
  1650                                  	; (INT 1Ah)
  1651                                  	;; Linux (v0.12) source code (main.c) by Linus Torvalds (1991)
  1652                                  time_of_day:
  1653 000009D5 E866010000              	call	UPD_IPR		; WAIT TILL UPDATE NOT IN PROGRESS
  1654 000009DA 726F                            jc      short rtc_retn 
  1655 000009DC B000                    	mov	al, CMOS_SECONDS
  1656 000009DE E847010000              	call	CMOS_READ
  1657 000009E3 A2[4C6B0000]            	mov	[time_seconds], al 
  1658 000009E8 B002                    	mov	al, CMOS_MINUTES
  1659 000009EA E83B010000              	call	CMOS_READ
  1660 000009EF A2[4D6B0000]            	mov	[time_minutes], al 
  1661 000009F4 B004                    	mov	al, CMOS_HOURS
  1662 000009F6 E82F010000              	call	CMOS_READ
  1663 000009FB A2[4E6B0000]                    mov     [time_hours], al
  1664 00000A00 B006                    	mov	al, CMOS_DAY_WEEK 
  1665 00000A02 E823010000              	call	CMOS_READ
  1666 00000A07 A2[4F6B0000]            	mov	[date_wday], al
  1667 00000A0C B007                     	mov	al, CMOS_DAY_MONTH
  1668 00000A0E E817010000              	call	CMOS_READ
  1669 00000A13 A2[506B0000]            	mov	[date_day], al
  1670 00000A18 B008                    	mov	al, CMOS_MONTH
  1671 00000A1A E80B010000              	call	CMOS_READ
  1672 00000A1F A2[516B0000]            	mov	[date_month], al
  1673 00000A24 B009                    	mov	al, CMOS_YEAR
  1674 00000A26 E8FF000000              	call	CMOS_READ
  1675 00000A2B A2[526B0000]            	mov	[date_year], al
  1676 00000A30 B032                    	mov	al, CMOS_CENTURY
  1677 00000A32 E8F3000000              	call	CMOS_READ
  1678 00000A37 A2[536B0000]            	mov	[date_century], al
  1679                                  	;
  1680 00000A3C B000                    	mov	al, CMOS_SECONDS
  1681 00000A3E E8E7000000              	call 	CMOS_READ
  1682 00000A43 3A05[4C6B0000]          	cmp	al, [time_seconds]
  1683 00000A49 758A                    	jne	short time_of_day
  1684                                  
  1685                                  rtc_retn:
  1686 00000A4B C3                      	retn
  1687                                  
  1688                                  rtci_default:
  1689                                  	; 26/02/2022 (Temporary!)
  1690                                  	; (default real time clock handler in multitasking mode)
  1691                                  	; ((2 rtc ticks per second after 'setup_rtc_int'))
  1692 00000A4C FF05[946B0000]          	inc	dword [rtc_ticks] ; real time clock counter
  1693                                  			; (not used in anywhere of kernel for now!)
  1694 00000A52 C3                      	retn
  1695                                  
  1696                                  rtc_p:	
  1697                                  	; 07/09/2014
  1698                                  	; 29/08/2014
  1699                                  	; 27/08/2014
  1700                                  	; 25/08/2014
  1701                                   	; Print Real Time Clock content
  1702                                  	;
  1703                                  	;
  1704 00000A53 E87DFFFFFF              	call	time_of_day
  1705 00000A58 72F1                    	jc	short rtc_retn
  1706                                  	;
  1707 00000A5A 3A05[18670000]          	cmp	al, [ptime_seconds]
  1708 00000A60 74E9                            je      short rtc_retn ; 29/08/2014
  1709                                  	;
  1710 00000A62 A2[18670000]            	mov	[ptime_seconds], al
  1711                                  	;
  1712 00000A67 A0[536B0000]            	mov	al, [date_century]
  1713 00000A6C E8EA000000              	call	bcd_to_ascii
  1714 00000A71 66A3[E5660000]          	mov	[datestr+6], ax
  1715 00000A77 A0[526B0000]            	mov	al, [date_year]
  1716 00000A7C E8DA000000              	call	bcd_to_ascii
  1717 00000A81 66A3[E7660000]          	mov	[datestr+8], ax
  1718 00000A87 A0[516B0000]            	mov	al, [date_month]
  1719 00000A8C E8CA000000              	call	bcd_to_ascii
  1720 00000A91 66A3[E2660000]          	mov	[datestr+3], ax
  1721 00000A97 A0[506B0000]            	mov	al, [date_day]
  1722 00000A9C E8BA000000              	call	bcd_to_ascii
  1723 00000AA1 66A3[DF660000]          	mov	[datestr], ax
  1724                                  	;
  1725 00000AA7 0FB61D[4F6B0000]        	movzx	ebx, byte [date_wday]
  1726 00000AAE C0E302                  	shl 	bl, 2
  1727 00000AB1 81C3[F8660000]          	add	ebx, daytmp
  1728 00000AB7 8B03                    	mov	eax, [ebx]
  1729 00000AB9 A3[EA660000]            	mov	[daystr], eax
  1730                                  	;
  1731 00000ABE A0[4E6B0000]            	mov	al, [time_hours]
  1732 00000AC3 E893000000              	call	bcd_to_ascii
  1733 00000AC8 66A3[EE660000]          	mov	[timestr], ax
  1734 00000ACE A0[4D6B0000]            	mov	al, [time_minutes]
  1735 00000AD3 E883000000              	call	bcd_to_ascii
  1736 00000AD8 66A3[F1660000]          	mov	[timestr+3], ax
  1737 00000ADE A0[4C6B0000]            	mov	al, [time_seconds]
  1738 00000AE3 E873000000              	call	bcd_to_ascii
  1739 00000AE8 66A3[F4660000]          	mov	[timestr+6], ax
  1740                                  	;		
  1741 00000AEE BE[CD660000]            	mov	esi, rtc_msg ; message offset
  1742                                  	; 23/02/2015
  1743 00000AF3 52                      	push	edx
  1744 00000AF4 51                      	push	ecx
  1745                                  	; 07/09/2014
  1746                                  	;mov	bx, 2	; Video page 2
  1747                                  	; 02/01/2022
  1748 00000AF5 29DB                    	sub	ebx, ebx
  1749 00000AF7 B307                    	mov	bl, 7	; Video page 7 
  1750                                  prtmsg:
  1751 00000AF9 AC                      	lodsb
  1752 00000AFA 08C0                    	or	al, al
  1753 00000AFC 740D                    	jz	short prtmsg_ok
  1754 00000AFE 56                      	push	esi
  1755                                  	; 02/01/2022
  1756 00000AFF 53                      	push	ebx
  1757                                  	;push	bx
  1758 00000B00 B43F                            mov	ah, 3Fh	; cyan (6) background, 
  1759                                  			; white (F) forecolor
  1760 00000B02 E8BF080000              	call 	write_tty
  1761                                  	;pop	bx
  1762                                  	; 02/01/2022
  1763 00000B07 5B                      	pop	ebx
  1764 00000B08 5E                      	pop	esi
  1765 00000B09 EBEE                    	jmp	short prtmsg
  1766                                  	;
  1767                                  	;mov	edi, 0B8000h+0A0h+0A0h ; Row 2
  1768                                  	;call	printk
  1769                                  prtmsg_ok:
  1770                                  	; 07/09/2014
  1771                                  	;xor	dx, dx		; column 0, row 0
  1772                                  	; 02/01/2022
  1773 00000B0B 31D2                    	xor	edx, edx
  1774 00000B0D E8BE090000              	call	set_cpos	; set curspor position to 0,0 
  1775                                  	; 23/02/2015
  1776 00000B12 59                      	pop	ecx
  1777 00000B13 5A                      	pop	edx
  1778 00000B14 C3                      	retn
  1779                                  
  1780                                  ; Default IRQ 7 handler against spurious IRQs (from master PIC)
  1781                                  ; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  1782                                  default_irq7:
  1783                                  	; 24/12/2021
  1784                                  	;push	ax
  1785 00000B15 50                      	push	eax
  1786 00000B16 B00B                    	mov	al, 0Bh  ; In-Service register
  1787 00000B18 E620                    	out	20h, al
  1788 00000B1A EB00                            jmp short $+2
  1789 00000B1C EB00                    	jmp short $+2
  1790 00000B1E E420                    	in	al, 20h
  1791 00000B20 2480                    	and 	al, 80h ; bit 7 (is it real IRQ 7 or fake?)
  1792 00000B22 7404                            jz      short irq7_iret ; Fake (spurious) IRQ, do not send EOI 
  1793 00000B24 B020                            mov     al, 20h ; EOI
  1794 00000B26 E620                    	out	20h, al 
  1795                                  irq7_iret:
  1796                                  	;pop	ax
  1797                                  	; 24/12/2021
  1798 00000B28 58                      	pop	eax
  1799 00000B29 CF                      	iretd	
  1800                                  	
  1801                                  	; 24/12/2021
  1802                                  	; 22/08/2014
  1803                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (test4.asm)
  1804                                  CMOS_READ:
  1805 00000B2A 9C                      	pushf		; SAVE INTERRUPT ENABLE STATUS AND FLAGS
  1806 00000B2B D0C0                    	rol	al, 1	; MOVE NMI BIT TO LOW POSITION
  1807 00000B2D F9                      	stc		; FORCE NMI BIT ON IN CARRY FLAG
  1808 00000B2E D0D8                    	rcr	al, 1	; HIGH BIT ON TO DISABLE NMI - OLD IN CY
  1809 00000B30 FA                      	cli		; DISABLE INTERRUPTS
  1810 00000B31 E670                    	out	CMOS_PORT, al	; ADDRESS LOCATION AND DISABLE NMI
  1811 00000B33 90                      	nop		; I/O DELAY
  1812 00000B34 E471                    	in	al, CMOS_DATA	; READ THE REQUESTED CMOS LOCATION
  1813                                  	;push	ax	; SAVE (AH) REGISTER VALUE AND CMOS BYTE
  1814                                  	; 24/12/2021
  1815 00000B36 50                      	push	eax
  1816                                  	; 15/03/2015 ; IBM PC/XT Model 286 BIOS source code 
  1817                                  		     ; ----- 10/06/85 (test4.asm)
  1818 00000B37 B01E                    	mov	al, CMOS_SHUT_DOWN*2 ; GET ADDRESS OF DEFAULT LOCATION
  1819                                  	;mov	al, CMOS_REG_D*2 ; GET ADDRESS OF DEFAULT LOCATION
  1820 00000B39 D0D8                    	rcr	al, 1	; PUT ORIGINAL NMI MASK BIT INTO ADDRESS
  1821 00000B3B E670                    	out	CMOS_PORT, al	; SET DEFAULT TO READ ONLY REGISTER
  1822                                  	;pop	ax	; RESTORE (AH) AND (AL), CMOS BYTE
  1823                                  	; 24/12/2021
  1824 00000B3D 58                      	pop	eax
  1825 00000B3E 9D                      	popf	
  1826 00000B3F C3                      	retn		; RETURN WITH FLAGS RESTORED
  1827                                  
  1828                                  	; 22/08/2014
  1829                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (bios2.asm)
  1830                                  UPD_IPR:				; WAIT TILL UPDATE NOT IN PROGRESS
  1831 00000B40 51                      	push	ecx
  1832 00000B41 B9FFFF0000              	mov	ecx, 65535		; SET TIMEOUT LOOP COUNT (= 800)
  1833                                  		; mov cx, 800	
  1834                                  UPD_10:
  1835 00000B46 B00A                    	mov	al, CMOS_REG_A		; ADDRESS STATUS REGISTER A
  1836 00000B48 FA                      	cli				; NO TIMER INTERRUPTS DURING UPDATES
  1837 00000B49 E8DCFFFFFF              	call	CMOS_READ		; READ UPDATE IN PROCESS FLAG
  1838 00000B4E A880                    	test	al, 80h			; IF UIP BIT IS ON ( CANNOT READ TIME )
  1839 00000B50 7406                    	jz	short UPD_90		; EXIT WITH CY= 0 IF CAN READ CLOCK NOW
  1840 00000B52 FB                      	sti				; ALLOW INTERRUPTS WHILE WAITING
  1841 00000B53 E2F1                    	loop	UPD_10			; LOOP TILL READY OR TIMEOUT
  1842 00000B55 31C0                    	xor	eax, eax		; CLEAR RESULTS IF ERROR
  1843                                  		; xor ax, ax
  1844 00000B57 F9                      	stc				; SET CARRY FOR ERROR
  1845                                  UPD_90:
  1846 00000B58 59                      	pop	ecx			; RESTORE CALLERS REGISTER
  1847 00000B59 FA                      	cli				; INTERRUPTS OFF DURING SET
  1848 00000B5A C3                      	retn				; RETURN WITH CY FLAG SET
  1849                                  
  1850                                  bcd_to_ascii:
  1851                                  	; 25/08/2014
  1852                                  	; INPUT ->
  1853                                  	;	al = Packed BCD number
  1854                                  	; OUTPUT ->
  1855                                  	;	ax  = ASCII word/number
  1856                                  	;
  1857                                  	; Erdogan Tan - 1998 (proc_hex) - TRDOS.ASM (2004-2011)
  1858                                  	;
  1859 00000B5B D410                    	db 0D4h,10h                     ; Undocumented inst. AAM
  1860                                  					; AH = AL / 10h
  1861                                  					; AL = AL MOD 10h
  1862 00000B5D 660D3030                	or ax,'00'                      ; Make it ASCII based
  1863                                  
  1864 00000B61 86E0                            xchg ah, al 
  1865                                  	
  1866 00000B63 C3                      	retn	
  1867                                  	
  1868                                  
  1869                                  %include 'keyboard.inc' ; 07/03/2015
  1870                              <1> ; Retro UNIX 386 v1 Kernel - KEYBOARD.INC
  1871                              <1> ; Last Modification: 23/02/2022
  1872                              <1> ;		    (Keyboard Data is in 'KYBDATA.INC')	
  1873                              <1> ;
  1874                              <1> ; ///////// KEYBOARD FUNCTIONS (PROCEDURES) ///////////////
  1875                              <1> 
  1876                              <1> ; 04/02/2022 (Retro UNIX 386 v1, Kernel v0.2.0.18)
  1877                              <1> ; 24/12/2021 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  1878                              <1> ; 30/06/2015
  1879                              <1> ; 11/03/2015
  1880                              <1> ; 28/02/2015
  1881                              <1> ; 25/02/2015
  1882                              <1> ; 20/02/2015
  1883                              <1> ; 18/02/2015
  1884                              <1> ; 03/12/2014
  1885                              <1> ; 07/09/2014
  1886                              <1> ; KEYBOARD INTERRUPT HANDLER
  1887                              <1> ; (kb_int - Retro UNIX 8086 v1 - U0.ASM, 30/06/2014)
  1888                              <1> 
  1889                              <1> ;getch:
  1890                              <1> ;	; 18/02/2015
  1891                              <1> ;	; This routine will be replaced with Retro UNIX 386
  1892                              <1> ;	; version of Retro UNIX 8086 getch (tty input)
  1893                              <1> ;	; routine, later... (multi tasking ability)
  1894                              <1> ;	; 28/02/2015
  1895                              <1> ;	sti	; enable interrupts
  1896                              <1> ;	;
  1897                              <1> ;	;push	esi
  1898                              <1> ;	;push	ebx
  1899                              <1> ;	;xor	ebx, ebx
  1900                              <1> ;	;mov	bl, [ptty]  ; active_page
  1901                              <1> ;	;mov	esi, ebx
  1902                              <1> ;	;shl 	si, 1
  1903                              <1> ;	;add	esi, ttychr
  1904                              <1> ;getch_1:
  1905                              <1> ;	;mov	ax, [esi]
  1906                              <1> ;	mov	ax, [ttychr] ; video page 0 (tty0)
  1907                              <1> ;	and	ax, ax
  1908                              <1> ;	jz	short getch_2
  1909                              <1> ;	mov	word [ttychr], 0
  1910                              <1> ;	;mov	word [esi], 0
  1911                              <1> ;	;pop	ebx
  1912                              <1> ;	;pop	esi
  1913                              <1> ;	retn
  1914                              <1> ;getch_2:
  1915                              <1> ;	hlt	; not proper for multi tasking!
  1916                              <1> ;		; (temporary halt for now)
  1917                              <1> ;		; 'sleep' on tty 
  1918                              <1> ;		; will (must) be located here		
  1919                              <1> ;	nop
  1920                              <1> ;	jmp	short getch_1
  1921                              <1> 
  1922                              <1> keyb_int:
  1923                              <1> 	; 23/02/2022
  1924                              <1> 	; 30/06/2015
  1925                              <1> 	; 25/02/2015
  1926                              <1> 	; 20/02/2015
  1927                              <1> 	; 03/12/2014 (getc_int - INT 16h modifications)
  1928                              <1> 	; 07/09/2014 - Retro UNIX 386 v1
  1929                              <1> 	; 30/06/2014
  1930                              <1> 	; 10/05/2013	
  1931                              <1>       	; Retro Unix 8086 v1 feature only!
  1932                              <1> 	; 03/03/2014
  1933                              <1> 	
  1934 00000B64 1E                  <1> 	push	ds
  1935 00000B65 53                  <1> 	push	ebx
  1936 00000B66 50                  <1> 	push	eax
  1937                              <1> 	;
  1938                              <1> 	; 23/02/2022
  1939 00000B67 9C                  <1> 	pushfd
  1940 00000B68 0E                  <1> 	push	cs
  1941                              <1> 	;mov	ax, KDATA
  1942 00000B69 31C0                <1> 	xor	eax, eax
  1943 00000B6B B010                <1> 	mov	al, KDATA
  1944 00000B6D 8ED8                <1> 	mov	ds, ax
  1945                              <1> 	;
  1946                              <1> 	;pushfd
  1947                              <1> 	;push	cs
  1948 00000B6F E810020000          <1> 	call	kb_int   ; int_09h
  1949                              <1> 	;
  1950 00000B74 B411                <1> 	mov	ah, 11h	 ; 03/12/2014	
  1951                              <1> 	;call	getc
  1952 00000B76 E854000000          <1> 	call	int_16h  ; 30/06/2015
  1953 00000B7B 744E                <1> 	jz	short keyb_int4
  1954                              <1> 	;
  1955 00000B7D B410                <1> 	mov	ah, 10h	 ; 03/12/2014
  1956                              <1> 	;call	getc
  1957 00000B7F E84B000000          <1> 	call	int_16h  ; 30/06/2015
  1958                              <1> 	;
  1959                              <1> 	; 20/02/2015
  1960 00000B84 0FB61D[066B0000]    <1>         movzx   ebx, byte [ptty]  ; active_page
  1961                              <1> 	;
  1962 00000B8B 20C0                <1> 	and 	al, al
  1963 00000B8D 751D                <1> 	jnz	short keyb_int1
  1964                              <1> 	;
  1965 00000B8F 80FC68              <1> 	cmp	ah, 68h	 ; ALT + F1 key
  1966 00000B92 7218                <1> 	jb	short keyb_int1
  1967 00000B94 80FC6F              <1> 	cmp	ah, 6Fh  ; ALT + F8 key	
  1968 00000B97 7713                <1> 	ja	short keyb_int1
  1969                              <1> 	;
  1970 00000B99 88D8                <1> 	mov	al, bl
  1971 00000B9B 0468                <1> 	add	al, 68h
  1972 00000B9D 38E0                <1> 	cmp	al, ah
  1973 00000B9F 7409                <1> 	je	short keyb_int0
  1974 00000BA1 88E0                <1> 	mov	al, ah
  1975 00000BA3 2C68                <1> 	sub	al, 68h
  1976 00000BA5 E83F0A0000          <1> 	call	tty_sw
  1977                              <1> 	;movzx	ebx, [ptty]  ; active_page
  1978                              <1> keyb_int0: ; 30/06/2015
  1979                              <1> 	;xor	ax, ax
  1980                              <1> 	; 23/02/2022
  1981 00000BAA 31C0                <1> 	xor	eax, eax
  1982                              <1> keyb_int1:
  1983 00000BAC D0E3                <1> 	shl	bl, 1
  1984 00000BAE 81C3[086B0000]      <1> 	add	ebx, ttychr
  1985                              <1> 	;
  1986                              <1> 	;23/02/2022
  1987 00000BB4 09C0                <1> 	or	eax, eax
  1988                              <1> 	;or	ax, ax
  1989 00000BB6 7406                <1> 	jz	short keyb_int2
  1990                              <1> 	;
  1991 00000BB8 66833B00            <1> 	cmp 	word [ebx], 0
  1992 00000BBC 7703                <1>         ja      short keyb_int3 
  1993                              <1> keyb_int2:
  1994 00000BBE 668903              <1>         mov	[ebx], ax  ; Save ascii code
  1995                              <1> 			   ; and scan code of the character
  1996                              <1> 			   ; for current tty (or last tty
  1997                              <1> 			   ; just before tty switch).
  1998                              <1> keyb_int3:
  1999 00000BC1 A0[066B0000]        <1>         mov     al, [ptty]
  2000 00000BC6 E8BD430000          <1> 	call	wakeup
  2001                              <1> 	;
  2002                              <1> keyb_int4:
  2003 00000BCB 58                  <1> 	pop	eax
  2004 00000BCC 5B                  <1> 	pop	ebx
  2005 00000BCD 1F                  <1> 	pop	ds
  2006 00000BCE CF                  <1> 	iret
  2007                              <1> 
  2008                              <1> ; 18/02/2015
  2009                              <1> ; REMINDER: Only 'keyb_int' (IRQ 9) must call getc.
  2010                              <1> ; 'keyb_int' always handles 'getc' at 1st and puts the
  2011                              <1> ; scancode and ascii code of the character 
  2012                              <1> ; in the tty input (ttychr) buffer. 
  2013                              <1> ; Test procedures must call 'getch' for tty input
  2014                              <1> ; otherwise, 'getc' will not be able to return to the caller
  2015                              <1> ; due to infinite (key press) waiting loop.
  2016                              <1> ; 
  2017                              <1> ; 03/12/2014
  2018                              <1> ; 26/08/2014
  2019                              <1> ; KEYBOARD I/O
  2020                              <1> ; (INT_16h - Retro UNIX 8086 v1 - U9.ASM, 30/06/2014)
  2021                              <1> 
  2022                              <1> ;NOTE: 'k0' to 'k7' are name of OPMASK registers.
  2023                              <1> ;	(The reason of using '_k' labels!!!) (27/08/2014)    
  2024                              <1> ;NOTE: 'NOT' keyword is '~' unary operator in NASM.
  2025                              <1> ;	('NOT LC_HC' --> '~LC_HC') (bit reversing operator)
  2026                              <1> 
  2027                              <1> int_16h: ; 30/06/2015
  2028                              <1> ;getc:
  2029 00000BCF 9C                  <1> 	pushfd	; 28/08/2014
  2030 00000BD0 0E                  <1> 	push 	cs
  2031 00000BD1 E826000000          <1> 	call 	getc_int
  2032 00000BD6 C3                  <1> 	retn
  2033                              <1> 
  2034                              <1> ; 24/12/2021
  2035                              <1> 
  2036                              <1> 	;-----	SHIFT STATUS
  2037                              <1> _K3E:                                   ; GET THE EXTENDED SHIFT STATUS FLAGS
  2038 00000BD7 8A25[04650000]      <1> 	mov	ah, [KB_FLAG_1]		; GET SYSTEM SHIFT KEY STATUS
  2039 00000BDD 80E404              <1> 	and	ah, SYS_SHIFT		; MASK ALL BUT SYS KEY BIT
  2040                              <1> 	;mov	cl, 5			; SHIFT THEW SYSTEMKEY BIT OVER TO
  2041                              <1> 	;shl	ah, cl			; BIT 7 POSITION
  2042 00000BE0 C0E405              <1>         shl	ah, 5
  2043 00000BE3 A0[04650000]        <1> 	mov	al, [KB_FLAG_1]		; GET SYSTEM SHIFT STATES BACK
  2044 00000BE8 2473                <1> 	and	al, 01110011b		; ELIMINATE SYS SHIFT, HOLD_STATE AND INS_SHIFT
  2045 00000BEA 08C4                <1> 	or	ah, al                  ; MERGE REMAINING BITS INTO AH
  2046 00000BEC A0[06650000]        <1> 	mov	al, [KB_FLAG_3]		; GET RIGHT CTL AND ALT
  2047 00000BF1 240C                <1> 	and	al, 00001100b		; ELIMINATE LC_E0 AND LC_E1
  2048 00000BF3 08C4                <1> 	or	ah, al			; OR THE SHIFT FLAGS TOGETHER
  2049                              <1> _K3:
  2050 00000BF5 A0[03650000]        <1> 	mov	al, [KB_FLAG]		; GET THE SHIFT STATUS FLAGS
  2051 00000BFA EB2B                <1> 	jmp	short _KIO_EXIT		; RETURN TO CALLER
  2052                              <1> 
  2053                              <1> getc_int:
  2054                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2055                              <1> 	; 28/02/2015
  2056                              <1> 	; 03/12/2014 (derivation from pc-xt-286 bios source code -1986-, 
  2057                              <1> 	;	      instead of pc-at bios - 1985-)
  2058                              <1> 	; 28/08/2014 (_k1d)
  2059                              <1> 	; 30/06/2014
  2060                              <1> 	; 03/03/2014
  2061                              <1> 	; 28/02/2014
  2062                              <1> 	; Derived from "KEYBOARD_IO_1" procedure of IBM "pc-xt-286" 
  2063                              <1> 	; rombios source code (21/04/1986)
  2064                              <1> 	;	 'keybd.asm', INT 16H, KEYBOARD_IO
  2065                              <1> 	;
  2066                              <1> 	; KYBD --- 03/06/86  KEYBOARD BIOS
  2067                              <1> 	;
  2068                              <1> 	;--- INT 16 H -----------------------------------------------------------------
  2069                              <1> 	; KEYBOARD I/O								      :
  2070                              <1> 	;	THESE ROUTINES PROVIDE READ KEYBOARD SUPPORT			      :
  2071                              <1> 	; INPUT									      :
  2072                              <1> 	;	(AH)= 00H  READ THE NEXT ASCII CHARACTER ENTERED FROM THE KEYBOARD,   :
  2073                              <1> 	;		   RETURN THE RESULT IN (AL), SCAN CODE IN (AH).              :
  2074                              <1> 	;		   THIS IS THE COMPATIBLE READ INTERFACE, EQUIVALENT TO THE   :
  2075                              <1> 	;                  STANDARD PC OR PCAT KEYBOARD				      :	
  2076                              <1> 	;-----------------------------------------------------------------------------:
  2077                              <1> 	;	(AH)= 01H  SET THE ZERO FLAG TO INDICATE IF AN ASCII CHARACTER IS     :
  2078                              <1> 	;		   AVAILABLE TO BE READ FROM THE KEYBOARD BUFFER.	      :
  2079                              <1> 	;		   (ZF)= 1 -- NO CODE AVAILABLE			              :
  2080                              <1> 	;		   (ZF)= 0 -- CODE IS AVAILABLE  (AX)= CHARACTER              :
  2081                              <1> 	;		   IF (ZF)= 0, THE NEXT CHARACTER IN THE BUFFER TO BE READ IS :
  2082                              <1> 	;		   IN (AX), AND THE ENTRY REMAINS IN THE BUFFER.              :
  2083                              <1> 	;		   THIS WILL RETURN ONLY PC/PCAT KEYBOARD COMPATIBLE CODES    :
  2084                              <1> 	;-----------------------------------------------------------------------------:	
  2085                              <1> 	;	(AH)= 02H  RETURN THE CURRENT SHIFT STATUS IN AL REGISTER             :
  2086                              <1> 	;		   THE BIT SETTINGS FOR THIS CODE ARE INDICATED IN THE        :
  2087                              <1> 	;		   EQUATES FOR @KB_FLAG		                              :
  2088                              <1> 	;-----------------------------------------------------------------------------:	
  2089                              <1> 	;	(AH)= 03H  SET TYPAMATIC RATE AND DELAY                               :
  2090                              <1> 	;	      (AL) = 05H                                                      :
  2091                              <1> 	;	      (BL) = TYPAMATIC RATE (BITS 5 - 7 MUST BE RESET TO 0)           :
  2092                              <1> 	;		       							      :
  2093                              <1> 	;                     REGISTER     RATE      REGISTER     RATE                :
  2094                              <1> 	;                      VALUE     SELECTED     VALUE     SELECTED              :
  2095                              <1> 	;                     --------------------------------------------            :
  2096                              <1> 	;			00H        30.0        10H        7.5                 :
  2097                              <1> 	;			01H        26.7        11H        6.7                 :
  2098                              <1> 	;			02H        24.0        12H        6.0                 :
  2099                              <1> 	;			03H        21.8        13H        5.5                 :
  2100                              <1> 	;			04H        20.0        14H        5.0                 :
  2101                              <1> 	;			05H        18.5        15H        4.6                 :
  2102                              <1> 	;			06H        17.1        16H        4.3                 :
  2103                              <1> 	;			07H        16.0        17H        4.0                 :
  2104                              <1> 	;			08H        15.0        18H        3.7                 :
  2105                              <1> 	;			09H        13.3        19H        3.3                 :
  2106                              <1> 	;			0AH        12.0        1AH        3.0                 :
  2107                              <1> 	;			0BH        10.9        1BH        2.7                 :
  2108                              <1>         ;			0CH        10.0        1CH        2.5                 :
  2109                              <1> 	;			0DH         9.2        1DH        2.3                 :
  2110                              <1> 	;			0EH         8.6        1EH        2.1                 :
  2111                              <1> 	;			0FH         8.0        1FH        2.0                 :
  2112                              <1> 	;									      :
  2113                              <1> 	;	      (BH) = TYPAMATIC DELAY  (BITS 2 - 7 MUST BE RESET TO 0)         :
  2114                              <1> 	;		       							      :
  2115                              <1> 	;                     REGISTER     DELAY                                      :
  2116                              <1> 	;                      VALUE       VALUE                                      :
  2117                              <1> 	;                     ------------------                                      :
  2118                              <1> 	;			00H        250 ms                                     :
  2119                              <1> 	;			01H        500 ms                                     :
  2120                              <1> 	;			02H        750 ms                                     :
  2121                              <1> 	;			03H       1000 ms                                     :
  2122                              <1> 	;-----------------------------------------------------------------------------:
  2123                              <1> 	;	(AH)= 05H  PLACE ASCII CHARACTER/SCAN CODE COMBINATION IN KEYBOARD    :
  2124                              <1> 	;		   BUFFER AS IF STRUCK FROM KEYBOARD                          :
  2125                              <1> 	;		   ENTRY:  (CL) = ASCII CHARACTER		              :
  2126                              <1> 	;		           (CH) = SCAN CODE                                   :
  2127                              <1> 	;		   EXIT:   (AH) = 00H = SUCCESSFUL OPERATION                  :
  2128                              <1> 	;		           (AL) = 01H = UNSUCCESSFUL - BUFFER FULL            :
  2129                              <1> 	;		   FLAGS:  CARRY IF ERROR                                     :
  2130                              <1> 	;-----------------------------------------------------------------------------:		
  2131                              <1> 	;	(AH)= 10H  EXTENDED READ INTERFACE FOR THE ENHANCED KEYBOARD,         :
  2132                              <1> 	;		   OTHERWISE SAME AS FUNCTION AH=0                            :
  2133                              <1> 	;-----------------------------------------------------------------------------:
  2134                              <1> 	;	(AH)= 11H  EXTENDED ASCII STATUS FOR THE ENHANCED KEYBOARD,           :
  2135                              <1> 	;		   OTHERWISE SAME AS FUNCTION AH=1                            :
  2136                              <1> 	;-----------------------------------------------------------------------------:	
  2137                              <1> 	;	(AH)= 12H  RETURN THE EXTENDED SHIFT STATUS IN AX REGISTER            :
  2138                              <1> 	;		   AL = BITS FROM KB_FLAG, AH = BITS FOR LEFT AND RIGHT       :
  2139                              <1> 	;		   CTL AND ALT KEYS FROM KB_FLAG_1 AND KB_FLAG_3              :
  2140                              <1> 	; OUTPUT					                              :
  2141                              <1> 	;	AS NOTED ABOVE, ONLY (AX) AND FLAGS CHANGED	                      :
  2142                              <1> 	;	ALL REGISTERS RETAINED		                                      :
  2143                              <1> 	;------------------------------------------------------------------------------
  2144                              <1> 	
  2145 00000BFC FB                  <1> 	sti				; INTERRUPTS BACK ON
  2146 00000BFD 1E                  <1> 	push	ds			; SAVE CURRENT DS
  2147 00000BFE 53                  <1> 	push	ebx			; SAVE BX TEMPORARILY
  2148                              <1> 	;push	ecx			; SAVE CX TEMPORARILY
  2149 00000BFF 66BB1000            <1>         mov     bx, KDATA 
  2150 00000C03 8EDB                <1> 	mov	ds, bx			; PUT SEGMENT VALUE OF DATA AREA INTO DS
  2151 00000C05 08E4                <1> 	or	ah, ah			; CHECK FOR (AH)= 00H
  2152 00000C07 742D                <1> 	jz	short _K1		; ASCII_READ
  2153 00000C09 FECC                <1> 	dec	ah                      ; CHECK FOR (AH)= 01H
  2154 00000C0B 7446                <1>         jz      short _K2               ; ASCII_STATUS
  2155 00000C0D FECC                <1> 	dec	ah			; CHECK FOR (AH)= 02H
  2156 00000C0F 74E4                <1>         jz      short _K3               ; SHIFT STATUS
  2157 00000C11 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 03H	
  2158 00000C13 745B                <1>         jz      short _K300             ; SET TYPAMATIC RATE/DELAY
  2159 00000C15 80EC02              <1> 	sub	ah, 2			; CHECK FOR (AH)= 05H	
  2160 00000C18 7479                <1>         jz      short _K500             ; KEYBOARD WRITE         
  2161                              <1> _KIO1:	
  2162 00000C1A 80EC0B              <1> 	sub	ah, 11			; AH =  10H
  2163 00000C1D 740B                <1> 	jz	short _K1E		; EXTENDED ASCII READ
  2164 00000C1F FECC                <1> 	dec	ah			; CHECK FOR (AH)= 11H
  2165 00000C21 7421                <1> 	jz	short _K2E		; EXTENDED_ASCII_STATUS
  2166 00000C23 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 12H
  2167 00000C25 74B0                <1> 	jz	short _K3E		; EXTENDED_SHIFT_STATUS
  2168                              <1> _KIO_EXIT:
  2169                              <1> 	;pop	ecx			; RECOVER REGISTER
  2170 00000C27 5B                  <1> 	pop	ebx			; RECOVER REGISTER
  2171 00000C28 1F                  <1> 	pop	ds			; RECOVER SEGMENT
  2172 00000C29 CF                  <1> 	iretd				; INVALID COMMAND, EXIT
  2173                              <1> 
  2174                              <1> 	;-----	ASCII CHARACTER
  2175                              <1> _K1E:	
  2176 00000C2A E891000000          <1> 	call	_K1S			; GET A CHARACTER FROM THE BUFFER (EXTENDED)
  2177 00000C2F E804010000          <1> 	call	_KIO_E_XLAT		; ROUTINE TO XLATE FOR EXTENDED CALLS
  2178 00000C34 EBF1                <1> 	jmp	short _KIO_EXIT         ; GIVE IT TO THE CALLER
  2179                              <1> _K1:	
  2180 00000C36 E885000000          <1> 	call	_K1S			; GET A CHARACTER FROM THE BUFFER
  2181 00000C3B E803010000          <1> 	call	_KIO_S_XLAT		; ROUTINE TO XLATE FOR STANDARD CALLS
  2182 00000C40 72F4                <1> 	jc	short _K1		; CARRY SET MEANS TROW CODE AWAY
  2183                              <1> _K1A:
  2184 00000C42 EBE3                <1> 	jmp	short _KIO_EXIT         ; RETURN TO CALLER
  2185                              <1> 
  2186                              <1> 	;-----	ASCII STATUS
  2187                              <1> _K2E:	
  2188 00000C44 E8C2000000          <1> 	call	_K2S			; TEST FOR CHARACTER IN BUFFER (EXTENDED)
  2189 00000C49 7420                <1> 	jz	short _K2B		; RETURN IF BUFFER EMPTY
  2190 00000C4B 9C                  <1> 	pushf				; SAVE ZF FROM TEST
  2191 00000C4C E8E7000000          <1> 	call	_KIO_E_XLAT		; ROUTINE TO XLATE FOR EXTENDED CALLS
  2192 00000C51 EB17                <1> 	jmp	short _K2A	        ; GIVE IT TO THE CALLER
  2193                              <1> _K2:	
  2194 00000C53 E8B3000000          <1> 	call	_K2S			; TEST FOR CHARACTER IN BUFFER
  2195 00000C58 7411                <1> 	jz	short _K2B		; RETURN IF BUFFER EMPTY
  2196 00000C5A 9C                  <1> 	pushf				; SAVE ZF FROM TEST
  2197 00000C5B E8E3000000          <1> 	call	_KIO_S_XLAT		; ROUTINE TO XLATE FOR STANDARD CALLS
  2198 00000C60 7308                <1> 	jnc	short _K2A	        ; CARRY CLEAR MEANS PASS VALID CODE
  2199 00000C62 9D                  <1> 	popf				; INVALID CODE FOR THIS TYPE OF CALL
  2200 00000C63 E858000000          <1> 	call	_K1S			; THROW THE CHARACTER AWAY
  2201 00000C68 EBE9                <1> 	jmp	short _K2		; GO LOOK FOR NEXT CHAR, IF ANY
  2202                              <1> _K2A:
  2203 00000C6A 9D                  <1> 	popf				; RESTORE ZF FROM TEST
  2204                              <1> _K2B:
  2205                              <1> 	;pop	ecx			; RECOVER REGISTER
  2206 00000C6B 5B                  <1> 	pop	ebx			; RECOVER REGISTER
  2207 00000C6C 1F                  <1> 	pop	ds			; RECOVER SEGMENT
  2208 00000C6D CA0400              <1> 	retf	4			; THROW AWAY (e)FLAGS
  2209                              <1> 
  2210                              <1> ; 24/12/2021
  2211                              <1> ;	;-----	SHIFT STATUS
  2212                              <1> ;_K3E:                                  ; GET THE EXTENDED SHIFT STATUS FLAGS
  2213                              <1> ;	mov	ah, [KB_FLAG_1]		; GET SYSTEM SHIFT KEY STATUS
  2214                              <1> ;	and	ah, SYS_SHIFT		; MASK ALL BUT SYS KEY BIT
  2215                              <1> ;	;mov	cl, 5			; SHIFT THEW SYSTEMKEY BIT OVER TO
  2216                              <1> ;	;shl	ah, cl			; BIT 7 POSITION
  2217                              <1> ;       shl	ah, 5
  2218                              <1> ;	mov	al, [KB_FLAG_1]		; GET SYSTEM SHIFT STATES BACK
  2219                              <1> ;	and	al, 01110011b		; ELIMINATE SYS SHIFT, HOLD_STATE AND INS_SHIFT
  2220                              <1> ;	or	ah, al                  ; MERGE REMAINING BITS INTO AH
  2221                              <1> ;	mov	al, [KB_FLAG_3]		; GET RIGHT CTL AND ALT
  2222                              <1> ;	and	al, 00001100b		; ELIMINATE LC_E0 AND LC_E1
  2223                              <1> ;	or	ah, al			; OR THE SHIFT FLAGS TOGETHER
  2224                              <1> ;_K3:
  2225                              <1> ;	mov	al, [KB_FLAG]		; GET THE SHIFT STATUS FLAGS
  2226                              <1> ;	jmp	short _KIO_EXIT		; RETURN TO CALLER
  2227                              <1> 
  2228                              <1> 	;-----	SET TYPAMATIC RATE AND DELAY
  2229                              <1> _K300:
  2230 00000C70 3C05                <1> 	cmp	al, 5			; CORRECT FUNCTION CALL?
  2231 00000C72 75B3                <1> 	jne	short _KIO_EXIT		; NO, RETURN
  2232 00000C74 F6C3E0              <1>      	test	bl, 0E0h		; TEST FOR OUT-OF-RANGE RATE
  2233 00000C77 75AE                <1> 	jnz	short _KIO_EXIT		; RETURN IF SO
  2234 00000C79 F6C7FC              <1> 	test	BH, 0FCh		; TEST FOR OUT-OF-RANGE DELAY
  2235 00000C7C 75A9                <1> 	jnz	short _KIO_EXIT		; RETURN IF SO
  2236 00000C7E B0F3                <1> 	mov	al, KB_TYPA_RD		; COMMAND FOR TYPAMATIC RATE/DELAY		
  2237 00000C80 E880060000          <1> 	call	SND_DATA		; SEND TO KEYBOARD	
  2238                              <1> 	;mov	cx, 5			; SHIFT COUNT
  2239                              <1> 	;shl	bh, cl			; SHIFT DELAY OVER
  2240 00000C85 C0E705              <1> 	shl	bh, 5
  2241 00000C88 88D8                <1> 	mov	al, bl			; PUT IN RATE
  2242 00000C8A 08F8                <1> 	or	al, bh			; AND DELAY
  2243 00000C8C E874060000          <1> 	call	SND_DATA		; SEND TO KEYBOARD	
  2244 00000C91 EB94                <1>         jmp     _KIO_EXIT               ; RETURN TO CALLER
  2245                              <1> 
  2246                              <1> 	;-----	WRITE TO KEYBOARD BUFFER
  2247                              <1> _K500:
  2248 00000C93 56                  <1> 	push	esi			; SAVE SI (esi)
  2249 00000C94 FA                  <1> 	cli				; 
  2250 00000C95 8B1D[14650000]      <1>      	mov	ebx, [BUFFER_TAIL]	; GET THE 'IN TO' POINTER TO THE BUFFER
  2251 00000C9B 89DE                <1> 	mov	esi, ebx		; SAVE A COPY IN CASE BUFFER NOT FULL
  2252 00000C9D E8D1000000          <1> 	call	_K4			; BUMP THE POINTER TO SEE IF BUFFER IS FULL
  2253 00000CA2 3B1D[10650000]      <1> 	cmp	ebx, [BUFFER_HEAD]	; WILL THE BUFFER OVERRUN IF WE STORE THIS?
  2254 00000CA8 740D                <1> 	je	short _K502		; YES - INFORM CALLER OF ERROR		
  2255 00000CAA 66890E              <1> 	mov	[esi], cx		; NO - PUT ASCII/SCAN CODE INTO BUFFER	
  2256 00000CAD 891D[14650000]      <1> 	mov	[BUFFER_TAIL], ebx	; ADJUST 'IN TO' POINTER TO REFLECT CHANGE
  2257 00000CB3 28C0                <1> 	sub	al, al			; TELL CALLER THAT OPERATION WAS SUCCESSFUL
  2258 00000CB5 EB02                <1> 	jmp	short _K504		; SUB INSTRUCTION ALSO RESETS CARRY FLAG
  2259                              <1> _K502:
  2260 00000CB7 B001                <1> 	mov	al, 01h			; BUFFER FULL INDICATION
  2261                              <1> _K504:
  2262 00000CB9 FB                  <1> 	sti				
  2263 00000CBA 5E                  <1> 	pop	esi			; RECOVER SI (esi)
  2264 00000CBB E967FFFFFF          <1>         jmp     _KIO_EXIT               ; RETURN TO CALLER WITH STATUS IN AL
  2265                              <1> 
  2266                              <1> 	;-----	READ THE KEY TO FIGURE OUT WHAT TO DO -----
  2267                              <1> _K1S:
  2268 00000CC0 FA                  <1> 	cli	; 03/12/2014
  2269 00000CC1 8B1D[10650000]      <1>         mov     ebx, [BUFFER_HEAD] 	; GET POINTER TO HEAD OF BUFFER
  2270 00000CC7 3B1D[14650000]      <1>         cmp     ebx, [BUFFER_TAIL] 	; TEST END OF BUFFER
  2271                              <1> 	;jne	short _K1U		; IF ANYTHING IN BUFFER SKIP INTERRUPT
  2272 00000CCD 750F                <1> 	jne	short _k1x ; 03/12/2014
  2273                              <1> 	;
  2274                              <1> 	; 03/12/2014
  2275                              <1> 	; 28/08/2014
  2276                              <1> 	; PERFORM OTHER FUNCTION ?? here !
  2277                              <1> 	;; MOV	AX, 9002h		; MOVE IN WAIT CODE & TYPE
  2278                              <1> 	;; INT 	15H			; PERFORM OTHER FUNCTION
  2279                              <1> _K1T:                                   ; ASCII READ
  2280 00000CCF FB                  <1> 	sti				; INTERRUPTS BACK ON DURING LOOP
  2281 00000CD0 90                  <1> 	nop				; ALLOW AN INTERRUPT TO OCCUR
  2282                              <1> _K1U:	
  2283 00000CD1 FA                  <1> 	cli				; INTERRUPTS BACK OFF
  2284 00000CD2 8B1D[10650000]      <1>         mov    	ebx, [BUFFER_HEAD] 	; GET POINTER TO HEAD OF BUFFER
  2285 00000CD8 3B1D[14650000]      <1>         cmp     ebx, [BUFFER_TAIL] 	; TEST END OF BUFFER
  2286                              <1> _k1x:
  2287 00000CDE 53                  <1> 	push	ebx			; SAVE ADDRESS		
  2288 00000CDF 9C                  <1> 	pushf				; SAVE FLAGS
  2289 00000CE0 E8D4060000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2290 00000CE5 8A1D[05650000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2291 00000CEB 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2292 00000CED 80E307              <1> 	and	bl, 07h	; KB_LEDS	; ISOLATE INDICATOR BITS
  2293 00000CF0 7406                <1> 	jz	short _K1V		; IF NO CHANGE BYPASS UPDATE
  2294 00000CF2 E86E060000          <1> 	call	SND_LED1
  2295 00000CF7 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2296                              <1> _K1V:
  2297 00000CF8 9D                  <1> 	popf				; RESTORE FLAGS
  2298 00000CF9 5B                  <1> 	pop	ebx			; RESTORE ADDRESS
  2299 00000CFA 74D3                <1>         je      short _K1T              ; LOOP UNTIL SOMETHING IN BUFFER
  2300                              <1> 	;
  2301 00000CFC 668B03              <1> 	mov	ax, [ebx] 		; GET SCAN CODE AND ASCII CODE
  2302 00000CFF E86F000000          <1>         call    _K4                     ; MOVE POINTER TO NEXT POSITION
  2303 00000D04 891D[10650000]      <1>         mov     [BUFFER_HEAD], ebx      ; STORE VALUE IN VARIABLE
  2304 00000D0A C3                  <1> 	retn				; RETURN
  2305                              <1> 
  2306                              <1> 	;-----	READ THE KEY TO SEE IF ONE IS PRESENT -----
  2307                              <1> _K2S:
  2308 00000D0B FA                  <1> 	cli				; INTERRUPTS OFF
  2309 00000D0C 8B1D[10650000]      <1>         mov     ebx, [BUFFER_HEAD]      ; GET HEAD POINTER
  2310 00000D12 3B1D[14650000]      <1>         cmp     ebx, [BUFFER_TAIL]      ; IF EQUAL (Z=1) THEN NOTHING THERE
  2311 00000D18 668B03              <1> 	mov	ax, [ebx]
  2312 00000D1B 9C                  <1> 	pushf				; SAVE FLAGS
  2313                              <1> 	;push	ax			; SAVE CODE
  2314                              <1> 	; 24/12/2021
  2315 00000D1C 50                  <1> 	push	eax
  2316 00000D1D E897060000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2317 00000D22 8A1D[05650000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2318 00000D28 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2319 00000D2A 80E307              <1> 	and	bl, 07h ; KB_LEDS	; ISOLATE INDICATOR BITS
  2320 00000D2D 7405                <1> 	jz	short _K2T		; IF NO CHANGE BYPASS UPDATE
  2321 00000D2F E81A060000          <1> 	call	SND_LED			; GO TURN ON MODE INDICATORS
  2322                              <1> _K2T:
  2323                              <1> 	;pop	ax			; RESTORE CODE
  2324                              <1> 	; 24/12/2021
  2325 00000D34 58                  <1> 	pop	eax
  2326 00000D35 9D                  <1> 	popf				; RESTORE FLAGS
  2327 00000D36 FB                  <1> 	sti				; INTERRUPTS BACK ON
  2328 00000D37 C3                  <1> 	retn				; RETURN
  2329                              <1> 
  2330                              <1> 	;-----	ROUTINE TO TRANSLATE SCAN CODE PAIRS FOR EXTENDED CALLS -----
  2331                              <1> _KIO_E_XLAT:
  2332 00000D38 3CF0                <1> 	cmp	al, 0F0h		; IS IT ONE OF THE FILL-INs?
  2333 00000D3A 7506                <1> 	jne	short _KIO_E_RET	; NO, PASS IT ON
  2334 00000D3C 08E4                <1>         or 	ah, ah			; AH = 0 IS SPECIAL CASE
  2335 00000D3E 7402                <1>         jz	short _KIO_E_RET        ; PASS THIS ON UNCHANGED
  2336 00000D40 30C0                <1> 	xor	al, al			; OTHERWISE SET AL = 0
  2337                              <1> _KIO_E_RET:				
  2338 00000D42 C3                  <1> 	retn				; GO BACK
  2339                              <1> 
  2340                              <1> 	;-----	ROUTINE TO TRANSLATE SCAN CODE PAIRS FOR STANDARD CALLS -----
  2341                              <1> _KIO_S_XLAT:
  2342 00000D43 80FCE0              <1> 	cmp	ah, 0E0h		; IS IT KEYPAD ENTER OR / ?
  2343 00000D46 750F                <1> 	jne	short _KIO_S2		; NO, CONTINUE
  2344 00000D48 3C0D                <1> 	cmp	al, 0Dh			; KEYPAD ENTER CODE?
  2345 00000D4A 7408                <1>         je	short _KIO_S1		; YES, MASSAGE A BIT
  2346 00000D4C 3C0A                <1> 	cmp	al, 0Ah			; CTRL KEYPAD ENTER CODE?
  2347 00000D4E 7404                <1>         je	short _KIO_S1		; YES, MASSAGE THE SAME
  2348 00000D50 B435                <1> 	mov	ah, 35h			; NO, MUST BE KEYPAD /
  2349                              <1> _kio_ret: ; 03/12/2014
  2350 00000D52 F8                  <1> 	clc
  2351 00000D53 C3                  <1> 	retn
  2352                              <1> 	;jmp	short _KIO_USE		; GIVE TO CALLER
  2353                              <1> _KIO_S1:				
  2354 00000D54 B41C                <1> 	mov	ah, 1Ch			; CONVERT TO COMPATIBLE OUTPUT
  2355                              <1> 	;jmp	short _KIO_USE		; GIVE TO CALLER
  2356 00000D56 C3                  <1> 	retn
  2357                              <1> _KIO_S2:		
  2358 00000D57 80FC84              <1> 	cmp	ah, 84h			; IS IT ONE OF EXTENDED ONES?
  2359 00000D5A 7715                <1> 	ja	short _KIO_DIS		; YES, THROW AWAY AND GET ANOTHER CHAR
  2360 00000D5C 3CF0                <1> 	cmp	al, 0F0h		; IS IT ONE OF THE FILL-INs?
  2361 00000D5E 7506                <1>         jne	short _KIO_S3		; NO, TRY LAST TEST
  2362 00000D60 08E4                <1> 	or	ah, ah			; AH = 0 IS SPECIAL CASE
  2363 00000D62 740C                <1>         jz	short _KIO_USE		; PASS THIS ON UNCHANGED
  2364 00000D64 EB0B                <1> 	jmp	short _KIO_DIS		; THROW AWAY THE REST
  2365                              <1> _KIO_S3:
  2366 00000D66 3CE0                <1> 	cmp	al, 0E0h		; IS IT AN EXTENSION OF A PREVIOUS ONE?
  2367                              <1> 	;jne	short _KIO_USE		; NO, MUST BE A STANDARD CODE
  2368 00000D68 75E8                <1> 	jne	short _kio_ret
  2369 00000D6A 08E4                <1> 	or	ah, ah			; AH = 0 IS SPECIAL CASE
  2370 00000D6C 7402                <1>         jz	short _KIO_USE		; JUMP IF AH = 0
  2371 00000D6E 30C0                <1> 	xor	al, al			; CONVERT TO COMPATIBLE OUTPUT
  2372                              <1> 	;jmp	short _KIO_USE		; PASS IT ON TO CALLER
  2373                              <1> _KIO_USE:
  2374                              <1> 	;clc				; CLEAR CARRY TO INDICATE GOOD CODE
  2375 00000D70 C3                  <1> 	retn				; RETURN	
  2376                              <1> _KIO_DIS:
  2377 00000D71 F9                  <1> 	stc				; SET CARRY TO INDICATE DISCARD CODE
  2378 00000D72 C3                  <1> 	retn				; RETURN
  2379                              <1> 
  2380                              <1> 	;-----	INCREMENT BUFFER POINTER ROUTINE -----
  2381                              <1> _K4:    
  2382 00000D73 43                  <1> 	inc     ebx
  2383 00000D74 43                  <1> 	inc	ebx			; MOVE TO NEXT WORD IN LIST
  2384 00000D75 3B1D[0C650000]      <1>         cmp     ebx, [BUFFER_END] 	; AT END OF BUFFER?
  2385                              <1>         ;jne    short _K5               ; NO, CONTINUE
  2386 00000D7B 7206                <1> 	jb	short _K5
  2387 00000D7D 8B1D[08650000]      <1>         mov     ebx, [BUFFER_START]     ; YES, RESET TO BUFFER BEGINNING
  2388                              <1> _K5:
  2389 00000D83 C3                  <1> 	retn
  2390                              <1> 
  2391                              <1> ; 20/02/2015
  2392                              <1> ; 05/12/2014
  2393                              <1> ; 26/08/2014
  2394                              <1> ; KEYBOARD (HARDWARE) INTERRUPT -  IRQ LEVEL 1
  2395                              <1> ; (INT_09h - Retro UNIX 8086 v1 - U9.ASM, 07/03/2014)
  2396                              <1> ;
  2397                              <1> ; Derived from "KB_INT_1" procedure of IBM "pc-at" 
  2398                              <1> ; rombios source code (06/10/1985)
  2399                              <1> ; 'keybd.asm', HARDWARE INT 09h - (IRQ Level 1)
  2400                              <1> 
  2401                              <1> ;--------- 8042 COMMANDS -------------------------------------------------------
  2402                              <1> ENA_KBD		equ	0AEh	; ENABLE KEYBOARD COMMAND
  2403                              <1> DIS_KBD		equ	0ADh	; DISABLE KEYBOARD COMMAND
  2404                              <1> SHUT_CMD	equ	0FEh	; CAUSE A SHUTDOWN COMMAND
  2405                              <1> ;--------- 8042 KEYBOARD INTERFACE AND DIAGNOSTIC CONTROL REGISTERS ------------
  2406                              <1> STATUS_PORT	equ	064h	; 8042 STATUS PORT
  2407                              <1> INPT_BUF_FULL	equ	00000010b ; 1 = +INPUT BUFFER FULL
  2408                              <1> PORT_A		equ	060h	; 8042 KEYBOARD SCAN CODE/CONTROL PORT
  2409                              <1> ;---------- 8042 KEYBOARD RESPONSE ---------------------------------------------
  2410                              <1> KB_ACK		equ	0FAh	; ACKNOWLEDGE PROM TRANSMISSION
  2411                              <1> KB_RESEND	equ	0FEh	; RESEND REQUEST
  2412                              <1> KB_OVER_RUN	equ	0FFh	; OVER RUN SCAN CODE
  2413                              <1> ;---------- KEYBOARD/LED COMMANDS ----------------------------------------------
  2414                              <1> KB_ENABLE	equ	0F4h		; KEYBOARD ENABLE
  2415                              <1> LED_CMD		equ	0EDh		; LED WRITE COMMAND
  2416                              <1> KB_TYPA_RD	equ	0F3h		; TYPAMATIC RATE/DELAY COMMAND
  2417                              <1> ;---------- KEYBOARD SCAN CODES ------------------------------------------------
  2418                              <1> NUM_KEY		equ	69		; SCAN CODE FOR	 NUMBER LOCK KEY
  2419                              <1> SCROLL_KEY	equ	70		; SCAN CODE FOR	 SCROLL LOCK KEY
  2420                              <1> ALT_KEY		equ	56		; SCAN CODE FOR	 ALTERNATE SHIFT KEY
  2421                              <1> CTL_KEY		equ	29		; SCAN CODE FOR	 CONTROL KEY
  2422                              <1> CAPS_KEY	equ	58		; SCAN CODE FOR	 SHIFT LOCK KEY
  2423                              <1> DEL_KEY		equ	83		; SCAN CODE FOR	 DELETE KEY
  2424                              <1> INS_KEY		equ	82		; SCAN CODE FOR	 INSERT KEY
  2425                              <1> LEFT_KEY	equ	42		; SCAN CODE FOR	 LEFT SHIFT
  2426                              <1> RIGHT_KEY	equ	54		; SCAN CODE FOR	 RIGHT SHIFT
  2427                              <1> SYS_KEY		equ	84		; SCAN CODE FOR	 SYSTEM KEY
  2428                              <1> ;---------- ENHANCED KEYBOARD SCAN CODES ---------------------------------------
  2429                              <1> ID_1		equ	0ABh		; 1ST ID CHARACTER FOR KBX
  2430                              <1> ID_2		equ	041h		; 2ND ID CHARACTER FOR KBX
  2431                              <1> ID_2A		equ	054h		; ALTERNATE 2ND ID CHARACTER FOR KBX
  2432                              <1> F11_M		equ	87		; F11 KEY MAKE
  2433                              <1> F12_M		equ	88		; F12 KEY MAKE
  2434                              <1> MC_E0		equ	224		; GENERAL MARKER CODE
  2435                              <1> MC_E1		equ	225		; PAUSE KEY MARKER CODE
  2436                              <1> ;---------- FLAG EQUATES WITHIN @KB_FLAG----------------------------------------
  2437                              <1> RIGHT_SHIFT	equ	00000001b	; RIGHT SHIFT KEY DEPRESSED
  2438                              <1> LEFT_SHIFT	equ	00000010b	; LEFT SHIFT KEY DEPRESSED
  2439                              <1> CTL_SHIFT	equ	00000100b	; CONTROL SHIFT KEY DEPRESSED
  2440                              <1> ALT_SHIFT	equ	00001000b	; ALTERNATE SHIFT KEY DEPRESSED
  2441                              <1> SCROLL_STATE	equ	00010000b	; SCROLL LOCK STATE IS ACTIVE
  2442                              <1> NUM_STATE	equ	00100000b	; NUM LOCK STATE IS ACTIVE
  2443                              <1> CAPS_STATE	equ	01000000b	; CAPS LOCK STATE IS ACTIVE
  2444                              <1> INS_STATE	equ	10000000b	; INSERT STATE IS ACTIVE
  2445                              <1> ;---------- FLAG EQUATES WITHIN	@KB_FLAG_1 -------------------------------------
  2446                              <1> L_CTL_SHIFT	equ	00000001b	; LEFT CTL KEY DOWN
  2447                              <1> L_ALT_SHIFT	equ	00000010b	; LEFT ALT KEY DOWN
  2448                              <1> SYS_SHIFT	equ	00000100b	; SYSTEM KEY DEPRESSED AND HELD
  2449                              <1> HOLD_STATE	equ	00001000b	; SUSPEND KEY HAS BEEN TOGGLED
  2450                              <1> SCROLL_SHIFT	equ	00010000b	; SCROLL LOCK KEY IS DEPRESSED
  2451                              <1> NUM_SHIFT	equ	00100000b	; NUM LOCK KEY IS DEPRESSED
  2452                              <1> CAPS_SHIFT	equ	01000000b	; CAPS LOCK KEY IS DEPRE55ED
  2453                              <1> INS_SHIFT	equ	10000000b	; INSERT KEY IS DEPRESSED
  2454                              <1> ;---------- FLAGS EQUATES WITHIN @KB_FLAG_2 -----------------------------------
  2455                              <1> KB_LEDS		equ	00000111b	; KEYBOARD LED STATE BITS
  2456                              <1> ;		equ	00000001b	; SCROLL LOCK INDICATOR
  2457                              <1> ;		equ	00000010b	; NUM LOCK INDICATOR
  2458                              <1> ;		equ	00000100b	; CAPS LOCK INDICATOR
  2459                              <1> ;		equ	00001000b	; RESERVED (MUST BE ZERO)
  2460                              <1> KB_FA		equ	00010000b	; ACKNOWLEDGMENT RECEIVED
  2461                              <1> KB_FE		equ	00100000b	; RESEND RECEIVED FLAG
  2462                              <1> KB_PR_LED	equ	01000000b	; MODE INDICATOR UPDATE
  2463                              <1> KB_ERR		equ	10000000b	; KEYBOARD TRANSMIT ERROR FLAG
  2464                              <1> ;----------- FLAGS EQUATES WITHIN @KB_FLAG_3 -----------------------------------
  2465                              <1> LC_E1		equ	00000001b	; LAST CODE WAS THE E1 HIDDEN CODE
  2466                              <1> LC_E0		equ	00000010b	; LAST CODE WAS THE E0 HIDDEN CODE
  2467                              <1> R_CTL_SHIFT	equ	00000100b	; RIGHT CTL KEY DOWN
  2468                              <1> R_ALT_SHIFT	equ	00001000b	; RIGHT ALT KEY DOWN
  2469                              <1> GRAPH_ON	equ	00001000b	; ALT GRAPHICS KEY DOWN (WT ONLY)	
  2470                              <1> KBX		equ	00010000b	; ENHANCED KEYBOARD INSTALLED
  2471                              <1> SET_NUM_LK	equ	00100000b	; FORCE NUM LOCK IF READ ID AND KBX
  2472                              <1> LC_AB		equ	01000000b	; LAST CHARACTER WAS FIRST ID CHARACTER
  2473                              <1> RD_ID		equ	10000000b	; DOING A READ ID (MUST BE BIT0)
  2474                              <1> ;
  2475                              <1> ;----------- INTERRUPT EQUATES -------------------------------------------------
  2476                              <1> EOI		equ	020h		; END OF INTERRUPT COMMAND TO 8259
  2477                              <1> INTA00		equ	020h		; 8259 PORT
  2478                              <1> 
  2479                              <1> 
  2480                              <1> kb_int:
  2481                              <1> 
  2482                              <1> ; 24/12/2021 (Retro UNIX 386 v1.1)
  2483                              <1> ; 17/10/2015 ('ctrlbrk') 
  2484                              <1> ; 05/12/2014
  2485                              <1> ; 04/12/2014 (derivation from pc-xt-286 bios source code -1986-, 
  2486                              <1> 	;	      instead of pc-at bios - 1985-)
  2487                              <1> ; 26/08/2014
  2488                              <1> ;
  2489                              <1> ; 03/06/86  KEYBOARD BIOS
  2490                              <1> ;
  2491                              <1> ;--- HARDWARE INT 09H -- (IRQ LEVEL 1) ------------------------------------------
  2492                              <1> ;										;
  2493                              <1> ;	KEYBOARD INTERRUPT ROUTINE						;
  2494                              <1> ;										;
  2495                              <1> ;--------------------------------------------------------------------------------
  2496                              <1> 
  2497                              <1> KB_INT_1:
  2498 00000D84 FB                  <1> 	sti				; ENABLE INTERRUPTS
  2499                              <1> 	;push	ebp
  2500 00000D85 50                  <1> 	push	eax
  2501 00000D86 53                  <1> 	push	ebx
  2502 00000D87 51                  <1> 	push	ecx
  2503 00000D88 52                  <1> 	push	edx
  2504 00000D89 56                  <1> 	push	esi
  2505 00000D8A 57                  <1> 	push	edi
  2506 00000D8B 1E                  <1> 	push	ds
  2507 00000D8C 06                  <1> 	push	es
  2508 00000D8D FC                  <1> 	cld				; FORWARD DIRECTION
  2509 00000D8E 66B81000            <1> 	mov	ax, KDATA
  2510 00000D92 8ED8                <1> 	mov	ds, ax
  2511 00000D94 8EC0                <1> 	mov	es, ax
  2512                              <1> 	;
  2513                              <1> 	;-----	WAIT FOR KEYBOARD DISABLE COMMAND TO BE ACCEPTED
  2514 00000D96 B0AD                <1> 	mov	al, DIS_KBD		; DISABLE THE KEYBOARD COMMAND
  2515 00000D98 E856050000          <1> 	call	SHIP_IT			; EXECUTE DISABLE
  2516 00000D9D FA                  <1> 	cli				; DISABLE INTERRUPTS
  2517 00000D9E B900000100          <1> 	mov	ecx, 10000h		; SET MAXIMUM TIMEOUT
  2518                              <1> KB_INT_01:
  2519 00000DA3 E464                <1> 	in	al, STATUS_PORT		; READ ADAPTER STATUS
  2520 00000DA5 A802                <1> 	test	al, INPT_BUF_FULL	; CHECK INPUT BUFFER FULL STATUS BIT
  2521 00000DA7 E0FA                <1> 	loopnz	KB_INT_01		; WAIT FOR COMMAND TO BE ACCEPTED
  2522                              <1> 	;
  2523                              <1> 	;-----	READ CHARACTER FROM KEYBOARD INTERFACE
  2524 00000DA9 E460                <1> 	in	al, PORT_A		; READ IN THE CHARACTER
  2525                              <1> 	;
  2526                              <1> 	;-----	SYSTEM HOOK INT 15H - FUNCTION 4FH (ON HARDWARE INT LEVEL 9H) 	
  2527                              <1> 	;MOV	AH, 04FH		; SYSTEM INTERCEPT - KEY CODE FUNCTION
  2528                              <1> 	;STC				; SET CY=1 (IN CASE OF IRET)
  2529                              <1> 	;INT	15H			; CASETTE CALL (AL)=KEY SCAN CODE
  2530                              <1> 	;				; RETURNS CY=1 FOR INVALID FUNCTION
  2531                              <1> 	;JC	KB_INT_02		; CONTINUE IF CARRY FLAG SET ((AL)=CODE)
  2532                              <1> 	;JMP	K26			; EXIT IF SYSTEM HANDLES SCAN CODE
  2533                              <1> 	;				; EXT HANDLES HARDWARE EOI AND ENABLE		
  2534                              <1> 	;
  2535                              <1> 	;-----	CHECK FOR A RESEND COMMAND TO KEYBOARD
  2536                              <1> KB_INT_02:				; 	  (AL)= SCAN CODE
  2537 00000DAB FB                  <1> 	sti				; ENABLE INTERRUPTS AGAIN
  2538 00000DAC 3CFE                <1> 	cmp	al, KB_RESEND		; IS THE INPUT A RESEND
  2539 00000DAE 7411                <1>         je      short KB_INT_4          ; GO IF RESEND
  2540                              <1> 	;
  2541                              <1> 	;-----	CHECK FOR RESPONSE TO A COMMAND TO KEYBOARD
  2542 00000DB0 3CFA                <1> 	cmp	al, KB_ACK		; IS THE INPUT AN ACKNOWLEDGE
  2543 00000DB2 751A                <1>         jne     short KB_INT_2          ; GO IF NOT
  2544                              <1> 	;
  2545                              <1> 	;-----	A COMMAND TO THE KEYBOARD WAS ISSUED
  2546 00000DB4 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2547 00000DB5 800D[05650000]10    <1> 	or	byte [KB_FLAG_2], KB_FA ; INDICATE ACK RECEIVED
  2548 00000DBC E963020000          <1>         jmp     K26                     ; RETURN IF NOT (ACK RETURNED FOR DATA)
  2549                              <1> 	;
  2550                              <1> 	;-----	RESEND THE LAST BYTE
  2551                              <1> KB_INT_4:
  2552 00000DC1 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2553 00000DC2 800D[05650000]20    <1> 	or	byte [KB_FLAG_2], KB_FE ; INDICATE RESEND RECEIVED
  2554 00000DC9 E956020000          <1>         jmp     K26                     ; RETURN IF NOT ACK RETURNED FOR DATA)
  2555                              <1> 	;
  2556                              <1> ;-----	UPDATE MODE INDICATORS IF CHANGE IN STATE
  2557                              <1> KB_INT_2:
  2558                              <1> 	;push 	ax			; SAVE DATA IN
  2559                              <1> 	; 24/12/2021
  2560 00000DCE 50                  <1> 	push	eax
  2561 00000DCF E8E5050000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2562 00000DD4 8A1D[05650000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2563 00000DDA 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2564 00000DDC 80E307              <1> 	and	bl, KB_LEDS		; ISOLATE INDICATOR BITS
  2565 00000DDF 7405                <1> 	jz	short UP0		; IF NO CHANGE BYPASS UPDATE
  2566 00000DE1 E868050000          <1> 	call	SND_LED			; GO TURN ON MODE INDICATORS
  2567                              <1> UP0:
  2568                              <1> 	;pop	ax			; RESTORE DATA IN
  2569                              <1> 	; 24/12/2021
  2570 00000DE6 58                  <1> 	pop	eax
  2571                              <1> ;------------------------------------------------------------------------
  2572                              <1> ;	START OF KEY PROCESSING						;
  2573                              <1> ;------------------------------------------------------------------------
  2574 00000DE7 88C4                <1> 	mov	ah, al			; SAVE SCAN CODE IN AH ALSO
  2575                              <1> 	;
  2576                              <1> 	;-----	TEST FOR OVERRUN SCAN CODE FROM KEYBOARD
  2577 00000DE9 3CFF                <1> 	cmp	al, KB_OVER_RUN		; IS THIS AN OVERRUN CHAR
  2578                              <1>         ;je	K62			; BUFFER_FULL_BEEP
  2579                              <1> 	; 24/12/2021
  2580 00000DEB 7505                <1> 	jne	short K16
  2581 00000DED E9ED040000          <1> 	jmp	K62
  2582                              <1> K16:	
  2583 00000DF2 8A3D[06650000]      <1> 	mov	bh, [KB_FLAG_3]		; LOAD FLAGS FOR TESTING
  2584                              <1> 	;
  2585                              <1> 	;-----	TEST TO SEE IF A READ_ID IS IN PROGRESS
  2586 00000DF8 F6C7C0              <1> 	test 	bh, RD_ID+LC_AB 	; ARE WE DOING A READ ID?
  2587 00000DFB 7442                <1> 	jz	short NOT_ID		; CONTINUE IF NOT
  2588 00000DFD 7914                <1> 	jns	short TST_ID_2		; IS THE RD_ID FLAG ON?
  2589 00000DFF 3CAB                <1> 	cmp	al, ID_1		; IS THIS THE 1ST ID CHARACTER?
  2590 00000E01 7507                <1> 	jne	short RST_RD_ID
  2591 00000E03 800D[06650000]40    <1> 	or	byte [KB_FLAG_3], LC_AB ; INDICATE 1ST ID WAS OK
  2592                              <1> RST_RD_ID:
  2593 00000E0A 8025[06650000]7F    <1> 	and	byte [KB_FLAG_3], ~RD_ID ; RESET THE READ ID FLAG
  2594 00000E11 EB27                <1>         jmp    short ID_EX		; AND EXIT
  2595                              <1> 	; 24/12/2021
  2596                              <1> 	;jmp	K26
  2597                              <1> 	;
  2598                              <1> TST_ID_2:
  2599 00000E13 8025[06650000]BF    <1> 	and	byte [KB_FLAG_3], ~LC_AB ; RESET FLAG
  2600 00000E1A 3C54                <1> 	cmp	al, ID_2A		; IS THIS THE 2ND ID CHARACTER?
  2601 00000E1C 7415                <1>         je	short KX_BIT		; JUMP IF SO
  2602 00000E1E 3C41                <1> 	cmp	al, ID_2		; IS THIS THE 2ND ID CHARACTER?
  2603 00000E20 7518                <1>         jne	short ID_EX		; LEAVE IF NOT
  2604                              <1> 	; 24/12/2021
  2605                              <1> 	;jne	K26
  2606                              <1> 	;
  2607                              <1> 	;-----	A READ ID SAID THAT IT WAS ENHANCED KEYBOARD
  2608 00000E22 F6C720              <1> 	test	bh, SET_NUM_LK 		; SHOULD WE SET NUM LOCK?
  2609 00000E25 740C                <1>         jz      short KX_BIT		; EXIT IF NOT
  2610 00000E27 800D[03650000]20    <1> 	or	byte [KB_FLAG], NUM_STATE ; FORCE NUM LOCK ON
  2611 00000E2E E81B050000          <1> 	call	SND_LED			; GO SET THE NUM LOCK INDICATOR
  2612                              <1> KX_BIT:
  2613 00000E33 800D[06650000]10    <1> 	or	byte [KB_FLAG_3], KBX	; INDICATE ENHANCED KEYBOARD WAS FOUND
  2614 00000E3A E9E5010000          <1> ID_EX:	jmp     K26			; EXIT
  2615                              <1> 	;
  2616                              <1> NOT_ID:
  2617 00000E3F 3CE0                <1> 	cmp	al, MC_E0		; IS THIS THE GENERAL MARKER CODE?
  2618 00000E41 750E                <1> 	jne	short TEST_E1
  2619 00000E43 800D[06650000]12    <1> 	or	byte [KB_FLAG_3], LC_E0+KBX ; SET FLAG BIT, SET KBX, AND
  2620 00000E4A EB10                <1> 	jmp	short EXIT		; THROW AWAY THIS CODE
  2621                              <1> 	; 24/12/2021
  2622 00000E4C E9DA010000          <1> 	jmp	K26A	
  2623                              <1> TEST_E1:	
  2624 00000E51 3CE1                <1> 	cmp	al, MC_E1		; IS THIS THE PAUSE KEY?
  2625 00000E53 750C                <1> 	jne	short NOT_HC
  2626 00000E55 800D[06650000]11    <1> 	or	byte [KB_FLAG_3], LC_E1+KBX ; SET FLAG BIT, SET KBX, AND
  2627 00000E5C E9CA010000          <1> EXIT:	jmp	K26A			; THROW AWAY THIS CODE
  2628                              <1> 	;
  2629                              <1> NOT_HC:
  2630 00000E61 247F                <1> 	and	al, 07Fh		; TURN OFF THE BREAK BIT
  2631 00000E63 F6C702              <1> 	test	bh, LC_E0		; LAST CODE THE E0 MARKER CODE
  2632 00000E66 740D                <1> 	jz	short NOT_LC_E0		; JUMP IF NOT
  2633                              <1> 	;
  2634 00000E68 BF[EE630000]        <1> 	mov	edi, _K6+6		; IS THIS A SHIFT KEY?
  2635 00000E6D AE                  <1> 	scasb
  2636                              <1> 	;je	K26 ; K16B              ; YES, THROW AWAY & RESET FLAG
  2637                              <1> 	; 24/12/2021
  2638 00000E6E 7458                <1> 	je	short K16B
  2639 00000E70 AE                  <1> 	scasb
  2640 00000E71 756A                <1> 	jne	short K16A		; NO, CONTINUE KEY PROCESSING
  2641 00000E73 EB53                <1> 	jmp	short K16B		; YES, THROW AWAY & RESET FLAG
  2642                              <1> 	; 24/12/2021
  2643                              <1> 	;jmp	K26
  2644                              <1> 	;
  2645                              <1> NOT_LC_E0:
  2646 00000E75 F6C701              <1> 	test	bh, LC_E1		; LAST CODE THE E1 MARKER CODE?
  2647 00000E78 7425                <1> 	jz	short T_SYS_KEY		; JUMP IF NOT
  2648 00000E7A B904000000          <1> 	mov	ecx, 4			; LENGHT OF SEARCH
  2649 00000E7F BF[EC630000]        <1> 	mov	edi, _K6+4		; IS THIS AN ALT, CTL, OR SHIFT?
  2650 00000E84 F2AE                <1> 	repne	scasb			; CHECK IT
  2651 00000E86 74D4                <1> 	je	short EXIT		; THROW AWAY IF SO
  2652                              <1> 	; 24/12/2021
  2653                              <1> 	;je	K26A			
  2654                              <1> 	;
  2655 00000E88 3C45                <1> 	cmp	al, NUM_KEY		; IS IT THE PAUSE KEY?
  2656 00000E8A 753C                <1> 	jne	short K16B		; NO, THROW AWAY & RESET FLAG
  2657                              <1> 	; 24/12/2021
  2658                              <1> 	;jne	K26
  2659 00000E8C F6C480              <1> 	test	ah, 80h			; YES, IS IT THE BREAK OF THE KEY?
  2660 00000E8F 7537                <1> 	jnz	short K16B		; YES, THROW THIS AWAY, TOO	
  2661                              <1> 	; 24/12/2021
  2662                              <1> 	;jnz	K26
  2663                              <1>         ; 20/02/2015 
  2664 00000E91 F605[04650000]08    <1> 	test	byte [KB_FLAG_1],HOLD_STATE ; NO, ARE WE PAUSED ALREADY?
  2665 00000E98 752E                <1> 	jnz	short K16B		; YES, THROW AWAY
  2666                              <1> 	; 24/12/2021
  2667                              <1> 	;jnz	K26
  2668 00000E9A E9D6020000          <1> 	jmp     K39P                    ; NO, THIS IS THE REAL PAUSE STATE
  2669                              <1> 	;
  2670                              <1> 	;-----	TEST FOR SYSTEM KEY
  2671                              <1> T_SYS_KEY:
  2672 00000E9F 3C54                <1> 	cmp	al, SYS_KEY		; IS IT THE SYSTEM KEY?
  2673 00000EA1 753A                <1> 	jnz	short K16A		; CONTINUE IF NOT
  2674                              <1> 	;
  2675 00000EA3 F6C480              <1> 	test	ah, 80h			; CHECK IF THIS A BREAK CODE
  2676 00000EA6 7525                <1> 	jnz	short K16C		; DO NOT TOUCH SYSTEM INDICATOR IF TRUE
  2677                              <1> 	;
  2678 00000EA8 F605[04650000]04    <1> 	test	byte [KB_FLAG_1], SYS_SHIFT ; SEE IF IN SYSTEM KEY HELD DOWN 
  2679 00000EAF 7517                <1> 	jnz	short K16B		; IF YES, DO NOT PROCESS SYSTEM INDICATOR	
  2680                              <1> 	;jnz	K26			
  2681                              <1> 	;
  2682 00000EB1 800D[04650000]04    <1> 	or	byte [KB_FLAG_1], SYS_SHIFT ; INDICATE SYSTEM KEY DEPRESSED
  2683 00000EB8 B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2684 00000EBA E620                <1> 	out	20h, al ;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  2685                              <1> 					; INTERRUPT-RETURN-NO-EOI
  2686 00000EBC B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2687 00000EBE E830040000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  2688                              <1> 	; !!! SYSREQ !!! function/system call (INTERRUPT) must be here !!!
  2689                              <1> 	;MOV	AL, 8500H		; FUNCTION VALUE FOR MAKE OF SYSTEM KEY
  2690                              <1> 	;STI				; MAKE SURE INTERRUPTS ENABLED
  2691                              <1> 	;INT	15H			; USER INTERRUPT	
  2692 00000EC3 E96F010000          <1>         jmp     K27A                    ; END PROCESSING
  2693                              <1> 	;
  2694 00000EC8 E957010000          <1> K16B:	jmp	K26			; IGNORE SYSTEM KEY
  2695                              <1> 	;
  2696                              <1> K16C:
  2697 00000ECD 8025[04650000]FB    <1> 	and	byte [KB_FLAG_1], ~SYS_SHIFT ; TURN OFF SHIFT KEY HELD DOWN
  2698 00000ED4 B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2699 00000ED6 E620                <1> 	out	20h, al ;out INTA00, al ; SEND COMMAND TO INTERRUPT CONTROL PORT
  2700                              <1> 					; INTERRUPT-RETURN-NO-EOI
  2701                              <1> 	;MOV	AL, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2702                              <1> 	;CALL	SHIP_IT			; EXECUTE ENABLE
  2703                              <1> 	;
  2704                              <1> 	;MOV	AX, 8501H		; FUNCTION VALUE FOR BREAK OF SYSTEM KEY
  2705                              <1> 	;STI				; MAKE SURE INTERRUPTS ENABLED
  2706                              <1> 	;INT	15H			; USER INTERRUPT
  2707                              <1> 	;JMP	K27A			; INGONRE SYSTEM KEY				
  2708                              <1> 	;
  2709 00000ED8 E953010000          <1> 	jmp     K27			; IGNORE SYSTEM KEY
  2710                              <1> 	;
  2711                              <1> 	;-----	TEST FOR SHIFT KEYS
  2712                              <1> K16A:
  2713 00000EDD 8A1D[03650000]      <1> 	mov	bl, [KB_FLAG]		; PUT STATE FLAGS IN BL
  2714 00000EE3 BF[E8630000]        <1> 	mov	edi, _K6		; SHIFT KEY TABLE offset
  2715 00000EE8 B908000000          <1> 	mov	ecx, _K6L		; LENGTH
  2716 00000EED F2AE                <1> 	repne	scasb			; LOOK THROUGH THE TABLE FOR A MATCH
  2717 00000EEF 88E0                <1> 	mov	al, ah			; RECOVER SCAN CODE
  2718                              <1>         ;jne    K25                     ; IF NO MATCH, THEN SHIFT NOT FOUND
  2719                              <1> 	; 24/12/2021
  2720 00000EF1 7405                <1> 	je	short K17
  2721 00000EF3 E914010000          <1> 	jmp	K25
  2722                              <1> 	;
  2723                              <1> 	;------	SHIFT KEY FOUND
  2724                              <1> K17:
  2725 00000EF8 81EF[E9630000]      <1>         sub     edi, _K6+1              ; ADJUST PTR TO SCAN CODE MATCH
  2726 00000EFE 8AA7[F0630000]      <1>        	mov     ah, [edi+_K7]       	; GET MASK INTO AH
  2727 00000F04 B102                <1> 	mov	cl, 2			; SETUP COUNT FOR FLAG SHIFTS
  2728 00000F06 A880                <1> 	test	al, 80h			; TEST FOR BREAK KEY
  2729                              <1>         ;jnz	K23                     ; JUMP OF BREAK
  2730                              <1> 	; 24/12/2021
  2731 00000F08 7405                <1> 	jz	short K17C
  2732 00000F0A E999000000          <1> 	jmp	K23
  2733                              <1> 	;
  2734                              <1> 	;-----	SHIFT MAKE FOUND, DETERMINE SET OR TOGGLE
  2735                              <1> K17C:
  2736 00000F0F 80FC10              <1> 	cmp	ah, SCROLL_SHIFT
  2737 00000F12 732C                <1> 	jae	short K18		; IF SCROLL SHIFT OR ABOVE, TOGGLE KEY
  2738                              <1> 	;
  2739                              <1> 	;-----	PLAIN SHIFT KEY, SET SHIFT ON
  2740 00000F14 0825[03650000]      <1> 	or	[KB_FLAG], ah		; TURN ON SHIFT BIT
  2741 00000F1A A80C                <1>         test	al, CTL_SHIFT+ALT_SHIFT ; IS IT ALT OR CTRL?
  2742 00000F1C 7505                <1> 	jnz	short K17D		; YES, MORE FLAGS TO SET
  2743                              <1> 	;jz	K26			; NO, INTERRUPT RETURN
  2744                              <1> 	; 24/12/2021
  2745 00000F1E E901010000          <1> 	jmp	K26
  2746                              <1> K17D:
  2747 00000F23 F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OF NEW KEYS?
  2748 00000F26 740B                <1> 	jz 	short K17E		; NO, JUMP
  2749 00000F28 0825[06650000]      <1> 	or	[KB_FLAG_3], ah		; SET BITS FOR RIGHT CTRL, ALT
  2750 00000F2E E9F1000000          <1> 	jmp	K26			; INTERRUPT RETURN
  2751                              <1> K17E:
  2752 00000F33 D2EC                <1> 	shr	ah, cl			; MOVE FLAG BITS TWO POSITIONS
  2753 00000F35 0825[04650000]      <1> 	or	[KB_FLAG_1], ah		; SET BITS FOR LEFT CTRL, ALT
  2754 00000F3B E9E4000000          <1> 	jmp	K26
  2755                              <1> 	;
  2756                              <1> 	;-----	TOGGLED SHIFT KEY, TEST FOR 1ST MAKE OR NOT
  2757                              <1> K18:					; SHIFT-TOGGLE
  2758 00000F40 F6C304              <1> 	test	bl, CTL_SHIFT 		; CHECK CTL SHIFT STATE
  2759 00000F43 7405                <1>         jz    	short K18A              ; JUMP IF NOT CTL STATE
  2760                              <1>         ;jnz	K25                     ; JUMP IF CTL STATE
  2761                              <1> 	; 24/12/2021
  2762 00000F45 E9C2000000          <1> 	jmp	K25
  2763                              <1> K18A:
  2764 00000F4A 3C52                <1> 	cmp	al, INS_KEY		; CHECK FOR INSERT KEY
  2765 00000F4C 7525                <1> 	jne	short K22		; JUMP IF NOT INSERT KEY
  2766 00000F4E F6C308              <1> 	test	bl, ALT_SHIFT 		; CHECK FOR ALTERNATE SHIFT
  2767 00000F51 7405                <1>       	jz	short K18B		; JUMP IF NOT ALTERNATE SHIFT	
  2768                              <1> 	;jnz	K25                     ; JUMP IF ALTERNATE SHIFT
  2769                              <1> 	; 24/12/2021
  2770 00000F53 E9B4000000          <1> 	jmp	K25
  2771                              <1> K18B:
  2772 00000F58 F6C702              <1> 	test	bh, LC_E0 ;20/02/2015	; IS THIS NEW INSERT KEY?
  2773 00000F5B 7516                <1> 	jnz	short K22		; YES, THIS ONE'S NEVER A '0'
  2774                              <1> K19:	
  2775 00000F5D F6C320              <1> 	test	bl, NUM_STATE 		; CHECK FOR BASE STATE
  2776 00000F60 750C                <1> 	jnz	short K21		; JUMP IF NUM LOCK IS ON
  2777 00000F62 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; TEST FOR SHIFT STATE
  2778 00000F65 740C                <1> 	jz	short K22		; JUMP IF BASE STATE
  2779                              <1> K20:					; NUMERIC ZERO, NOT INSERT KEY
  2780 00000F67 88C4                <1> 	mov	ah, al			; PUT SCAN CODE BACK IN AH
  2781 00000F69 E99E000000          <1>         jmp	K25               	; NUMERAL '0', STNDRD. PROCESSING
  2782                              <1> K21:					; MIGHT BE NUMERIC
  2783 00000F6E F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT
  2784 00000F71 74F4                <1> 	jz	short K20		; IS NUMERIC, STD. PROC.
  2785                              <1> 	;
  2786                              <1> K22:					; SHIFT TOGGLE KEY HIT; PROCESS IT
  2787 00000F73 8425[04650000]      <1> 	test	ah, [KB_FLAG_1] 	; IS KEY ALREADY DEPRESSED
  2788                              <1> 	;jnz	K26
  2789                              <1> 	; 24/12/2021
  2790 00000F79 7405                <1> 	jz	short K22A
  2791 00000F7B E9A4000000          <1> 	jmp	K26			; JUMP IF KEY ALREADY DEPRESSED
  2792                              <1> K22A:
  2793 00000F80 0825[04650000]      <1>         or      [KB_FLAG_1], ah 	; INDICATE THAT THE KEY IS DEPRESSED
  2794 00000F86 3025[03650000]      <1> 	xor	[KB_FLAG], ah		; TOGGLE THE SHIFT STATE
  2795                              <1> 	;
  2796                              <1> 	;-----	TOGGLE LED IF CAPS, NUM  OR SCROLL KEY DEPRESSED
  2797 00000F8C F6C470              <1> 	test	ah, CAPS_SHIFT+NUM_SHIFT+SCROLL_SHIFT ; SHIFT TOGGLE?
  2798 00000F8F 7407                <1> 	jz	short K22B		; GO IF NOT
  2799                              <1> 	;
  2800                              <1> 	; 24/12/2021
  2801                              <1> 	;push	ax			; SAVE SCAN CODE AND SHIFT MASK
  2802 00000F91 50                  <1> 	push	eax
  2803 00000F92 E8B7030000          <1> 	call	SND_LED			; GO TURN MODE INDICATORS ON
  2804                              <1> 	;pop	ax			; RESTORE SCAN CODE
  2805 00000F97 58                  <1> 	pop	eax
  2806                              <1> K22B:
  2807 00000F98 3C52                <1> 	cmp	al, INS_KEY		; TEST FOR 1ST MAKE OF INSERT KEY
  2808                              <1>         ;jne	K26			; JUMP IF NOT INSERT KEY
  2809                              <1> 	; 24/12/2021
  2810 00000F9A 7405                <1> 	je	short K22C
  2811 00000F9C E983000000          <1> 	jmp	K26			; JUMP IF NOT INSERT KEY
  2812                              <1> K22C:
  2813 00000FA1 88C4                <1> 	mov	ah, al		        ; SCAN CODE IN BOTH HALVES OF AX
  2814 00000FA3 E999000000          <1>         jmp	K28			; FLAGS UPDATED, PROC. FOR BUFFER
  2815                              <1> 	;
  2816                              <1> 	;-----	BREAK SHIFT FOUND
  2817                              <1> K23:					; BREAK-SHIFT-FOUND
  2818 00000FA8 80FC10              <1> 	cmp	ah, SCROLL_SHIFT	; IS THIS A TOGGLE KEY
  2819 00000FAB F6D4                <1> 	not	ah			; INVERT MASK
  2820 00000FAD 7355                <1> 	jae	short K24		; YES, HANDLE BREAK TOGGLE
  2821 00000FAF 2025[03650000]      <1> 	and	[KB_FLAG], ah		; TURN OFF SHIFT BIT
  2822 00000FB5 80FCFB              <1> 	cmp	ah, ~CTL_SHIFT		; IS THIS ALT OR CTL?
  2823 00000FB8 7730                <1> 	ja	short K23D		; NO, ALL DONE
  2824                              <1> 	;
  2825 00000FBA F6C702              <1> 	test	bh, LC_E0		; 2ND ALT OR CTL?
  2826 00000FBD 7408                <1> 	jz	short K23A		; NO, HANSLE NORMALLY
  2827 00000FBF 2025[06650000]      <1> 	and 	[KB_FLAG_3], ah		; RESET BIT FOR RIGHT ALT OR CTL
  2828 00000FC5 EB08                <1> 	jmp	short K23B		; CONTINUE
  2829                              <1> K23A:
  2830 00000FC7 D2FC                <1> 	sar	ah, cl			; MOVE THE MASK BIT TWO POSITIONS
  2831 00000FC9 2025[04650000]      <1> 	and	[KB_FLAG_1], ah		; RESET BIT FOR LEFT ALT AND CTL
  2832                              <1> K23B:
  2833 00000FCF 88C4                <1> 	mov	ah, al			; SAVE SCAN CODE
  2834 00000FD1 A0[06650000]        <1> 	mov	al, [KB_FLAG_3]		; GET RIGHT ALT & CTRL FLAGS
  2835 00000FD6 D2E8                <1> 	shr	al, cl			; MOVE TO BITS 1 & 0
  2836 00000FD8 0A05[04650000]      <1> 	or	al, [KB_FLAG_1]		; PUT IN LEFT ALT & CTL FLAGS
  2837 00000FDE D2E0                <1> 	shl	al, cl			; MOVE BACK TO BITS 3 & 2
  2838 00000FE0 240C                <1> 	and	al, ALT_SHIFT+CTL_SHIFT ; FILTER OUT OTHER GARBAGE
  2839 00000FE2 0805[03650000]      <1> 	or	[KB_FLAG], al		; PUT RESULT IN THE REAL FLAGS	
  2840 00000FE8 88E0                <1> 	mov	al, ah
  2841                              <1> K23D:
  2842 00000FEA 3CB8                <1> 	cmp	al, ALT_KEY+80h		; IS THIS ALTERNATE SHIFT RELEASE
  2843 00000FEC 7536                <1> 	jne	short K26		; INTERRUPT RETURN
  2844                              <1> 	;	
  2845                              <1> 	;-----	ALTERNATE SHIFT KEY RELEASED, GET THE VALUE INTO BUFFER
  2846 00000FEE A0[07650000]        <1> 	mov	al, [ALT_INPUT]
  2847 00000FF3 B400                <1> 	mov	ah, 0			; SCAN CODE OF 0
  2848 00000FF5 8825[07650000]      <1> 	mov	[ALT_INPUT], ah 	; ZERO OUT THE FIELD
  2849 00000FFB 3C00                <1> 	cmp	al, 0			; WAS THE INPUT = 0?
  2850 00000FFD 7425                <1> 	je	short K26		; INTERRUPT_RETURN
  2851 00000FFF E9B8020000          <1>         jmp     K61                     ; IT WASN'T, SO PUT IN BUFFER
  2852                              <1> 	;
  2853                              <1> K24:					; BREAK-TOGGLE
  2854 00001004 2025[04650000]      <1> 	and	[KB_FLAG_1], ah 	; INDICATE NO LONGER DEPRESSED
  2855 0000100A EB18                <1> 	jmp	short K26		; INTERRUPT_RETURN
  2856                              <1> 	;
  2857                              <1> 	;-----	TEST FOR HOLD STATE
  2858                              <1> 					; AL, AH = SCAN CODE
  2859                              <1> K25:					; NO-SHIFT-FOUND
  2860 0000100C 3C80                <1> 	cmp	al, 80h			; TEST FOR BREAK KEY
  2861 0000100E 7314                <1> 	jae	short K26		; NOTHING FOR BREAK CHARS FROM HERE ON
  2862 00001010 F605[04650000]08    <1> 	test	byte [KB_FLAG_1], HOLD_STATE ; ARE WE IN HOLD STATE
  2863 00001017 7428                <1> 	jz	short K28		; BRANCH AROUND TEST IF NOT
  2864 00001019 3C45                <1> 	cmp	al, NUM_KEY
  2865 0000101B 7407                <1> 	je	short K26		; CAN'T END HOLD ON NUM_LOCK
  2866 0000101D 8025[04650000]F7    <1> 	and	byte [KB_FLAG_1], ~HOLD_STATE ; TURN OFF THE HOLD STATE BIT
  2867                              <1> 	;
  2868                              <1> K26:
  2869 00001024 8025[06650000]FC    <1> 	and	byte [KB_FLAG_3], ~(LC_E0+LC_E1) ; RESET LAST CHAR H.C. FLAG
  2870                              <1> K26A:					; INTERRUPT-RETURN
  2871 0000102B FA                  <1> 	cli				; TURN OFF INTERRUPTS
  2872 0000102C B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2873 0000102E E620                <1> 	out	20h, al	;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  2874                              <1> K27:					; INTERRUPT-RETURN-NO-EOI
  2875 00001030 B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2876 00001032 E8BC020000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  2877                              <1> K27A:
  2878 00001037 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2879 00001038 07                  <1> 	pop	es			; RESTORE REGISTERS
  2880 00001039 1F                  <1> 	pop	ds
  2881 0000103A 5F                  <1> 	pop	edi
  2882 0000103B 5E                  <1> 	pop	esi
  2883 0000103C 5A                  <1> 	pop	edx
  2884 0000103D 59                  <1> 	pop	ecx
  2885 0000103E 5B                  <1> 	pop	ebx
  2886 0000103F 58                  <1> 	pop	eax
  2887                              <1> 	;pop	ebp
  2888 00001040 CF                  <1> 	iret				; RETURN
  2889                              <1> 
  2890                              <1> 	;-----	NOT IN	HOLD STATE
  2891                              <1> K28:					; NO-HOLD-STATE
  2892 00001041 3C58                <1> 	cmp	al, 88			; TEST FOR OUT-OF-RANGE SCAN CODES
  2893 00001043 77DF                <1> 	ja	short K26		; IGNORE IF OUT-OF-RANGE	
  2894                              <1> 	;
  2895 00001045 F6C308              <1> 	test	bl, ALT_SHIFT 		; ARE WE IN ALTERNATE SHIFT
  2896 00001048 740E                <1>         jz	short K28A		; IF NOT ALTERNATE
  2897                              <1>         ; 24/12/2021
  2898                              <1> 	;jz      K38
  2899                              <1> 	;
  2900 0000104A F6C710              <1> 	test	bh, KBX			; IS THIS THE ENCHANCED KEYBOARD?
  2901 0000104D 740E                <1> 	jz	short K29		; NO, ALT STATE IS REAL
  2902                              <1> 	; 28/02/2015
  2903 0000104F F605[04650000]04    <1> 	test	byte [KB_FLAG_1], SYS_SHIFT ; YES, IS SYSREQ KEY DOWN?
  2904 00001056 7405                <1> 	jz	short K29		; NO, ALT STATE IS REAL
  2905                              <1> 	; 24/12/2021
  2906                              <1> 	;jnz	K38			; YES, THIS IS PHONY ALT STATE 
  2907                              <1>         ;				; DUE TO PRESSING SYSREQ	
  2908 00001058 E9D1000000          <1> K28A:	jmp	K38
  2909                              <1> 	;
  2910                              <1> 	;-----	TEST FOR RESET KEY SEQUENCE (CTL ALT DEL)
  2911                              <1> K29:					; TEST-RESET
  2912 0000105D F6C304              <1> 	test	bl, CTL_SHIFT 		; ARE WE IN CONTROL SHIFT ALSO?
  2913 00001060 740B                <1> 	jz	short K31		; NO_RESET
  2914 00001062 3C53                <1> 	cmp	al, DEL_KEY		; CTL-ALT STATE, TEST FOR DELETE KEY
  2915 00001064 7507                <1> 	jne	short K31		; NO_RESET, IGNORE
  2916                              <1> 	;
  2917                              <1> 	;-----	CTL-ALT-DEL HAS BEEN FOUND
  2918                              <1>  	; 26/08/2014
  2919                              <1> cpu_reset:
  2920                              <1> 	; IBM PC/AT ROM BIOS source code - 10/06/85 (TEST4.ASM - PROC_SHUTDOWN)
  2921                              <1> 	; Send FEh (system reset command) to the keyboard controller.
  2922 00001066 B0FE                <1> 	mov	al, SHUT_CMD		; SHUTDOWN COMMAND
  2923 00001068 E664                <1> 	out	STATUS_PORT, al		; SEND TO KEYBOARD CONTROL PORT
  2924                              <1> khere:
  2925 0000106A F4                  <1> 	hlt				; WAIT FOR 80286 RESET
  2926 0000106B EBFD                <1> 	jmp 	short khere		; INSURE HALT
  2927                              <1> 
  2928                              <1> 	;
  2929                              <1> 	;-----	IN ALTERNATE SHIFT, RESET NOT FOUND
  2930                              <1> K31:					; NO-RESET
  2931 0000106D 3C39                <1> 	cmp	al, 57			; TEST FOR SPACE KEY
  2932 0000106F 7507                <1> 	jne	short K311		; NOT THERE
  2933 00001071 B020                <1> 	mov	al, ' '			; SET SPACE CHAR
  2934 00001073 E936020000          <1>         jmp     K57                     ; BUFFER_FILL
  2935                              <1> K311:
  2936 00001078 3C0F                <1> 	cmp	al, 15			; TEST FOR TAB KEY
  2937 0000107A 7509                <1> 	jne	short K312		; NOT THERE
  2938 0000107C 66B800A5            <1> 	mov	ax, 0A500h		; SET SPECIAL CODE FOR ALT-TAB
  2939 00001080 E929020000          <1>         jmp     K57                     ; BUFFER_FILL
  2940                              <1> K312:
  2941 00001085 3C4A                <1> 	cmp	al, 74			; TEST FOR KEY PAD -
  2942 00001087 7471                <1>         je	short K37B              ; GO PROCESS
  2943 00001089 3C4E                <1> 	cmp	al, 78			; TEST FOR KEY PAD +
  2944 0000108B 746D                <1>         je	short K37B              ; GO PROCESS
  2945                              <1> 	;
  2946                              <1> 	;-----	LOOK FOR KEY PAD ENTRY
  2947                              <1> K32:					; ALT-KEY-PAD
  2948 0000108D BF[C4630000]        <1> 	mov	edi, K30		; ALT-INPUT-TABLE offset
  2949 00001092 B90A000000          <1> 	mov	ecx, 10			; LOOK FOR ENTRY USING KEYPAD
  2950 00001097 F2AE                <1> 	repne	scasb			; LOOK FOR MATCH
  2951 00001099 7523                <1> 	jne	short K33		; NO_ALT_KEYPAD
  2952 0000109B F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OF THE NEW KEYS?
  2953                              <1>         ;jnz	short K37C		; YES, JUMP, NOT NUMPAD KEY
  2954                              <1> 	; 24/12/2021
  2955 0000109E 751C                <1> 	jnz	short K32B
  2956 000010A0 81EF[C5630000]      <1> 	sub	edi, K30+1		; DI NOW HAS ENTRY VALUE
  2957 000010A6 A0[07650000]        <1> 	mov	al, [ALT_INPUT] 	; GET THE CURRENT BYTE
  2958 000010AB B40A                <1> 	mov	ah, 10			; MULTIPLY BY 10
  2959 000010AD F6E4                <1> 	mul	ah
  2960 000010AF 6601F8              <1> 	add	ax, di			; ADD IN THE LATEST ENTRY
  2961 000010B2 A2[07650000]        <1> 	mov	[ALT_INPUT], al 	; STORE IT AWAY
  2962                              <1> K32A:
  2963 000010B7 E968FFFFFF          <1>         jmp     K26                     ; THROW AWAY THAT KEYSTROKE
  2964                              <1> K32B:
  2965                              <1> 	; 24/12/2021
  2966 000010BC EB6A                <1> 	jmp	K37C
  2967                              <1> 	;
  2968                              <1> 	;-----	LOOK FOR SUPERSHIFT ENTRY
  2969                              <1> K33:					; NO-ALT-KEYPAD
  2970 000010BE C605[07650000]00    <1>         mov     byte [ALT_INPUT], 0     ; ZERO ANY PREVIOUS ENTRY INTO INPUT
  2971 000010C5 B91A000000          <1> 	mov	ecx, 26			; (DI),(ES) ALREADY POINTING
  2972 000010CA F2AE                <1> 	repne	scasb			; LOOK FOR MATCH IN ALPHABET
  2973 000010CC 7453                <1> 	je	short K37A		; MATCH FOUND, GO FILLL THE BUFFER
  2974                              <1> 	;
  2975                              <1> 	;-----	LOOK FOR TOP ROW OF ALTERNATE SHIFT
  2976                              <1> K34:					; ALT-TOP-ROW
  2977 000010CE 3C02                <1> 	cmp	al, 2			; KEY WITH '1' ON IT
  2978 000010D0 7228                <1> 	jb	short K37B		; MUST BE ESCAPE
  2979 000010D2 3C0D                <1> 	cmp	al, 13			; IS IT IN THE REGION
  2980 000010D4 7705                <1> 	ja	short K35		; NO, ALT SOMETHING ELSE
  2981 000010D6 80C476              <1> 	add	ah, 118			; CONVERT PSEUDO SCAN CODE TO RANGE
  2982 000010D9 EB46                <1> 	jmp	short K37A		; GO FILL THE BUFFER
  2983                              <1> 	;
  2984                              <1> 	;-----	TRANSLATE ALTERNATE SHIFT PSEUDO SCAN CODES
  2985                              <1> K35:					; ALT-FUNCTION
  2986 000010DB 3C57                <1> 	cmp	al, F11_M		; IS IT F11?	
  2987 000010DD 7209                <1> 	jb	short K35A ; 20/02/2015	; NO, BRANCH
  2988 000010DF 3C58                <1> 	cmp	al, F12_M		; IS IT F12?
  2989 000010E1 7705                <1> 	ja	short K35A ; 20/02/2015	; NO, BRANCH
  2990 000010E3 80C434              <1> 	add	ah, 52			; CONVERT TO PSEUDO SCAN CODE
  2991 000010E6 EB39                <1> 	jmp	short K37A		; GO FILL THE BUFFER
  2992                              <1> K35A:
  2993 000010E8 F6C702              <1> 	test	bh, LC_E0		; DO WE HAVE ONE OF THE NEW KEYS?
  2994 000010EB 7425                <1> 	jz	short K37		; NO, JUMP
  2995 000010ED 3C1C                <1> 	cmp	al, 28			; TEST FOR KEYPAD ENTER
  2996 000010EF 7510                <1>         jne     short K35B              ; NOT THERE
  2997 000010F1 66B800A6            <1> 	mov	ax, 0A600h		; SPECIAL CODE
  2998 000010F5 E9B4010000          <1> 	jmp	K57			; BUFFER FILL
  2999                              <1> K37B:
  3000 000010FA B0F0                <1> 	mov	al, 0F0h		; USE SPECIAL ASCII CODE
  3001 000010FC E9AD010000          <1> 	jmp     K57                     ; PUT IT IN THE BUFFER
  3002                              <1> K35B:
  3003 00001101 3C53                <1> 	cmp	al, 83			; TEST FOR DELETE KEY
  3004 00001103 7423                <1> 	je	short K37C		; HANDLE WITH OTHER EDIT KEYS
  3005 00001105 3C35                <1> 	cmp	al, 53			; TEST FOR KEYPAD /
  3006 00001107 75AE                <1> 	jne	short K32A		; NOT THERE, NO OTHER E0 SPECIALS	
  3007                              <1>         ; 24/12/2021
  3008                              <1> 	;jne	K26
  3009 00001109 66B800A4            <1> 	mov	ax, 0A400h		; SPECIAL CODE
  3010 0000110D E99C010000          <1> 	jmp	K57			; BUFFER FILL
  3011                              <1> K37:
  3012 00001112 3C3B                <1> 	cmp	al, 59			; TEST FOR FUNCTION KEYS (F1)
  3013 00001114 72E4                <1>         jb      short K37B		; NO FN, HANDLE W/OTHER EXTENDED
  3014 00001116 3C44                <1> 	cmp	al, 68			; IN KEYPAD REGION?
  3015                              <1>         ;ja	short K32A		; IF SO, IGNORE
  3016 00001118 0F8706FFFFFF        <1>         ja      K26
  3017 0000111E 80C42D              <1> 	add	ah, 45			; CONVERT TO PSEUDO SCAN CODE
  3018                              <1> K37A:
  3019 00001121 B000                <1> 	mov	al, 0			; ASCII CODE OF ZERO
  3020 00001123 E986010000          <1>         jmp     K57                     ; PUT IT IN THE BUFFER
  3021                              <1> K37C:
  3022 00001128 0450                <1> 	add	al, 80			; CONVERT SCAN CODE (EDIT KEYS)
  3023 0000112A 88C4                <1> 	mov	ah, al			; (SCAN CODE NOT IN AH FOR INSERT)
  3024 0000112C EBF3                <1> 	jmp     short K37A              ; PUT IT IN THE BUFFER
  3025                              <1> 	;
  3026                              <1> 	;-----	NOT IN ALTERNATE SHIFT
  3027                              <1> K38:					; NOT-ALT-SHIFT
  3028                              <1> 					; BL STILL HAS SHIFT FLAGS
  3029 0000112E F6C304              <1> 	test	bl, CTL_SHIFT 		; ARE WE IN CONTROL SHIFT?
  3030 00001131 7505                <1> 	jnz	short K38A		; YES, START PROCESSING	
  3031                              <1>         ;jz	K44                     ; NOT-CTL-SHIFT
  3032                              <1> 	; 24/12/2021
  3033 00001133 E9AB000000          <1> 	jmp	K44
  3034                              <1> 	;
  3035                              <1> 	;-----	CONTROL SHIFT, TEST SPECIAL CHARACTERS
  3036                              <1> 	;-----	TEST FOR BREAK
  3037                              <1> K38A:
  3038 00001138 3C46                <1> 	cmp	al, SCROLL_KEY		; TEST FOR BREAK
  3039 0000113A 7530                <1> 	jne	short K39		; JUMP, NO-BREAK
  3040 0000113C F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3041 0000113F 7405                <1> 	jz	short K38B		; NO, BREAK IS VALID	
  3042 00001141 F6C702              <1> 	test	bh, LC_E0		; YES, WAS LAST CODE AN E0?
  3043 00001144 7426                <1> 	jz	short K39		; NO-BREAK, TEST FOR PAUSE	
  3044                              <1> K38B:
  3045 00001146 8B1D[10650000]      <1> 	mov	ebx, [BUFFER_HEAD] 	; RESET BUFFER TO EMPTY
  3046 0000114C 891D[14650000]      <1> 	mov	[BUFFER_TAIL], ebx
  3047 00001152 C605[02650000]80    <1> 	mov	byte [BIOS_BREAK], 80h  ; TURN ON BIOS_BREAK BIT
  3048                              <1> 	;
  3049                              <1> 	;-----	ENABLE KEYBOARD
  3050 00001159 B0AE                <1> 	mov	al, ENA_KBD		; ENABLE KEYBOARD
  3051 0000115B E893010000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3052                              <1> 	;
  3053                              <1> 	; CTRL+BREAK code here !!!
  3054                              <1> 	;INT	1BH			; BREAK INTERRUPT VECTOR
  3055                              <1> 	; 17/10/2015	
  3056 00001160 E85B220000          <1> 	call	ctrlbrk ; control+break subroutine
  3057                              <1> 	;
  3058                              <1> 	;sub	ax, ax			; PUT OUT DUMMY CHARACTER
  3059                              <1> 	; 24/12/2021
  3060 00001165 29C0                <1> 	sub	eax, eax
  3061 00001167 E942010000          <1> 	jmp     K57                     ; BUFFER_FILL
  3062                              <1> 	;
  3063                              <1> 	;-----	TEST FOR PAUSE
  3064                              <1> K39:					; NO_BREAK
  3065 0000116C F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3066 0000116F 7537                <1> 	jnz	short K41		; YES, THEN THIS CAN'T BE PAUSE	
  3067 00001171 3C45                <1> 	cmp	al, NUM_KEY		; LOOK FOR PAUSE KEY
  3068 00001173 7533                <1> 	jne	short K41		; NO-PAUSE
  3069                              <1> K39P:
  3070 00001175 800D[04650000]08    <1> 	or	byte [KB_FLAG_1], HOLD_STATE ; TURN ON THE HOLD FLAG
  3071                              <1> 	;
  3072                              <1> 	;-----	ENABLE KEYBOARD
  3073 0000117C B0AE                <1> 	mov	al, ENA_KBD		; ENABLE KEYBOARD
  3074 0000117E E870010000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3075                              <1> K39A:
  3076 00001183 B020                <1> 	mov	al, EOI			; END OF INTERRUPT TO CONTROL PORT
  3077 00001185 E620                <1> 	out	20h, al ;out INTA00, al	; ALLOW FURTHER KEYSTROKE INTERRUPTS
  3078                              <1> 	;
  3079                              <1> 	;-----	DURING PAUSE INTERVAL, TURN COLOR CRT BACK ON
  3080 00001187 803D[00650000]07    <1>         cmp     byte [CRT_MODE], 7      ; IS THIS BLACK AND WHITE CARD
  3081 0000118E 740A                <1>         je      short K40              	; YES, NOTHING TO DO
  3082 00001190 66BAD803            <1> 	mov	dx, 03D8h		; PORT FOR COLOR CARD
  3083 00001194 A0[01650000]        <1>         mov     al, [CRT_MODE_SET] 	; GET THE VALUE OF THE CURRENT MODE
  3084 00001199 EE                  <1> 	out	dx, al			; SET THE CRT MODE, SO THAT CRT IS ON
  3085                              <1> 	;
  3086                              <1> K40:					; PAUSE-LOOP
  3087 0000119A F605[04650000]08    <1>         test    byte [KB_FLAG_1], HOLD_STATE ; CHECK HOLD STATE FLAG
  3088 000011A1 75F7                <1> 	jnz	short K40		; LOOP UNTIL FLAG TURNED OFF
  3089                              <1> 	;
  3090 000011A3 E988FEFFFF          <1>         jmp     K27                     ; INTERRUPT_RETURN_NO_EOI
  3091                              <1>         ;
  3092                              <1> 	;-----	TEST SPECIAL CASE KEY 55
  3093                              <1> K41:					; NO-PAUSE
  3094 000011A8 3C37                <1> 	cmp	al, 55			; TEST FOR */PRTSC KEY
  3095 000011AA 7513                <1> 	jne	short K42		; NOT-KEY-55
  3096 000011AC F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3097 000011AF 7405                <1> 	jz	short K41A		; NO, CTL-PRTSC IS VALID	
  3098 000011B1 F6C702              <1> 	test	bh, LC_E0		; YES, WAS LAST CODE AN E0?
  3099 000011B4 7421                <1> 	jz	short K42B		; NO, TRANSLATE TO A FUNCTION
  3100                              <1> K41A:	
  3101 000011B6 66B80072            <1> 	mov	ax, 114*256		; START/STOP PRINTING SWITCH
  3102 000011BA E9EF000000          <1>         jmp     K57                     ; BUFFER_FILL
  3103                              <1> 	;
  3104                              <1> 	;-----	SET UP TO TRANSLATE CONTROL SHIFT
  3105                              <1> K42:					; NOT-KEY-55
  3106 000011BF 3C0F                <1> 	cmp	al, 15			; IS IT THE TAB KEY?
  3107 000011C1 7414                <1> 	je	short K42B		; YES, XLATE TO FUNCTION CODE
  3108 000011C3 3C35                <1> 	cmp	al, 53			; IS IT THE / KEY?
  3109 000011C5 750E                <1> 	jne	short K42A		; NO, NO MORE SPECIAL CASES	
  3110 000011C7 F6C702              <1> 	test	bh, LC_E0		; YES, IS IT FROM THE KEY PAD?
  3111 000011CA 7409                <1> 	jz	short K42A		; NO, JUST TRANSLATE
  3112 000011CC 66B80095            <1> 	mov	ax, 9500h		; YES, SPECIAL CODE FOR THIS ONE
  3113 000011D0 E9D9000000          <1> 	jmp	K57			; BUFFER FILL	
  3114                              <1> K42A:
  3115                              <1> 	;mov	ebx, _K8		; SET UP TO TRANSLATE CTL
  3116 000011D5 3C3B                <1> 	cmp	al, 59			; IS IT IN CHARACTER TABLE?
  3117                              <1>         ;jb	short K45F              ; YES, GO TRANSLATE CHAR
  3118                              <1> 	;;jb	K56 ; 20/02/2015
  3119                              <1> 	;;jmp	K64 ; 20/02/2015
  3120                              <1> K42B:
  3121 000011D7 BB[F8630000]        <1> 	mov	ebx, _K8		; SET UP TO TRANSLATE CTL
  3122                              <1> 	;;jmp	K64
  3123                              <1> 	;jb	K56 ;; 20/02/2015	
  3124                              <1> 	; 24/12/2021
  3125 000011DC 7267                <1> 	jb	short K45F
  3126 000011DE E9B9000000          <1> 	jmp	K64	
  3127                              <1>         ;
  3128                              <1> 	;-----	NOT IN CONTROL SHIFT
  3129                              <1> K44:					; NOT-CTL-SHIFT
  3130 000011E3 3C37                <1> 	cmp	al, 55			; PRINT SCREEN KEY?
  3131 000011E5 7528                <1> 	jne	short K45		; NOT PRINT SCREEN
  3132 000011E7 F6C710              <1> 	test	bh, KBX			; IS THIS ENHANCED KEYBOARD?
  3133 000011EA 7407                <1> 	jz	short K44A		; NO, TEST FOR SHIFT STATE	
  3134 000011EC F6C702              <1> 	test	bh, LC_E0		; YES, LAST CODE A MARKER?
  3135 000011EF 7507                <1> 	jnz	short K44B		; YES, IS PRINT SCREEN
  3136 000011F1 EB41                <1> 	jmp	short K45C		; NO, TRANSLATE TO '*' CHARACTER
  3137                              <1> K44A:
  3138 000011F3 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; NOT 101 KBD, SHIFT KEY DOWN?
  3139 000011F6 743C                <1> 	jz	short K45C		; NO, TRANSLATE TO '*' CHARACTER
  3140                              <1> 	;
  3141                              <1> 	;-----	ISSUE INTERRUPT TO INDICATE PRINT SCREEN FUNCTION
  3142                              <1> K44B:
  3143 000011F8 B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  3144 000011FA E8F4000000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3145 000011FF B020                <1> 	mov	al, EOI			; END OF CURRENT INTERRUPT
  3146 00001201 E620                <1> 	out	20h, al ;out INTA00, al	; SO FURTHER THINGS CAN HAPPEN
  3147                              <1> 	; Print Screen !!!		; ISSUE PRINT SCREEN INTERRUPT (INT 05h)
  3148                              <1> 	;PUSH 	BP			; SAVE POINTER
  3149                              <1> 	;INT 	5H			; ISSUE PRINT SCREEN INTERRUPT
  3150                              <1> 	;POP	BP			; RESTORE POINTER
  3151 00001203 8025[06650000]FC    <1>         and     byte [KB_FLAG_3], ~(LC_E0+LC_E1) ; ZERO OUT THESE FLAGS
  3152 0000120A E921FEFFFF          <1>         jmp     K27                     ; GO BACK WITHOUT EOI OCCURRING
  3153                              <1> 	;
  3154                              <1> 	;-----	HANDLE IN-CORE KEYS
  3155                              <1> K45:					; NOT-PRINT-SCREEN
  3156 0000120F 3C3A                <1> 	cmp	al, 58			; TEST FOR IN-CORE AREA
  3157 00001211 7734                <1> 	ja	short K46		; JUMP IF NOT
  3158 00001213 3C35                <1> 	cmp	al, 53			; IS THIS THE '/' KEY?
  3159 00001215 7505                <1> 	jne	short K45A		; NO, JUMP
  3160 00001217 F6C702              <1> 	test	bh, LC_E0		; WAS THE LAST CODE THE MARKER?
  3161 0000121A 7518                <1> 	jnz	short K45C		; YES, TRANSLATE TO CHARACTER
  3162                              <1> K45A:
  3163 0000121C B91A000000          <1> 	mov	ecx, 26			; LENGHT OF SEARCH
  3164 00001221 BF[CE630000]        <1> 	mov	edi, K30+10		; POINT TO TABLE OF A-Z CHARS
  3165 00001226 F2AE                <1> 	repne	scasb			; IS THIS A LETTER KEY?
  3166                              <1> 		; 20/02/2015
  3167 00001228 7505                <1> 	jne	short K45B              ; NO, SYMBOL KEY
  3168                              <1> 	;
  3169 0000122A F6C340              <1> 	test	bl, CAPS_STATE		; ARE WE IN CAPS_LOCK?
  3170 0000122D 750C                <1> 	jnz	short K45D		; TEST FOR SURE
  3171                              <1> K45B:
  3172 0000122F F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; ARE WE IN SHIFT STATE?
  3173 00001232 750C                <1> 	jnz	short K45E		; YES, UPPERCASE
  3174                              <1> 					; NO, LOWERCASE
  3175                              <1> K45C:
  3176 00001234 BB[50640000]        <1> 	mov	ebx, K10		; TRANSLATE TO LOWERCASE LETTERS
  3177 00001239 EB51                <1> 	jmp	short K56	
  3178                              <1> K45D:					; ALMOST-CAPS-STATE
  3179 0000123B F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; CL ON. IS SHIFT ON, TOO?
  3180 0000123E 75F4                <1> 	jnz	short K45C		; SHIFTED TEMP OUT OF CAPS STATE
  3181                              <1> K45E:
  3182 00001240 BB[A8640000]        <1> 	mov	ebx, K11		; TRANSLATE TO UPPER CASE LETTERS
  3183 00001245 EB45                <1> K45F:	jmp	short K56
  3184                              <1> 	;
  3185                              <1> 	;-----	TEST FOR KEYS F1 - F10
  3186                              <1> K46:					; NOT IN-CORE AREA
  3187 00001247 3C44                <1> 	cmp	al, 68			; TEST FOR F1 - F10
  3188                              <1> 	;ja	short K47		; JUMP IF NOT
  3189                              <1> 	;jmp	short K53		; YES, GO DO FN KEY PROCESS			
  3190 00001249 7635                <1> 	jna	short K53		
  3191                              <1> 	;
  3192                              <1> 	;-----	HANDLE THE NUMERIC PAD KEYS
  3193                              <1> K47:					; NOT F1 - F10
  3194 0000124B 3C53                <1> 	cmp	al, 83			; TEST NUMPAD KEYS
  3195 0000124D 772D                <1> 	ja	short K52		; JUMP IF NOT
  3196                              <1> 	;
  3197                              <1> 	;-----	KEYPAD KEYS, MUST TEST NUM LOCK FOR DETERMINATION
  3198                              <1> K48:
  3199 0000124F 3C4A                <1> 	cmp	al , 74			; SPECIAL CASE FOR MINUS
  3200 00001251 74ED                <1> 	je	short K45E		; GO TRANSLATE
  3201 00001253 3C4E                <1> 	cmp	al , 78			; SPECIAL CASE FOR PLUS
  3202 00001255 74E9                <1> 	je	short K45E		; GO TRANSLATE
  3203 00001257 F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OFTHE NEW KEYS?
  3204 0000125A 750A                <1> 	jnz	short K49		; YES, TRANSLATE TO BASE STATE
  3205                              <1> 	;		
  3206 0000125C F6C320              <1> 	test 	bl, NUM_STATE		; ARE WE IN NUM LOCK
  3207 0000125F 7514                <1> 	jnz	short K50		; TEST FOR SURE
  3208 00001261 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; ARE WE IN SHIFT STATE?
  3209                              <1> 	;jnz	short K51		; IF SHIFTED, REALLY NUM STATE
  3210 00001264 75DA                <1> 	jnz	short K45E
  3211                              <1> 	;
  3212                              <1> 	;-----	BASE CASE FOR KEYPAD
  3213                              <1> K49:					
  3214 00001266 3C4C                <1> 	cmp	al, 76			; SPECIAL CASE FOR BASE STATE 5
  3215 00001268 7504                <1> 	jne	short K49A		; CONTINUE IF NOT KEYPAD 5
  3216 0000126A B0F0                <1> 	mov	al, 0F0h		; SPECIAL ASCII CODE	
  3217 0000126C EB40                <1> 	jmp	short K57		; BUFFER FILL
  3218                              <1> K49A:
  3219 0000126E BB[50640000]        <1> 	mov	ebx, K10		; BASE CASE TABLE	
  3220 00001273 EB27                <1> 	jmp	short K64		; CONVERT TO PSEUDO SCAN
  3221                              <1> 	;
  3222                              <1> 	;-----	MIGHT BE NUM LOCK, TEST SHIFT STATUS
  3223                              <1> K50:					; ALMOST-NUM-STATE
  3224 00001275 F6C303              <1>         test    bl, LEFT_SHIFT+RIGHT_SHIFT
  3225 00001278 75EC                <1> 	jnz 	short K49		; SHIFTED TEMP OUT OF NUM STATE
  3226 0000127A EBC4                <1> K51:	jmp	short K45E		; REALLY NUM STATE
  3227                              <1> 	;
  3228                              <1> 	;-----	TEST FOR THE NEW KEYS ON WT KEYBOARDS 
  3229                              <1> K52:					; NOT A NUMPAD KEY
  3230 0000127C 3C56                <1> 	cmp	al, 86			; IS IT THE NEW WT KEY?
  3231                              <1> 	;jne	short K53		; JUMP IF NOT
  3232                              <1> 	;jmp	short K45B		; HANDLE WITH REST OF LETTER KEYS
  3233 0000127E 74AF                <1> 	je	short K45B		
  3234                              <1> 	;
  3235                              <1> 	;-----	MUST BE F11 OR F12 
  3236                              <1> K53:					; F1 - F10 COME HERE, TOO
  3237 00001280 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; TEST SHIFT STATE
  3238 00001283 74E1                <1> 	jz	short K49		; JUMP, LOWER CASE PSEUDO SC'S
  3239                              <1> 		; 20/02/2015 
  3240 00001285 BB[A8640000]        <1> 	mov	ebx, K11		; UPPER CASE PSEUDO SCAN CODES
  3241 0000128A EB10                <1> 	jmp	short K64		; TRANSLATE SCAN
  3242                              <1> 	;
  3243                              <1> 	;-----	TRANSLATE THE CHARACTER
  3244                              <1> K56:					; TRANSLATE-CHAR
  3245 0000128C FEC8                <1> 	dec	al			; CONVERT ORIGIN
  3246 0000128E D7                  <1> 	xlat    			; CONVERT THE SCAN CODE TO ASCII
  3247 0000128F F605[06650000]02    <1> 	test	byte [KB_FLAG_3], LC_E0	; IS THIS A NEW KEY?
  3248 00001296 7416                <1> 	jz	short K57		; NO, GO FILL BUFFER
  3249 00001298 B4E0                <1> 	mov	ah, MC_E0		; YES, PUT SPECIAL MARKER IN AH
  3250 0000129A EB12                <1> 	jmp	short K57		; PUT IT INTO THE BUFFER	
  3251                              <1> 	;
  3252                              <1> 	;-----	TRANSLATE SCAN FOR PSEUDO SCAN CODES
  3253                              <1> K64:					; TRANSLATE-SCAN-ORGD
  3254 0000129C FEC8                <1> 	dec	al			; CONVERT ORIGIN
  3255 0000129E D7                  <1>        	xlat    	                ; CTL TABLE SCAN
  3256 0000129F 88C4                <1> 	mov	ah, al			; PUT VALUE INTO AH
  3257 000012A1 B000                <1> 	mov	al, 0			; ZERO ASCII CODE
  3258 000012A3 F605[06650000]02    <1> 	test	byte [KB_FLAG_3], LC_E0	; IS THIS A NEW KEY?
  3259 000012AA 7402                <1> 	jz	short K57		; NO, GO FILL BUFFER
  3260 000012AC B0E0                <1> 	mov	al, MC_E0		; YES, PUT SPECIAL MARKER IN AL
  3261                              <1> 	;
  3262                              <1> 	;-----	PUT CHARACTER INTO BUFFER
  3263                              <1> K57:					; BUFFER_FILL
  3264 000012AE 3CFF                <1> 	cmp	al, -1			; IS THIS AN IGNORE CHAR
  3265 000012B0 7405                <1>         je	short K59		; YES, DO NOTHING WITH IT
  3266                              <1> 	; 24/12/2021
  3267                              <1> 	;je	K26			; YES, DO NOTHING WITH IT
  3268 000012B2 80FCFF              <1> 	cmp	ah, -1			; LOOK FOR -1 PSEUDO SCAN
  3269                              <1> 	; 24/12/2021
  3270 000012B5 7505                <1>         jne	short K61		; NEAR_INTERRUPT_RETURN
  3271                              <1> 	;je	K26			; INTERRUPT_RETURN
  3272                              <1> K59:					; NEAR_INTERRUPT_RETURN
  3273 000012B7 E968FDFFFF          <1> 	jmp	K26			; INTERRUPT_RETURN
  3274                              <1> K61:					; NOT-CAPS-STATE
  3275 000012BC 8B1D[14650000]      <1> 	mov	ebx, [BUFFER_TAIL] 	; GET THE END POINTER TO THE BUFFER
  3276 000012C2 89DE                <1> 	mov	esi, ebx		; SAVE THE VALUE
  3277 000012C4 E8AAFAFFFF          <1> 	call	_K4			; ADVANCE THE TAIL
  3278 000012C9 3B1D[10650000]      <1> 	cmp	ebx, [BUFFER_HEAD] 	; HAS THE BUFFER WRAPPED AROUND
  3279 000012CF 740E                <1> 	je	short K62		; BUFFER_FULL_BEEP
  3280 000012D1 668906              <1> 	mov	[esi], ax		; STORE THE VALUE
  3281 000012D4 891D[14650000]      <1> 	mov	[BUFFER_TAIL], ebx 	; MOVE THE POINTER UP
  3282 000012DA E945FDFFFF          <1> 	jmp	K26
  3283                              <1> 	;;cli				; TURN OFF INTERRUPTS
  3284                              <1> 	;;mov	al, EOI			; END OF INTERRUPT COMMAND
  3285                              <1> 	;;out	INTA00, al		; SEND COMMAND TO INTERRUPT CONTROL PORT
  3286                              <1> 	;MOV	AL, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  3287                              <1> 	;CALL	SHIP_IT			; EXECUTE ENABLE
  3288                              <1> 	;MOV	AX, 9102H		; MOVE IN POST CODE & TYPE
  3289                              <1> 	;INT	15H			; PERFORM OTHER FUNCTION
  3290                              <1> 	;;and	byte [KB_FLAG_3],~(LC_E0+LC_E1) ; RESET LAST CHAR H.C. FLAG
  3291                              <1> 	;JMP	K27A			; INTERRUPT_RETURN
  3292                              <1> 	;;jmp   K27                    
  3293                              <1> 	;
  3294                              <1> 	;-----	BUFFER IS FULL SOUND THE BEEPER
  3295                              <1> K62:
  3296 000012DF B020                <1> 	mov	al, EOI			; ENABLE INTERRUPT CONTROLLER CHIP
  3297 000012E1 E620                <1> 	out	INTA00, al
  3298 000012E3 66B9A602            <1> 	mov	cx, 678			; DIVISOR FOR 1760 HZ
  3299 000012E7 B304                <1> 	mov	bl, 4			; SHORT BEEP COUNT (1/16 + 1/64 DELAY)
  3300 000012E9 E883010000          <1> 	call	beep			; GO TO COMMON BEEP HANDLER
  3301 000012EE E93DFDFFFF          <1> 	jmp     K27			; EXIT   
  3302                              <1> 
  3303                              <1> SHIP_IT:
  3304                              <1> 	;---------------------------------------------------------------------------------
  3305                              <1> 	; SHIP_IT
  3306                              <1> 	;	THIS ROUTINES HANDLES TRANSMISSION OF COMMAND AND DATA BYTES
  3307                              <1> 	;	TO THE KEYBOARD CONTROLLER.
  3308                              <1> 	;---------------------------------------------------------------------------------
  3309                              <1> 	;
  3310                              <1> 	;push	ax			; SAVE DATA TO SEND
  3311                              <1> 	; 24/12/2021
  3312 000012F3 50                  <1> 	push	eax
  3313                              <1> 	;-----	WAIT FOR COMMAND TO ACCEPTED
  3314 000012F4 FA                  <1> 	cli				; DISABLE INTERRUPTS TILL DATA SENT
  3315                              <1> 	; xor	ecx, ecx		; CLEAR TIMEOUT COUNTER
  3316 000012F5 B900000100          <1> 	mov	ecx, 10000h			
  3317                              <1> S10:
  3318 000012FA E464                <1> 	in	al, STATUS_PORT		; READ KEYBOARD CONTROLLER STATUS
  3319 000012FC A802                <1> 	test	al, INPT_BUF_FULL	; CHECK FOR ITS INPUT BUFFER BUSY
  3320 000012FE E0FA                <1> 	loopnz	S10			; WAIT FOR COMMAND TO BE ACCEPTED
  3321                              <1> 
  3322                              <1> 	;pop	ax			; GET DATA TO SEND
  3323                              <1> 	; 24/12/2021
  3324 00001300 58                  <1> 	pop	eax
  3325 00001301 E664                <1> 	out	STATUS_PORT, al		; SEND TO KEYBOARD CONTROLLER
  3326 00001303 FB                  <1> 	sti				; ENABLE INTERRUPTS AGAIN
  3327 00001304 C3                  <1> 	retn				; RETURN TO CALLER
  3328                              <1> 
  3329                              <1> SND_DATA:
  3330                              <1> 	; ---------------------------------------------------------------------------------
  3331                              <1> 	; SND_DATA
  3332                              <1> 	;	THIS ROUTINES HANDLES TRANSMISSION OF COMMAND AND DATA BYTES
  3333                              <1> 	;	TO THE KEYBOARD AND RECEIPT OF ACKNOWLEDGEMENTS. IT ALSO
  3334                              <1> 	;	HANDLES ANY RETRIES IF REQUIRED
  3335                              <1> 	; ---------------------------------------------------------------------------------
  3336                              <1> 	;
  3337                              <1> 	;push	ax			; SAVE REGISTERS
  3338                              <1> 	;push	bx
  3339                              <1> 	; 24/12/2021
  3340 00001305 50                  <1> 	push	eax
  3341 00001306 53                  <1> 	push	ebx
  3342 00001307 51                  <1> 	push	ecx
  3343 00001308 88C7                <1> 	mov	bh, al			; SAVE TRANSMITTED BYTE FOR RETRIES
  3344 0000130A B303                <1> 	mov	bl, 3			; LOAD RETRY COUNT
  3345                              <1> SD0:
  3346 0000130C FA                  <1> 	cli				; DISABLE INTERRUPTS
  3347 0000130D 8025[05650000]CF    <1> 	and	byte [KB_FLAG_2], ~(KB_FE+KB_FA) ; CLEAR ACK AND RESEND FLAGS
  3348                              <1> 	;
  3349                              <1> 	;-----	WAIT FOR COMMAND TO BE ACCEPTED
  3350 00001314 B900000100          <1> 	mov	ecx, 10000h		; MAXIMUM WAIT COUNT
  3351                              <1> SD5:
  3352 00001319 E464                <1> 	in	al, STATUS_PORT		; READ KEYBOARD PROCESSOR STATUS PORT
  3353 0000131B A802                <1> 	test	al, INPT_BUF_FULL	; CHECK FOR ANY PENDING COMMAND
  3354 0000131D E0FA                <1> 	loopnz	SD5			; WAIT FOR COMMAND TO BE ACCEPTED
  3355                              <1> 	;
  3356 0000131F 88F8                <1> 	mov	al, bh			; REESTABLISH BYTE TO TRANSMIT
  3357 00001321 E660                <1> 	out	PORT_A, al		; SEND BYTE
  3358 00001323 FB                  <1> 	sti				; ENABLE INTERRUPTS
  3359                              <1> 	;mov	cx, 01A00h		; LOAD COUNT FOR 10 ms+
  3360 00001324 B9FFFF0000          <1> 	mov	ecx, 0FFFFh
  3361                              <1> SD1:
  3362 00001329 F605[05650000]30    <1> 	test	byte [KB_FLAG_2], KB_FE+KB_FA ; SEE IF EITHER BIT SET
  3363 00001330 750F                <1> 	jnz	short SD3		; IF SET, SOMETHING RECEIVED GO PROCESS
  3364 00001332 E2F5                <1> 	loop	SD1			; OTHERWISE WAIT
  3365                              <1> SD2:
  3366 00001334 FECB                <1> 	dec	bl			; DECREMENT RETRY COUNT
  3367 00001336 75D4                <1> 	jnz	short SD0		; RETRY TRANSMISSION
  3368 00001338 800D[05650000]80    <1> 	or	byte [KB_FLAG_2], KB_ERR ; TURN ON TRANSMIT ERROR FLAG
  3369 0000133F EB09                <1> 	jmp	short SD4		; RETRIES EXHAUSTED FORGET TRANSMISSION
  3370                              <1> SD3:
  3371 00001341 F605[05650000]10    <1> 	test	byte [KB_FLAG_2], KB_FA ; SEE IF THIS IS AN ACKNOWLEDGE
  3372 00001348 74EA                <1> 	jz	short SD2		; IF NOT, GO RESEND
  3373                              <1> SD4:	
  3374 0000134A 59                  <1> 	pop	ecx			; RESTORE REGISTERS
  3375                              <1> 	;pop	bx
  3376                              <1> 	;pop	ax
  3377                              <1> 	; 24/12/2021
  3378 0000134B 5B                  <1> 	pop	ebx
  3379 0000134C 58                  <1> 	pop	eax
  3380 0000134D C3                  <1> 	retn				; RETURN, GOOD TRANSMISSION
  3381                              <1> 
  3382                              <1> SND_LED:
  3383                              <1> 	; ---------------------------------------------------------------------------------
  3384                              <1> 	; SND_LED
  3385                              <1> 	;	THIS ROUTINES TURNS ON THE MODE INDICATORS.
  3386                              <1> 	;
  3387                              <1> 	;----------------------------------------------------------------------------------
  3388                              <1> 	;
  3389 0000134E FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3390 0000134F F605[05650000]40    <1> 	test	byte [KB_FLAG_2], KB_PR_LED ; CHECK FOR MODE INDICATOR UPDATE
  3391 00001356 755F                <1> 	jnz 	short SL1		; DON'T UPDATE AGAIN IF UPDATE UNDERWAY
  3392                              <1> 	;
  3393 00001358 800D[05650000]40    <1> 	or	byte [KB_FLAG_2], KB_PR_LED ; TURN ON UPDATE IN PROCESS
  3394 0000135F B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  3395 00001361 E620                <1> 	out	20h, al ;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  3396 00001363 EB11                <1> 	jmp	short SL0		; GO SEND MODE INDICATOR COMMAND
  3397                              <1> SND_LED1:
  3398 00001365 FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3399 00001366 F605[05650000]40    <1> 	test	byte [KB_FLAG_2], KB_PR_LED ; CHECK FOR MODE INDICATOR UPDATE
  3400 0000136D 7548                <1> 	jnz	short SL1		; DON'T UPDATE AGAIN IF UPDATE UNDERWAY
  3401                              <1> 	;
  3402 0000136F 800D[05650000]40    <1> 	or	byte [KB_FLAG_2], KB_PR_LED ; TURN ON UPDATE IN PROCESS
  3403                              <1> SL0:
  3404 00001376 B0ED                <1> 	mov	al, LED_CMD		; LED CMD BYTE
  3405 00001378 E888FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3406 0000137D FA                  <1> 	cli
  3407 0000137E E836000000          <1> 	call	MAKE_LED		; GO FORM INDICATOR DATA BYTE
  3408 00001383 8025[05650000]F8    <1> 	and	byte [KB_FLAG_2], 0F8h	; ~KB_LEDS ; CLEAR MODE INDICATOR BITS
  3409 0000138A 0805[05650000]      <1> 	or	[KB_FLAG_2], al 	; SAVE PRESENT INDICATORS FOR NEXT TIME
  3410 00001390 F605[05650000]80    <1> 	test	byte [KB_FLAG_2], KB_ERR ; TRANSMIT ERROR DETECTED
  3411 00001397 750F                <1> 	jnz	short SL2		; IF SO, BYPASS SECOND BYTE TRANSMISSION
  3412                              <1> 	;
  3413 00001399 E867FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3414 0000139E FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3415 0000139F F605[05650000]80    <1> 	test	byte [KB_FLAG_2], KB_ERR ; TRANSMIT ERROR DETECTED
  3416 000013A6 7408                <1> 	jz	short SL3		; IF NOT, DON'T SEND AN ENABLE COMMAND
  3417                              <1> SL2:
  3418 000013A8 B0F4                <1> 	mov	al, KB_ENABLE		; GET KEYBOARD CSA ENABLE COMMAND
  3419 000013AA E856FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3420 000013AF FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3421                              <1> SL3:
  3422 000013B0 8025[05650000]3F    <1> 	and	byte [KB_FLAG_2], ~(KB_PR_LED+KB_ERR) ; TURN OFF MODE INDICATOR
  3423                              <1> SL1:					; UPDATE AND TRANSMIT ERROR FLAG
  3424 000013B7 FB                  <1> 	sti				; ENABLE INTERRUPTS
  3425 000013B8 C3                  <1> 	retn				; RETURN TO CALLER
  3426                              <1> 
  3427                              <1> MAKE_LED:
  3428                              <1> 	;---------------------------------------------------------------------------------
  3429                              <1> 	; MAKE_LED
  3430                              <1> 	;	THIS ROUTINES FORMS THE DATA BYTE NECESSARY TO TURN ON/OFF
  3431                              <1> 	;	THE MODE INDICATORS.
  3432                              <1> 	;---------------------------------------------------------------------------------
  3433                              <1> 	;
  3434                              <1> 	;push 	cx			; SAVE CX
  3435 000013B9 A0[03650000]        <1> 	mov	al, [KB_FLAG]		; GET CAPS & NUM LOCK INDICATORS
  3436 000013BE 2470                <1> 	and	al, CAPS_STATE+NUM_STATE+SCROLL_STATE ; ISOLATE INDICATORS
  3437                              <1> 	;mov	cl, 4			; SHIFT COUNT
  3438                              <1> 	;rol	al, cl			; SHIFT BITS OVER TO TURN ON INDICATORS
  3439 000013C0 C0C004              <1> 	rol	al, 4 ; 20/02/2015
  3440 000013C3 2407                <1> 	and	al, 07h			; MAKE SURE ONLY MODE BITS ON
  3441                              <1> 	;pop	cx
  3442 000013C5 C3                  <1> 	retn				; RETURN TO CALLER
  3443                              <1> 
  3444                              <1> ; % include 'kybdata.inc'   ; KEYBOARD DATA ; 11/03/2015
  3445                              <1> 
  3446                              <1> ; /// End Of KEYBOARD FUNCTIONS ///
  1870                                  
  1871                                  %include 'video.inc' ; 07/03/2015
  1872                              <1> ; Retro UNIX 386 v1 Kernel - VIDEO.INC
  1873                              <1> ; Last Modification: 26/02/2022
  1874                              <1> ;		  (Video Data is in 'VIDATA.INC')
  1875                              <1> ;
  1876                              <1> ; ///////// VIDEO (CGA) FUNCTIONS ///////////////
  1877                              <1> 
  1878                              <1> ; 07/02/2022
  1879                              <1> ; 02/02/2022 (simplified scroll up)
  1880                              <1> ; 16/01/2016
  1881                              <1> ; 30/06/2015
  1882                              <1> ; 27/06/2015
  1883                              <1> ; 11/03/2015
  1884                              <1> ; 02/09/2014
  1885                              <1> ; 30/08/2014
  1886                              <1> ; VIDEO FUNCTIONS
  1887                              <1> ; (write_tty - Retro UNIX 8086 v1 - U9.ASM, 01/02/2014)
  1888                              <1> 
  1889                              <1> write_tty:
  1890                              <1> 	; 02/02/2022
  1891                              <1> 	; 13/08/2015
  1892                              <1> 	; 02/09/2014
  1893                              <1> 	; 30/08/2014 (Retro UNIX 386 v1 - beginning)
  1894                              <1> 	; 01/02/2014 (Retro UNIX 8086 v1 - last update)
  1895                              <1> 	; 03/12/2013 (Retro UNIX 8086 v1 - beginning)	
  1896                              <1> 	; (Modified registers: EAX, EBX, ECX, EDX, ESI, EDI)
  1897                              <1> 	;
  1898                              <1> 	; INPUT -> AH = Color (Forecolor, Backcolor)
  1899                              <1> 	;	   AL = Character to be written
  1900                              <1> 	;	   EBX = Video Page (0 to 7)
  1901                              <1> 	;	   (BH = 0 --> Video Mode 3)
  1902                              <1> 
  1903                              <1> RVRT	equ	00001000b	; VIDEO VERTICAL RETRACE BIT
  1904                              <1> RHRZ	equ	00000001b	; VIDEO HORIZONTAL RETRACE BIT
  1905                              <1> 
  1906                              <1> ; Derived from "WRITE_TTY" procedure of IBM "pc-at" rombios source code
  1907                              <1> ; (06/10/1985), 'video.asm', INT 10H, VIDEO_IO
  1908                              <1> ;
  1909                              <1> ; 06/10/85  VIDEO DISPLAY BIOS
  1910                              <1> ;
  1911                              <1> ;--- WRITE_TTY ------------------------------------------------------------------
  1912                              <1> ;										:
  1913                              <1> ;   THIS INTERFACE PROVIDES A TELETYPE LIKE INTERFACE TO THE			:
  1914                              <1> ;   VIDEO CARDS. THE INPUT CHARACTER IS WRITTEN TO THE CURRENT			:
  1915                              <1> ;   CURSOR POSITION, AND THE CURSOR IS MOVED TO THE NEXT POSITION.		:
  1916                              <1> ;   IF THE CURSOR LEAVES THE LAST COLUMN OF THE FIELD, THE COLUMN		:
  1917                              <1> ;   IS SET TO ZERO, AND THE ROW VALUE IS INCREMENTED. IF THE ROW		:
  1918                              <1> ;   ROW VALUE LEAVES THE FIELD, THE CURSOR IS PLACED ON THE LAST ROW,		:
  1919                              <1> ;   FIRST COLUMN, AND THE ENTIRE SCREEN IS SCROLLED UP ONE LINE.		:
  1920                              <1> ;   WHEN THE SCREEN IS SCROLLED UP, THE ATTRIBUTE FOR FILLING THE		:
  1921                              <1> ;   NEWLY BLANKED LINE IS READ FROM THE CURSOR POSITION ON THE PREVIOUS		:
  1922                              <1> ;   LINE BEFORE THE SCROLL, IN CHARACTER MODE. IN GRAPHICS MODE,		:
  1923                              <1> ;   THE 0 COLOR IS USED.							:
  1924                              <1> ;   ENTRY --									:
  1925                              <1> ;     (AH) = CURRENT CRT MODE							:
  1926                              <1> ;     (AL) = CHARACTER TO BE WRITTEN						:
  1927                              <1> ;	    NOTE THAT BACK SPACE, CARRIAGE RETURN, BELL AND LINE FEED ARE	:
  1928                              <1> ;	    HANDLED AS COMMANDS RATHER THAN AS DISPLAY GRAPHICS CHARACTERS	:
  1929                              <1> ;     (BL) = FOREGROUND COLOR FOR CHAR WRITE IF CURRENTLY IN A GRAPHICS MODE	:
  1930                              <1> ;   EXIT -- 									:
  1931                              <1> ;     ALL REGISTERS SAVED							:
  1932                              <1> ;--------------------------------------------------------------------------------
  1933                              <1> 
  1934 000013C6 FA                  <1> 	cli
  1935                              <1> 	;
  1936                              <1> 	; READ CURSOR (04/12/2013)
  1937                              <1> 	; Retro UNIX 386 v1 Modifications: 30/08/2014
  1938 000013C7 08FF                <1> 	or	bh, bh
  1939                              <1> 	;jnz	beeper
  1940                              <1> 	; 02/02/2022
  1941 000013C9 7405                <1> 	jz	short u14
  1942 000013CB E992000000          <1> 	jmp	beeper
  1943                              <1> u14:
  1944                              <1> 	; 02/02/2022
  1945                              <1> 	;; 01/09/2014
  1946                              <1> 	;cmp	byte [CRT_MODE], 3
  1947                              <1> 	;je	short m3
  1948                              <1> 	;;
  1949                              <1> 	;call	set_mode
  1950                              <1> m3:
  1951 000013D0 89DE                <1> 	mov 	esi, ebx ; 13/08/2015 (0 to 7)
  1952                              <1> 	;shl	si, 1
  1953                              <1> 	; 02/02/2022
  1954 000013D2 D1E6                <1> 	shl	esi, 1
  1955 000013D4 81C6[F66A0000]      <1> 	add	esi, cursor_posn
  1956 000013DA 668B16              <1> 	mov	dx, [esi]
  1957                              <1> 	;
  1958                              <1> 	; dx now has the current cursor position
  1959                              <1> 	;
  1960 000013DD 3C0D                <1> 	cmp	al, 0Dh		; is it carriage return or control character
  1961 000013DF 7647                <1> 	jbe	short u8
  1962                              <1> 	;
  1963                              <1> 	; write the char to the screen
  1964                              <1> u0:	
  1965                              <1> 	; ah = attribute/color
  1966                              <1> 	; al = character
  1967                              <1> 	; bl = video page number (0 to 7)
  1968                              <1> 	; bh = 0
  1969                              <1> 	;
  1970 000013E1 E8D6010000          <1> 	call	write_c_current
  1971                              <1> 	;
  1972                              <1> 	; position the cursor for next char
  1973 000013E6 FEC2                <1> 	inc	dl		; next column
  1974                              <1> 	;cmp	dl, [CRT_COLS]
  1975 000013E8 80FA50              <1> 	cmp	dl, 80		; test for column overflow 
  1976                              <1>         ;jne	set_cpos
  1977                              <1> 	; 02/02/2022
  1978 000013EB 7405                <1> 	je	short u13
  1979 000013ED E9DE000000          <1> 	jmp	set_cpos
  1980                              <1> u13:
  1981 000013F2 B200                <1> 	mov	dl, 0		; column = 0
  1982                              <1> u10:				; (line feed found)
  1983 000013F4 80FE18              <1> 	cmp	dh, 25-1 	; check for last row
  1984 000013F7 7228                <1> 	jb 	short u6
  1985                              <1> 	;
  1986                              <1> 	; scroll required
  1987                              <1> u1:	
  1988                              <1> 	; SET CURSOR POSITION (04/12/2013)
  1989 000013F9 E8D2000000          <1> 	call	set_cpos
  1990                              <1> 	;
  1991                              <1> 	; determine value to fill with during scroll
  1992                              <1> u2:
  1993                              <1> 	; READ_AC_CURRENT		:
  1994                              <1> 	;   THIS ROUTINE READS THE ATTRIBUTE AND CHARACTER
  1995                              <1> 	;    AT THE CURRENT CURSOR POSITION
  1996                              <1> 	;
  1997                              <1> 	; INPUT				
  1998                              <1> 	;	(AH) = CURRENT CRT MODE
  1999                              <1> 	;	(BH) = DISPLAY PAGE ( ALPHA MODES ONLY )
  2000                              <1> 	;	(DS) = DATA SEGMENT
  2001                              <1> 	;	(ES) = REGEN SEGMENT
  2002                              <1> 	; OUTPUT			
  2003                              <1> 	;	(AL) = CHARACTER READ
  2004                              <1> 	;	(AH) = ATTRIBUTE READ
  2005                              <1> 	;
  2006                              <1> 	; mov	ah, [CRT_MODE] ; move current mode into ah
  2007                              <1> 	;
  2008                              <1> 	; bl = video page number
  2009                              <1> 	;
  2010 000013FE E82D010000          <1> 	call	find_position	; get regen location and port address
  2011                              <1> 	; dx = status port
  2012                              <1> 	; esi = cursor location/address
  2013                              <1> p11:
  2014 00001403 FB                  <1> 	sti			; enable interrupts
  2015 00001404 90                  <1> 	nop			; allow for small interupts window
  2016 00001405 FA                  <1> 	cli			; blocks interrupts for single loop
  2017 00001406 EC                  <1> 	in	al, dx		; get status from adapter
  2018 00001407 A801                <1> 	test	al, RHRZ	; is horizontal retrace low
  2019 00001409 75F8                <1> 	jnz	short p11	; wait until it is
  2020                              <1> p12:				; now wait for either retrace high
  2021 0000140B EC                  <1> 	in	al, dx		; get status
  2022 0000140C A809                <1> 	test	al, RVRT+RHRZ	; is horizontal or vertical retrace high
  2023 0000140E 74FB                <1> 	jz	short p12	; wait until either is active	
  2024                              <1> p13:
  2025 00001410 81C600800B00        <1> 	add	esi, 0B8000h	; 30/08/2014 (Retro UNIX 386 v1)
  2026 00001416 668B06              <1> 	mov 	ax, [esi]	; get the character and attribute
  2027                              <1> 	;
  2028                              <1> 	; al = character, ah = attribute
  2029                              <1> 	;
  2030 00001419 FB                  <1> 	sti
  2031                              <1> 	; bl = video page number 	
  2032                              <1> u3:
  2033                              <1> 	;;mov	ax, 0601h 	; scroll one line
  2034                              <1> 	;;sub	cx, cx		; upper left corner
  2035                              <1> 	;;mov	dh, 25-1 	; lower right row
  2036                              <1> 	;;;mov	dl, [CRT_COLS]
  2037                              <1> 	;mov	dl, 80		; lower right column	
  2038                              <1> 	;;dec	dl
  2039                              <1> 	;;mov	dl, 79
  2040                              <1> 
  2041                              <1> 	;;call	scroll_up	; 04/12/2013
  2042                              <1> 	;;; 11/03/2015
  2043                              <1> 	; 02/09/2014
  2044                              <1> 	;;;mov	cx, [crt_ulc] ; Upper left corner  (0000h)
  2045                              <1> 	;;;mov	dx, [crt_lrc] ; Lower right corner (184Fh)
  2046                              <1> 	; 11/03/2015
  2047                              <1> 	;sub	cx, cx
  2048                              <1> 	;mov	dx, 184Fh ; dl= 79 (column), dh = 24 (row)
  2049                              <1> 	;
  2050                              <1> 	; 02/02/2022 (simplied scroll up)
  2051                              <1> 	; ((retro unix 8086 v1 'scroll_up' in 'u9.s'))
  2052                              <1> 	;
  2053 0000141A B001                <1> 	mov	al, 1		; scroll 1 line up
  2054                              <1> 		; ah = attribute
  2055 0000141C E939010000          <1> 	jmp	scroll_up
  2056                              <1> ;u4:
  2057                              <1> 	;;int	10h		; video-call return
  2058                              <1> 				; scroll up the screen
  2059                              <1> 				; tty return
  2060                              <1> ;u5:
  2061                              <1> 	;retn			; return to the caller
  2062                              <1> 
  2063                              <1> u6:				; set-cursor-inc
  2064 00001421 FEC6                <1> 	inc	dh		; next row
  2065                              <1> 				; set cursor
  2066                              <1> ;u7:					
  2067                              <1> 	;;mov	ah, 02h
  2068                              <1> 	;;jmp	short u4 	; establish the new cursor
  2069                              <1> 	;call	set_cpos
  2070                              <1> 	;jmp 	short u5
  2071 00001423 E9A8000000          <1> 	jmp     set_cpos
  2072                              <1> 
  2073                              <1> 	; check for control characters
  2074                              <1> u8:
  2075 00001428 7434                <1> 	je	short u9
  2076 0000142A 3C0A                <1> 	cmp	al, 0Ah		; is it a line feed (0Ah)
  2077 0000142C 74C6                <1> 	je	short u10
  2078 0000142E 3C07                <1> 	cmp	al, 07h 	; is it a bell
  2079 00001430 7430                <1> 	je	short u11
  2080 00001432 3C08                <1> 	cmp	al, 08h		; is it a backspace
  2081                              <1> 	;jne	short u0
  2082 00001434 7420                <1> 	je	short bs	; 12/12/2013
  2083                              <1> 	; 12/12/2013 (tab stop)
  2084 00001436 3C09                <1> 	cmp	al, 09h		; is it a tab stop
  2085 00001438 75A7                <1> 	jne	short u0
  2086 0000143A 88D0                <1> 	mov	al, dl
  2087 0000143C 6698                <1> 	cbw
  2088 0000143E B108                <1> 	mov	cl, 8
  2089 00001440 F6F1                <1> 	div	cl
  2090 00001442 28E1                <1> 	sub	cl, ah
  2091                              <1> ts:
  2092                              <1> 	; 02/09/2014
  2093                              <1> 	; 01/09/2014
  2094 00001444 B020                <1> 	mov	al, 20h
  2095                              <1> tsloop:
  2096                              <1> 	;push	cx
  2097                              <1> 	;push	ax
  2098                              <1> 	; 02/02/2022
  2099 00001446 51                  <1> 	push	ecx
  2100 00001447 50                  <1> 	push	eax
  2101 00001448 30FF                <1> 	xor 	bh, bh
  2102                              <1> 	;mov	bl, [active_page]
  2103 0000144A E881FFFFFF          <1> 	call	m3
  2104                              <1> 	; 02/02/2022
  2105 0000144F 58                  <1> 	pop	eax
  2106 00001450 59                  <1>  	pop	ecx
  2107                              <1> 	;pop	ax  ; ah = attribute/color
  2108                              <1> 	;pop	cx
  2109 00001451 FEC9                <1> 	dec	cl
  2110 00001453 75F1                <1> 	jnz	short tsloop
  2111 00001455 C3                  <1> 	retn
  2112                              <1> bs:	
  2113                              <1> 	; back space found
  2114 00001456 08D2                <1> 	or	dl, dl 		; is it already at start of line
  2115                              <1> 	;je	short u7 	; set_cursor
  2116 00001458 7476                <1> 	jz	short set_cpos
  2117                              <1> 	;dec	dx     		; no -- just move it back
  2118                              <1> 	; 02/02/2022
  2119 0000145A FECA                <1> 	dec	dl
  2120                              <1> 	;jmp	short u7
  2121 0000145C EB72                <1> 	jmp	short set_cpos
  2122                              <1> 
  2123                              <1> 	; carriage return found
  2124                              <1> u9:
  2125 0000145E B200                <1> 	mov	dl, 0 		; move to first column
  2126                              <1> 	;jmp	short u7
  2127 00001460 EB6E                <1> 	jmp	short set_cpos
  2128                              <1> 
  2129                              <1> 	; line feed found
  2130                              <1> ;u10:
  2131                              <1> ;	cmp	dh, 25-1 	; bottom of screen
  2132                              <1> ;	jne	short u6 	; no, just set the cursor
  2133                              <1> ;       jmp     u1              ; yes, scroll the screen
  2134                              <1> 
  2135                              <1> beeper: 
  2136                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2137                              <1> 	; 18/01/2014
  2138                              <1> 	; 03/12/2013
  2139                              <1> 	; bell found
  2140                              <1> u11:
  2141 00001462 FB                  <1> 	sti
  2142 00001463 3A1D[066B0000]      <1> 	cmp	bl, [active_page]
  2143 00001469 7551                <1> 	jne	short u12	; Do not sound the beep 
  2144                              <1> 				; if it is not written on the active page
  2145 0000146B 66B93305            <1> 	mov	cx, 1331 	; divisor for 896 hz tone
  2146 0000146F B31F                <1> 	mov	bl, 31		; set count for 31/64 second for beep
  2147                              <1> 	;call	beep		; sound the pod bell
  2148                              <1> 	;jmp	short u5 	; tty_return
  2149                              <1> 	;retn
  2150                              <1> 	
  2151                              <1> TIMER	equ 	040h   		; 8254 TIMER - BASE ADDRESS
  2152                              <1> PORT_B	equ	061h		; PORT B READ/WRITE DIAGNOSTIC REGISTER
  2153                              <1> GATE2	equ	00000001b	; TIMER 2 INPUT CATE CLOCK BIT
  2154                              <1> SPK2	equ	00000010b	; SPEAKER OUTPUT DATA ENABLE BIT
  2155                              <1> 
  2156                              <1> beep:
  2157                              <1> 	; 07/02/2015
  2158                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2159                              <1> 	; 18/01/2014
  2160                              <1> 	; 03/12/2013
  2161                              <1> 	;
  2162                              <1> 	; TEST4.ASM - 06/10/85  POST AND BIOS UTILITY ROUTINES
  2163                              <1> 	;
  2164                              <1> 	; ROUTINE TO SOUND THE BEEPER USING TIMER 2 FOR TONE
  2165                              <1> 	;
  2166                              <1> 	; ENTRY:
  2167                              <1> 	;    (BL) = DURATION COUNTER ( 1 FOR 1/64 SECOND )
  2168                              <1> 	;    (CX) = FREQUENCY DIVISOR (1193180/FREQUENCY) (1331 FOR 886 HZ)
  2169                              <1> 	; EXIT:			:
  2170                              <1> 	;    (AX),(BL),(CX) MODIFIED.
  2171                              <1> 
  2172 00001471 9C                  <1> 	pushf  ; 18/01/2014	; save interrupt status
  2173 00001472 FA                  <1> 	cli			; block interrupts during update
  2174 00001473 B0B6                <1> 	mov	al, 10110110b	; select timer 2, lsb, msb binary
  2175 00001475 E643                <1> 	out	TIMER+3, al 	; write timer mode register
  2176 00001477 EB00                <1> 	jmp	$+2		; I/O delay
  2177 00001479 88C8                <1> 	mov	al, cl		; divisor for hz (low)
  2178 0000147B E642                <1> 	out	TIMER+2,AL	; write timer 2 count - lsb
  2179 0000147D EB00                <1> 	jmp	$+2		; I/O delay
  2180 0000147F 88E8                <1> 	mov	al, ch		; divisor for hz (high)
  2181 00001481 E642                <1> 	out	TIMER+2, al	; write timer 2 count - msb
  2182 00001483 E461                <1> 	in	al, PORT_B	; get current setting of port
  2183 00001485 88C4                <1> 	mov	ah, al		; save that setting
  2184 00001487 0C03                <1> 	or	al, GATE2+SPK2	; gate timer 2 and turn speaker on
  2185 00001489 E661                <1> 	out	PORT_B, al	; and restore interrupt status
  2186                              <1> 	;popf	; 18/01/2014
  2187 0000148B FB                  <1> 	sti
  2188                              <1> g7:				; 1/64 second per count (bl)
  2189 0000148C B90B040000          <1> 	mov	ecx, 1035	; delay count for 1/64 of a second	
  2190 00001491 E827000000          <1> 	call	waitf		; go to beep delay 1/64 count
  2191 00001496 FECB                <1> 	dec	bl		; (bl) length count expired?
  2192 00001498 75F2                <1> 	jnz	short g7	; no - continue beeping speaker
  2193                              <1> 	;
  2194                              <1> 	;pushf			; save interrupt status
  2195 0000149A FA                  <1> 	cli  	; 18/01/2014	; block interrupts during update
  2196 0000149B E461                <1> 	in	al, PORT_B	; get current port value
  2197                              <1>         ;or	al, not (GATE2+SPK2) ; isolate current speaker bits in case
  2198 0000149D 0CFC                <1>         or      al, ~(GATE2+SPK2)
  2199 0000149F 20C4                <1>         and	ah, al		; someone turned them off during beep
  2200 000014A1 88E0                <1> 	mov	al, ah		; recover value of port
  2201                              <1>         ;or	al, not (GATE2+SPK2) ; force speaker data off
  2202 000014A3 0CFC                <1> 	or 	al, ~(GATE2+SPK2) ; isolate current speaker bits in case
  2203 000014A5 E661                <1> 	out	PORT_B, al	; and stop speaker timer
  2204                              <1> 	;popf			; restore interrupt flag state
  2205 000014A7 FB                  <1> 	sti
  2206 000014A8 B90B040000          <1> 	mov	ecx, 1035	; force 1/64 second delay (short)
  2207 000014AD E80B000000          <1> 	call	waitf		; minimum delay between all beeps
  2208                              <1> 	;pushf			; save interrupt status
  2209 000014B2 FA                  <1> 	cli			; block interrupts during update
  2210 000014B3 E461                <1> 	in	al, PORT_B	; get current port value in case	
  2211 000014B5 2403                <1> 	and	al, GATE2+SPK2	; someone turned them on
  2212 000014B7 08E0                <1> 	or	al, ah		; recover value of port_b
  2213 000014B9 E661                <1> 	out	PORT_B, al	; restore speaker status
  2214 000014BB 9D                  <1> 	popf			; restore interrupt flag state
  2215                              <1> u12:	
  2216 000014BC C3                  <1> 	retn
  2217                              <1> 
  2218                              <1> REFRESH_BIT equ	00010000b 	; REFRESH TEST BIT
  2219                              <1> 
  2220                              <1> WAITF:
  2221                              <1> waitf:
  2222                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2223                              <1> 	; 03/12/2013
  2224                              <1> 	;
  2225                              <1> ;	push	ax		; save work register (ah)	
  2226                              <1> ;waitf1:
  2227                              <1> 				; use timer 1 output bits
  2228                              <1> ;	in	al, PORT_B	; read current counter output status
  2229                              <1> ;	and	al, REFRESH_BIT	; mask for refresh determine bit
  2230                              <1> ;	cmp	al, ah		; did it just change
  2231                              <1> ;	je	short waitf1	; wait for a change in output line
  2232                              <1> ;	;
  2233                              <1> ;	mov	ah, al		; save new lflag state
  2234                              <1> ;	loop	waitf1		; decrement half cycles till count end		
  2235                              <1> ;	;
  2236                              <1> ;	pop	ax		; restore (ah)
  2237                              <1> ;	retn			; return (cx)=0
  2238                              <1> 
  2239                              <1> ; 02/02/2022
  2240                              <1> ; 06/02/2015 (unix386.s <-- dsectrm2.s)
  2241                              <1> ; 17/12/2014 (dsectrm2.s)
  2242                              <1> ; WAITF
  2243                              <1> ; /// IBM PC-XT Model 286 System BIOS Source Code - Test 4 - 06/10/85 ///
  2244                              <1> ;
  2245                              <1> ;---WAITF-----------------------------------------------------------------------
  2246                              <1> ;	FIXED TIME WAIT ROUTINE (HARDWARE CONTROLLED - NOT PROCESSOR)
  2247                              <1> ; ENTRY:
  2248                              <1> ;	(CX) =	COUNT OF 15.085737 MICROSECOND INTERVALS TO WAIT
  2249                              <1> ;	      	MEMORY REFRESH TIMER 1 OUTPUT USED AS REFERENCE
  2250                              <1> ; EXIT:
  2251                              <1> ;	       	AFTER (CX) TIME COUNT (PLUS OR MINUS 16 MICROSECONDS)
  2252                              <1> ;	(CX) = 0	
  2253                              <1> ;-------------------------------------------------------------------------------
  2254                              <1> 
  2255                              <1> ; Refresh period: 30 micro seconds (15-80 us)
  2256                              <1> ; (16/12/2014 - AWARDBIOS 1999 - ATORGS.ASM, WAIT_REFRESH)
  2257                              <1> 
  2258                              <1> ;WAITF:					; DELAY FOR (CX)*15.085737 US
  2259 000014BD 50                  <1> 	push	eax ; 02/02/2022	; SAVE WORK REGISTER (AH)
  2260                              <1> 	;push	ax
  2261                              <1> 	; 16/12/2014
  2262                              <1> 	;shr	cx, 1			; convert to count of 30 micro seconds
  2263 000014BE D1E9                <1> 	shr	ecx, 1	; 21/02/2015
  2264                              <1> ;17/12/2014	
  2265                              <1> ;WAITF1:
  2266                              <1> ;	IN	AL, PORT_B   ;061h	; READ CURRENT COUNTER OUTPUT STATUS
  2267                              <1> ;	AND	AL, REFRESH_BIT	;00010000b ; MASK FOR REFRESH DETERMINE BIT
  2268                              <1> ;	CMP	AL, AH			; DID IT JUST CHANGE
  2269                              <1> ;	JE	short WAITF1		; WAIT FOR A CHANGE IN OUTPUT LINE
  2270                              <1> ;	MOV	AH, AL			; SAVE NEW FLAG STATE
  2271                              <1> ;	LOOP	WAITF1			; DECREMENT HALF CYCLES TILL COUNT END		
  2272                              <1> 	;
  2273                              <1> 	; 17/12/2014
  2274                              <1> 	;
  2275                              <1> 	; Modification from 'WAIT_REFRESH' procedure of AWARD BIOS - 1999
  2276                              <1> 	;
  2277                              <1> ;WAIT_REFRESH:  Uses port 61, bit 4 to have CPU speed independent waiting.
  2278                              <1> ;   	INPUT:  CX = number of refresh periods to wait
  2279                              <1> ;     	       (refresh periods = 1 per 30 microseconds on most machines)
  2280                              <1> WR_STATE_0:
  2281 000014C0 E461                <1> 	IN	AL,PORT_B		; IN AL,SYS1
  2282 000014C2 A810                <1> 	TEST	AL,010H
  2283 000014C4 74FA                <1> 	JZ	SHORT WR_STATE_0
  2284                              <1> WR_STATE_1:
  2285 000014C6 E461                <1> 	IN	AL,PORT_B		; IN AL,SYS1
  2286 000014C8 A810                <1> 	TEST	AL,010H
  2287 000014CA 75FA                <1> 	JNZ	SHORT WR_STATE_1
  2288 000014CC E2F2                <1>         LOOP    WR_STATE_0
  2289                              <1> 	;
  2290                              <1> 	;pop	ax
  2291 000014CE 58                  <1> 	pop	eax ; 02/02/2022	; RESTORE (AH)
  2292 000014CF C3                  <1> 	RETn				; (CX) = 0
  2293                              <1> 
  2294                              <1> set_cpos:
  2295                              <1> 	; 26/02/2022
  2296                              <1> 	; 02/02/2022
  2297                              <1> 	; 27/06/2015
  2298                              <1> 	; 01/09/2014
  2299                              <1> 	; 30/08/2014 (Retro UNIX 386 v1 - beginning)
  2300                              <1> 	;
  2301                              <1> 	; 12/12/2013 (Retro UNIX 8086 v1 - last update) 
  2302                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - beginning)
  2303                              <1> 	;
  2304                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2305                              <1> 	;
  2306                              <1> 	; SET_CPOS
  2307                              <1> 	;	THIS ROUTINE SETS THE CURRENT CURSOR POSITION TO THE
  2308                              <1> 	;	NEW X-Y VALUES PASSED
  2309                              <1> 	; INPUT
  2310                              <1> 	;	DX - ROW,COLUMN OF NEW CURSOR
  2311                              <1> 	;	BH - DISPLAY PAGE OF CURSOR
  2312                              <1> 	; OUTPUT
  2313                              <1> 	;	CURSOR IS SET AT 6845 IF DISPLAY PAGE IS CURRENT DISPLAY
  2314                              <1> 	;
  2315 000014D0 0FB6C3              <1>         movzx   eax, bl	; BL = video page number ; 27/06/2015 (movzx)
  2316 000014D3 D0E0                <1>         shl     al, 1   ; word offset
  2317 000014D5 BE[F66A0000]        <1> 	mov	esi, cursor_posn
  2318 000014DA 01C6                <1>         add     esi, eax
  2319 000014DC 668916              <1> 	mov	[esi], dx ; save the pointer
  2320 000014DF 381D[066B0000]      <1> 	cmp	[active_page], bl
  2321 000014E5 7536                <1> 	jne	short m17
  2322                              <1> 
  2323 000014E7 FA                  <1> 	cli	; 26/02/2022
  2324                              <1> 
  2325                              <1> 	;call	m18	; CURSOR SET
  2326                              <1> ;m17:			; SET_CPOS_RETURN
  2327                              <1> 	; 01/09/2014
  2328                              <1> ;	retn
  2329                              <1> 		; DX = row/column
  2330                              <1> m18:
  2331 000014E8 E835000000          <1> 	call	position ; determine location in regen buffer	
  2332                              <1> 	;mov	cx, [CRT_START]
  2333                              <1> 	; 26/02/2022
  2334 000014ED 0FB70D[F46A0000]    <1> 	movzx	ecx, word [CRT_START]
  2335 000014F4 01C1                <1> 	add	ecx, eax
  2336                              <1> 	;add	cx, ax  ; add char position in regen buffer
  2337                              <1> 			; to the start address (offset) for this page
  2338                              <1> 	;shr	cx, 1	; divide by 2 for char only count
  2339                              <1> 	; 26/02/2022
  2340 000014F6 D1E9                <1> 	shr	ecx, 1
  2341 000014F8 B40E                <1> 	mov	ah, 14	; register number for cursor
  2342                              <1> 	
  2343 000014FA E802000000          <1> 	call	m16	; output value to the 6845
  2344 000014FF FB                  <1> 	sti	; 26/02/2022
  2345 00001500 C3                  <1> 	retn
  2346                              <1> 
  2347                              <1> 	; 26/02/2022
  2348                              <1> 	; 02/02/2022
  2349                              <1> 	;-----	THIS ROUTINE OUTPUTS THE CX REGISTER
  2350                              <1> 	;	TO THE 6845 REGISTERS NAMED IN (AH)
  2351                              <1> m16:
  2352                              <1> 	;cli	; 26/02/2022
  2353                              <1> 	;mov	dx, [addr_6845] ; address register
  2354 00001501 66BAD403            <1> 	mov 	dx, 03D4h ; I/O address of color card
  2355 00001505 88E0                <1> 	mov	al, ah	; get value
  2356 00001507 EE                  <1> 	out	dx, al	; register set
  2357                              <1> 	;inc	dx	; data register
  2358                              <1> 	; 02/02/2022
  2359 00001508 FEC2                <1> 	inc	dl
  2360 0000150A EB00                <1> 	jmp	$+2	; i/o delay
  2361 0000150C 88E8                <1> 	mov	al, ch	; data
  2362 0000150E EE                  <1> 	out	dx, al	
  2363                              <1> 	;dec	dx
  2364                              <1> 	; 02/02/2022	
  2365 0000150F FECA                <1> 	dec	dl
  2366 00001511 88E0                <1> 	mov	al, ah
  2367 00001513 FEC0                <1> 	inc	al	; point to other data register
  2368 00001515 EE                  <1> 	out	dx, al	; set for second register
  2369                              <1> 	;inc	dx
  2370                              <1> 	; 02/02/2022
  2371 00001516 FEC2                <1> 	inc	dl
  2372 00001518 EB00                <1> 	jmp	$+2	; i/o delay
  2373 0000151A 88C8                <1> 	mov	al, cl	; second data value
  2374 0000151C EE                  <1> 	out	dx, al
  2375                              <1> 	;sti	; 26/02/2022
  2376                              <1> m17:
  2377 0000151D C3                  <1> 	retn
  2378                              <1> 
  2379                              <1> set_ctype:
  2380                              <1> 	; 07/02/2022
  2381                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2382                              <1> 	;
  2383                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2384                              <1> 
  2385                              <1> ;	CH) = BITS 4-0 = START LINE FOR CURSOR
  2386                              <1> ;       ** HARDWARE WILL ALWAYS CAUSE BLINK
  2387                              <1> ;       ** SETTING BIT 5 OR 6 WILL CAUSE ERRATIC BLINKING
  2388                              <1> ;          OR NO CURSOR AT ALL
  2389                              <1> ;	(CL) = BITS 4-0 = END LINE FOR CURSOR
  2390                              <1> 
  2391                              <1> ;------------------------------------------------
  2392                              <1> ; SET_CTYPE
  2393                              <1> ;	THIS ROUTINE SETS THE CURSOR VALUE
  2394                              <1> ; INPUT
  2395                              <1> ;	(CX) HAS CURSOR VALUE CH-START LINE, CL-STOP LINE
  2396                              <1> ; OUTPUT	
  2397                              <1> ;	NONE
  2398                              <1> ;------------------------------------------------
  2399                              <1> 
  2400 0000151E B40A                <1> 	mov	ah, 10	; 6845 register for cursor set
  2401                              <1> 	;mov	[CURSOR_MODE], cx ; save in data area
  2402                              <1> 	;call	m16	; output cx register
  2403                              <1> 	;retn
  2404                              <1> 	; 07/02/2022
  2405 00001520 EBDF                <1> 	jmp	short m16
  2406                              <1> 
  2407                              <1> position:
  2408                              <1> 	; 26/02/2022
  2409                              <1> 	; 02/02/2022
  2410                              <1> 	; 27/06/2015
  2411                              <1> 	; 02/09/2014
  2412                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2413                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1)
  2414                              <1> 	;
  2415                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2416                              <1> 	;
  2417                              <1> 	; POSITION
  2418                              <1> 	;	THIS SERVICE ROUTINE CALCULATES THE REGEN BUFFER ADDRESS
  2419                              <1> 	;	OF A CHARACTER IN THE ALPHA MODE
  2420                              <1> 	; INPUT
  2421                              <1> 	;	AX = ROW, COLUMN POSITION
  2422                              <1> 	; OUTPUT
  2423                              <1> 	;	AX = OFFSET OF CHAR POSITION IN REGEN BUFFER
  2424                              <1> 
  2425                              <1> 		; DX = ROW, COLUMN POSITION
  2426                              <1> 	;movzx	eax, byte [CRT_COLS] ; 27/06/2015
  2427 00001522 31C0                <1> 	xor	eax, eax ; 02/09/2014
  2428 00001524 B050                <1> 	mov	al, 80	; determine bytes to row	
  2429 00001526 F6E6                <1> 	mul	dh	; row value
  2430                              <1> 	;xor	dh, dh	; 0
  2431                              <1> 	;add	ax, dx	; add column value to the result
  2432                              <1> 	; 26/02/2022
  2433 00001528 00D0                <1> 	add	al, dl
  2434 0000152A 80D400              <1> 	adc	ah, 0	
  2435                              <1> 	;shl	ax, 1	; * 2 for attribute bytes
  2436                              <1> 	; 02/02/2022
  2437 0000152D D1E0                <1> 	shl	eax, 1
  2438                              <1> 		; EAX = AX = OFFSET OF CHAR POSITION IN REGEN BUFFER
  2439 0000152F C3                  <1> 	retn
  2440                              <1> 
  2441                              <1> find_position:
  2442                              <1> 	; 02/02/2022
  2443                              <1> 	; 27/06/2015
  2444                              <1> 	; 07/09/2014
  2445                              <1> 	; 02/09/2014
  2446                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2447                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2448 00001530 0FB6CB              <1> 	movzx	ecx, bl ; video page number ; 27/06/2015 (movzx)
  2449 00001533 89CE                <1> 	mov	esi, ecx
  2450                              <1> 	;shl	si, 1
  2451                              <1> 	; 02/02/2022
  2452 00001535 D1E6                <1> 	shl	esi, 1
  2453 00001537 668B96[F66A0000]    <1> 	mov	dx, [esi+cursor_posn]
  2454 0000153E 7409                <1> 	jz	short p21
  2455                              <1> 	;xor	si, si
  2456                              <1> 	; 02/02/2022
  2457 00001540 31F6                <1> 	xor	esi, esi
  2458                              <1> p20:
  2459                              <1> 	;add	si, [CRT_LEN]
  2460 00001542 6681C6A00F          <1> 	add	si, 80*25*2 ; add length of buffer for one page		
  2461 00001547 E2F9                <1> 	loop	p20
  2462                              <1> p21:
  2463 00001549 6621D2              <1> 	and	dx, dx
  2464 0000154C 7407                <1> 	jz	short p22
  2465 0000154E E8CFFFFFFF          <1> 	call 	position ; determine location in regen in page
  2466 00001553 01C6                <1> 	add	esi, eax ; add location to start of regen page
  2467                              <1> p22:	
  2468                              <1> 	;mov	dx, [addr_6845] ; get base address of active display			
  2469                              <1> 	;mov	dx, 03D4h ; I/O address of color card
  2470                              <1> 	;add	dx, 6	; point at status port
  2471 00001555 66BADA03            <1> 	mov	dx, 03DAh ; status port
  2472                              <1> 	; cx = 0
  2473 00001559 C3                  <1> 	retn
  2474                              <1> 
  2475                              <1> scroll_up:
  2476                              <1> 	; 02/02/2022 (simplified scroll up)
  2477                              <1> 	;	((retro unix 8086 v1 'scroll_up' in 'u9.s'))
  2478                              <1> 	; 16/01/2016
  2479                              <1> 	; 07/09/2014
  2480                              <1> 	; 02/09/2014
  2481                              <1> 	; 01/09/2014 (Retro UNIX 386 v1 - beginning)
  2482                              <1> 	; 04/04/2014
  2483                              <1> 	; 04/12/2013
  2484                              <1> 	;
  2485                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2486                              <1> 	;
  2487                              <1> 	; SCROLL UP
  2488                              <1> 	;	THIS ROUTINE MOVES A BLOCK OF CHARACTERS UP
  2489                              <1> 	;	ON THE SCREEN
  2490                              <1> 	; INPUT
  2491                              <1> 	;	(AH) = CURRENT CRT MODE
  2492                              <1> 	;	(AL) = NUMBER OF ROWS TO SCROLL
  2493                              <1> 	;	(CX) = ROW/COLUMN OF UPPER LEFT CORNER
  2494                              <1> 	;	(DX) = ROW/COLUMN OF LOWER RIGHT CORNER
  2495                              <1> 	;	(BH) = ATTRIBUTE TO BE USED ON BLANKED LINE
  2496                              <1> 	;	(DS) = DATA SEGMENT
  2497                              <1> 	;	(ES) = REGEN BUFFER SEGMENT
  2498                              <1> 	; OUTPUT
  2499                              <1> 	;	NONE -- THE REGEN BUFFER IS MODIFIED
  2500                              <1> 	;
  2501                              <1> 	;	bh = 0  (02/09/2014)
  2502                              <1> 	;
  2503                              <1> 	; ((ah = 3))
  2504                              <1> 	; cl = left upper column
  2505                              <1> 	; ch = left upper row
  2506                              <1> 	; dl = right lower column
  2507                              <1> 	; dh = right lower row
  2508                              <1> 	;
  2509                              <1> 	; al = line count 
  2510                              <1> 	; ah = attribute to be used on blanked line
  2511                              <1> 	; bl = video page number (0 to 7)
  2512                              <1> 	; 
  2513                              <1> 
  2514                              <1> 	; 02/02/2022 'scroll_up' code
  2515                              <1> 	; ------------------------------------------------------
  2516                              <1> 	; (ref: Retro UNIX 8086 v1 'scroll_up' code in 'u9.asm')
  2517                              <1> 
  2518                              <1> 	; INPUT:
  2519                              <1> 	;		
  2520                              <1> 	; al = line count 
  2521                              <1> 	;	(0 or 1) .. 0 -> clear video page
  2522                              <1> 	; ah = attribute to be used on blanked line
  2523                              <1> 	; bl = video page number (0 to 7)
  2524                              <1> 
  2525                              <1> 	;cli
  2526 0000155A 31C9                <1> 	xor	ecx, ecx
  2527 0000155C 88C1                <1> 	mov	cl, al ; line count (cl)
  2528 0000155E BE00800B00          <1> 	mov	esi, 0B8000h
  2529 00001563 3A1D[066B0000]      <1> 	cmp	bl, [active_page]
  2530 00001569 7411                <1> 	je	short n1
  2531 0000156B 20DB                <1> 	and	bl, bl
  2532 0000156D 7422                <1> 	jz	short n3
  2533 0000156F 88DD                <1> 	mov	ch, bl ; video page number
  2534                              <1> n0:
  2535 00001571 6681C6A00F          <1> 	add	si, 25*80*2
  2536 00001576 FECD                <1> 	dec	ch
  2537 00001578 75F7                <1> 	jnz	short n0
  2538 0000157A EB15                <1> 	jmp	short n3
  2539                              <1> n1:
  2540 0000157C 660335[F46A0000]    <1> 	add	si, [CRT_START]
  2541                              <1> 	;
  2542 00001583 66BADA03            <1> 	mov	dx, 3DAh ; guaranteed to be color card here	
  2543                              <1> n2:			 ; wait_display_enable
  2544 00001587 EC                  <1> 	in	al, dx	 ; get port
  2545 00001588 A808                <1> 	test	al, RVRT ; wait for vertical retrace	
  2546 0000158A 74FB                <1> 	jz	short n2 ; wait_display_enable
  2547 0000158C B025                <1> 	mov	al, 25h
  2548 0000158E B2D8                <1> 	mov	dl, 0D8h ; address control port
  2549 00001590 EE                  <1> 	out	dx, al	 ; turn off video during vertical retrace
  2550                              <1> n3:
  2551                              <1> 	; cl = line count
  2552                              <1> 	; ah = attribute/color
  2553 00001591 89F7                <1> 	mov	edi, esi
  2554 00001593 20C9                <1> 	and	cl, cl
  2555 00001595 741F                <1> 	jz	short n6
  2556 00001597 6681C6A000          <1> 	add	si, 80*2 ; + 160 bytes
  2557 0000159C 66B98007            <1> 	mov	cx, 24*80 ; 24 rows/lines
  2558 000015A0 F366A5              <1> 	rep	movsw
  2559 000015A3 B150                <1> 	mov	cl, 80 ; 1 row (will be cleared)
  2560                              <1> n4:
  2561                              <1> 	; ah = character attribute/cocor
  2562 000015A5 B020                <1> 	mov	al, 20h ; fill with blanks
  2563 000015A7 F366AB              <1> 	rep	stosw
  2564                              <1> 
  2565 000015AA 3A1D[066B0000]      <1> 	cmp	bl, [active_page]
  2566 000015B0 7503                <1> 	jne	short n5
  2567                              <1> 
  2568                              <1> 	;mov	al, [crt_mode_set] ; get the value of mode set
  2569 000015B2 B029                <1> 	mov	al, 29h ; (ORGS.ASM), M7 mode set table value for mode 3	
  2570                              <1> 	;mov	dx, 03D8h ; always set color card port
  2571 000015B4 EE                  <1> 	out	dx, al
  2572                              <1> n5:
  2573 000015B5 C3                  <1> 	retn
  2574                              <1> n6:
  2575                              <1> 	; clear video page
  2576 000015B6 66B9D007            <1> 	mov	cx, 25*80 ; 25 rows/lines
  2577 000015BA EBE9                <1> 	jmp	short n4
  2578                              <1> 
  2579                              <1> 	; 26/02/2022
  2580                              <1> %if 0	; 16/01/2016 'scroll_up' code
  2581                              <1> 	; ------------------------------------------------------
  2582                              <1> 
  2583                              <1> 	; Test	Line Count
  2584                              <1> 	or	al, al
  2585                              <1> 	jz	short al_set
  2586                              <1> 	mov	bh, dh	; subtract lower row from upper row
  2587                              <1> 	sub	bh, ch
  2588                              <1> 	inc	bh	; adjust difference by 1
  2589                              <1> 	cmp	bh, al 	; line count = amount of rows in window?
  2590                              <1> 	jne	short al_set ; if not the we're all set
  2591                              <1> 	xor	al, al	; otherwise set al to zero
  2592                              <1> al_set:
  2593                              <1> 	xor	bh, bh	; 0
  2594                              <1> 	;push	ax
  2595                              <1> 	push	eax ; 26/02/2022
  2596                              <1> 	;mov 	esi, [crt_base]
  2597                              <1>         mov     esi, 0B8000h  
  2598                              <1>         cmp     bl, [active_page]
  2599                              <1> 	jne	short n0
  2600                              <1> 	;
  2601                              <1>         mov     ax, [CRT_START]
  2602                              <1>         add     si, ax
  2603                              <1>         jmp     short n1
  2604                              <1> n0:
  2605                              <1>         and     bl, bl
  2606                              <1> 	jz	short n1
  2607                              <1> 	mov	al, bl
  2608                              <1> n0x:
  2609                              <1>         ;add    si, [CRT_LEN]
  2610                              <1>         ;add    esi, 80*25*2 
  2611                              <1>         add     si, 80*25*2
  2612                              <1>         dec	al
  2613                              <1> 	jnz	short n0x
  2614                              <1> n1:	
  2615                              <1>         ; Scroll position
  2616                              <1> 	;push	dx ; 26/02/2022
  2617                              <1> 	mov	dx, cx	; now, upper left position in DX
  2618                              <1> 	call	position
  2619                              <1> 	add	esi, eax
  2620                              <1> 	mov	edi, esi
  2621                              <1> 	;pop	dx	; lower right position in DX
  2622                              <1> 	sub	dx, cx
  2623                              <1> 	inc	dh	; dh = #rows 
  2624                              <1> 	inc	dl	; dl = #cols in block
  2625                              <1> 	;pop	ax	; al = line count, ah = attribute
  2626                              <1> 	pop	eax ; 26/02/2022
  2627                              <1> 	xor	ecx, ecx
  2628                              <1> 	mov	cx, ax
  2629                              <1> 	;mov	ah, [CRT_COLS]
  2630                              <1> 	mov	ah, 80
  2631                              <1> 	mul	ah	; determine offset to from address
  2632                              <1> 	add	ax, ax  ; *2 for attribute byte
  2633                              <1> 	;
  2634                              <1> 	;push	ax	; offset 
  2635                              <1> 	;push	dx
  2636                              <1> 	; 26/02/2022
  2637                              <1> 	push	eax
  2638                              <1> 	push	edx
  2639                              <1> 	;
  2640                              <1> 	; 04/04/2014
  2641                              <1> 	mov	dx, 3DAh ; guaranteed to be color card here
  2642                              <1> n8:                      ; wait_display_enable
  2643                              <1>         in      al, dx   ; get port
  2644                              <1> 	test	al, RVRT ; wait for vertical retrace
  2645                              <1> 	jz	short n8 ; wait_display_enable
  2646                              <1> 	mov	al, 25h
  2647                              <1> 	mov	dl, 0D8h ; address control port
  2648                              <1> 	out	dx, al	; turn off video during vertical retrace
  2649                              <1> 	;pop	dx	; #rows, #cols
  2650                              <1>        	;pop	ax	; offset
  2651                              <1> 	; 26/02/2022
  2652                              <1> 	pop	edx
  2653                              <1> 	pop	eax
  2654                              <1> 	xchg	ax, cx	; 
  2655                              <1> 	; ecx = offset, al = line count, ah = attribute
  2656                              <1> ;n9:
  2657                              <1> 	or	al, al
  2658                              <1>         jz      short n3 
  2659                              <1>         add     esi, ecx ; from address for scroll
  2660                              <1> 	mov	bh, dh  ; #rows in block
  2661                              <1> 	sub	bh, al	; #rows to be moved
  2662                              <1> n2:
  2663                              <1> 	; Move rows
  2664                              <1> 	mov	cl, dl	; get # of cols to move
  2665                              <1> 	push	esi
  2666                              <1> 	push	edi	; save start address
  2667                              <1> n10:
  2668                              <1> 	movsw		; move that line on screen
  2669                              <1> 	dec	cl
  2670                              <1>         jnz     short n10
  2671                              <1> 	pop	edi
  2672                              <1> 	pop	esi	; recover addresses
  2673                              <1>         ;mov    cl, [CRT_COLS] 
  2674                              <1> 	;add	cl, cl
  2675                              <1>         ;mov    ecx, 80*2
  2676                              <1>         mov     cx, 80*2
  2677                              <1>         add     esi, ecx  ; next line
  2678                              <1>         add     edi, ecx
  2679                              <1> 	dec	bh	 ; count of lines to move
  2680                              <1> 	jnz	short n2 ; row loop
  2681                              <1> 	; bh = 0
  2682                              <1> 	mov	dh, al	 ; #rows	
  2683                              <1> n3:
  2684                              <1> 	; attribute in ah
  2685                              <1> 	mov	al, ' '	 ; fill with blanks
  2686                              <1> n3x:
  2687                              <1> 	; Clear rows
  2688                              <1>                 ; dh =  #rows
  2689                              <1>         mov	cl, dl	; get # of cols to clear
  2690                              <1>         push    edi     ; save address
  2691                              <1> n11:
  2692                              <1>         stosw           ; store fill character
  2693                              <1> 	dec	cl
  2694                              <1>         jnz     short n11
  2695                              <1>         pop     edi     ; recover address
  2696                              <1> 	;mov	cl, [CRT_COLS]
  2697                              <1> 	;add	cl, cl
  2698                              <1>         ;mov    ecx, 80*2
  2699                              <1>         mov	cl, 80*2
  2700                              <1>         add     edi, ecx
  2701                              <1> 	dec	dh
  2702                              <1> 	jnz	short n3x ; 16/01/2016
  2703                              <1> 	;
  2704                              <1> 	cmp	bl, [active_page]
  2705                              <1> 	jne	short n6
  2706                              <1> 	;mov	al, [CRT_MODE_SET] ; get the value of mode set
  2707                              <1> 	mov	al, 29h ; (ORGS.ASM), M7 mode set table value for mode 3
  2708                              <1> 	mov	dx, 03D8h ; always set color card port
  2709                              <1> 	out	dx, al
  2710                              <1> n6:
  2711                              <1> 	retn
  2712                              <1> 
  2713                              <1> %endif
  2714                              <1> 
  2715                              <1> write_c_current:
  2716                              <1> 	; 02/02/2022
  2717                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2718                              <1> 	; 18/01/2014
  2719                              <1> 	; 04/12/2013
  2720                              <1> 	;
  2721                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2722                              <1> 	;
  2723                              <1> 	; WRITE_C_CURRENT
  2724                              <1> 	;	THIS ROUTINE WRITES THE CHARACTER AT
  2725                              <1> 	;	THE CURRENT CURSOR POSITION, ATTRIBUTE UNCHANGED
  2726                              <1> 	; INPUT	
  2727                              <1> 	;	(AH) = CURRENT CRT MODE
  2728                              <1> 	;	(BH) = DISPLAY PAGE
  2729                              <1> 	;	(CX) = COUNT OF CHARACTERS TO WRITE
  2730                              <1> 	;	(AL) = CHAR TO WRITE
  2731                              <1> 	;	(DS) = DATA SEGMENT
  2732                              <1> 	;	(ES) = REGEN SEGMENT
  2733                              <1> 	; OUTPUT
  2734                              <1> 	;	DISPLAY REGEN BUFFER UPDATED
  2735                              <1> 
  2736 000015BC FA                  <1> 	cli		
  2737                              <1> 	; bl = video page
  2738                              <1> 	; al = character
  2739                              <1> 	; ah = color/attribute
  2740                              <1> 	;push	dx
  2741                              <1> 	;push	ax	; save character & attribute/color
  2742                              <1> 	; 02/02/2022
  2743 000015BD 52                  <1> 	push	edx
  2744 000015BE 50                  <1> 	push	eax
  2745 000015BF E86CFFFFFF          <1> 	call 	find_position  ; get regen location and port address
  2746                              <1> 	; esi = regen location
  2747                              <1> 	; dx = status port
  2748                              <1> 	;
  2749                              <1> 	; WAIT FOR HORIZONTAL RETRACE OR VERTICAL RETRACE
  2750                              <1> 	;
  2751                              <1> p41:			; wait for horizontal retrace is low or vertical
  2752 000015C4 FB                  <1> 	sti		; enable interrupts first
  2753 000015C5 3A1D[066B0000]      <1>         cmp     bl, [active_page]
  2754 000015CB 7510                <1> 	jne	short p44 
  2755 000015CD FA                  <1> 	cli 		; block interrupts for single loop
  2756 000015CE EC                  <1> 	in	al, dx	; get status from the adapter
  2757 000015CF A808                <1> 	test	al, RVRT ; check for vertical retrace first
  2758 000015D1 7509                <1> 	jnz	short p43 ; Do fast write now if vertical retrace
  2759 000015D3 A801                <1> 	test	al, RHRZ  ; is horizontal retrace low
  2760 000015D5 75ED                <1> 	jnz	short p41 ; wait until it is
  2761                              <1> p42:			; wait for either retrace high
  2762 000015D7 EC                  <1> 	in	al, dx	; get status again
  2763 000015D8 A809                <1> 	test	al, RVRT+RHRZ ; is horizontal or vertical retrace high
  2764 000015DA 74FB                <1> 	jz	short p42 ; wait until either retrace active
  2765                              <1> p43:	
  2766 000015DC FB                  <1> 	sti
  2767                              <1> p44:
  2768                              <1> 	;pop	ax	; restore the character (al) & attribute (ah)
  2769                              <1> 	; 02/02/2022
  2770 000015DD 58                  <1> 	pop	eax
  2771 000015DE 81C600800B00        <1> 	add	esi, 0B8000h ; 30/08/2014 (crt_base) 
  2772                              <1> 			; Retro UNIX 386 v1 feature only!
  2773 000015E4 668906              <1> 	mov	[esi], ax
  2774                              <1> 	;pop	dx
  2775                              <1> 	; 02/02/2022
  2776 000015E7 5A                  <1> 	pop	edx
  2777 000015E8 C3                  <1> 	retn
  2778                              <1> 
  2779                              <1> %if 0	; 02/02/2022
  2780                              <1> 
  2781                              <1> set_mode:
  2782                              <1> 	; 02/02/2022
  2783                              <1> 	; 16/01/2016
  2784                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2785                              <1> 	;
  2786                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2787                              <1> 
  2788                              <1> ;------------------------------------------------------
  2789                              <1> ; SET MODE					      :
  2790                              <1> ;	THIS ROUTINE INITIALIZES THE ATTACHMENT TO    :
  2791                              <1> ;	THE SELECTED MODE, THE SCREEN IS BLANKED.     :
  2792                              <1> ; INPUT						      :
  2793                              <1> ;	(AL) - MODE SELECTED (RANGE 0-7)	      :
  2794                              <1> ; OUTPUT					      :
  2795                              <1> ;	NONE					      :
  2796                              <1> ;------------------------------------------------------
  2797                              <1> 
  2798                              <1> 	push	edi ; 16/01/2016
  2799                              <1> 	push	ebx
  2800                              <1> 	push	edx
  2801                              <1> 	push	ecx ; 16/01/2016
  2802                              <1>         push    eax
  2803                              <1> 
  2804                              <1> 	;mov	dx, 03D4h 	; address or color card
  2805                              <1> 	mov	al, 3
  2806                              <1> ;M8:
  2807                              <1> 	mov	[CRT_MODE], al  ; save mode in global variable
  2808                              <1> 	mov	al, 29h
  2809                              <1> 	;mov	[CRT_MODE_SET], al ; save the mode set value
  2810                              <1> 	and	al, 037h	; video off, save high resolution bit	
  2811                              <1> 	;push	dx  		; save port value
  2812                              <1> 	;add	dx, 4		; point to control register
  2813                              <1> 	mov	dx, 3D8h
  2814                              <1> 	out	dx, al		; reset video to off to suppress rolling
  2815                              <1> 	;pop	dx
  2816                              <1> ;M9:
  2817                              <1> 	mov	ebx, video_params ; initialization table
  2818                              <1> 	;mov	ax, [ebx+10]      ; get the cursor mode from the table	
  2819                              <1> 	;xchg 	ah, al
  2820                              <1> 	;mov	[CURSOR_MODE], ax ; save cursor mode
  2821                              <1> 	xor	ah, ah		  ; ah is register number during loop 
  2822                              <1> 	
  2823                              <1> ;-----	LOOP THROUGH TABLE, OUTPUTTING REGISTER ADDRESS, THEN VALUE FROM TABLE
  2824                              <1> 	; 02/02/2022
  2825                              <1> 	; dx = 3D8h
  2826                              <1> 	xor	ecx, ecx
  2827                              <1> 	mov	cl, 16
  2828                              <1> 	;mov	ecx, 16 ; 16/01/2016
  2829                              <1> M10:			;  initialization loop
  2830                              <1> 	mov	al, ah 	; get 6845 register number
  2831                              <1> 	out	dx, al
  2832                              <1> 	;inc	dx      ; point to data port
  2833                              <1> 	; 02/02/2022
  2834                              <1> 	inc	dl ; 3D9h
  2835                              <1> 	inc	ah	; next register value
  2836                              <1> 	mov	al, [ebx] ; get table value
  2837                              <1> 	out	dx, al	; out to chip
  2838                              <1> 	inc	ebx	; next in table
  2839                              <1> 	;dec	dx	; back to pointer register
  2840                              <1> 	; 02/02/2022
  2841                              <1> 	dec	dl ; 3D8h
  2842                              <1> 	loop	M10	; do the whole table
  2843                              <1> 	
  2844                              <1> ;-----	FILL REGEN AREA WITH BLANK
  2845                              <1> 	;xor	ax, ax  
  2846                              <1> 	;mov	[CRT_START], ax  ; start address saved in global
  2847                              <1> 	;mov	[ACTIVE_PAGE], al ; 0 ; (re)set page value
  2848                              <1> 	;mov	ecx, 8192 ; number of words in color card
  2849                              <1> 	; black background, light gray characeter color, space character
  2850                              <1> 	;mov	ax, 0720h ; fill char for alpha - attribute
  2851                              <1> ;M13:			  ; clear buffer
  2852                              <1> 	;add	edi, 0B8000h ; [crt_base]
  2853                              <1> 	;rep	stosw	; FILL THE REGEN BUFFER WITH BLANKS
  2854                              <1> 
  2855                              <1> ;-----	ENABLE VIDEO AND CORRECT PORT SETTING
  2856                              <1> 	;mov	dx, 3D4h ; mov dx, word [ADDR_6845]
  2857                              <1> 			 ; prepare to output to video enable port
  2858                              <1> 	;;add	dx, 4	 ; point to the mode control gerister
  2859                              <1> 	; 02/02/2022
  2860                              <1> 	;mov	dx, 3D8h
  2861                              <1> 	; 
  2862                              <1> 	;mov	al, [CRT_MODE_SET] ; get the mode set value
  2863                              <1> 	mov	al, 29h
  2864                              <1> 	out	dx, al	 ; set video enable port
  2865                              <1> 
  2866                              <1> ;----- 	DETERMINE NUMBER OF COLUMNS, BOTH FOR ENTIRE DISPLAY
  2867                              <1> ;----- 	AND THE NUMBER TO BE USED FOR TTY INTERFACE
  2868                              <1> 	;
  2869                              <1> 	;mov byte [CRT_COLS], 80h ; initialize number of columns count
  2870                              <1> 	;
  2871                              <1> ;-----	SET CURSOR POSITIONS
  2872                              <1> 	;push	edi
  2873                              <1> 	;mov	word [CRT_LEN], 80*25*2
  2874                              <1> 	mov	edi, cursor_posn
  2875                              <1> 	mov	ecx, 4	; clear all cursor positions (16 bytes)
  2876                              <1> 	xor	eax, eax
  2877                              <1> 	rep 	stosd	; fill with zeroes
  2878                              <1> 	;pop	edi
  2879                              <1> 
  2880                              <1> ;-----	SET UP OVERSCAN REGISTER
  2881                              <1> 	inc	dx	; set overscan port to a default
  2882                              <1> 	mov	al, 30h	; 30H valuye for all modes except 640X200 bw
  2883                              <1> ;M14:
  2884                              <1> 	out	dx, al	; output the correct value to 3D9 port
  2885                              <1> 	;mov	[CRT_PALETTE], al ; save the value for future use
  2886                              <1> 
  2887                              <1> ;-----	NORMAL RETURN FROM ALL VIDEO RETURNS
  2888                              <1> 	;
  2889                              <1> 	pop	eax
  2890                              <1> 	pop	ecx ; 16/01/2016
  2891                              <1> 	pop	edx
  2892                              <1> 	pop	ebx
  2893                              <1> 	pop	edi ; 16/01/2016
  2894                              <1> 	retn
  2895                              <1> 
  2896                              <1> %endif
  2897                              <1> 	
  2898                              <1> tty_sw:
  2899                              <1> 	; 02/02/2022
  2900                              <1> 	; 30/06/2015
  2901                              <1> 	; 27/06/2015 
  2902                              <1> 	; 07/09/2014
  2903                              <1> 	; 02/09/2014 (Retro UNIX 386 v1 - beginning)
  2904                              <1> 	;
  2905                              <1> 	; (Modified registers : EAX)
  2906                              <1> 	;
  2907                              <1>         ;mov     byte [u.quant], 0  ; 04/03/2014
  2908                              <1> 	;
  2909                              <1> ;act_disp_page:
  2910                              <1> 	; 30/06/2015
  2911                              <1> 	; 04/03/2014  (act_disp_page --> tty_sw)
  2912                              <1> 	; 10/12/2013
  2913                              <1> 	; 04/12/2013
  2914                              <1> 	;
  2915                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2916                              <1> 	;
  2917                              <1> 	; ACT_DISP_PAGE
  2918                              <1> 	;	THIS ROUTINE SETS THE ACTIVE DISPLAY PAGE, ALLOWING
  2919                              <1> 	;	THE FULL USE OF THE MEMORY SET ASIDE FOR THE VIDEO ATTACHMENT
  2920                              <1> 	; INPUT
  2921                              <1> 	;	AL HAS THE NEW ACTIVE DISPLAY PAGE
  2922                              <1> 	; OUTPUT
  2923                              <1> 	;	THE 6845 IS RESET TO DISPLAY THAT PAGE
  2924                              <1> 
  2925                              <1> 	;cli
  2926                              <1> 
  2927 000015E9 53                  <1> 	push	ebx
  2928                              <1> 	;push	cx
  2929                              <1> 	;push	dx
  2930                              <1> 	; 02/02/2022
  2931 000015EA 51                  <1> 	push	ecx
  2932 000015EB 52                  <1> 	push	edx
  2933                              <1> 	;
  2934 000015EC A2[066B0000]        <1> 	mov	[active_page], al ; save active page value ; [ptty]
  2935                              <1> 	;;mov	cx, [CRT_LEN] ; get saved length of regen buffer
  2936                              <1> 	;mov	cx, 25*80*2
  2937                              <1> 	; 02/02/2022
  2938 000015F1 B9A00F0000          <1> 	mov	ecx, 25*80*2
  2939                              <1> 	; 27/06/2015
  2940 000015F6 0FB6D8              <1> 	movzx	ebx, al
  2941                              <1> 	; 02/02/2022
  2942 000015F9 89D8                <1> 	mov	eax, ebx
  2943                              <1> 	;
  2944                              <1> 	;cbw	; 07/09/2014 (ah=0)
  2945                              <1> 	;mul 	cx	; display page times regen length
  2946                              <1> 	; 02/02/2022
  2947 000015FB F7E1                <1> 	mul	ecx	
  2948                              <1> 	; 10/12/2013
  2949 000015FD 66A3[F46A0000]      <1> 	mov	[CRT_START], ax ; save start address for later
  2950                              <1> 	;mov	cx, ax	; start address to cx
  2951                              <1> 	; 02/02/2022
  2952 00001603 89C1                <1> 	mov	ecx, eax
  2953                              <1> 	;sar	cx, 1
  2954                              <1> 	;shr	cx, 1	; divide by 2 for 6845 handling
  2955                              <1> 	; 02/02/2022
  2956 00001605 D1E9                <1> 	shr	ecx, 1
  2957 00001607 B40C                <1> 	mov	ah, 12	; 6845 register for start address
  2958 00001609 E8F3FEFFFF          <1> 	call	m16
  2959                              <1> 	;sal	bx, 1
  2960                              <1> 	; 01/09/2014
  2961 0000160E D0E3                <1> 	shl	bl, 1	; * 2 for word offset
  2962 00001610 81C3[F66A0000]      <1> 	add	ebx, cursor_posn
  2963 00001616 668B13              <1> 	mov	dx, [ebx] ; get cursor for this page
  2964 00001619 E8CAFEFFFF          <1> 	call	m18
  2965                              <1> 	;
  2966                              <1> 	;pop	dx
  2967                              <1> 	;pop	cx
  2968                              <1> 	; 02/02/2022
  2969 0000161E 5A                  <1> 	pop	edx
  2970 0000161F 59                  <1> 	pop	ecx
  2971 00001620 5B                  <1> 	pop	ebx
  2972                              <1> 	;
  2973                              <1> 	;sti
  2974                              <1> 	;
  2975 00001621 C3                  <1> 	retn
  2976                              <1> 
  2977                              <1> ; %include 'vidata.inc' ; VIDEO DATA ; 11/03/2015
  2978                              <1> 
  2979                              <1> ; /// End Of VIDEO FUNCTIONS ///
  1872                                  
  1873                                  setup_rtc_int:
  1874                                  ; source: http://wiki.osdev.org/RTC
  1875 00001622 FA                      	cli		; disable interrupts
  1876                                  	; default int frequency is 1024 Hz (Lower 4 bits of register A is 0110b or 6)
  1877                                  	; in order to change this ...
  1878                                  	; frequency  = 32768 >> (rate-1) --> 32768 >> 5 = 1024
  1879                                  	; (rate must be above 2 and not over 15)
  1880                                  	; new rate = 15 --> 32768 >> (15-1) = 2 Hz
  1881 00001623 B08A                    	mov	al, 8Ah 
  1882 00001625 E670                    	out	70h, al ; set index to register A, disable NMI
  1883 00001627 90                      	nop
  1884 00001628 E471                    	in	al, 71h ; get initial value of register A
  1885 0000162A 88C4                    	mov 	ah, al
  1886 0000162C 80E4F0                  	and	ah, 0F0h
  1887 0000162F B08A                    	mov	al, 8Ah 
  1888 00001631 E670                    	out	70h, al ; reset index to register A
  1889 00001633 88E0                    	mov	al, ah
  1890 00001635 0C0F                    	or	al, 0Fh	; new rate (0Fh -> 15)
  1891 00001637 E671                    	out	71h, al ; write only our rate to A. Note, rate is the bottom 4 bits. 
  1892                                  	; enable RTC interrupt
  1893 00001639 B08B                    	mov	al, 8Bh ;
  1894 0000163B E670                    	out	70h, al ; select register B and disable NMI
  1895 0000163D 90                      	nop
  1896 0000163E E471                    	in	al, 71h ; read the current value of register B
  1897 00001640 88C4                    	mov	ah, al  ;
  1898 00001642 B08B                    	mov 	al, 8Bh ;
  1899 00001644 E670                    	out	70h, al ; set the index again (a read will reset the index to register B)	
  1900 00001646 88E0                    	mov	al, ah  ;
  1901 00001648 0C40                    	or	al, 40h ;
  1902 0000164A E671                    	out	71h, al ; write the previous value ORed with 0x40. This turns on bit 6 of register B
  1903 0000164C FB                      	sti
  1904 0000164D C3                      	retn
  1905                                  
  1906                                  ; Write memory information
  1907                                  ; Temporary Code
  1908                                  ; 06/11/2014
  1909                                  ; 14/08/2015 
  1910                                  memory_info:	
  1911 0000164E A1[DC6A0000]            	mov	eax, [memory_size] ; in pages
  1912 00001653 50                      	push	eax
  1913 00001654 C1E00C                  	shl	eax, 12		   ; in bytes
  1914 00001657 BB0A000000              	mov	ebx, 10
  1915 0000165C 89D9                    	mov	ecx, ebx	   ; 10
  1916 0000165E BE[41670000]            	mov	esi, mem_total_b_str	
  1917 00001663 E8AE000000              	call	bintdstr
  1918 00001668 58                      	pop	eax
  1919 00001669 B107                    	mov	cl, 7
  1920 0000166B BE[65670000]            	mov	esi, mem_total_p_str
  1921 00001670 E8A1000000              	call	bintdstr	
  1922                                  	; 14/08/2015
  1923 00001675 E8B9000000              	call	calc_free_mem
  1924                                  	; edx = calculated free pages
  1925                                  	; ecx = 0
  1926 0000167A A1[E06A0000]            	mov 	eax, [free_pages]
  1927 0000167F 39D0                    	cmp	eax, edx ; calculated free mem value 
  1928                                  		; and initial free mem value are same or not?
  1929 00001681 751D                    	jne 	short pmim ; print mem info with '?' if not
  1930 00001683 52                      	push 	edx ; free memory in pages	
  1931                                  	;mov 	eax, edx
  1932 00001684 C1E00C                  	shl	eax, 12 ; convert page count
  1933                                  			; to byte count
  1934 00001687 B10A                    	mov	cl, 10
  1935 00001689 BE[85670000]            	mov	esi, free_mem_b_str
  1936 0000168E E883000000              	call	bintdstr
  1937 00001693 58                      	pop	eax
  1938 00001694 B107                    	mov	cl, 7
  1939 00001696 BE[A9670000]            	mov	esi, free_mem_p_str
  1940 0000169B E876000000              	call	bintdstr
  1941                                  pmim:
  1942 000016A0 BE[2F670000]            	mov	esi, msg_memory_info
  1943                                  pmim_nb:	
  1944 000016A5 AC                      	lodsb
  1945 000016A6 08C0                    	or	al, al
  1946 000016A8 740D                    	jz	short pmim_ok
  1947 000016AA 56                      	push	esi
  1948 000016AB 31DB                    	xor	ebx, ebx ; 0
  1949                                  			; Video page 0 (bl=0)
  1950 000016AD B407                    	mov	ah, 07h ; Black background, 
  1951                                  			; light gray forecolor
  1952 000016AF E812FDFFFF              	call	write_tty
  1953 000016B4 5E                      	pop	esi
  1954 000016B5 EBEE                    	jmp	short pmim_nb
  1955                                  pmim_ok:
  1956 000016B7 C3                      	retn
  1957                                  
  1958                                  ; Convert binary number to hexadecimal string
  1959                                  ; 10/05/2015  
  1960                                  ; dsectpm.s (28/02/2015)
  1961                                  ; Retro UNIX 386 v1 - Kernel v0.2.0.6  
  1962                                  ; 01/12/2014
  1963                                  ; 25/11/2014
  1964                                  ;
  1965                                  bytetohex:
  1966                                  	; INPUT ->
  1967                                  	; 	AL = byte (binary number)
  1968                                  	; OUTPUT ->
  1969                                  	;	AX = hexadecimal string
  1970                                  	;
  1971 000016B8 53                      	push	ebx
  1972 000016B9 31DB                    	xor	ebx, ebx
  1973 000016BB 88C3                    	mov	bl, al
  1974 000016BD C0EB04                  	shr	bl, 4
  1975 000016C0 8A9B[06170000]          	mov	bl, [ebx+hexchrs]
  1976 000016C6 86D8                    	xchg	bl, al
  1977 000016C8 80E30F                  	and	bl, 0Fh
  1978 000016CB 8AA3[06170000]          	mov	ah, [ebx+hexchrs]
  1979 000016D1 5B                      	pop	ebx	
  1980 000016D2 C3                      	retn
  1981                                  
  1982                                  wordtohex:
  1983                                  	; INPUT ->
  1984                                  	; 	AX = word (binary number)
  1985                                  	; OUTPUT ->
  1986                                  	;	EAX = hexadecimal string
  1987                                  	;
  1988 000016D3 53                      	push	ebx
  1989 000016D4 31DB                    	xor	ebx, ebx
  1990 000016D6 86E0                    	xchg	ah, al
  1991 000016D8 6650                    	push	ax
  1992 000016DA 88E3                    	mov	bl, ah
  1993 000016DC C0EB04                  	shr	bl, 4
  1994 000016DF 8A83[06170000]          	mov	al, [ebx+hexchrs]
  1995 000016E5 88E3                    	mov	bl, ah
  1996 000016E7 80E30F                  	and	bl, 0Fh
  1997 000016EA 8AA3[06170000]          	mov	ah, [ebx+hexchrs]
  1998 000016F0 C1E010                  	shl	eax, 16
  1999 000016F3 6658                    	pop	ax
  2000 000016F5 5B                      	pop	ebx
  2001 000016F6 EBC0                    	jmp	short bytetohex
  2002                                  	;mov	bl, al
  2003                                  	;shr	bl, 4
  2004                                  	;mov	bl, [ebx+hexchrs]
  2005                                  	;xchg	bl, al	 	
  2006                                  	;and	bl, 0Fh
  2007                                  	;mov	ah, [ebx+hexchrs]
  2008                                  	;pop	ebx	
  2009                                  	;retn
  2010                                  
  2011                                  dwordtohex:
  2012                                  	; INPUT ->
  2013                                  	; 	EAX = dword (binary number)
  2014                                  	; OUTPUT ->
  2015                                  	;	EDX:EAX = hexadecimal string
  2016                                  	;
  2017 000016F8 50                      	push	eax
  2018 000016F9 C1E810                  	shr	eax, 16
  2019 000016FC E8D2FFFFFF              	call	wordtohex
  2020 00001701 89C2                    	mov	edx, eax
  2021 00001703 58                      	pop	eax
  2022                                  	;call	wordtohex
  2023                                  	;retn
  2024                                  	; 02/01/2022
  2025 00001704 EBCD                    	jmp	short wordtohex
  2026                                  
  2027                                  ; 10/05/2015
  2028                                  hex_digits:
  2029                                  hexchrs:
  2030 00001706 303132333435363738-     	db '0123456789ABCDEF'
  2030 0000170F 39414243444546     
  2031                                  
  2032                                  ; Convert binary number to decimal/numeric string
  2033                                  ; 06/11/2014
  2034                                  ; Temporary Code
  2035                                  ;
  2036                                  
  2037                                  bintdstr:
  2038                                  	; EAX = binary number
  2039                                  	; ESI = decimal/numeric string address
  2040                                  	; EBX = divisor (10)
  2041                                  	; ECX = string length (<=10)
  2042 00001716 01CE                    	add	esi, ecx
  2043                                  btdstr0:
  2044 00001718 4E                      	dec	esi
  2045 00001719 31D2                    	xor	edx, edx
  2046 0000171B F7F3                    	div	ebx
  2047 0000171D 80C230                  	add	dl, 30h
  2048 00001720 8816                    	mov	[esi], dl
  2049 00001722 FEC9                    	dec	cl
  2050 00001724 740C                    	jz	short btdstr2 ; 02/01/2022 (short jump)
  2051 00001726 09C0                    	or	eax, eax
  2052 00001728 75EE                    	jnz	short btdstr0
  2053                                  btdstr1:
  2054 0000172A 4E                      	dec	esi
  2055 0000172B C60620                          mov     byte [esi], 20h ; blank space
  2056 0000172E FEC9                    	dec	cl
  2057 00001730 75F8                    	jnz	short btdstr1
  2058                                  btdstr2:
  2059 00001732 C3                      	ret
  2060                                  
  2061                                  ; Calculate free memory pages on M.A.T.
  2062                                  ; 06/11/2014
  2063                                  ; Temporary Code
  2064                                  ;
  2065                                  
  2066                                  calc_free_mem:
  2067 00001733 31D2                    	xor	edx, edx
  2068                                  	;xor	ecx, ecx
  2069                                  	;mov	cx, [mat_size] ; in pages
  2070                                  	; 02/01/2022
  2071 00001735 8B0D[F06A0000]          	mov	ecx, [mat_size] ; in pages
  2072 0000173B C1E10A                  	shl	ecx, 10	; 1024 dwords per page
  2073 0000173E BE00001000              	mov	esi, MEM_ALLOC_TBL
  2074                                  cfm0:
  2075 00001743 AD                      	lodsd
  2076 00001744 51                      	push	ecx
  2077 00001745 B920000000              	mov	ecx, 32
  2078                                  cfm1:
  2079 0000174A D1E8                    	shr	eax, 1
  2080 0000174C 7301                    	jnc	short cfm2
  2081 0000174E 42                      	inc	edx
  2082                                  cfm2:
  2083 0000174F E2F9                    	loop	cfm1
  2084 00001751 59                      	pop	ecx
  2085 00001752 E2EF                    	loop	cfm0
  2086 00001754 C3                      	ret
  2087                                  
  2088                                  %include 'diskio.inc'  ; 07/03/2015
  2089                              <1> ; Retro UNIX 386 v1.1 Kernel - DISKIO.INC
  2090                              <1> ; Last Modification: 24/12/2021
  2091                              <1> ; 	(Initialized Disk Parameters Data is in 'DISKDATA.INC') 
  2092                              <1> ; 	(Uninitialized Disk Parameters Data is in 'DISKBSS.INC') 
  2093                              <1> 
  2094                              <1> ; DISK I/O SYSTEM - Erdogan Tan (Retro UNIX 386 v1 project)
  2095                              <1> 
  2096                              <1> ; ///////// DISK I/O SYSTEM ///////////////
  2097                              <1> 
  2098                              <1> ; 06/02/2015
  2099                              <1> diskette_io:
  2100 00001755 9C                  <1> 	pushfd
  2101 00001756 0E                  <1> 	push 	cs
  2102 00001757 E809000000          <1> 	call 	DISKETTE_IO_1
  2103 0000175C C3                  <1> 	retn
  2104                              <1> 	
  2105                              <1> ;;;;;; DISKETTE I/O ;;;;;;;;;;;;;;;;;;;; 06/02/2015 ;;;
  2106                              <1> ;//////////////////////////////////////////////////////
  2107                              <1> 
  2108                              <1> ; DISKETTE I/O - Erdogan Tan (Retro UNIX 386 v1 project)
  2109                              <1> ; 20/02/2015
  2110                              <1> ; 06/02/2015 (unix386.s)
  2111                              <1> ; 16/12/2014 - 02/01/2015 (dsectrm2.s)
  2112                              <1> ;
  2113                              <1> ; Code (DELAY) modifications - AWARD BIOS 1999 (ADISK.EQU, COMMON.MAC)
  2114                              <1> ;
  2115                              <1> ; ADISK.EQU
  2116                              <1> 
  2117                              <1> ;----- Wait control constants 
  2118                              <1> 
  2119                              <1> ;amount of time to wait while RESET is active.
  2120                              <1> 
  2121                              <1> WAITCPU_RESET_ON   EQU	21		;Reset on must last at least 14us
  2122                              <1> 					;at 250 KBS xfer rate.
  2123                              <1> 					;see INTEL MCS, 1985, pg. 5-456
  2124                              <1> 
  2125                              <1> WAITCPU_FOR_STATUS EQU	100		;allow 30 microseconds for
  2126                              <1> 					;status register to become valid
  2127                              <1> 					;before re-reading.
  2128                              <1> 
  2129                              <1> ;After sending a byte to NEC, status register may remain
  2130                              <1> ;incorrectly set for 24 us.
  2131                              <1> 
  2132                              <1> WAITCPU_RQM_LOW	   EQU	24		;number of loops to check for
  2133                              <1> 					;RQM low.
  2134                              <1> 
  2135                              <1> ; COMMON.MAC
  2136                              <1> ;
  2137                              <1> ;	Timing macros
  2138                              <1> ;
  2139                              <1> 
  2140                              <1> %macro 		SIODELAY 0 		; SHORT IODELAY
  2141                              <1> 		jmp short $+2
  2142                              <1> %endmacro		
  2143                              <1> 
  2144                              <1> %macro		IODELAY  0		; NORMAL IODELAY
  2145                              <1> 		jmp short $+2
  2146                              <1> 		jmp short $+2
  2147                              <1> %endmacro
  2148                              <1> 
  2149                              <1> %macro		NEWIODELAY 0
  2150                              <1> 		out	0EBh,al
  2151                              <1> %endmacro 
  2152                              <1> 
  2153                              <1> ; (According to) AWARD BIOS 1999 - ATORGS.ASM (dw -> equ, db -> equ)
  2154                              <1> ;;; WAIT_FOR_MEM
  2155                              <1> ;WAIT_FDU_INT_LO	equ	017798		; 2.5 secs in 30 micro units.
  2156                              <1> ;WAIT_FDU_INT_HI	equ	1
  2157                              <1> WAIT_FDU_INT_LH		equ	83334		; 27/02/2015 (2.5 seconds waiting)
  2158                              <1> ;;; WAIT_FOR_PORT
  2159                              <1> ;WAIT_FDU_SEND_LO	equ	16667		; .5 secons in 30 us units.
  2160                              <1> ;WAIT_FDU_SEND_HI	equ	0
  2161                              <1> WAIT_FDU_SEND_LH	equ 	16667		; 27/02/2015	
  2162                              <1> ;Time to wait while waiting for each byte of NEC results = .5
  2163                              <1> ;seconds.  .5 seconds = 500,000 micros.  500,000/30 = 16,667.
  2164                              <1> ;WAIT_FDU_RESULTS_LO	equ	16667		; .5 seconds in 30 micro units.
  2165                              <1> ;WAIT_FDU_RESULTS_HI	equ	0
  2166                              <1> WAIT_FDU_RESULTS_LH	equ	16667  ; 27/02/2015
  2167                              <1> ;;; WAIT_REFRESH
  2168                              <1> ;amount of time to wait for head settle, per unit in parameter
  2169                              <1> ;table = 1 ms.
  2170                              <1> WAIT_FDU_HEAD_SETTLE	equ	33		; 1 ms in 30 micro units.
  2171                              <1> 
  2172                              <1> 
  2173                              <1> ; //////////////// DISKETTE I/O ////////////////
  2174                              <1> 
  2175                              <1> ; 11/12/2014 (copy from IBM PC-XT Model 286 BIOS - POSTEQU.INC)
  2176                              <1> 
  2177                              <1> ;----------------------------------------
  2178                              <1> ;	EQUATES USED BY POST AND BIOS	:
  2179                              <1> ;----------------------------------------
  2180                              <1> 
  2181                              <1> ;--------- 8042 KEYBOARD INTERFACE AND DIAGNOSTIC CONTROL REGISTERS ------------
  2182                              <1> ;PORT_A		EQU	060H		; 8042 KEYBOARD SCAN CODE/CONTROL PORT
  2183                              <1> ;PORT_B		EQU	061H		; PORT B READ/WRITE DIAGNOSTIC REGISTER
  2184                              <1> ;REFRESH_BIT	EQU	00010000B	; REFRESH TEST BIT
  2185                              <1> 
  2186                              <1> ;----------------------------------------
  2187                              <1> ;	CMOS EQUATES FOR THIS SYSTEM	:
  2188                              <1> ;-------------------------------------------------------------------------------
  2189                              <1> ;CMOS_PORT	EQU	070H		; I/O ADDRESS OF CMOS ADDRESS PORT
  2190                              <1> ;CMOS_DATA	EQU	071H		; I/O ADDRESS OF CMOS DATA PORT
  2191                              <1> ;NMI		EQU	10000000B	; DISABLE NMI INTERRUPTS MASK -
  2192                              <1> 					;  HIGH BIT OF CMOS LOCATION ADDRESS
  2193                              <1> 
  2194                              <1> ;---------- CMOS TABLE LOCATION ADDRESS'S ## -----------------------------------
  2195                              <1> CMOS_DISKETTE	EQU	010H		; DISKETTE DRIVE TYPE BYTE	      ;
  2196                              <1> ;		EQU	011H		; - RESERVED			      ;C
  2197                              <1> CMOS_DISK	EQU	012H		; FIXED DISK TYPE BYTE		      ;H
  2198                              <1> ;		EQU	013H		; - RESERVED			      ;E
  2199                              <1> CMOS_EQUIP	EQU	014H		; EQUIPMENT WORD LOW BYTE	      ;C
  2200                              <1> 
  2201                              <1> ;---------- DISKETTE EQUATES ---------------------------------------------------
  2202                              <1> INT_FLAG	EQU	10000000B	; INTERRUPT OCCURRENCE FLAG
  2203                              <1> DSK_CHG 	EQU	10000000B	; DISKETTE CHANGE FLAG MASK BIT
  2204                              <1> DETERMINED	EQU	00010000B	; SET STATE DETERMINED IN STATE BITS
  2205                              <1> HOME		EQU	00010000B	; TRACK 0 MASK
  2206                              <1> SENSE_DRV_ST	EQU	00000100B	; SENSE DRIVE STATUS COMMAND
  2207                              <1> TRK_SLAP	EQU	030H		; CRASH STOP (48 TPI DRIVES)
  2208                              <1> QUIET_SEEK	EQU	00AH		; SEEK TO TRACK 10
  2209                              <1> ;MAX_DRV 	EQU	2		; MAX NUMBER OF DRIVES
  2210                              <1> HD12_SETTLE	EQU	15		; 1.2 M HEAD SETTLE TIME
  2211                              <1> HD320_SETTLE	EQU	20		; 320 K HEAD SETTLE TIME
  2212                              <1> MOTOR_WAIT	EQU	37		; 2 SECONDS OF COUNTS FOR MOTOR TURN OFF
  2213                              <1> 
  2214                              <1> ;---------- DISKETTE ERRORS ----------------------------------------------------
  2215                              <1> ;TIME_OUT	EQU	080H		; ATTACHMENT FAILED TO RESPOND
  2216                              <1> ;BAD_SEEK	EQU	040H		; SEEK OPERATION FAILED
  2217                              <1> BAD_NEC 	EQU	020H		; DISKETTE CONTROLLER HAS FAILED
  2218                              <1> BAD_CRC 	EQU	010H		; BAD CRC ON DISKETTE READ
  2219                              <1> MED_NOT_FND	EQU	00CH		; MEDIA TYPE NOT FOUND
  2220                              <1> DMA_BOUNDARY	EQU	009H		; ATTEMPT TO DMA ACROSS 64K BOUNDARY
  2221                              <1> BAD_DMA 	EQU	008H		; DMA OVERRUN ON OPERATION
  2222                              <1> MEDIA_CHANGE	EQU	006H		; MEDIA REMOVED ON DUAL ATTACH CARD
  2223                              <1> RECORD_NOT_FND	EQU	004H		; REQUESTED SECTOR NOT FOUND
  2224                              <1> WRITE_PROTECT	EQU	003H		; WRITE ATTEMPTED ON WRITE PROTECT DISK
  2225                              <1> BAD_ADDR_MARK	EQU	002H		; ADDRESS MARK NOT FOUND
  2226                              <1> BAD_CMD 	EQU	001H		; BAD COMMAND PASSED TO DISKETTE I/O
  2227                              <1> 
  2228                              <1> ;---------- DISK CHANGE LINE EQUATES -------------------------------------------
  2229                              <1> NOCHGLN 	EQU	001H		; NO DISK CHANGE LINE AVAILABLE
  2230                              <1> CHGLN		EQU	002H		; DISK CHANGE LINE AVAILABLE
  2231                              <1> 
  2232                              <1> ;---------- MEDIA/DRIVE STATE INDICATORS ---------------------------------------
  2233                              <1> TRK_CAPA	EQU	00000001B	; 80 TRACK CAPABILITY
  2234                              <1> FMT_CAPA	EQU	00000010B	; MULTIPLE FORMAT CAPABILITY (1.2M)
  2235                              <1> DRV_DET 	EQU	00000100B	; DRIVE DETERMINED
  2236                              <1> MED_DET 	EQU	00010000B	; MEDIA DETERMINED BIT
  2237                              <1> DBL_STEP	EQU	00100000B	; DOUBLE STEP BIT
  2238                              <1> RATE_MSK	EQU	11000000B	; MASK FOR CLEARING ALL BUT RATE
  2239                              <1> RATE_500	EQU	00000000B	; 500 KBS DATA RATE
  2240                              <1> RATE_300	EQU	01000000B	; 300 KBS DATA RATE
  2241                              <1> RATE_250	EQU	10000000B	; 250 KBS DATA RATE
  2242                              <1> STRT_MSK	EQU	00001100B	; OPERATION START RATE MASK
  2243                              <1> SEND_MSK	EQU	11000000B	; MASK FOR SEND RATE BITS
  2244                              <1> 
  2245                              <1> ;---------- MEDIA/DRIVE STATE INDICATORS COMPATIBILITY -------------------------
  2246                              <1> M3D3U		EQU	00000000B	; 360 MEDIA/DRIVE NOT ESTABLISHED
  2247                              <1> M3D1U		EQU	00000001B	; 360 MEDIA,1.2DRIVE NOT ESTABLISHED
  2248                              <1> M1D1U		EQU	00000010B	; 1.2 MEDIA/DRIVE NOT ESTABLISHED
  2249                              <1> MED_UNK 	EQU	00000111B	; NONE OF THE ABOVE
  2250                              <1> 
  2251                              <1> ;---------- INTERRUPT EQUATES --------------------------------------------------
  2252                              <1> ;EOI		EQU	020H		; END OF INTERRUPT COMMAND TO 8259
  2253                              <1> ;INTA00		EQU	020H		; 8259 PORT
  2254                              <1> INTA01		EQU	021H		; 8259 PORT
  2255                              <1> INTB00		EQU	0A0H		; 2ND 8259
  2256                              <1> INTB01		EQU	0A1H		;
  2257                              <1> 
  2258                              <1> ;-------------------------------------------------------------------------------
  2259                              <1> DMA08		EQU	008H		; DMA STATUS REGISTER PORT ADDRESS
  2260                              <1> DMA		EQU	000H		; DMA CH.0 ADDRESS REGISTER PORT ADDRESS
  2261                              <1> DMA18		EQU	0D0H		; 2ND DMA STATUS PORT ADDRESS
  2262                              <1> DMA1		EQU	0C0H		; 2ND DMA CH.0 ADDRESS REGISTER ADDRESS
  2263                              <1> ;-------------------------------------------------------------------------------
  2264                              <1> ;TIMER		EQU	040H		; 8254 TIMER - BASE ADDRESS
  2265                              <1> 
  2266                              <1> ;-------------------------------------------------------------------------------
  2267                              <1> DMA_PAGE	EQU	081H		; START OF DMA PAGE REGISTERS
  2268                              <1> 
  2269                              <1> ; 06/02/2015 (unix386.s, protected mode modifications)
  2270                              <1> ; (unix386.s <-- dsectrm2.s)
  2271                              <1> ; 11/12/2014 (copy from IBM PC-XT Model 286 BIOS - DSEG.INC)
  2272                              <1> 
  2273                              <1> ; 10/12/2014
  2274                              <1> ;
  2275                              <1> ;int40h:
  2276                              <1> ;	pushf
  2277                              <1> ;	push 	cs
  2278                              <1> ;	;cli
  2279                              <1> ;	call 	DISKETTE_IO_1
  2280                              <1> ;	retn
  2281                              <1> 
  2282                              <1> ; DSKETTE ----- 04/21/86 DISKETTE BIOS
  2283                              <1> ; (IBM PC XT Model 286 System BIOS Source Code, 04-21-86)
  2284                              <1> ;
  2285                              <1> 
  2286                              <1> ;-- INT13H ---------------------------------------------------------------------
  2287                              <1> ; DISKETTE I/O
  2288                              <1> ;	THIS INTERFACE PROVIDES ACCESS TO THE 5 1/4 INCH 360 KB,
  2289                              <1> ;	1.2 MB, 720 KB AND 1.44 MB DISKETTE DRIVES.
  2290                              <1> ; INPUT
  2291                              <1> ;	(AH) =  00H RESET DISKETTE SYSTEM
  2292                              <1> ;		HARD RESET TO NEC, PREPARE COMMAND, RECALIBRATE REQUIRED
  2293                              <1> ;		ON ALL DRIVES
  2294                              <1> ;------------------------------------------------------------------------------- 
  2295                              <1> ;	(AH)= 01H  READ THE STATUS OF THE SYSTEM INTO (AH)
  2296                              <1> ;		@DISKETTE_STATUS FROM LAST OPERATION IS USED
  2297                              <1> ;-------------------------------------------------------------------------------
  2298                              <1> ;	REGISTERS FOR READ/WRITE/VERIFY/FORMAT
  2299                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2300                              <1> ;	(DH) - HEAD NUMBER (0-1 ALLOWED, NOT VALUE CHECKED)
  2301                              <1> ;	(CH) - TRACK NUMBER (NOT VALUE CHECKED)
  2302                              <1> ;		MEDIA	DRIVE	TRACK NUMBER
  2303                              <1> ;		320/360	320/360	    0-39
  2304                              <1> ;		320/360	1.2M	    0-39
  2305                              <1> ;		1.2M	1.2M	    0-79
  2306                              <1> ;		720K	720K	    0-79
  2307                              <1> ;		1.44M	1.44M	    0-79	
  2308                              <1> ;	(CL) - 	SECTOR NUMBER (NOT VALUE CHECKED, NOT USED FOR FORMAT)
  2309                              <1> ;		MEDIA	DRIVE	SECTOR NUMBER
  2310                              <1> ;		320/360	320/360	     1-8/9
  2311                              <1> ;		320/360	1.2M	     1-8/9
  2312                              <1> ;		1.2M	1.2M	     1-15
  2313                              <1> ;		720K	720K	     1-9
  2314                              <1> ;		1.44M	1.44M	     1-18		
  2315                              <1> ;	(AL)	NUMBER OF SECTORS (NOT VALUE CHECKED)
  2316                              <1> ;		MEDIA	DRIVE	MAX NUMBER OF SECTORS
  2317                              <1> ;		320/360	320/360	        8/9
  2318                              <1> ;		320/360	1.2M	        8/9
  2319                              <1> ;		1.2M	1.2M		15
  2320                              <1> ;		720K	720K		9
  2321                              <1> ;		1.44M	1.44M		18
  2322                              <1> ;
  2323                              <1> ;	(ES:BX) - ADDRESS OF BUFFER (NOT REQUIRED FOR VERIFY)
  2324                              <1> ;
  2325                              <1> ;-------------------------------------------------------------------------------
  2326                              <1> ;	(AH)= 02H  READ THE DESIRED SECTORS INTO MEMORY
  2327                              <1> ;-------------------------------------------------------------------------------
  2328                              <1> ;	(AH)= 03H  WRITE THE DESIRED SECTORS FROM MEMORY
  2329                              <1> ;-------------------------------------------------------------------------------
  2330                              <1> ;	(AH)= 04H  VERIFY THE DESIRED SECTORS
  2331                              <1> ;-------------------------------------------------------------------------------
  2332                              <1> ;	(AH)= 05H  FORMAT THE DESIRED TRACK
  2333                              <1> ;		(ES,BX) MUST POINT TO THE COLLECTION OF DESIRED ADDRESS FIELDS
  2334                              <1> ;		FOR THE	TRACK. EACH FIELD IS COMPOSED OF 4 BYTES, (C,H,R,N),
  2335                              <1> ;		WHERE C = TRACK NUMBER, H=HEAD NUMBER, R = SECTOR NUMBER, 
  2336                              <1> ;		N= NUMBER OF BYTES PER SECTOR (00=128,01=256,02=512,03=1024),
  2337                              <1> ;		THERE MUST BE ONE ENTRY FOR EVERY SECTOR ON THE TRACK.
  2338                              <1> ;		THIS INFORMATION IS USED TO FIND THE REQUESTED SECTOR DURING 
  2339                              <1> ;		READ/WRITE ACCESS.
  2340                              <1> ;		PRIOR TO FORMATTING A DISKETTE, IF THERE EXISTS MORE THAN
  2341                              <1> ;		ONE SUPPORTED MEDIA FORMAT TYPE WITHIN THE DRIVE IN QUESTION,
  2342                              <1> ;		THEN "SET DASD TYPE" (INT 13H, AH = 17H) OR 'SET MEDIA TYPE'
  2343                              <1> ;		(INT 13H, AH =  18H) MUST BE CALLED TO SET THE DISKETTE TYPE
  2344                              <1> ;		THAT IS TO BE FORMATTED. IF "SET DASD TYPE" OR "SET MEDIA TYPE"
  2345                              <1> ;		IS NOT CALLED, THE FORMAT ROUTINE WILL ASSUME THE 
  2346                              <1> ;		MEDIA FORMAT TO BE THE MAXIMUM CAPACITY OF THE DRIVE.
  2347                              <1> ;
  2348                              <1> ;		THESE PARAMETERS OF DISK BASE MUST BE CHANGED IN ORDER TO
  2349                              <1> ;		FORMAT THE FOLLOWING MEDIAS:
  2350                              <1> ;		---------------------------------------------
  2351                              <1> ;		: MEDIA  :     DRIVE      : PARM 1 : PARM 2 :
  2352                              <1> ;		---------------------------------------------
  2353                              <1> ;		: 320K	 : 320K/360K/1.2M :  50H   :   8    :
  2354                              <1> ;		: 360K	 : 320K/360K/1.2M :  50H   :   9    :
  2355                              <1> ;		: 1.2M	 : 1.2M           :  54H   :  15    :
  2356                              <1> ;		: 720K	 : 720K/1.44M     :  50H   :   9    :
  2357                              <1> ;		: 1.44M	 : 1.44M          :  6CH   :  18    :		  	
  2358                              <1> ;		---------------------------------------------
  2359                              <1> ;		NOTES: - PARM 1 = GAP LENGTH FOR FORMAT
  2360                              <1> ;		       - PARM 2 = EOT (LAST SECTOR ON TRACK)
  2361                              <1> ;		       - DISK BASE IS POINTED BY DISK POINTER LOCATED
  2362                              <1> ;			 AT ABSOLUTE ADDRESS 0:78.
  2363                              <1> ;		       - WHEN FORMAT OPERATIONS ARE COMPLETE, THE PARAMETERS
  2364                              <1> ;			 SHOULD BE RESTORED TO THEIR RESPECTIVE INITIAL VALUES.			
  2365                              <1> ;-------------------------------------------------------------------------------
  2366                              <1> ;	(AH) = 08H READ DRIVE PARAMETERS
  2367                              <1> ;	REGISTERS
  2368                              <1> ;	  INPUT
  2369                              <1> ;	    (DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2370                              <1> ;	  OUTPUT
  2371                              <1> ;	    (ES:DI) POINTS TO DRIVE PARAMETER TABLE
  2372                              <1> ;	    (CH) - LOW ORDER 8 OF 10 BITS MAXIMUM NUMBER OF TRACKS
  2373                              <1> ;	    (CL) - BITS 7 & 6 - HIGH ORDER TWO BITS OF MAXIMUM TRACKS
  2374                              <1> ;	           BITS 5 THRU 0 - MAXIMUM SECTORS PER TRACK
  2375                              <1> ;	    (DH) - MAXIMUM HEAD NUMBER
  2376                              <1> ;	    (DL) - NUMBER OF DISKETTE DRIVES INSTALLED
  2377                              <1> ;	    (BH) - 0
  2378                              <1> ;	    (BL) - BITS 7 THRU 4 - 0
  2379                              <1> ;	           BITS 3 THRU 0 - VALID DRIVE TYPE VALUE IN CMOS
  2380                              <1> ;	    (AX) - 0
  2381                              <1> ;	 UNDER THE FOLLOWING CIRCUMSTANCES:
  2382                              <1> ;	    (1) THE DRIVE NUMBER IS INVALID,
  2383                              <1> ;	    (2) THE DRIVE TYPE IS UNKNOWN AND CMOS IS NOT PRESENT, 
  2384                              <1> ;	    (3) THE DRIVE TYPE IS UNKNOWN AND CMOS IS BAD,
  2385                              <1> ;	    (4) OR THE DRIVE TYPE IS UNKNOWN AND THE CMOS DRIVE TYPE IS INVALID
  2386                              <1> ;	    THEN ES,AX,BX,CX,DH,DI=0 ; DL=NUMBER OF DRIVES. 
  2387                              <1> ;	    IF NO DRIVES ARE PRESENT THEN: ES,AX,BX,CX,DX,DI=0.
  2388                              <1> ;	    @DISKETTE_STATUS = 0 AND CY IS RESET.
  2389                              <1> ;-------------------------------------------------------------------------------
  2390                              <1> ;	(AH)= 15H  READ DASD TYPE
  2391                              <1> ;	OUTPUT REGISTERS
  2392                              <1> ;	(AH) - ON RETURN IF CARRY FLAG NOT SET, OTHERWISE ERROR	
  2393                              <1> ;		00 - DRIVE NOT PRESENT	
  2394                              <1> ;		01 - DISKETTE, NO CHANGE LINE AVAILABLE
  2395                              <1> ;		02 - DISKETTE, CHANGE LINE AVAILABLE	
  2396                              <1> ;		03 - RESERVED (FIXED DISK)
  2397                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2398                              <1> ;-------------------------------------------------------------------------------
  2399                              <1> ;	(AH)= 16H  DISK CHANGE LINE STATUS
  2400                              <1> ;	OUTPUT REGISTERS
  2401                              <1> ;	(AH) - 00 - DISK CHANGE LINE NOT ACTIVE	
  2402                              <1> ;	       06 - DISK CHANGE LINE ACTIVE & CARRY BIT ON
  2403                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2404                              <1> ;-------------------------------------------------------------------------------
  2405                              <1> ;	(AH)= 17H  SET DASD TYPE FOR FORMAT
  2406                              <1> ;	INPUT REGISTERS
  2407                              <1> ;	(AL) -	00 - NOT USED	
  2408                              <1> ;		01 - DISKETTE 320/360K IN 360K DRIVE	
  2409                              <1> ;		02 - DISKETTE 360K IN 1.2M DRIVE
  2410                              <1> ;		03 - DISKETTE 1.2M IN 1.2M DRIVE
  2411                              <1> ;		04 - DISKETTE 720K IN 720K DRIVE
  2412                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED:
  2413                              <1> ;	       (DO NOT USE WHEN DISKETTE ATTACH CARD USED)
  2414                              <1> ;-------------------------------------------------------------------------------
  2415                              <1> ;	(AH)= 18H  SET MEDIA TYPE FOR FORMAT
  2416                              <1> ;	INPUT REGISTERS
  2417                              <1> ;	(CH) - LOW ORDER 8 OF 10 BITS MAXIMUM TRACKS
  2418                              <1> ;	(CL) - BITS 7 & 6 - HIGH ORDER TWO BITS OF MAXIMUM TRACKS
  2419                              <1> ;	       BITS 5 THRU 0 - MAXIMUM SECTORS PER TRACK
  2420                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHACKED)
  2421                              <1> ;	OUTPUT REGISTERS:
  2422                              <1> ;	(ES:DI) - POINTER TO DRIVE PARAMETERS TABLE FOR THIS MEDIA TYPE,
  2423                              <1> ;		  UNCHANGED IF (AH) IS NON-ZERO
  2424                              <1> ;	(AH) - 00H, CY = 0, TRACK AND SECTORS/TRACK COMBINATION IS SUPPORTED
  2425                              <1> ;	     - 01H, CY = 1, FUNCTION IS NOT AVAILABLE
  2426                              <1> ;	     - 0CH, CY = 1, TRACK AND SECTORS/TRACK COMBINATION IS NOT SUPPORTED
  2427                              <1> ;	     - 80H, CY = 1, TIME OUT (DISKETTE NOT PRESENT)		
  2428                              <1> ;-------------------------------------------------------------------------------
  2429                              <1> ;	DISK CHANGE STATUS IS ONLY CHECKED WHEN A MEDIA SPECIFIED IS OTHER
  2430                              <1> ;	THAN 360 KB DRIVE. IF THE DISK CHANGE LINE IS FOUND TO BE
  2431                              <1> ;	ACTIVE THE FOLLOWING ACTIONS TAKE PLACE:
  2432                              <1> ;		ATTEMPT TO RESET DISK CHANGE LINE TO INACTIVE STATE. 
  2433                              <1> ;		IF ATTEMPT SUCCEEDS SET DASD TYPE FOR FORMAT AND RETURN DISK 
  2434                              <1> ;		CHANGE ERROR CODE
  2435                              <1> ;		IF ATTEMPT FAILS RETURN TIMEOUT ERROR CODE AND SET DASD TYPE 
  2436                              <1> ;		TO A PREDETERMINED STATE INDICATING MEDIA TYPE UNKNOWN.
  2437                              <1> ;	IF THE DISK CHANGE LINE IN INACTIVE PERFORM SET DASD TYPE FOR FORMAT.
  2438                              <1> ;
  2439                              <1> ; DATA VARIABLE -- @DISK_POINTER
  2440                              <1> ;	DOUBLE WORD POINTER TO THE CURRENT SET OF DISKETTE PARAMETERS
  2441                              <1> ;-------------------------------------------------------------------------------
  2442                              <1> ; OUTPUT FOR ALL FUNCTIONS
  2443                              <1> ;	AH = STATUS OF OPERATION
  2444                              <1> ;		STATUS BITS ARE DEFINED IN THE EQUATES FOR @DISKETTE_STATUS
  2445                              <1> ;		VARIABLE IN THE DATA SEGMENT OF THIS MODULE
  2446                              <1> ;	CY = 0	SUCCESSFUL OPERATION (AH=0 ON RETURN, EXCEPT FOR READ DASD
  2447                              <1> ;		TYPE AH=(15)).
  2448                              <1> ;	CY = 1	FAILED OPERATION (AH HAS ERROR REASON)
  2449                              <1> ;	FOR READ/WRITE/VERIFY
  2450                              <1> ;		DS,BX,DX,CX PRESERVED
  2451                              <1> ;	NOTE: IF AN ERROR IS REPORTED BY THE DISKETTE CODE, THE APPROPRIATE 
  2452                              <1> ;		ACTION IS TO RESET THE DISKETTE, THEN RETRY THE OPERATION.
  2453                              <1> ;		ON READ ACCESSES, NO MOTOR START DELAY IS TAKEN, SO THAT 
  2454                              <1> ;		THREE RETRIES ARE REQUIRED ON READS TO ENSURE THAT THE 
  2455                              <1> ;		PROBLEM IS NOT DUE TO MOTOR START-UP.
  2456                              <1> ;-------------------------------------------------------------------------------
  2457                              <1> ;
  2458                              <1> ; DISKETTE STATE MACHINE - ABSOLUTE ADDRESS 40:90 (DRIVE A) & 91 (DRIVE B)
  2459                              <1> ;
  2460                              <1> ;   -----------------------------------------------------------------
  2461                              <1> ;   |       |       |       |       |       |       |       |       |
  2462                              <1> ;   |   7   |   6   |   5   |   4   |   3   |   2   |   1   |   0   |
  2463                              <1> ;   |       |       |       |       |       |       |       |       |
  2464                              <1> ;   -----------------------------------------------------------------
  2465                              <1> ;	|	|	|	|	|	|	|	|
  2466                              <1> ;	|	|	|	|	|	-----------------
  2467                              <1> ;	|	|	|	|	|		|
  2468                              <1> ;	|	|	|	|    RESERVED		|
  2469                              <1> ;	|	|	|	|		  PRESENT STATE
  2470                              <1> ;	|	|	|	|	000: 360K IN 360K DRIVE UNESTABLISHED
  2471                              <1> ;	|	|	|	|	001: 360K IN 1.2M DRIVE UNESTABLISHED
  2472                              <1> ;	|	|	|	|	010: 1.2M IN 1.2M DRIVE UNESTABLISHED
  2473                              <1> ;	|	|	|	|	011: 360K IN 360K DRIVE ESTABLISHED
  2474                              <1> ;	|	|	|	|	100: 360K IN 1.2M DRIVE ESTABLISHED
  2475                              <1> ;	|	|	|	|	101: 1.2M IN 1.2M DRIVE ESTABLISHED
  2476                              <1> ;	|	|	|	|	110: RESERVED
  2477                              <1> ;	|	|	|	|	111: NONE OF THE ABOVE
  2478                              <1> ;	|	|	|	|
  2479                              <1> ;	|	|	|	------>	MEDIA/DRIVE ESTABLISHED
  2480                              <1> ;	|	|	|
  2481                              <1> ;	|	|	-------------->	DOUBLE STEPPING REQUIRED (360K IN 1.2M
  2482                              <1> ;	|	|			DRIVE)
  2483                              <1> ;	|	|
  2484                              <1> ;	------------------------------>	DATA TRANSFER RATE FOR THIS DRIVE:
  2485                              <1> ;
  2486                              <1> ;						00: 500 KBS
  2487                              <1> ;						01: 300 KBS
  2488                              <1> ;						10: 250 KBS
  2489                              <1> ;						11: RESERVED
  2490                              <1> ;
  2491                              <1> ;
  2492                              <1> ;-------------------------------------------------------------------------------
  2493                              <1> ; STATE OPERATION STARTED - ABSOLUTE ADDRESS 40:92 (DRIVE A) & 93 (DRIVE B)
  2494                              <1> ;-------------------------------------------------------------------------------
  2495                              <1> ; PRESENT CYLINDER NUMBER - ABSOLUTE ADDRESS 40:94 (DRIVE A) & 95 (DRIVE B)
  2496                              <1> ;-------------------------------------------------------------------------------
  2497                              <1> 
  2498                              <1> struc MD
  2499 00000000 ??                  <1> 	.SPEC1		resb	1	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2500 00000001 ??                  <1> 	.SPEC2		resb	1	; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2501 00000002 ??                  <1> 	.OFF_TIM	resb	1	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2502 00000003 ??                  <1> 	.BYT_SEC	resb	1	; 512 BYTES/SECTOR
  2503 00000004 ??                  <1> 	.SEC_TRK	resb	1	; EOT (LAST SECTOR ON TRACK)
  2504 00000005 ??                  <1> 	.GAP		resb	1	; GAP LENGTH
  2505 00000006 ??                  <1> 	.DTL		resb	1	; DTL
  2506 00000007 ??                  <1> 	.GAP3		resb	1	; GAP LENGTH FOR FORMAT
  2507 00000008 ??                  <1> 	.FIL_BYT	resb	1	; FILL BYTE FOR FORMAT
  2508 00000009 ??                  <1> 	.HD_TIM		resb	1	; HEAD SETTLE TIME (MILLISECONDS)
  2509 0000000A ??                  <1> 	.STR_TIM	resb	1	; MOTOR START TIME (1/8 SECONDS)
  2510 0000000B ??                  <1> 	.MAX_TRK	resb	1	; MAX. TRACK NUMBER
  2511 0000000C ??                  <1> 	.RATE		resb	1	; DATA TRANSFER RATE
  2512                              <1> endstruc
  2513                              <1> 
  2514                              <1> BIT7OFF	EQU	7FH
  2515                              <1> BIT7ON	EQU	80H
  2516                              <1> 
  2517                              <1> ;;int13h: ; 16/02/2015
  2518                              <1> ;; 16/02/2015 - 21/02/2015
  2519                              <1> int40h:
  2520 0000175D 9C                  <1> 	pushfd
  2521 0000175E 0E                  <1> 	push 	cs
  2522 0000175F E801000000          <1> 	call 	DISKETTE_IO_1
  2523 00001764 C3                  <1> 	retn	
  2524                              <1> 
  2525                              <1> DISKETTE_IO_1:
  2526                              <1> 
  2527 00001765 FB                  <1> 	STI				; INTERRUPTS BACK ON
  2528 00001766 55                  <1> 	PUSH	eBP			; USER REGISTER
  2529 00001767 57                  <1> 	PUSH	eDI			; USER REGISTER
  2530 00001768 52                  <1> 	PUSH	eDX			; HEAD #, DRIVE # OR USER REGISTER
  2531 00001769 53                  <1> 	PUSH	eBX			; BUFFER OFFSET PARAMETER OR REGISTER
  2532 0000176A 51                  <1> 	PUSH	eCX			; TRACK #-SECTOR # OR USER REGISTER
  2533 0000176B 89E5                <1> 	MOV	eBP,eSP			; BP     => PARAMETER LIST DEP. ON AH
  2534                              <1> 					; [BP]   = SECTOR #
  2535                              <1> 					; [BP+1] = TRACK #
  2536                              <1> 					; [BP+2] = BUFFER OFFSET
  2537                              <1> 					; FOR RETURN OF DRIVE PARAMETERS:
  2538                              <1> 					; CL/[BP] = BITS 7&6 HI BITS OF MAX CYL
  2539                              <1> 					; 	    BITS 0-5 MAX SECTORS/TRACK
  2540                              <1> 					; CH/[BP+1] = LOW 8 BITS OF MAX CYL.
  2541                              <1> 					; BL/[BP+2] = BITS 7-4 = 0
  2542                              <1> 					;	      BITS 3-0 = VALID CMOS TYPE
  2543                              <1> 					; BH/[BP+3] = 0
  2544                              <1> 					; DL/[BP+4] = # DRIVES INSTALLED
  2545                              <1> 					; DH/[BP+5] = MAX HEAD #
  2546                              <1> 					; DI/[BP+6] = OFFSET TO DISK BASE
  2547 0000176D 06                  <1> 	push	es ; 06/02/2015	
  2548 0000176E 1E                  <1> 	PUSH	DS			; BUFFER SEGMENT PARM OR USER REGISTER
  2549 0000176F 56                  <1> 	PUSH	eSI			; USER REGISTERS
  2550                              <1> 	;CALL	DDS			; SEGMENT OF BIOS DATA AREA TO DS
  2551                              <1> 	;mov	cx, cs
  2552                              <1> 	;mov	ds, cx
  2553 00001770 66B91000            <1> 	mov	cx, KDATA
  2554 00001774 8ED9                <1>         mov     ds, cx
  2555 00001776 8EC1                <1>         mov     es, cx
  2556                              <1> 
  2557                              <1> 	;CMP	AH,(FNC_TAE-FNC_TAB)/2	; CHECK FOR > LARGEST FUNCTION
  2558 00001778 80FC19              <1> 	cmp	ah,(FNC_TAE-FNC_TAB)/4 ; 18/02/2015
  2559 0000177B 7202                <1> 	JB	short OK_FUNC		; FUNCTION OK
  2560 0000177D B414                <1> 	MOV	AH,14H			; REPLACE WITH KNOWN INVALID FUNCTION
  2561                              <1> OK_FUNC:
  2562 0000177F 80FC01              <1> 	CMP	AH,1			; RESET OR STATUS ?
  2563 00001782 760C                <1> 	JBE	short OK_DRV		; IF RESET OR STATUS DRIVE ALWAYS OK
  2564 00001784 80FC08              <1> 	CMP	AH,8			; READ DRIVE PARMS ?
  2565 00001787 7407                <1> 	JZ	short OK_DRV		; IF SO DRIVE CHECKED LATER
  2566 00001789 80FA01              <1> 	CMP	DL,1			; DRIVES 0 AND 1 OK
  2567 0000178C 7602                <1> 	JBE	short OK_DRV		; IF 0 OR 1 THEN JUMP
  2568 0000178E B414                <1> 	MOV	AH,14H			; REPLACE WITH KNOWN INVALID FUNCTION
  2569                              <1> OK_DRV:
  2570 00001790 31C9                <1> 	xor	ecx, ecx
  2571                              <1> 	;mov	esi, ecx ; 08/02/2015
  2572                              <1> 	; 24/12/2021
  2573 00001792 89CE                <1> 	mov	esi, ecx
  2574 00001794 89CF                <1> 	mov	edi, ecx ; 08/02/2015
  2575 00001796 88E1                <1> 	MOV	CL,AH			; CL = FUNCTION
  2576                              <1> 	;XOR	CH,CH			; CX = FUNCTION
  2577                              <1> 	;SHL	CL, 1			; FUNCTION TIMES 2
  2578 00001798 C0E102              <1> 	SHL	CL, 2 ; 20/02/2015	; FUNCTION TIMES 4 (for 32 bit offset)
  2579 0000179B BB[D3170000]        <1> 	MOV	eBX,FNC_TAB		; LOAD START OF FUNCTION TABLE
  2580 000017A0 01CB                <1> 	ADD	eBX,eCX			; ADD OFFSET INTO TABLE => ROUTINE
  2581 000017A2 88F4                <1> 	MOV	AH,DH			; AX = HEAD #,# OF SECTORS OR DASD TYPE
  2582 000017A4 30F6                <1> 	XOR	DH,DH			; DX = DRIVE #
  2583 000017A6 6689C6              <1> 	MOV	SI,AX			; SI = HEAD #,# OF SECTORS OR DASD TYPE
  2584 000017A9 6689D7              <1> 	MOV     DI,DX                   ; DI = DRIVE #
  2585                              <1> 	;
  2586                              <1> 	; 11/12/2014
  2587 000017AC 8815[C1650000]      <1>         mov     [cfd], dl               ; current floppy drive (for 'GET_PARM')        
  2588                              <1> 	;
  2589 000017B2 8A25[5C6B0000]      <1> 	MOV	AH, [DSKETTE_STATUS]	; LOAD STATUS TO AH FOR STATUS FUNCTION
  2590 000017B8 C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; INITIALIZE FOR ALL OTHERS
  2591                              <1> 
  2592                              <1> ;	THROUGHOUT THE DISKETTE BIOS, THE FOLLOWING INFORMATION IS CONTAINED IN
  2593                              <1> ;	THE FOLLOWING MEMORY LOCATIONS AND REGISTERS. NOT ALL DISKETTE BIOS
  2594                              <1> ;	FUNCTIONS REQUIRE ALL OF THESE PARAMETERS.
  2595                              <1> ;
  2596                              <1> ;		DI	: DRIVE #
  2597                              <1> ;		SI-HI	: HEAD #
  2598                              <1> ;		SI-LOW	: # OF SECTORS OR DASD TYPE FOR FORMAT
  2599                              <1> ;		ES	: BUFFER SEGMENT
  2600                              <1> ;		[BP]	: SECTOR #
  2601                              <1> ;		[BP+1]	: TRACK #
  2602                              <1> ;		[BP+2]	: BUFFER OFFSET
  2603                              <1> ;
  2604                              <1> ;	ACROSS CALLS TO SUBROUTINES THE CARRY FLAG (CY=1), WHERE INDICATED IN 
  2605                              <1> ;	SUBROUTINE PROLOGUES, REPRESENTS AN EXCEPTION RETURN (NORMALLY AN ERROR 
  2606                              <1> ;	CONDITION). IN MOST CASES, WHEN CY = 1, @DSKETTE_STATUS CONTAINS THE 
  2607                              <1> ;	SPECIFIC ERROR CODE.
  2608                              <1> ;
  2609                              <1> 					; (AH) = @DSKETTE_STATUS
  2610 000017BF FF13                <1> 	CALL	dWORD [eBX]		; CALL THE REQUESTED FUNCTION
  2611 000017C1 5E                  <1> 	POP	eSI			; RESTORE ALL REGISTERS
  2612 000017C2 1F                  <1> 	POP	DS
  2613 000017C3 07                  <1> 	pop	es	; 06/02/2015
  2614 000017C4 59                  <1> 	POP	eCX
  2615 000017C5 5B                  <1> 	POP	eBX
  2616 000017C6 5A                  <1> 	POP	eDX
  2617 000017C7 5F                  <1> 	POP	eDI
  2618 000017C8 89E5                <1> 	MOV	eBP, eSP
  2619 000017CA 50                  <1> 	PUSH	eAX
  2620 000017CB 9C                  <1> 	PUSHFd
  2621 000017CC 58                  <1> 	POP	eAX
  2622                              <1> 	;MOV	[BP+6], AX
  2623 000017CD 89450C              <1> 	mov	[ebp+12], eax  ; 18/02/2015, flags
  2624 000017D0 58                  <1> 	POP	eAX
  2625 000017D1 5D                  <1> 	POP	eBP
  2626 000017D2 CF                  <1> 	IRETd
  2627                              <1> 
  2628                              <1> ;-------------------------------------------------------------------------------
  2629                              <1> ; DW --> dd (06/02/2015)
  2630 000017D3 [37180000]          <1> FNC_TAB	dd	DSK_RESET		; AH = 00H; RESET
  2631 000017D7 [AC180000]          <1> 	dd	DSK_STATUS		; AH = 01H; STATUS
  2632 000017DB [BC180000]          <1> 	dd	DSK_READ		; AH = 02H; READ
  2633 000017DF [CD180000]          <1> 	dd	DSK_WRITE		; AH = 03H; WRITE
  2634 000017E3 [DE180000]          <1> 	dd	DSK_VERF		; AH = 04H; VERIFY
  2635 000017E7 [EF180000]          <1> 	dd	DSK_FORMAT		; AH = 05H; FORMAT
  2636 000017EB [73190000]          <1> 	dd	FNC_ERR			; AH = 06H; INVALID
  2637 000017EF [73190000]          <1> 	dd	FNC_ERR			; AH = 07H; INVALID
  2638 000017F3 [7F190000]          <1> 	dd	DSK_PARMS		; AH = 08H; READ DRIVE PARAMETERS
  2639 000017F7 [73190000]          <1> 	dd	FNC_ERR			; AH = 09H; INVALID
  2640 000017FB [73190000]          <1> 	dd	FNC_ERR			; AH = 0AH; INVALID
  2641 000017FF [73190000]          <1> 	dd	FNC_ERR			; AH = 0BH; INVALID
  2642 00001803 [73190000]          <1> 	dd	FNC_ERR			; AH = 0CH; INVALID
  2643 00001807 [73190000]          <1> 	dd	FNC_ERR			; AH = 0DH; INVALID
  2644 0000180B [73190000]          <1> 	dd	FNC_ERR			; AH = 0EH; INVALID
  2645 0000180F [73190000]          <1> 	dd	FNC_ERR			; AH = 0FH; INVALID
  2646 00001813 [73190000]          <1> 	dd	FNC_ERR			; AH = 10H; INVALID
  2647 00001817 [73190000]          <1> 	dd	FNC_ERR			; AH = 11H; INVALID
  2648 0000181B [73190000]          <1> 	dd	FNC_ERR			; AH = 12H; INVALID
  2649 0000181F [73190000]          <1> 	dd	FNC_ERR			; AH = 13H; INVALID
  2650 00001823 [73190000]          <1> 	dd	FNC_ERR			; AH = 14H; INVALID
  2651 00001827 [3E1A0000]          <1> 	dd	DSK_TYPE		; AH = 15H; READ DASD TYPE
  2652 0000182B [661A0000]          <1> 	dd	DSK_CHANGE		; AH = 16H; CHANGE STATUS
  2653 0000182F [9F1A0000]          <1> 	dd	FORMAT_SET		; AH = 17H; SET DASD TYPE
  2654 00001833 [201B0000]          <1> 	dd	SET_MEDIA		; AH = 18H; SET MEDIA TYPE	
  2655                              <1> FNC_TAE EQU     $                       ; END
  2656                              <1> 
  2657                              <1> ;-------------------------------------------------------------------------------
  2658                              <1> ; DISK_RESET	(AH = 00H)	
  2659                              <1> ;		RESET THE DISKETTE SYSTEM.
  2660                              <1> ;
  2661                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2662                              <1> ;-------------------------------------------------------------------------------
  2663                              <1> DSK_RESET:
  2664 00001837 66BAF203            <1> 	MOV	DX,03F2H		; ADAPTER CONTROL PORT
  2665 0000183B FA                  <1> 	CLI				; NO INTERRUPTS
  2666 0000183C A0[5A6B0000]        <1> 	MOV	AL,[MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  2667 00001841 243F                <1> 	AND	AL,00111111B		; KEEP SELECTED AND MOTOR ON BITS
  2668 00001843 C0C004              <1> 	ROL	AL,4			; MOTOR VALUE TO HIGH NIBBLE
  2669                              <1> 					; DRIVE SELECT TO LOW NIBBLE
  2670 00001846 0C08                <1> 	OR	AL,00001000B		; TURN ON INTERRUPT ENABLE
  2671 00001848 EE                  <1> 	OUT	DX,AL			; RESET THE ADAPTER
  2672 00001849 C605[596B0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; SET RECALIBRATE REQUIRED ON ALL DRIVES
  2673                              <1> 	;JMP	$+2			; WAIT FOR I/O
  2674                              <1> 	;JMP	$+2			; WAIT FOR I/O (TO INSURE MINIMUM
  2675                              <1> 					;      PULSE WIDTH)
  2676                              <1> 	; 19/12/2014
  2677                              <1> 	NEWIODELAY
  2150 00001850 E6EB                <2>  out 0EBh,al
  2678                              <1> 
  2679                              <1> 	; 17/12/2014 
  2680                              <1> 	; AWARD BIOS 1999 - RESETDRIVES (ADISK.ASM)
  2681 00001852 B915000000          <1> 	mov	ecx, WAITCPU_RESET_ON	; cx = 21 -- Min. 14 micro seconds !?
  2682                              <1> wdw1:
  2683                              <1> 	NEWIODELAY   ; 27/02/2015
  2150 00001857 E6EB                <2>  out 0EBh,al
  2684 00001859 E2FC                <1> 	loop	wdw1
  2685                              <1> 	;
  2686 0000185B 0C04                <1> 	OR	AL,00000100B		; TURN OFF RESET BIT
  2687 0000185D EE                  <1> 	OUT	DX,AL			; RESET THE ADAPTER
  2688                              <1> 	; 16/12/2014
  2689                              <1> 	IODELAY
  2145 0000185E EB00                <2>  jmp short $+2
  2146 00001860 EB00                <2>  jmp short $+2
  2690                              <1> 	;
  2691                              <1> 	;STI				; ENABLE THE INTERRUPTS
  2692 00001862 E8EC0B0000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  2693 00001867 723A                <1> 	JC	short DR_ERR		; IF ERROR, RETURN IT
  2694 00001869 66B9C000            <1> 	MOV	CX,11000000B		; CL = EXPECTED @NEC_STATUS
  2695                              <1> NXT_DRV:
  2696                              <1> 	;PUSH	CX			; SAVE FOR CALL
  2697                              <1> 	; 24/12/2021
  2698 0000186D 51                  <1> 	push	ecx
  2699 0000186E B8[A2180000]        <1> 	MOV	eAX, DR_POP_ERR 	; LOAD NEC_OUTPUT ERROR ADDRESS
  2700 00001873 50                  <1> 	PUSH	eAX			; "
  2701 00001874 B408                <1> 	MOV	AH,08H			; SENSE INTERRUPT STATUS COMMAND
  2702 00001876 E8CE0A0000          <1> 	CALL	NEC_OUTPUT
  2703 0000187B 58                  <1> 	POP	eAX			; THROW AWAY ERROR RETURN
  2704 0000187C E8020C0000          <1> 	CALL	RESULTS			; READ IN THE RESULTS
  2705                              <1> 	;POP	CX			; RESTORE AFTER CALL
  2706                              <1> 	; 24/12/2021
  2707 00001881 59                  <1> 	pop	ecx
  2708 00001882 721F                <1> 	JC	short DR_ERR		; ERROR RETURN
  2709 00001884 3A0D[5D6B0000]      <1> 	CMP	CL, [NEC_STATUS]	; TEST FOR DRIVE READY TRANSITION
  2710 0000188A 7517                <1> 	JNZ	short DR_ERR		; EVERYTHING OK
  2711 0000188C FEC1                <1> 	INC	CL			; NEXT EXPECTED @NEC_STATUS
  2712 0000188E 80F9C3              <1> 	CMP	CL,11000011B		; ALL POSSIBLE DRIVES CLEARED
  2713 00001891 76DA                <1> 	JBE	short NXT_DRV		; FALL THRU IF 11000100B OR >
  2714                              <1> 	;
  2715 00001893 E843030000          <1> 	CALL	SEND_SPEC		; SEND SPECIFY COMMAND TO NEC
  2716                              <1> RESBAC:
  2717 00001898 E8D8080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2718                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2719                              <1> 	; 24/12/2021
  2720 0000189D 89F3                <1> 	mov	ebx, esi
  2721 0000189F 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2722 000018A1 C3                  <1> 	RETn		
  2723                              <1> DR_POP_ERR:
  2724                              <1> 	;POP	CX			; CLEAR STACK
  2725                              <1> 	; 24/12/2021
  2726 000018A2 59                  <1> 	pop	ecx
  2727                              <1> DR_ERR:
  2728 000018A3 800D[5C6B0000]20    <1> 	OR	byte [DSKETTE_STATUS],BAD_NEC ; SET ERROR CODE
  2729 000018AA EBEC                <1> 	JMP	SHORT RESBAC		; RETURN FROM RESET
  2730                              <1> 
  2731                              <1> ;-------------------------------------------------------------------------------
  2732                              <1> ; DISK_STATUS	(AH = 01H)
  2733                              <1> ;	DISKETTE STATUS.
  2734                              <1> ;
  2735                              <1> ; ON ENTRY:	AH : STATUS OF PREVIOUS OPERATION
  2736                              <1> ;
  2737                              <1> ; ON EXIT:	AH, @DSKETTE_STATUS, CY REFLECT STATUS OF PREVIOUS OPERATION.
  2738                              <1> ;-------------------------------------------------------------------------------
  2739                              <1> DSK_STATUS:
  2740 000018AC 8825[5C6B0000]      <1> 	MOV	[DSKETTE_STATUS],AH	; PUT BACK FOR SETUP END
  2741 000018B2 E8BE080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2742                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2743                              <1> 	; 24/12/2021
  2744 000018B7 89F3                <1> 	mov	ebx, esi
  2745 000018B9 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2746 000018BB C3                  <1> 	RETn		
  2747                              <1> 
  2748                              <1> ;-------------------------------------------------------------------------------
  2749                              <1> ; DISK_READ	(AH = 02H)	
  2750                              <1> ;	DISKETTE READ.
  2751                              <1> ;
  2752                              <1> ; ON ENTRY:	DI	: DRIVE #
  2753                              <1> ;		SI-HI	: HEAD #
  2754                              <1> ;		SI-LOW	: # OF SECTORS
  2755                              <1> ;		ES	: BUFFER SEGMENT
  2756                              <1> ;		[BP]	: SECTOR #
  2757                              <1> ;		[BP+1]	: TRACK #
  2758                              <1> ;		[BP+2]	: BUFFER OFFSET
  2759                              <1> ;
  2760                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2761                              <1> ;-------------------------------------------------------------------------------
  2762                              <1> 
  2763                              <1> ; 06/02/2015, ES:BX -> EBX (unix386.s)
  2764                              <1> 
  2765                              <1> DSK_READ:
  2766 000018BC 8025[5A6B0000]7F    <1> 	AND	byte [MOTOR_STATUS],01111111B ; INDICATE A READ OPERATION
  2767 000018C3 66B846E6            <1> 	MOV	AX,0E646H		; AX = NEC COMMAND, DMA COMMAND
  2768 000018C7 E815040000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2769 000018CC C3                  <1> 	RETn
  2770                              <1> 
  2771                              <1> ;-------------------------------------------------------------------------------
  2772                              <1> ; DISK_WRITE	(AH = 03H)
  2773                              <1> ;	DISKETTE WRITE.
  2774                              <1> ;
  2775                              <1> ; ON ENTRY:	DI	: DRIVE #
  2776                              <1> ;		SI-HI	: HEAD #
  2777                              <1> ;		SI-LOW	: # OF SECTORS
  2778                              <1> ;		ES	: BUFFER SEGMENT
  2779                              <1> ;		[BP]	: SECTOR #
  2780                              <1> ;		[BP+1]	: TRACK #
  2781                              <1> ;		[BP+2]	: BUFFER OFFSET
  2782                              <1> ;
  2783                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2784                              <1> ;-------------------------------------------------------------------------------
  2785                              <1> 
  2786                              <1> ; 06/02/2015, ES:BX -> EBX (unix386.s)
  2787                              <1> 
  2788                              <1> DSK_WRITE:
  2789 000018CD 66B84AC5            <1> 	MOV	AX,0C54AH		; AX = NEC COMMAND, DMA COMMAND
  2790 000018D1 800D[5A6B0000]80    <1>         OR      byte [MOTOR_STATUS],10000000B ; INDICATE WRITE OPERATION
  2791 000018D8 E804040000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2792 000018DD C3                  <1> 	RETn
  2793                              <1> 
  2794                              <1> ;-------------------------------------------------------------------------------
  2795                              <1> ; DISK_VERF	(AH = 04H)
  2796                              <1> ;	DISKETTE VERIFY.
  2797                              <1> ;
  2798                              <1> ; ON ENTRY:	DI	: DRIVE #
  2799                              <1> ;		SI-HI	: HEAD #
  2800                              <1> ;		SI-LOW	: # OF SECTORS
  2801                              <1> ;		ES	: BUFFER SEGMENT
  2802                              <1> ;		[BP]	: SECTOR #
  2803                              <1> ;		[BP+1]	: TRACK #
  2804                              <1> ;		[BP+2]	: BUFFER OFFSET
  2805                              <1> ;
  2806                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2807                              <1> ;-------------------------------------------------------------------------------
  2808                              <1> DSK_VERF:
  2809 000018DE 8025[5A6B0000]7F    <1> 	AND	byte [MOTOR_STATUS],01111111B ; INDICATE A READ OPERATION
  2810 000018E5 66B842E6            <1> 	MOV	AX,0E642H		; AX = NEC COMMAND, DMA COMMAND
  2811 000018E9 E8F3030000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2812 000018EE C3                  <1> 	RETn
  2813                              <1> 
  2814                              <1> ;-------------------------------------------------------------------------------
  2815                              <1> ; DISK_FORMAT	(AH = 05H)
  2816                              <1> ;	DISKETTE FORMAT.
  2817                              <1> ;
  2818                              <1> ; ON ENTRY:	DI	: DRIVE #
  2819                              <1> ;		SI-HI	: HEAD #
  2820                              <1> ;		SI-LOW	: # OF SECTORS
  2821                              <1> ;		ES	: BUFFER SEGMENT
  2822                              <1> ;		[BP]	: SECTOR #
  2823                              <1> ;		[BP+1]	: TRACK #
  2824                              <1> ;		[BP+2]	: BUFFER OFFSET
  2825                              <1> ;		@DISK_POINTER POINTS TO THE PARAMETER TABLE OF THIS DRIVE
  2826                              <1> ;
  2827                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2828                              <1> ;-------------------------------------------------------------------------------
  2829                              <1> DSK_FORMAT:
  2830 000018EF E830030000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  2831 000018F4 E81D050000          <1> 	CALL	FMT_INIT		; ESTABLISH STATE IF UNESTABLISHED
  2832 000018F9 800D[5A6B0000]80    <1>         OR      byte [MOTOR_STATUS], 10000000B ; INDICATE WRITE OPERATION
  2833 00001900 E865050000          <1> 	CALL	MED_CHANGE		; CHECK MEDIA CHANGE AND RESET IF SO
  2834 00001905 725D                <1>         JC      short FM_DON            ; MEDIA CHANGED, SKIP
  2835 00001907 E8CF020000          <1> 	CALL	SEND_SPEC		; SEND SPECIFY COMMAND TO NEC
  2836 0000190C E8C9050000          <1> 	CALL	CHK_LASTRATE		; ZF=1 ATTEMPT RATE IS SAME AS LAST RATE
  2837 00001911 7405                <1>         JZ      short FM_WR             ; YES, SKIP SPECIFY COMMAND
  2838 00001913 E8A2050000          <1> 	CALL	SEND_RATE		; SEND DATA RATE TO CONTROLLER
  2839                              <1> FM_WR:
  2840 00001918 E84F060000          <1> 	CALL	FMTDMA_SET		; SET UP THE DMA FOR FORMAT
  2841 0000191D 7245                <1>         JC      short FM_DON            ; RETURN WITH ERROR
  2842 0000191F B44D                <1> 	MOV	AH,04DH			; ESTABLISH THE FORMAT COMMAND
  2843 00001921 E8A7060000          <1> 	CALL	NEC_INIT		; INITIALIZE THE NEC
  2844 00001926 723C                <1>         JC      short FM_DON            ; ERROR - EXIT
  2845 00001928 B8[64190000]        <1>         MOV     eAX, FM_DON             ; LOAD ERROR ADDRESS
  2846 0000192D 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  2847 0000192E B203                <1> 	MOV	DL,3			; BYTES/SECTOR VALUE TO NEC
  2848 00001930 E80E090000          <1> 	CALL	GET_PARM
  2849 00001935 E80F0A0000          <1> 	CALL	NEC_OUTPUT
  2850 0000193A B204                <1> 	MOV	DL,4			; SECTORS/TRACK VALUE TO NEC
  2851 0000193C E802090000          <1> 	CALL	GET_PARM
  2852 00001941 E8030A0000          <1> 	CALL	NEC_OUTPUT
  2853 00001946 B207                <1> 	MOV	DL,7			; GAP LENGTH VALUE TO NEC
  2854 00001948 E8F6080000          <1> 	CALL	GET_PARM
  2855 0000194D E8F7090000          <1> 	CALL	NEC_OUTPUT
  2856 00001952 B208                <1> 	MOV	DL,8			; FILLER BYTE TO NEC
  2857 00001954 E8EA080000          <1> 	CALL	GET_PARM
  2858 00001959 E8EB090000          <1> 	CALL	NEC_OUTPUT
  2859 0000195E 58                  <1> 	POP	eAX			; THROW AWAY ERROR
  2860 0000195F E8E5060000          <1> 	CALL	NEC_TERM		; TERMINATE, RECEIVE STATUS, ETC,
  2861                              <1> FM_DON:
  2862 00001964 E8EC020000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  2863 00001969 E807080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2864                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2865 0000196E 89F3                <1> 	mov	ebx, esi ; 24/12/2021
  2866 00001970 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2867 00001972 C3                  <1> 	RETn
  2868                              <1> 
  2869                              <1> ;-------------------------------------------------------------------------------
  2870                              <1> ; FNC_ERR
  2871                              <1> ;	INVALID FUNCTION REQUESTED OR INVALID DRIVE: 
  2872                              <1> ;	SET BAD COMMAND IN STATUS.
  2873                              <1> ;
  2874                              <1> ; ON EXIT: 	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2875                              <1> ;-------------------------------------------------------------------------------
  2876                              <1> FNC_ERR:				; INVALID FUNCTION REQUEST
  2877                              <1> 	;MOV	AX,SI			; RESTORE AL
  2878                              <1> 	; 24/12/2021
  2879 00001973 89F0                <1> 	mov	eax, esi
  2880 00001975 B401                <1> 	MOV	AH,BAD_CMD		; SET BAD COMMAND ERROR
  2881 00001977 8825[5C6B0000]      <1> 	MOV	[DSKETTE_STATUS],AH	; STORE IN DATA AREA
  2882 0000197D F9                  <1> 	STC				; SET CARRY INDICATING ERROR
  2883 0000197E C3                  <1> 	RETn
  2884                              <1> 
  2885                              <1> ;-------------------------------------------------------------------------------
  2886                              <1> ; DISK_PARMS	(AH = 08H)	
  2887                              <1> ;	READ DRIVE PARAMETERS.
  2888                              <1> ;
  2889                              <1> ; ON ENTRY:	DI : DRIVE #
  2890                              <1> ;
  2891                              <1> ; ON EXIT:	CL/[BP]   = BITS 7 & 6 HI 2 BITS OF MAX CYLINDER
  2892                              <1> ;		            BITS 0-5 MAX SECTORS/TRACK
  2893                              <1> ;		CH/[BP+1] = LOW 8 BITS OF MAX CYLINDER
  2894                              <1> ;		BL/[BP+2] = BITS 7-4 = 0
  2895                              <1> ;		            BITS 3-0 = VALID CMOS DRIVE TYPE
  2896                              <1> ;		BH/[BP+3] = 0
  2897                              <1> ;		DL/[BP+4] = # DRIVES INSTALLED (VALUE CHECKED)
  2898                              <1> ;		DH/[BP+5] = MAX HEAD #
  2899                              <1> ;		DI/[BP+6] = OFFSET TO DISK_BASE
  2900                              <1> ;		ES        = SEGMENT OF DISK_BASE
  2901                              <1> ;		AX        = 0
  2902                              <1> ;
  2903                              <1> ;		NOTE : THE ABOVE INFORMATION IS STORED IN THE USERS STACK AT
  2904                              <1> ;		       THE LOCATIONS WHERE THE MAIN ROUTINE WILL POP THEM
  2905                              <1> ;		       INTO THE APPROPRIATE REGISTERS BEFORE RETURNING TO THE
  2906                              <1> ;		       CALLER.
  2907                              <1> ;-------------------------------------------------------------------------------
  2908                              <1> DSK_PARMS:
  2909 0000197F E8A0020000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH,
  2910                              <1>      ;	MOV	WORD [BP+2],0		; DRIVE TYPE = 0
  2911 00001984 29D2                <1> 	sub     edx, edx ; 20/02/2015
  2912 00001986 895504              <1>         mov	[ebp+4], edx ; 20/02/2015
  2913                              <1>      ;  MOV     AX, [EQUIP_FLAG]        ; LOAD EQUIPMENT FLAG FOR # DISKETTES
  2914                              <1>      ;  AND     AL,11000001B            ; KEEP DISKETTE DRIVE BITS
  2915                              <1>      ;  MOV     DL,2                    ; DISKETTE DRIVES = 2
  2916                              <1>      ;  CMP     AL,01000001B            ; 2 DRIVES INSTALLED ?
  2917                              <1>      ;  JZ      short STO_DL            ; IF YES JUMP
  2918                              <1>      ;  DEC     DL                      ; DISKETTE DRIVES = 1
  2919                              <1>      ;  CMP     AL,00000001B            ; 1 DRIVE INSTALLED ?
  2920                              <1>      ;  JNZ     short NON_DRV           ; IF NO JUMP
  2921                              <1> 	;sub	edx, edx
  2922 00001989 66A1[CE650000]      <1> 	mov     ax, [fd0_type]
  2923 0000198F 6621C0              <1> 	and     ax, ax
  2924 00001992 7473                <1> 	jz      short NON_DRV
  2925 00001994 FEC2                <1> 	inc     dl
  2926 00001996 20E4                <1> 	and     ah, ah
  2927 00001998 7402                <1> 	jz      short STO_DL
  2928 0000199A FEC2                <1> 	inc     dl
  2929                              <1> STO_DL:
  2930                              <1> 	;MOV	[BP+4],DL		; STORE NUMBER OF DRIVES
  2931 0000199C 895508              <1> 	mov	[ebp+8], edx ; 20/02/2015	 	
  2932 0000199F 6683FF01            <1> 	CMP	DI,1			; CHECK FOR VALID DRIVE
  2933 000019A3 7765                <1> 	JA	short NON_DRV1		; DRIVE INVALID
  2934                              <1> 	;MOV	BYTE [BP+5],1		; MAXIMUM HEAD NUMBER =	1
  2935 000019A5 C6450901            <1> 	mov	byte [ebp+9], 1  ; 20/02/2015	
  2936 000019A9 E88C080000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL
  2937                              <1> 	;;20/02/2015
  2938                              <1> 	;;JC	short CHK_EST		; IF CMOS BAD CHECKSUM ESTABLISHED
  2939                              <1> 	;;OR	AL,AL			; TEST FOR NO DRIVE TYPE
  2940 000019AE 7412                <1> 	JZ	short CHK_EST		; JUMP IF SO
  2941 000019B0 E8FD010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2942 000019B5 720B                <1> 	JC	short CHK_EST		; TYPE NOT IN TABLE (POSSIBLE BAD CMOS)
  2943                              <1> 	;MOV	[BP+2],AL		; STORE VALID CMOS DRIVE TYPE
  2944 000019B7 884504              <1>         mov	[ebp+4], al ; 06/02/2015
  2945 000019BA 8A4B04              <1> 	MOV     CL, [eBX+MD.SEC_TRK]     ; GET SECTOR/TRACK
  2946 000019BD 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]     ; GET MAX. TRACK NUMBER
  2947 000019C0 EB36                <1> 	JMP	SHORT STO_CX		; CMOS GOOD, USE CMOS
  2948                              <1> CHK_EST:
  2949 000019C2 8AA7[696B0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; LOAD STATE FOR THIS DRIVE
  2950 000019C8 F6C410              <1> 	TEST	AH,MED_DET		; CHECK FOR ESTABLISHED STATE
  2951 000019CB 743D                <1> 	JZ	short NON_DRV1		; CMOS BAD/INVALID OR UNESTABLISHED
  2952                              <1> USE_EST:
  2953 000019CD 80E4C0              <1> 	AND	AH,RATE_MSK		; ISOLATE STATE
  2954 000019D0 80FC80              <1> 	CMP	AH,RATE_250		; RATE 250 ?
  2955 000019D3 7555                <1> 	JNE	short USE_EST2		; NO, GO CHECK OTHER RATE
  2956                              <1> 
  2957                              <1> ;-----	DATA RATE IS 250 KBS, TRY 360 KB TABLE FIRST
  2958                              <1> 
  2959 000019D5 B001                <1> 	MOV	AL,01			; DRIVE TYPE 1 (360KB)
  2960 000019D7 E8D6010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2961 000019DC 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  2962 000019DF 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  2963 000019E2 F687[696B0000]01    <1> 	TEST	byte [DSK_STATE+eDI],TRK_CAPA ; 80 TRACK ?
  2964 000019E9 740D                <1> 	JZ	short STO_CX		; MUST BE 360KB DRIVE 
  2965                              <1> 
  2966                              <1> ;-----	IT IS 1.44 MB DRIVE
  2967                              <1> 
  2968                              <1> PARM144:
  2969 000019EB B004                <1> 	MOV	AL,04			; DRIVE TYPE 4 (1.44MB)
  2970 000019ED E8C0010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2971 000019F2 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  2972 000019F5 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  2973                              <1> STO_CX:
  2974 000019F8 894D00              <1> 	MOV	[eBP],eCX		; SAVE POINTER IN STACK FOR RETURN
  2975                              <1> ES_DI:
  2976                              <1> 	;MOV	[BP+6],BX		; ADDRESS OF MEDIA/DRIVE PARM TABLE 
  2977 000019FB 895D0C              <1> 	mov	[ebp+12], ebx ; 06/02/2015
  2978                              <1> 	;MOV	AX,CS			; SEGMENT MEDIA/DRIVE PARAMETER TABLE
  2979                              <1> 	;MOV	ES,AX			; ES IS SEGMENT OF TABLE
  2980                              <1> DP_OUT:
  2981 000019FE E852020000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  2982                              <1> 	;XOR	AX,AX			; CLEAR
  2983                              <1> 	; 24/12/2021
  2984 00001A03 31C0                <1> 	xor	eax, eax
  2985 00001A05 F8                  <1> 	CLC
  2986 00001A06 C3                  <1> 	RETn
  2987                              <1> 
  2988                              <1> ;-----	NO DRIYE PRESENT HANDLER
  2989                              <1> 
  2990                              <1> NON_DRV:
  2991                              <1> 	;MOV	BYTE [BP+4],0		; CLEAR NUMBER OF DRIVES
  2992 00001A07 895508              <1> 	mov	[ebp+8], edx ; 0 ; 20/02/2015
  2993                              <1> NON_DRV1:
  2994 00001A0A 6681FF8000          <1> 	CMP	DI,80H			; CHECK FOR FIXED MEDIA TYPE REQUEST
  2995 00001A0F 720B                <1> 	JB	short NON_DRV2		; CONTINUE IF NOT REQUEST FALL THROUGH
  2996                              <1> 
  2997                              <1> ;-----	FIXED DISK REQUEST FALL THROUGH ERROR
  2998                              <1> 	
  2999 00001A11 E83F020000          <1> 	CALL	XLAT_OLD		; ELSE TRANSLATE TO COMPATIBLE MODE
  3000                              <1> 	;MOV	AX,SI			; RESTORE AL
  3001 00001A16 89F0                <1> 	mov	eax, esi ; 24/12/2021
  3002 00001A18 B401                <1> 	MOV	AH,BAD_CMD		; SET BAD COMMAND ERROR
  3003 00001A1A F9                  <1> 	STC
  3004 00001A1B C3                  <1> 	RETn
  3005                              <1> 
  3006                              <1> NON_DRV2:
  3007                              <1> 	;XOR	AX,AX			; CLEAR PARMS IF NO DRIVES OR CMOS BAD
  3008 00001A1C 31C0                <1> 	xor	eax, eax	
  3009 00001A1E 66894500            <1> 	MOV	[eBP],AX		; TRACKS, SECTORS/TRACK = 0
  3010                              <1> 	;MOV	[BP+5],AH		; HEAD = 0
  3011 00001A22 886509              <1> 	mov	[ebp+9], ah ; 06/02/2015
  3012                              <1> 	;MOV	[BP+6],AX		; OFFSET TO DISK_BASE = 0
  3013 00001A25 89450C              <1> 	mov	[ebp+12], eax
  3014                              <1> 	;MOV	ES,AX			; ES IS SEGMENT OF TABLE
  3015 00001A28 EBD4                <1> 	JMP	SHORT DP_OUT
  3016                              <1> 
  3017                              <1> ;-----	DATA RATE IS EITHER 300 KBS OR 500 KBS, TRY 1.2 MB TABLE FIRST
  3018                              <1> 
  3019                              <1> USE_EST2:
  3020 00001A2A B002                <1> 	MOV	AL,02			; DRIVE TYPE 2 (1.2MB)
  3021 00001A2C E881010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  3022 00001A31 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  3023 00001A34 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  3024 00001A37 80FC40              <1> 	CMP	AH,RATE_300		; RATE 300 ?
  3025 00001A3A 74BC                <1> 	JZ	short STO_CX		; MUST BE 1.2MB DRIVE
  3026 00001A3C EBAD                <1> 	JMP	SHORT PARM144		; ELSE, IT IS 1.44MB DRIVE 
  3027                              <1> 
  3028                              <1> ;-------------------------------------------------------------------------------
  3029                              <1> ; DISK_TYPE (AH = 15H)	
  3030                              <1> ;	THIS ROUTINE RETURNS THE TYPE OF MEDIA INSTALLED.
  3031                              <1> ;
  3032                              <1> ;  ON ENTRY:	DI = DRIVE #
  3033                              <1> ;
  3034                              <1> ;  ON EXIT:	AH = DRIVE TYPE, CY=0
  3035                              <1> ;-------------------------------------------------------------------------------
  3036                              <1> DSK_TYPE:
  3037 00001A3E E8E1010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3038 00001A43 8A87[696B0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET PRESENT STATE INFORMATION
  3039 00001A49 08C0                <1> 	OR	AL,AL			; CHECK FOR NO DRIVE
  3040 00001A4B 7415                <1> 	JZ	short NO_DRV
  3041 00001A4D B401                <1> 	MOV	AH,NOCHGLN		; NO CHANGE LINE FOR 40 TRACK DRIVE
  3042 00001A4F A801                <1> 	TEST	AL,TRK_CAPA		; IS THIS DRIVE AN 80 TRACK DRIVE?
  3043 00001A51 7402                <1> 	JZ	short DT_BACK			; IF NO JUMP
  3044 00001A53 B402                <1> 	MOV	AH,CHGLN		; CHANGE LINE FOR 80 TRACK DRIVE
  3045                              <1> DT_BACK:
  3046                              <1> 	;PUSH	AX			; SAVE RETURN VALUE
  3047 00001A55 50                  <1> 	push	eax ; 24/12/2021
  3048 00001A56 E8FA010000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3049                              <1> 	;POP	AX			; RESTORE RETURN VALUE
  3050 00001A5B 58                  <1> 	pop	eax ; 24/12/2021
  3051 00001A5C F8                  <1> 	CLC				; NO ERROR
  3052                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  3053                              <1> 	; 24/12/2021
  3054 00001A5D 89F3                <1> 	mov	ebx, esi
  3055 00001A5F 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3056 00001A61 C3                  <1> 	RETn
  3057                              <1> NO_DRV:	
  3058 00001A62 30E4                <1> 	XOR	AH,AH			; NO DRIVE PRESENT OR UNKNOWN
  3059 00001A64 EBEF                <1> 	JMP	SHORT DT_BACK
  3060                              <1> 
  3061                              <1> ;-------------------------------------------------------------------------------
  3062                              <1> ; DISK_CHANGE	(AH = 16H)
  3063                              <1> ;	THIS ROUTINE RETURNS THE STATE OF THE DISK CHANGE LINE.
  3064                              <1> ;
  3065                              <1> ; ON ENTRY:	DI = DRIVE #
  3066                              <1> ;
  3067                              <1> ; ON EXIT:	AH = @DSKETTE_STATUS
  3068                              <1> ;		     00 - DISK CHANGE LINE INACTIVE, CY = 0
  3069                              <1> ;		     06 - DISK CHANGE LINE ACTIVE, CY = 1
  3070                              <1> ;-------------------------------------------------------------------------------
  3071                              <1> DSK_CHANGE:
  3072 00001A66 E8B9010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3073 00001A6B 8A87[696B0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET MEDIA STATE INFORMATION
  3074 00001A71 08C0                <1> 	OR	AL,AL			; DRIVE PRESENT ?
  3075 00001A73 7421                <1> 	JZ	short DC_NON		; JUMP IF NO DRIVE
  3076 00001A75 A801                <1> 	TEST	AL,TRK_CAPA		; 80 TRACK DRIVE ?
  3077 00001A77 7407                <1> 	JZ	short SETIT		; IF SO , CHECK CHANGE LINE
  3078                              <1> DC0:
  3079 00001A79 E8600A0000          <1>         CALL    READ_DSKCHNG            ; GO CHECK STATE OF DISK CHANGE LINE
  3080 00001A7E 7407                <1> 	JZ	short FINIS		; CHANGE LINE NOT ACTIVE
  3081                              <1> 
  3082 00001A80 C605[5C6B0000]06    <1> SETIT:	MOV	byte [DSKETTE_STATUS], MEDIA_CHANGE ; INDICATE MEDIA REMOVED
  3083                              <1> 
  3084 00001A87 E8C9010000          <1> FINIS:	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3085 00001A8C E8E4060000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3086                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  3087                              <1> 	; 24/12/2021
  3088 00001A91 89F3                <1> 	mov	ebx, esi
  3089 00001A93 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3090 00001A95 C3                  <1> 	RETn
  3091                              <1> DC_NON:
  3092 00001A96 800D[5C6B0000]80    <1> 	OR	byte [DSKETTE_STATUS], TIME_OUT ; SET TIMEOUT, NO DRIVE
  3093 00001A9D EBE8                <1> 	JMP	SHORT FINIS
  3094                              <1> 
  3095                              <1> ;-------------------------------------------------------------------------------
  3096                              <1> ; FORMAT_SET	(AH = 17H)
  3097                              <1> ;	THIS ROUTINE IS USED TO ESTABLISH THE TYPE OF MEDIA TO BE USED
  3098                              <1> ;	FOR THE FOLLOWING FORMAT OPERATION.
  3099                              <1> ;
  3100                              <1> ; ON ENTRY:	SI LOW = DASD TYPE FOR FORMAT
  3101                              <1> ;		DI     = DRIVE #
  3102                              <1> ;
  3103                              <1> ; ON EXIT:	@DSKETTE_STATUS REFLECTS STATUS
  3104                              <1> ;		AH = @DSKETTE_STATUS
  3105                              <1> ;		CY = 1 IF ERROR
  3106                              <1> ;-------------------------------------------------------------------------------
  3107                              <1> FORMAT_SET:
  3108 00001A9F E880010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3109                              <1> 	;PUSH	SI			; SAVE DASD TYPE
  3110                              <1> 	; 24/12/2021
  3111 00001AA4 56                  <1> 	push	esi
  3112 00001AA5 6689F0              <1> 	MOV	AX,SI			; AH = ? , AL , DASD TYPE
  3113 00001AA8 30E4                <1> 	XOR	AH,AH			; AH , 0 , AL , DASD TYPE
  3114 00001AAA 6689C6              <1> 	MOV	SI,AX			; SI = DASD TYPE
  3115 00001AAD 80A7[696B0000]0F    <1> 	AND	byte [DSK_STATE+eDI], ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR STATE
  3116 00001AB4 664E                <1> 	DEC	SI			; CHECK FOR 320/360K MEDIA & DRIVE
  3117 00001AB6 7509                <1> 	JNZ	short NOT_320		; BYPASS IF NOT
  3118 00001AB8 808F[696B0000]90    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+RATE_250 ; SET TO 320/360
  3119 00001ABF EB48                <1> 	JMP	SHORT S0
  3120                              <1> NOT_320:
  3121 00001AC1 E8A4030000          <1> 	CALL	MED_CHANGE		; CHECK FOR TIME_OUT
  3122 00001AC6 803D[5C6B0000]80    <1> 	CMP	byte [DSKETTE_STATUS], TIME_OUT
  3123 00001ACD 743A                <1> 	JZ	short S0		; IF TIME OUT TELL CALLER
  3124                              <1> S3:
  3125 00001ACF 664E                <1> 	DEC	SI			; CHECK FOR 320/360K IN 1.2M DRIVE
  3126 00001AD1 7509                <1> 	JNZ	short NOT_320_12	; BYPASS IF NOT
  3127 00001AD3 808F[696B0000]70    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+DBL_STEP+RATE_300 ; SET STATE
  3128 00001ADA EB2D                <1> 	JMP	SHORT S0
  3129                              <1> NOT_320_12:
  3130 00001ADC 664E                <1> 	DEC	SI			; CHECK FOR 1.2M MEDIA IN 1.2M DRIVE
  3131 00001ADE 7509                <1> 	JNZ	short NOT_12		; BYPASS IF NOT
  3132 00001AE0 808F[696B0000]10    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+RATE_500 ; SET STATE VARIABLE
  3133 00001AE7 EB20                <1> 	JMP	SHORT S0		; RETURN TO CALLER
  3134                              <1> NOT_12:	
  3135 00001AE9 664E                <1> 	DEC	SI			; CHECK FOR SET DASD TYPE 04
  3136 00001AEB 752A                <1> 	JNZ	short FS_ERR		; BAD COMMAND EXIT IF NOT VALID TYPE
  3137                              <1> 
  3138 00001AED F687[696B0000]04    <1> 	TEST	byte [DSK_STATE+eDI], DRV_DET ; DRIVE DETERMINED ?
  3139 00001AF4 740B                <1> 	JZ	short ASSUME		; IF STILL NOT DETERMINED ASSUME
  3140 00001AF6 B050                <1> 	MOV	AL,MED_DET+RATE_300
  3141 00001AF8 F687[696B0000]02    <1>         TEST    byte [DSK_STATE+eDI], FMT_CAPA ; MULTIPLE FORMAT CAPABILITY ?
  3142 00001AFF 7502                <1> 	JNZ	short OR_IT_IN		; IF 1.2 M THEN DATA RATE 300
  3143                              <1> ASSUME:
  3144 00001B01 B090                <1> 	MOV	AL,MED_DET+RATE_250	; SET UP
  3145                              <1> OR_IT_IN:
  3146 00001B03 0887[696B0000]      <1> 	OR	[DSK_STATE+eDI], AL	; OR IN THE CORRECT STATE
  3147                              <1> S0:
  3148 00001B09 E847010000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3149 00001B0E E862060000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3150                              <1> 	;POP	BX			; GET SAVED AL TO BL
  3151                              <1> 	; 24/12/2021
  3152 00001B13 5B                  <1> 	pop	ebx
  3153 00001B14 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3154 00001B16 C3                  <1> 	RETn
  3155                              <1> FS_ERR:
  3156 00001B17 C605[5C6B0000]01    <1> 	MOV	byte [DSKETTE_STATUS], BAD_CMD ; UNKNOWN STATE,BAD COMMAND
  3157 00001B1E EBE9                <1> 	JMP	SHORT S0
  3158                              <1> 
  3159                              <1> ;-------------------------------------------------------------------------------
  3160                              <1> ; SET_MEDIA	(AH = 18H)
  3161                              <1> ;	THIS ROUTINE SETS THE TYPE OF MEDIA AND DATA RATE 
  3162                              <1> ;	TO BE USED FOR THE FOLLOWING FORMAT OPERATION.
  3163                              <1> ;
  3164                              <1> ; ON ENTRY:
  3165                              <1> ;	[BP]	= SECTOR PER TRACK
  3166                              <1> ;	[BP+1]	= TRACK #
  3167                              <1> ;	DI	= DRIVE #
  3168                              <1> ;
  3169                              <1> ; ON EXIT:
  3170                              <1> ;	@DSKETTE_STATUS REFLECTS STATUS
  3171                              <1> ;	IF NO ERROR:
  3172                              <1> ;		AH = 0
  3173                              <1> ;		CY = 0
  3174                              <1> ;		ES = SEGMENT OF MEDIA/DRIVE PARAMETER TABLE
  3175                              <1> ;		DI/[BP+6] = OFFSET OF MEDIA/DRIVE PARAMETER TABLE
  3176                              <1> ;	IF ERROR:	
  3177                              <1> ;		AH = @DSKETTE_STATUS
  3178                              <1> ;		CY = 1
  3179                              <1> ;-------------------------------------------------------------------------------
  3180                              <1> SET_MEDIA:
  3181 00001B20 E8FF000000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3182 00001B25 F687[696B0000]01    <1>         TEST    byte [DSK_STATE+eDI], TRK_CAPA ; CHECK FOR CHANGE LINE AVAILABLE
  3183 00001B2C 7415                <1> 	JZ	short SM_CMOS		; JUMP IF 40 TRACK DRIVE
  3184 00001B2E E837030000          <1> 	CALL	MED_CHANGE		; RESET CHANGE LINE
  3185 00001B33 803D[5C6B0000]80    <1> 	CMP	byte [DSKETTE_STATUS], TIME_OUT ; IF TIME OUT TELL CALLER
  3186 00001B3A 746B                <1> 	JE	short SM_RTN
  3187 00001B3C C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS], 0 ; CLEAR STATUS
  3188                              <1> SM_CMOS:
  3189 00001B43 E8F2060000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  3190                              <1> 	;;20/02/2015
  3191                              <1> 	;;JC	short MD_NOT_FND	; ERROR IN CMOS
  3192                              <1> 	;;OR	AL,AL			; TEST FOR NO DRIVE
  3193 00001B48 745D                <1> 	JZ	short SM_RTN		; RETURN IF SO
  3194 00001B4A E863000000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  3195 00001B4F 7231                <1> 	JC	short MD_NOT_FND	; TYPE NOT IN TABLE (BAD CMOS)
  3196 00001B51 57                  <1> 	PUSH	eDI			; SAVE REG.
  3197 00001B52 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR. TYPE TABLE
  3198 00001B54 B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3199                              <1> DR_SEARCH:
  3200 00001B59 8AA3[4C650000]      <1> 	MOV	AH, [DR_TYPE+eBX]	; GET DRIVE TYPE
  3201 00001B5F 80E47F              <1> 	AND	AH,BIT7OFF		; MASK OUT MSB
  3202 00001B62 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH ?
  3203 00001B64 7516                <1> 	JNE	short NXT_MD		; NO, CHECK NEXT DRIVE TYPE
  3204                              <1> DR_FND:
  3205 00001B66 8BBB[4D650000]      <1> 	MOV	eDI, [DR_TYPE+eBX+1] 	; DI = MEDIA/DRIVE PARAM TABLE
  3206                              <1> MD_SEARCH:
  3207 00001B6C 8A6704              <1>         MOV     AH, [eDI+MD.SEC_TRK]    ; GET SECTOR/TRACK
  3208 00001B6F 386500              <1> 	CMP	[eBP],AH		; MATCH?
  3209 00001B72 7508                <1> 	JNE	short NXT_MD		; NO, CHECK NEXT MEDIA
  3210 00001B74 8A670B              <1>         MOV     AH, [eDI+MD.MAX_TRK]    ; GET MAX. TRACK #
  3211 00001B77 386501              <1> 	CMP 	[eBP+1],AH		; MATCH?
  3212 00001B7A 740F                <1> 	JE	short MD_FND		; YES, GO GET RATE
  3213                              <1> NXT_MD:
  3214                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3215 00001B7C 83C305              <1>         add	ebx, 5 ; 18/02/2015
  3216 00001B7F E2D8                <1> 	LOOP    DR_SEARCH
  3217 00001B81 5F                  <1> 	POP	eDI			; RESTORE REG.
  3218                              <1> MD_NOT_FND:
  3219 00001B82 C605[5C6B0000]0C    <1> 	MOV	byte [DSKETTE_STATUS], MED_NOT_FND ; ERROR, MEDIA TYPE NOT FOUND
  3220 00001B89 EB1C                <1> 	JMP	SHORT SM_RTN		; RETURN
  3221                              <1> MD_FND:
  3222 00001B8B 8A470C              <1>         MOV     AL, [eDI+MD.RATE]       ; GET RATE
  3223 00001B8E 3C40                <1> 	CMP	AL,RATE_300		; DOUBLE STEP REQUIRED FOR RATE 300
  3224 00001B90 7502                <1> 	JNE	short MD_SET
  3225 00001B92 0C20                <1> 	OR	AL,DBL_STEP
  3226                              <1> MD_SET:
  3227                              <1> 	;MOV	[BP+6],DI		; SAVE TABLE POINTER IN STACK
  3228 00001B94 897D0C              <1> 	mov	[ebp+12], edi ; 18/02/2015
  3229 00001B97 0C10                <1> 	OR	AL,MED_DET		; SET MEDIA ESTABLISHED
  3230 00001B99 5F                  <1> 	POP	eDI
  3231 00001B9A 80A7[696B0000]0F    <1> 	AND	byte [DSK_STATE+eDI], ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR STATE
  3232 00001BA1 0887[696B0000]      <1> 	OR	[DSK_STATE+eDI], AL
  3233                              <1> 	;MOV	AX, CS			; SEGMENT OF MEDIA/DRIVE PARAMETER TABLE
  3234                              <1> 	;MOV	ES, AX			; ES IS SEGMENT OF TABLE
  3235                              <1> SM_RTN:
  3236 00001BA7 E8A9000000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3237 00001BAC E8C4050000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3238 00001BB1 C3                  <1> 	RETn
  3239                              <1> 
  3240                              <1> ;----------------------------------------------------------------
  3241                              <1> ; DR_TYPE_CHECK							:
  3242                              <1> ;	CHECK IF THE GIVEN DRIVE TYPE IN REGISTER (AL)		:
  3243                              <1> ;	IS SUPPORTED IN BIOS DRIVE TYPE TABLE			:
  3244                              <1> ; ON ENTRY:							:
  3245                              <1> ;	AL = DRIVE TYPE						:
  3246                              <1> ; ON EXIT:							:
  3247                              <1> ;	CS = SEGMENT MEDIA/DRIVE PARAMETER TABLE (CODE)		:
  3248                              <1> ;	CY = 0 	DRIVE TYPE SUPPORTED				:
  3249                              <1> ;	     BX = OFFSET TO MEDIA/DRIVE PARAMETER TABLE		:
  3250                              <1> ;	CY = 1	DRIVE TYPE NOT SUPPORTED 			:
  3251                              <1> ; REGISTERS ALTERED: eBX						:
  3252                              <1> ;----------------------------------------------------------------		
  3253                              <1> DR_TYPE_CHECK:
  3254                              <1> 	;PUSH	AX			
  3255                              <1> 	; 24/12/2021
  3256 00001BB2 50                  <1> 	push	eax
  3257 00001BB3 51                  <1> 	PUSH	eCX
  3258 00001BB4 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR_TYPE TABLE
  3259 00001BB6 B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3260                              <1> TYPE_CHK:	
  3261 00001BBB 8AA3[4C650000]      <1> 	MOV	AH,[DR_TYPE+eBX]	; GET DRIVE TYPE
  3262 00001BC1 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH?
  3263 00001BC3 740D                <1> 	JE	short DR_TYPE_VALID	; YES, RETURN WITH CARRY RESET
  3264                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3265 00001BC5 83C305              <1>         add	ebx, 5	; 16/02/2015 (32 bit address modification)
  3266 00001BC8 E2F1                <1> 	LOOP    TYPE_CHK
  3267                              <1> 	;
  3268 00001BCA BB[AB650000]        <1> 	mov	ebx, MD_TBL6		; 1.44MB fd parameter table
  3269                              <1> 					; Default for GET_PARM (11/12/2014)
  3270                              <1> 	;
  3271 00001BCF F9                  <1> 	STC				; DRIVE TYPE NOT FOUND IN TABLE
  3272 00001BD0 EB06                <1> 	JMP	SHORT TYPE_RTN
  3273                              <1> DR_TYPE_VALID:
  3274 00001BD2 8B9B[4D650000]      <1> 	MOV	eBX,[DR_TYPE+eBX+1] 	; BX = MEDIA TABLE
  3275                              <1> TYPE_RTN:
  3276 00001BD8 59                  <1> 	POP	eCX
  3277                              <1> 	;POP	AX
  3278                              <1> 	; 24/12/2021
  3279 00001BD9 58                  <1> 	pop	eax
  3280 00001BDA C3                  <1> 	RETn	
  3281                              <1> 		
  3282                              <1> ;----------------------------------------------------------------
  3283                              <1> ; SEND_SPEC							:
  3284                              <1> ;	SEND THE SPECIFY COMMAND TO CONTROLLER USING DATA FROM	:
  3285                              <1> ;	THE DRIVE PARAMETER TABLE POINTED BY @DISK_POINTER	:
  3286                              <1> ; ON ENTRY:	@DISK_POINTER = DRIVE PARAMETER TABLE		:
  3287                              <1> ; ON EXIT:	NONE						:	
  3288                              <1> ; REGISTERS ALTERED: CX, DX					:
  3289                              <1> ;----------------------------------------------------------------		
  3290                              <1> SEND_SPEC:
  3291 00001BDB 50                  <1> 	PUSH	eAX			; SAVE AX
  3292 00001BDC B8[021C0000]        <1> 	MOV	eAX, SPECBAC		; LOAD ERROR ADDRESS
  3293 00001BE1 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  3294 00001BE2 B403                <1> 	MOV	AH,03H			; SPECIFY COMMAND
  3295 00001BE4 E860070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3296 00001BE9 28D2                <1> 	SUB	DL,DL			; FIRST SPECIFY BYTE
  3297 00001BEB E853060000          <1> 	CALL	GET_PARM		; GET PARAMETER TO AH
  3298 00001BF0 E854070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3299 00001BF5 B201                <1> 	MOV	DL,1			; SECOND SPECIFY BYTE
  3300 00001BF7 E847060000          <1> 	CALL	GET_PARM		; GET PARAMETER TO AH
  3301 00001BFC E848070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3302 00001C01 58                  <1> 	POP	eAX			; POP ERROR RETURN
  3303                              <1> SPECBAC:
  3304 00001C02 58                  <1> 	POP	eAX			; RESTORE ORIGINAL AX VALUE
  3305 00001C03 C3                  <1> 	RETn
  3306                              <1> 
  3307                              <1> ;----------------------------------------------------------------
  3308                              <1> ; SEND_SPEC_MD							:
  3309                              <1> ;	SEND THE SPECIFY COMMAND TO CONTROLLER USING DATA FROM	:
  3310                              <1> ;	THE MEDIA/DRIVE PARAMETER TABLE POINTED BY (CS:BX)	:
  3311                              <1> ; ON ENTRY:	CS:BX = MEDIA/DRIVE PARAMETER TABLE		:
  3312                              <1> ; ON EXIT:	NONE						:	
  3313                              <1> ; REGISTERS ALTERED: AX						:
  3314                              <1> ;----------------------------------------------------------------		
  3315                              <1> SEND_SPEC_MD:
  3316 00001C04 50                  <1> 	PUSH	eAX			; SAVE RATE DATA
  3317 00001C05 B8[221C0000]        <1> 	MOV	eAX, SPEC_ESBAC		; LOAD ERROR ADDRESS
  3318 00001C0A 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  3319 00001C0B B403                <1> 	MOV	AH,03H			; SPECIFY COMMAND
  3320 00001C0D E837070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3321 00001C12 8A23                <1>         MOV     AH, [eBX+MD.SPEC1]      ; GET 1ST SPECIFY BYTE
  3322 00001C14 E830070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3323 00001C19 8A6301              <1>         MOV     AH, [eBX+MD.SPEC2]      ; GET SECOND SPECIFY BYTE
  3324 00001C1C E828070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3325 00001C21 58                  <1> 	POP	eAX			; POP ERROR RETURN
  3326                              <1> SPEC_ESBAC:
  3327 00001C22 58                  <1> 	POP	eAX			; RESTORE ORIGINAL AX VALUE
  3328 00001C23 C3                  <1> 	RETn
  3329                              <1> 
  3330                              <1> ;-------------------------------------------------------------------------------
  3331                              <1> ; XLAT_NEW  
  3332                              <1> ;	TRANSLATES DISKETTE STATE LOCATIONS FROM COMPATIBLE
  3333                              <1> ;	MODE TO NEW ARCHITECTURE.
  3334                              <1> ;
  3335                              <1> ; ON ENTRY:	DI = DRIVE #
  3336                              <1> ;-------------------------------------------------------------------------------
  3337                              <1> XLAT_NEW:
  3338 00001C24 83FF01              <1> 	CMP	eDI,1				; VALID DRIVE
  3339 00001C27 7725                <1> 	JA	short XN_OUT			; IF INVALID BACK
  3340 00001C29 80BF[696B0000]00    <1> 	CMP	byte [DSK_STATE+eDI], 0		; NO DRIVE ?
  3341 00001C30 741D                <1> 	JZ	short DO_DET			; IF NO DRIVE ATTEMPT DETERMINE
  3342 00001C32 6689F9              <1> 	MOV	CX,DI				; CX = DRIVE NUMBER
  3343 00001C35 C0E102              <1> 	SHL	CL,2				; CL = SHIFT COUNT, A=0, B=4
  3344 00001C38 A0[686B0000]        <1> 	MOV	AL, [HF_CNTRL]			; DRIVE INFORMATION
  3345 00001C3D D2C8                <1> 	ROR	AL,CL				; TO LOW NIBBLE
  3346 00001C3F 2407                <1> 	AND	AL,DRV_DET+FMT_CAPA+TRK_CAPA	; KEEP DRIVE BITS
  3347 00001C41 80A7[696B0000]F8    <1>         AND     byte [DSK_STATE+eDI], ~(DRV_DET+FMT_CAPA+TRK_CAPA)
  3348 00001C48 0887[696B0000]      <1> 	OR	[DSK_STATE+eDI], AL		; UPDATE DRIVE STATE
  3349                              <1> XN_OUT:
  3350 00001C4E C3                  <1> 	RETn
  3351                              <1> DO_DET:
  3352 00001C4F E897080000          <1> 	CALL	DRIVE_DET			; TRY TO DETERMINE
  3353 00001C54 C3                  <1> 	RETn
  3354                              <1> 
  3355                              <1> ;-------------------------------------------------------------------------------
  3356                              <1> ; XLAT_OLD 
  3357                              <1> ;	TRANSLATES DISKETTE STATE LOCATIONS FROM NEW
  3358                              <1> ;	ARCHITECTURE TO COMPATIBLE MODE.
  3359                              <1> ;
  3360                              <1> ; ON ENTRY:	DI = DRIVE
  3361                              <1> ;-------------------------------------------------------------------------------
  3362                              <1> XLAT_OLD:
  3363 00001C55 83FF01              <1> 	CMP	eDI,1			; VALID DRIVE ?
  3364                              <1>         ;JA     short XO_OUT            ; IF INVALID BACK
  3365                              <1>         ;ja	XO_OUT
  3366                              <1>         ; 24/12/2021
  3367 00001C58 77F4                <1> 	ja	short XN_OUT
  3368 00001C5A 80BF[696B0000]00    <1> 	CMP	byte [DSK_STATE+eDI],0	; NO DRIVE ?
  3369 00001C61 747D                <1> 	JZ	short XO_OUT		; IF NO DRIVE TRANSLATE DONE
  3370                              <1> 
  3371                              <1> ;-----	TEST FOR SAVED DRIVE INFORMATION ALREADY SET
  3372                              <1> 
  3373 00001C63 6689F9              <1> 	MOV	CX,DI			; CX = DRIVE NUMBER
  3374 00001C66 C0E102              <1> 	SHL	CL,2			; CL = SHIFT COUNT, A=0, B=4
  3375 00001C69 B402                <1> 	MOV	AH,FMT_CAPA		; LOAD MULTIPLE DATA RATE BIT MASK
  3376 00001C6B D2CC                <1> 	ROR	AH,CL			; ROTATE BY MASK
  3377 00001C6D 8425[686B0000]      <1> 	TEST	[HF_CNTRL], AH		; MULTIPLE-DATA RATE DETERMINED ?
  3378 00001C73 751C                <1> 	JNZ	short SAVE_SET		; IF SO, NO NEED TO RE-SAVE
  3379                              <1> 
  3380                              <1> ;-----	ERASE DRIVE BITS IN @HF_CNTRL FOR THIS DRIVE
  3381                              <1> 
  3382 00001C75 B407                <1> 	MOV	AH,DRV_DET+FMT_CAPA+TRK_CAPA ; MASK TO KEEP
  3383 00001C77 D2CC                <1> 	ROR	AH,CL			; FIX MASK TO KEEP
  3384 00001C79 F6D4                <1> 	NOT	AH			; TRANSLATE MASK
  3385 00001C7B 2025[686B0000]      <1> 	AND	[HF_CNTRL], AH		; KEEP BITS FROM OTHER DRIVE INTACT
  3386                              <1> 
  3387                              <1> ;-----	ACCESS CURRENT DRIVE BITS AND STORE IN @HF_CNTRL
  3388                              <1> 
  3389 00001C81 8A87[696B0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; ACCESS STATE
  3390 00001C87 2407                <1> 	AND	AL,DRV_DET+FMT_CAPA+TRK_CAPA ; KEEP DRIVE BITS
  3391 00001C89 D2C8                <1> 	ROR	AL,CL			; FIX FOR THIS DRIVE
  3392 00001C8B 0805[686B0000]      <1> 	OR	[HF_CNTRL], AL		; UPDATE SAVED DRIVE STATE
  3393                              <1> 
  3394                              <1> ;-----	TRANSLATE TO COMPATIBILITY MODE
  3395                              <1> 
  3396                              <1> SAVE_SET:
  3397 00001C91 8AA7[696B0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; ACCESS STATE
  3398 00001C97 88E7                <1> 	MOV	BH,AH			; TO BH FOR LATER
  3399 00001C99 80E4C0              <1> 	AND	AH,RATE_MSK		; KEEP ONLY RATE
  3400 00001C9C 80FC00              <1> 	CMP	AH,RATE_500		; RATE 500 ?
  3401 00001C9F 7410                <1> 	JZ	short CHK_144		; YES 1.2/1.2 OR 1.44/1.44
  3402 00001CA1 B001                <1> 	MOV	AL,M3D1U		; AL = 360 IN 1.2 UNESTABLISHED
  3403 00001CA3 80FC40              <1> 	CMP	AH,RATE_300		; RATE 300 ?
  3404 00001CA6 7518                <1> 	JNZ	short CHK_250		; NO, 360/360, 720/720 OR 720/1.44
  3405 00001CA8 F6C720              <1> 	TEST	BH,DBL_STEP		; CHECK FOR DOUBLE STEP
  3406 00001CAB 751F                <1> 	JNZ	short TST_DET		; MUST BE 360 IN 1.2
  3407                              <1> UNKNO:
  3408 00001CAD B007                <1> 	MOV	AL,MED_UNK		; NONE OF THE ABOVE
  3409 00001CAF EB22                <1> 	JMP	SHORT AL_SET		; PROCESS COMPLETE
  3410                              <1> CHK_144:
  3411 00001CB1 E884050000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  3412                              <1> 	;;20/02/2015
  3413                              <1> 	;;JC	short UNKNO		; ERROR, SET 'NONE OF ABOVE'
  3414 00001CB6 74F5                <1> 	jz	short UNKNO ;; 20/02/2015
  3415 00001CB8 3C02                <1> 	CMP	AL,2			; 1.2MB DRIVE ?
  3416 00001CBA 75F1                <1> 	JNE	short UNKNO		; NO, GO SET 'NONE OF ABOVE'
  3417 00001CBC B002                <1> 	MOV	AL,M1D1U		; AL = 1.2 IN 1.2 UNESTABLISHED
  3418 00001CBE EB0C                <1> 	JMP	SHORT TST_DET
  3419                              <1> CHK_250:
  3420 00001CC0 B000                <1> 	MOV	AL,M3D3U		; AL = 360 IN 360 UNESTABLISHED
  3421 00001CC2 80FC80              <1> 	CMP	AH,RATE_250		; RATE 250 ?
  3422 00001CC5 75E6                <1> 	JNZ	short UNKNO		; IF SO FALL IHRU
  3423 00001CC7 F6C701              <1> 	TEST	BH,TRK_CAPA		; 80 TRACK CAPABILITY ?
  3424 00001CCA 75E1                <1> 	JNZ	short UNKNO		; IF SO JUMP, FALL THRU TEST DET
  3425                              <1> TST_DET:
  3426 00001CCC F6C710              <1> 	TEST	BH,MED_DET		; DETERMINED ?
  3427 00001CCF 7402                <1> 	JZ	short AL_SET		; IF NOT THEN SET
  3428 00001CD1 0403                <1> 	ADD	AL,3			; MAKE DETERMINED/ESTABLISHED
  3429                              <1> AL_SET:
  3430 00001CD3 80A7[696B0000]F8    <1> 	AND	byte [DSK_STATE+eDI], ~(DRV_DET+FMT_CAPA+TRK_CAPA) ; CLEAR DRIVE
  3431 00001CDA 0887[696B0000]      <1> 	OR	[DSK_STATE+eDI], AL	; REPLACE WITH COMPATIBLE MODE
  3432                              <1> XO_OUT:
  3433 00001CE0 C3                  <1> 	RETn
  3434                              <1> 
  3435                              <1> ;-------------------------------------------------------------------------------
  3436                              <1> ; RD_WR_VF
  3437                              <1> ;	COMMON READ, WRITE AND VERIFY: 
  3438                              <1> ;	MAIN LOOP FOR STATE RETRIES.
  3439                              <1> ;
  3440                              <1> ; ON ENTRY:	AH = READ/WRITE/VERIFY NEC PARAMETER
  3441                              <1> ;		AL = READ/WRITE/VERIFY DMA PARAMETER
  3442                              <1> ;
  3443                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3444                              <1> ;-------------------------------------------------------------------------------
  3445                              <1> RD_WR_VF:
  3446                              <1> 	;PUSH	AX			; SAVE DMA, NEC PARAMETERS
  3447 00001CE1 50                  <1> 	push	eax ; 24/12/2021
  3448 00001CE2 E83DFFFFFF          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3449 00001CE7 E8E9000000          <1> 	CALL	SETUP_STATE		; INITIALIZE START AND END RATE
  3450                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY
  3451 00001CEC 58                  <1> 	pop	eax ; 24/12/2021
  3452                              <1> DO_AGAIN:
  3453                              <1> 	;PUSH	AX			; SAVE READ/WRITE/VERIFY PARAMETER
  3454 00001CED 50                  <1> 	push	eax ; 24/12/2021
  3455 00001CEE E877010000          <1> 	CALL	MED_CHANGE		; MEDIA CHANGE AND RESET IF CHANGED
  3456                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY
  3457 00001CF3 58                  <1> 	pop	eax ; 24/12/2021
  3458                              <1> 	;JC	RWV_END                 ; MEDIA CHANGE ERROR OR TIME-OUT
  3459                              <1> 	; 24/12/2021
  3460 00001CF4 7305                <1> 	jnc	short RWV
  3461 00001CF6 E9C3000000          <1> 	jmp	RWV_END
  3462                              <1> RWV:
  3463                              <1> 	;PUSH	AX			; SAVE READ/WRITE/VERIFY PARAMETER
  3464 00001CFB 50                  <1> 	push	eax ; 24/12/2021
  3465 00001CFC 8AB7[696B0000]      <1> 	MOV	DH, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3466 00001D02 80E6C0              <1> 	AND	DH,RATE_MSK		; KEEP ONLY RATE
  3467 00001D05 E830050000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL (AL)
  3468                              <1> 	;;20/02/2015
  3469                              <1> 	;;JC	short RWV_ASSUME	; ERROR IN CMOS
  3470 00001D0A 7451                <1> 	jz	short RWV_ASSUME ; 20/02/2015
  3471 00001D0C 3C01                <1> 	CMP	AL,1			; 40 TRACK DRIVE?
  3472 00001D0E 750D                <1> 	JNE	short RWV_1		; NO, BYPASS CMOS VALIDITY CHECK
  3473 00001D10 F687[696B0000]01    <1> 	TEST	byte [DSK_STATE+eDI], TRK_CAPA ; CHECK FOR 40 TRACK DRIVE
  3474 00001D17 7413                <1> 	JZ	short RWV_2		; YES, CMOS IS CORRECT
  3475 00001D19 B002                <1> 	MOV	AL,2			; CHANGE TO 1.2M
  3476 00001D1B EB0F                <1> 	JMP	SHORT RWV_2
  3477                              <1> RWV_1:
  3478 00001D1D 720D                <1> 	JB	short RWV_2		; NO DRIVE SPECIFIED, CONTINUE
  3479 00001D1F F687[696B0000]01    <1> 	TEST    byte [DSK_STATE+eDI], TRK_CAPA ; IS IT REALLY 40 TRACK?
  3480 00001D26 7504                <1> 	JNZ	short RWV_2		; NO, 80 TRACK
  3481 00001D28 B001                <1> 	MOV	AL,1			; IT IS 40 TRACK, FIX CMOS VALUE
  3482 00001D2A EB04                <1> 	jmp	short rwv_3
  3483                              <1> RWV_2:
  3484 00001D2C 08C0                <1> 	OR	AL,AL			; TEST FOR NO DRIVE
  3485 00001D2E 742D                <1> 	JZ	short RWV_ASSUME	; ASSUME TYPE, USE MAX TRACK
  3486                              <1> rwv_3:
  3487 00001D30 E87DFEFFFF          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL.
  3488 00001D35 7226                <1> 	JC	short RWV_ASSUME	; TYPE NOT IN TABLE (BAD CMOS)
  3489                              <1> 
  3490                              <1> ;-----	SEARCH FOR MEDIA/DRIVE PARAMETER TABLE
  3491                              <1> 
  3492 00001D37 57                  <1> 	PUSH	eDI			; SAVE DRIVE #
  3493 00001D38 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR_TYPE TABLE
  3494 00001D3A B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3495                              <1> RWV_DR_SEARCH:
  3496 00001D3F 8AA3[4C650000]      <1> 	MOV	AH, [DR_TYPE+eBX]	; GET DRIVE TYPE
  3497 00001D45 80E47F              <1> 	AND	AH,BIT7OFF		; MASK OUT MSB
  3498 00001D48 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH?
  3499 00001D4A 750B                <1> 	JNE	short RWV_NXT_MD	; NO, CHECK NEXT DRIVE TYPE
  3500                              <1> RWV_DR_FND:
  3501 00001D4C 8BBB[4D650000]      <1> 	MOV	eDI, [DR_TYPE+eBX+1] 	; DI = MEDIA/DRIVE PARAMETER TABLE
  3502                              <1> RWV_MD_SEARH:
  3503 00001D52 3A770C              <1>         CMP     DH, [eDI+MD.RATE]       ; MATCH?
  3504 00001D55 741B                <1> 	JE	short RWV_MD_FND	; YES, GO GET 1ST SPECIFY BYTE
  3505                              <1> RWV_NXT_MD:
  3506                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3507 00001D57 83C305              <1> 	add	eBX, 5
  3508 00001D5A E2E3                <1> 	LOOP	RWV_DR_SEARCH
  3509 00001D5C 5F                  <1> 	POP	eDI			; RESTORE DRIVE #
  3510                              <1> 
  3511                              <1> ;-----	ASSUME PRIMARY DRIVE IS INSTALLED AS SHIPPED
  3512                              <1> 
  3513                              <1> RWV_ASSUME:
  3514 00001D5D BB[6A650000]        <1> 	MOV	eBX, MD_TBL1		; POINT TO 40 TRACK 250 KBS
  3515 00001D62 F687[696B0000]01    <1> 	TEST 	byte [DSK_STATE+eDI], TRK_CAPA ; TEST FOR 80 TRACK
  3516 00001D69 740A                <1> 	JZ	short RWV_MD_FND1	; MUST BE 40 TRACK
  3517 00001D6B BB[84650000]        <1> 	MOV	eBX, MD_TBL3		; POINT TO 80 TRACK 500 KBS
  3518 00001D70 EB03                <1> 	JMP	short RWV_MD_FND1	; GO SPECIFY PARAMTERS
  3519                              <1> 
  3520                              <1> ;-----	CS:BX POINTS TO MEDIA/DRIVE PARAMETER TABLE
  3521                              <1> 	 			
  3522                              <1> RWV_MD_FND:
  3523 00001D72 89FB                <1> 	MOV	eBX,eDI			; BX = MEDIA/DRIVE PARAMETER TABLE
  3524 00001D74 5F                  <1> 	POP	eDI			; RESTORE DRIVE #
  3525                              <1> 	
  3526                              <1> ;-----	SEND THE SPECIFY COMMAND TO THE CONTROLLER
  3527                              <1> 
  3528                              <1> RWV_MD_FND1:
  3529 00001D75 E88AFEFFFF          <1> 	CALL	SEND_SPEC_MD
  3530 00001D7A E85B010000          <1> 	CALL	CHK_LASTRATE		; ZF=1 ATTEMP RATE IS SAME AS LAST RATE
  3531 00001D7F 7405                <1> 	JZ	short RWV_DBL		; YES,SKIP SEND RATE COMMAND
  3532 00001D81 E834010000          <1> 	CALL	SEND_RATE		; SEND DATA RATE TO NEC
  3533                              <1> RWV_DBL:
  3534 00001D86 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3535 00001D87 E809040000          <1> 	CALL	SETUP_DBL		; CHECK FOR DOUBLE STEP
  3536 00001D8C 5B                  <1> 	POP	eBX			; RESTORE ADDRESS
  3537 00001D8D 7222                <1> 	JC	short CHK_RET		; ERROR FROM READ ID, POSSIBLE RETRY
  3538                              <1> 	;POP	AX			; RESTORE NEC, DMA COMMAND
  3539 00001D8F 58                  <1> 	pop	eax ; 24/12/2021
  3540                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  3541 00001D90 50                  <1> 	push	eax ; 24/12/2021
  3542 00001D91 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3543 00001D92 E858010000          <1> 	CALL	DMA_SETUP		; SET UP THE DMA
  3544 00001D97 5B                  <1> 	POP	eBX 
  3545                              <1> 	;POP	AX			; RESTORE NEC COMMAND
  3546 00001D98 58                  <1> 	pop	eax ; 24/12/2021
  3547 00001D99 722D                <1> 	JC	short RWV_BAC		; CHECK FOR DMA BOUNDARY ERROR
  3548                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  3549 00001D9B 50                  <1> 	push	eax ; 24/12/2021
  3550 00001D9C 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3551 00001D9D E82B020000          <1> 	CALL	NEC_INIT		; INITIALIZE NEC
  3552 00001DA2 5B                  <1> 	POP	eBX			; RESTORE ADDRESS
  3553 00001DA3 720C                <1> 	JC	short CHK_RET		; ERROR - EXIT
  3554 00001DA5 E853020000          <1> 	CALL	RWV_COM			; OP CODE COMMON TO READ/WRITE/VERIFY
  3555 00001DAA 7205                <1> 	JC	short CHK_RET		; ERROR - EXIT
  3556 00001DAC E898020000          <1> 	CALL	NEC_TERM		; TERMINATE, GET STATUS, ETC.
  3557                              <1> CHK_RET:
  3558 00001DB1 E837030000          <1> 	CALL	RETRY			; CHECK FOR, SETUP RETRY
  3559                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY PARAMETER
  3560 00001DB6 58                  <1> 	pop	eax ; 24/12/2021
  3561 00001DB7 7305                <1> 	JNC	short RWV_END		; CY = 0 NO RETRY
  3562 00001DB9 E92FFFFFFF          <1>         JMP     DO_AGAIN                ; CY = 1 MEANS RETRY
  3563                              <1> RWV_END:
  3564 00001DBE E8E2020000          <1> 	CALL	DSTATE			; ESTABLISH STATE IF SUCCESSFUL
  3565 00001DC3 E875030000          <1> 	CALL	NUM_TRANS		; AL = NUMBER TRANSFERRED
  3566                              <1> RWV_BAC:				; BAD DMA ERROR ENTRY
  3567                              <1> 	;PUSH	AX			; SAVE NUMBER TRANSFERRED
  3568 00001DC8 50                  <1> 	push	eax ; 24/12/2021
  3569 00001DC9 E887FEFFFF          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3570                              <1> 	;POP	AX			; RESTORE NUMBER TRANSFERRED
  3571 00001DCE 58                  <1> 	pop	eax ; 24/12/2021
  3572 00001DCF E8A1030000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3573 00001DD4 C3                  <1> 	RETn
  3574                              <1> 
  3575                              <1> ;-------------------------------------------------------------------------------
  3576                              <1> ; SETUP_STATE:	INITIALIZES START AND END RATES.
  3577                              <1> ;-------------------------------------------------------------------------------
  3578                              <1> SETUP_STATE:
  3579 00001DD5 F687[696B0000]10    <1> 	TEST	byte [DSK_STATE+eDI], MED_DET ; MEDIA DETERMINED ?
  3580 00001DDC 7537                <1> 	JNZ	short J1C		; NO STATES IF DETERMINED
  3581 00001DDE 66B84000            <1>         MOV     AX,(RATE_500*256)+RATE_300  ; AH = START RATE, AL = END RATE
  3582 00001DE2 F687[696B0000]04    <1> 	TEST	byte [DSK_STATE+eDI],DRV_DET ; DRIVE ?
  3583 00001DE9 740D                <1> 	JZ	short AX_SET		; DO NOT KNOW DRIVE
  3584 00001DEB F687[696B0000]02    <1> 	TEST	byte [DSK_STATE+eDI], FMT_CAPA ; MULTI-RATE?
  3585 00001DF2 7504                <1> 	JNZ	short AX_SET		; JUMP IF YES
  3586 00001DF4 66B88080            <1>         MOV     AX,RATE_250*257         ; START A END RATE 250 FOR 360 DRIVE
  3587                              <1> AX_SET:	
  3588 00001DF8 80A7[696B0000]1F    <1> 	AND	byte [DSK_STATE+eDI], ~(RATE_MSK+DBL_STEP) ; TURN OFF THE RATE
  3589 00001DFF 08A7[696B0000]      <1> 	OR	[DSK_STATE+eDI], AH	; RATE FIRST TO TRY
  3590 00001E05 8025[646B0000]F3    <1> 	AND	byte [LASTRATE], ~STRT_MSK ; ERASE LAST TO TRY RATE BITS
  3591 00001E0C C0C804              <1> 	ROR	AL,4			; TO OPERATION LAST RATE LOCATION
  3592 00001E0F 0805[646B0000]      <1> 	OR	[LASTRATE], AL		; LAST RATE
  3593                              <1> J1C:	
  3594 00001E15 C3                  <1> 	RETn
  3595                              <1> 
  3596                              <1> ;-------------------------------------------------------------------------------
  3597                              <1> ;  FMT_INIT: ESTABLISH STATE IF UNESTABLISHED AT FORMAT TIME.
  3598                              <1> ;-------------------------------------------------------------------------------
  3599                              <1> FMT_INIT:
  3600 00001E16 F687[696B0000]10    <1> 	TEST	byte [DSK_STATE+eDI], MED_DET ; IS MEDIA ESTABLISHED
  3601 00001E1D 7546                <1> 	JNZ	short F1_OUT		; IF SO RETURN
  3602 00001E1F E816040000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL
  3603                              <1> 	;; 20/02/2015
  3604                              <1> 	;;JC	short CL_DRV		; ERROR IN CMOS ASSUME NO DRIVE
  3605 00001E24 7440                <1> 	jz	short CL_DRV ;; 20/02/2015
  3606 00001E26 FEC8                <1> 	DEC	AL			; MAKE ZERO ORIGIN
  3607                              <1> 	;;JS	short CL_DRV		; NO DRIVE IF AL 0
  3608 00001E28 8AA7[696B0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; AH = CURRENT STATE
  3609 00001E2E 80E40F              <1> 	AND	AH, ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR
  3610 00001E31 08C0                <1> 	OR	AL,AL			; CHECK FOR 360
  3611 00001E33 7505                <1> 	JNZ	short N_360		; IF 360 WILL BE 0
  3612 00001E35 80CC90              <1> 	OR	AH,MED_DET+RATE_250	; ESTABLISH MEDIA
  3613 00001E38 EB25                <1> 	JMP	SHORT SKP_STATE		; SKIP OTHER STATE PROCESSING
  3614                              <1> N_360:	
  3615 00001E3A FEC8                <1> 	DEC	AL			; 1.2 M DRIVE
  3616 00001E3C 7505                <1> 	JNZ	short N_12		; JUMP IF NOT
  3617                              <1> F1_RATE:
  3618 00001E3E 80CC10              <1> 	OR	AH,MED_DET+RATE_500	; SET FORMAT RATE
  3619 00001E41 EB1C                <1> 	JMP	SHORT SKP_STATE		; SKIP OTHER STATE PROCESSING
  3620                              <1> N_12:	
  3621 00001E43 FEC8                <1> 	DEC	AL			; CHECK FOR TYPE 3
  3622 00001E45 750F                <1> 	JNZ	short N_720		; JUMP IF NOT
  3623 00001E47 F6C404              <1> 	TEST	AH,DRV_DET		; IS DRIVE DETERMINED
  3624 00001E4A 7410                <1> 	JZ	short ISNT_12		; TREAT AS NON 1.2 DRIVE
  3625 00001E4C F6C402              <1> 	TEST	AH,FMT_CAPA		; IS 1.2M
  3626 00001E4F 740B                <1> 	JZ	short ISNT_12		; JUMP IF NOT
  3627 00001E51 80CC50              <1> 	OR	AH,MED_DET+RATE_300	; RATE 300
  3628 00001E54 EB09                <1> 	JMP	SHORT SKP_STATE		; CONTINUE
  3629                              <1> N_720:
  3630 00001E56 FEC8                <1> 	DEC	AL			; CHECK FOR TYPE 4
  3631 00001E58 750C                <1> 	JNZ	short CL_DRV		; NO DRIVE, CMOS BAD
  3632 00001E5A EBE2                <1> 	JMP	SHORT F1_RATE
  3633                              <1> ISNT_12: 
  3634 00001E5C 80CC90              <1> 	OR	AH,MED_DET+RATE_250	; MUST BE RATE 250
  3635                              <1> 
  3636                              <1> SKP_STATE:
  3637 00001E5F 88A7[696B0000]      <1> 	MOV	[DSK_STATE+eDI], AH	; STORE AWAY
  3638                              <1> F1_OUT:
  3639 00001E65 C3                  <1> 	RETn
  3640                              <1> CL_DRV:	
  3641 00001E66 30E4                <1> 	XOR	AH,AH			; CLEAR STATE
  3642 00001E68 EBF5                <1> 	JMP	SHORT SKP_STATE		; SAVE IT
  3643                              <1> 
  3644                              <1> ;-------------------------------------------------------------------------------
  3645                              <1> ; MED_CHANGE	
  3646                              <1> ;	CHECKS FOR MEDIA CHANGE, RESETS MEDIA CHANGE, 
  3647                              <1> ;	CHECKS MEDIA CHANGE AGAIN.
  3648                              <1> ;
  3649                              <1> ; ON EXIT:	CY = 1 MEANS MEDIA CHANGE OR TIMEOUT
  3650                              <1> ;		@DSKETTE_STATUS = ERROR CODE
  3651                              <1> ;-------------------------------------------------------------------------------
  3652                              <1> MED_CHANGE:
  3653 00001E6A E86F060000          <1> 	CALL	READ_DSKCHNG		; READ DISK CHANCE LINE STATE
  3654 00001E6F 7447                <1> 	JZ	short MC_OUT		; BYPASS HANDLING DISK CHANGE LINE
  3655 00001E71 80A7[696B0000]EF    <1> 	AND	byte [DSK_STATE+eDI], ~MED_DET ; CLEAR STATE FOR THIS DRIVE
  3656                              <1> 
  3657                              <1> ;	THIS SEQUENCE ENSURES WHENEVER A DISKETTE IS CHANGED THAT
  3658                              <1> ;	ON THE NEXT OPERATION THE REQUIRED MOTOR START UP TIME WILL
  3659                              <1> ;	BE WAITED. (DRIVE MOTOR MAY GO OFF UPON DOOR OPENING).
  3660                              <1> 
  3661 00001E78 6689F9              <1> 	MOV	CX,DI			; CL = DRIVE 0
  3662 00001E7B B001                <1> 	MOV	AL,1			; MOTOR ON BIT MASK
  3663 00001E7D D2E0                <1> 	SHL	AL,CL			; TO APPROPRIATE POSITION
  3664 00001E7F F6D0                <1> 	NOT	AL			; KEEP ALL BUT MOTOR ON
  3665 00001E81 FA                  <1> 	CLI				; NO INTERRUPTS
  3666 00001E82 2005[5A6B0000]      <1> 	AND	[MOTOR_STATUS], AL	; TURN MOTOR OFF INDICATOR
  3667 00001E88 FB                  <1> 	STI				; INTERRUPTS ENABLED
  3668 00001E89 E8FA030000          <1> 	CALL	MOTOR_ON		; TURN MOTOR ON
  3669                              <1> 
  3670                              <1> ;-----	THIS SEQUENCE OF SEEKS IS USED TO RESET DISKETTE CHANGE SIGNAL
  3671                              <1> 
  3672 00001E8E E8A4F9FFFF          <1> 	CALL	DSK_RESET		; RESET NEC
  3673 00001E93 B501                <1> 	MOV	CH,01H			; MOVE TO CYLINDER 1
  3674 00001E95 E8E8040000          <1> 	CALL	SEEK			; ISSUE SEEK
  3675 00001E9A 30ED                <1> 	XOR	CH,CH			; MOVE TO CYLINDER 0
  3676 00001E9C E8E1040000          <1> 	CALL	SEEK			; ISSUE SEEK
  3677 00001EA1 C605[5C6B0000]06    <1> 	MOV	byte [DSKETTE_STATUS], MEDIA_CHANGE ; STORE IN STATUS
  3678                              <1> OK1:
  3679 00001EA8 E831060000          <1> 	CALL	READ_DSKCHNG		; CHECK MEDIA CHANGED AGAIN
  3680 00001EAD 7407                <1> 	JZ	short OK2		; IF ACTIVE, NO DISKETTE, TIMEOUT
  3681                              <1> OK4:
  3682 00001EAF C605[5C6B0000]80    <1> 	MOV	byte [DSKETTE_STATUS], TIME_OUT ; TIMEOUT IF DRIVE EMPTY
  3683                              <1> OK2:		
  3684 00001EB6 F9                  <1> 	STC				; MEDIA CHANGED, SET CY
  3685 00001EB7 C3                  <1> 	RETn
  3686                              <1> MC_OUT:
  3687 00001EB8 F8                  <1> 	CLC				; NO MEDIA CHANGED, CLEAR CY
  3688 00001EB9 C3                  <1> 	RETn
  3689                              <1> 
  3690                              <1> ;-------------------------------------------------------------------------------
  3691                              <1> ; SEND_RATE
  3692                              <1> ;	SENDS DATA RATE COMMAND TO NEC
  3693                              <1> ; ON ENTRY:	DI = DRIVE #
  3694                              <1> ; ON EXIT:	NONE
  3695                              <1> ; REGISTERS ALTERED: DX
  3696                              <1> ;-------------------------------------------------------------------------------
  3697                              <1> SEND_RATE:
  3698                              <1> 	;PUSH	AX			; SAVE REG.
  3699                              <1> 	; 24/12/2021
  3700 00001EBA 50                  <1> 	push	eax
  3701 00001EBB 8025[646B0000]3F    <1> 	AND	byte [LASTRATE], ~SEND_MSK ; ELSE CLEAR LAST RATE ATTEMPTED
  3702 00001EC2 8A87[696B0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3703 00001EC8 24C0                <1> 	AND	AL,SEND_MSK		; KEEP ONLY RATE BITS
  3704 00001ECA 0805[646B0000]      <1> 	OR	[LASTRATE], AL		; SAVE NEW RATE FOR NEXT CHECK
  3705 00001ED0 C0C002              <1> 	ROL	AL,2			; MOVE TO BIT OUTPUT POSITIONS
  3706 00001ED3 66BAF703            <1> 	MOV	DX,03F7H		; OUTPUT NEW DATA RATE
  3707 00001ED7 EE                  <1> 	OUT	DX,AL
  3708                              <1> 	;POP	AX			; RESTORE REG.
  3709                              <1> 	; 24/12/2021
  3710 00001ED8 58                  <1> 	pop	eax
  3711 00001ED9 C3                  <1> 	RETn
  3712                              <1> 
  3713                              <1> ;-------------------------------------------------------------------------------
  3714                              <1> ; CHK_LASTRATE
  3715                              <1> ;	CHECK PREVIOUS DATE RATE SNT TO THE CONTROLLER.
  3716                              <1> ; ON ENTRY:
  3717                              <1> ;	DI = DRIVE #
  3718                              <1> ; ON EXIT:
  3719                              <1> ;	ZF =  1 DATA RATE IS THE SAME AS THE LAST RATE SENT TO NEC
  3720                              <1> ;	ZF =  0 DATA RATE IS DIFFERENT FROM LAST RATE
  3721                              <1> ; REGISTERS ALTERED: DX
  3722                              <1> ;-------------------------------------------------------------------------------
  3723                              <1> CHK_LASTRATE:
  3724                              <1> 	;PUSH	AX			; SAVE REG.
  3725                              <1> 	; 24/12/2021
  3726 00001EDA 50                  <1> 	push	eax
  3727 00001EDB 2225[646B0000]      <1> 	AND	AH, [LASTRATE]		; GET LAST DATA RATE SELECTED
  3728 00001EE1 8A87[696B0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3729 00001EE7 6625C0C0            <1>         AND     AX, SEND_MSK*257        ; KEEP ONLY RATE BITS OF BOTH
  3730 00001EEB 38E0                <1> 	CMP	AL, AH			; COMPARE TO PREVIOUSLY TRIED
  3731                              <1> 					; ZF = 1 RATE IS THE SAME
  3732                              <1> 	;POP	AX			; RESTORE REG.
  3733                              <1> 	; 24/12/2021
  3734 00001EED 58                  <1> 	pop	eax
  3735 00001EEE C3                  <1> 	RETn
  3736                              <1> 
  3737                              <1> ;-------------------------------------------------------------------------------
  3738                              <1> ; DMA_SETUP
  3739                              <1> ;	THIS ROUTINE SETS UP THE DMA FOR READ/WRITE/VERIFY OPERATIONS.
  3740                              <1> ;
  3741                              <1> ; ON ENTRY:	AL = DMA COMMAND
  3742                              <1> ;
  3743                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3744                              <1> ;-------------------------------------------------------------------------------
  3745                              <1> 
  3746                              <1> ; SI = Head #, # of Sectors or DASD Type
  3747                              <1> 
  3748                              <1> ; 22/08/2015
  3749                              <1> ; 08/02/2015 - Protected Mode Modification
  3750                              <1> ; 06/02/2015 - 07/02/2015
  3751                              <1> ; NOTE: Buffer address must be in 1st 16MB of Physical Memory (24 bit limit).
  3752                              <1> ; (DMA Addres = Physical Address)
  3753                              <1> ; (Retro UNIX 386 v1 Kernel/System Mode Virtual Address = Physical Address)
  3754                              <1> ;
  3755                              <1> ; 04/02/2016 (clc)
  3756                              <1> ; 20/02/2015 modification (source: AWARD BIOS 1999, DMA_SETUP)
  3757                              <1> ; 16/12/2014 (IODELAY)
  3758                              <1> 
  3759                              <1> DMA_SETUP:
  3760                              <1> 
  3761                              <1> ;; 20/02/2015
  3762 00001EEF 8B5504              <1> 	mov	edx, [ebp+4] 		; Buffer address
  3763 00001EF2 F7C2000000FF        <1> 	test	edx, 0FF000000h		; 16 MB limit (22/08/2015, bugfix)
  3764 00001EF8 7569                <1> 	jnz	short dma_bnd_err_stc
  3765                              <1> 	;
  3766                              <1> 	;push	ax			; DMA command
  3767                              <1> 	; 24/12/2021
  3768 00001EFA 50                  <1> 	push	eax
  3769 00001EFB 52                  <1> 	push	edx			; *
  3770 00001EFC B203                <1> 	mov	dl, 3			; GET BYTES/SECTOR PARAMETER
  3771 00001EFE E840030000          <1> 	call	GET_PARM		; 
  3772 00001F03 88E1                <1> 	mov	cl, ah 			; SHIFT COUNT (0=128, 1=256, 2=512 ETC)
  3773                              <1> 	;mov	ax, si			; Sector count
  3774                              <1> 	;mov	ah, al			; AH = # OF SECTORS
  3775                              <1> 	;sub	al, al			; AL = 0, AX = # SECTORS * 256
  3776                              <1> 	;shr	ax, 1			; AX = # SECTORS * 128
  3777                              <1> 	;shl	ax, cl			; SHIFT BY PARAMETER VALUE
  3778                              <1> 	; 24/12/2021
  3779 00001F05 89F2                <1> 	mov	edx, esi
  3780 00001F07 29C0                <1> 	sub	eax, eax
  3781 00001F09 88D4                <1> 	mov	ah, dl
  3782 00001F0B D1E8                <1> 	shr	eax, 1
  3783 00001F0D D3E0                <1> 	shl	eax, cl
  3784                              <1> 	;
  3785 00001F0F 6648                <1> 	dec	ax			; -1 FOR DMA VALUE
  3786 00001F11 6689C1              <1> 	mov	cx, ax
  3787 00001F14 5A                  <1> 	pop	edx			; *
  3788                              <1> 	;pop	ax
  3789                              <1> 	; 24/12/2021
  3790 00001F15 58                  <1> 	pop	eax
  3791 00001F16 3C42                <1> 	cmp	al, 42h
  3792 00001F18 7507                <1>         jne     short NOT_VERF
  3793 00001F1A BA0000FF00          <1> 	mov	edx, 0FF0000h
  3794 00001F1F EB08                <1> 	jmp	short J33
  3795                              <1> NOT_VERF:
  3796 00001F21 6601CA              <1> 	add	dx, cx			; check for overflow
  3797 00001F24 723E                <1> 	jc	short dma_bnd_err
  3798                              <1> 	;
  3799 00001F26 6629CA              <1> 	sub	dx, cx			; Restore start address
  3800                              <1> J33:
  3801 00001F29 FA                  <1> 	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3802 00001F2A E60C                <1> 	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3803                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001F2C EB00                <2>  jmp short $+2
  2146 00001F2E EB00                <2>  jmp short $+2
  3804 00001F30 E60B                <1> 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3805 00001F32 89D0                <1> 	mov	eax,edx			; Buffer address
  3806 00001F34 E604                <1> 	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3807                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001F36 EB00                <2>  jmp short $+2
  2146 00001F38 EB00                <2>  jmp short $+2
  3808 00001F3A 88E0                <1> 	MOV	AL,AH
  3809 00001F3C E604                <1> 	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3810 00001F3E C1E810              <1> 	shr	eax,16
  3811                              <1> 	IODELAY				; I/O WAIT STATE
  2145 00001F41 EB00                <2>  jmp short $+2
  2146 00001F43 EB00                <2>  jmp short $+2
  3812 00001F45 E681                <1> 	OUT	081H,AL			; OUTPUT highest BITS TO PAGE REGISTER
  3813                              <1> 	IODELAY
  2145 00001F47 EB00                <2>  jmp short $+2
  2146 00001F49 EB00                <2>  jmp short $+2
  3814 00001F4B 6689C8              <1> 	mov	ax,cx			; Byte count - 1
  3815 00001F4E E605                <1> 	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3816                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001F50 EB00                <2>  jmp short $+2
  2146 00001F52 EB00                <2>  jmp short $+2
  3817 00001F54 88E0                <1> 	MOV	AL,AH
  3818 00001F56 E605                <1> 	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3819                              <1> 	IODELAY
  2145 00001F58 EB00                <2>  jmp short $+2
  2146 00001F5A EB00                <2>  jmp short $+2
  3820 00001F5C FB                  <1> 	STI				; RE-ENABLE INTERRUPTS
  3821 00001F5D B002                <1> 	MOV	AL,2			; MODE FOR 8237
  3822 00001F5F E60A                <1> 	OUT	DMA+10,AL		; INITIALIZE THE DISKETTE CHANNEL
  3823                              <1> 
  3824 00001F61 F8                  <1> 	clc	; 04/02/2016
  3825 00001F62 C3                  <1> 	retn
  3826                              <1> 
  3827                              <1> dma_bnd_err_stc:
  3828 00001F63 F9                  <1> 	stc
  3829                              <1> dma_bnd_err:
  3830 00001F64 C605[5C6B0000]09    <1> 	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  3831 00001F6B C3                  <1> 	RETn				; CY SET BY ABOVE IF ERROR
  3832                              <1> 
  3833                              <1> ;; 16/12/2014
  3834                              <1> ;;	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3835                              <1> ;;	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3836                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3837                              <1> ;;	IODELAY
  3838                              <1> ;; 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3839                              <1> ;;	;SIODELAY
  3840                              <1> ;;      ;CMP	AL, 42H			; DMA VERIFY COMMAND
  3841                              <1> ;;      ;JNE	short NOT_VERF		; NO
  3842                              <1> ;;      ;XOR	AX, AX			; START ADDRESS
  3843                              <1> ;;      ;JMP	SHORT J33
  3844                              <1> ;;;NOT_VERF:	
  3845                              <1> ;;	;MOV	AX,ES			; GET THE ES VALUE
  3846                              <1> ;;	;ROL	AX,4			; ROTATE LEFT
  3847                              <1> ;;	;MOV	CH,AL			; GET HIGHEST NIBBLE OF ES TO CH
  3848                              <1> ;;	;AND	AL,11110000B		; ZERO THE LOW NIBBLE FROM SEGMENT
  3849                              <1> ;;	;ADD	AX,[BP+2]		; TEST FOR CARRY FROM ADDITION
  3850                              <1> ;;	mov	eax, [ebp+4] ; 06/02/2015	
  3851                              <1> ;;	;JNC	short J33
  3852                              <1> ;;	;INC	CH			; CARRY MEANS HIGH 4 BITS MUST BE INC
  3853                              <1> ;;;J33:
  3854                              <1> ;;	PUSH	eAX			; SAVE START ADDRESS
  3855                              <1> ;;	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3856                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3857                              <1> ;;	IODELAY
  3858                              <1> ;;	MOV	AL,AH
  3859                              <1> ;;	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3860                              <1> ;;	shr	eax, 16	     ; 07/02/2015
  3861                              <1> ;;	;MOV	AL,CH			; GET HIGH 4 BITS
  3862                              <1> ;;	;JMP	$+2			; I/O WAIT STATE
  3863                              <1> ;;	IODELAY
  3864                              <1> ;;	;AND	AL,00001111B
  3865                              <1> ;;	OUT	081H,AL			; OUTPUT HIGH 4 BITS TO PAGE REGISTER
  3866                              <1> ;;	;SIODELAY
  3867                              <1> ;;
  3868                              <1> ;;;----- DETERMINE COUNT
  3869                              <1> ;;	sub	eax, eax ; 08/02/2015
  3870                              <1> ;;	MOV	AX, SI			; AL =  # OF SECTORS
  3871                              <1> ;;	XCHG	AL, AH			; AH =  # OF SECTORS
  3872                              <1> ;;	SUB	AL, AL			; AL = 0, AX = # SECTORS * 256
  3873                              <1> ;;	SHR	AX, 1			; AX = # SECTORS * 128
  3874                              <1> ;;	PUSH	AX			; SAVE # OF SECTORS * 128
  3875                              <1> ;;	MOV	DL, 3			; GET BYTES/SECTOR PARAMETER
  3876                              <1> ;;	CALL	GET_PARM		; "
  3877                              <1> ;;	MOV	CL,AH			; SHIFT COUNT (0=128, 1=256, 2=512 ETC)
  3878                              <1> ;;	POP	AX			; AX = # SECTORS * 128
  3879                              <1> ;;	SHL	AX,CL			; SHIFT BY PARAMETER VALUE
  3880                              <1> ;;	DEC	AX			; -1 FOR DMA VALUE
  3881                              <1> ;;	PUSH	eAX  ; 08/02/2015	; SAVE COUNT VALUE
  3882                              <1> ;;	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3883                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3884                              <1> ;;	IODELAY
  3885                              <1> ;;	MOV	AL, AH
  3886                              <1> ;;	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3887                              <1> ;;	;IODELAY
  3888                              <1> ;;	STI				; RE-ENABLE INTERRUPTS
  3889                              <1> ;;	POP	eCX  ; 08/02/2015 	; RECOVER COUNT VALUE
  3890                              <1> ;;	POP	eAX  ; 08/02/2015	; RECOVER ADDRESS VALUE
  3891                              <1> ;;	;ADD	AX, CX			; ADD, TEST FOR 64K OVERFLOW
  3892                              <1> ;;	add	ecx, eax ; 08/02/2015
  3893                              <1> ;;	MOV	AL, 2			; MODE FOR 8237
  3894                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3895                              <1> ;;	SIODELAY
  3896                              <1> ;;	OUT	DMA+10, AL		; INITIALIZE THE DISKETTE CHANNEL
  3897                              <1> ;;	;JNC	short NO_BAD		; CHECK FOR ERROR
  3898                              <1> ;;	jc	short dma_bnd_err ; 08/02/2015
  3899                              <1> ;;	and	ecx, 0FFF00000h ; 16 MB limit
  3900                              <1> ;;	jz	short NO_BAD
  3901                              <1> ;;dma_bnd_err:
  3902                              <1> ;;	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  3903                              <1> ;;NO_BAD:
  3904                              <1> ;;	RETn				; CY SET BY ABOVE IF ERROR
  3905                              <1> 
  3906                              <1> ;-------------------------------------------------------------------------------
  3907                              <1> ; FMTDMA_SET
  3908                              <1> ;	THIS ROUTINE SETS UP THE DMA CONTROLLER FOR A FORMAT OPERATION.
  3909                              <1> ;
  3910                              <1> ; ON ENTRY:	NOTHING REQUIRED
  3911                              <1> ;
  3912                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3913                              <1> ;-------------------------------------------------------------------------------
  3914                              <1> 
  3915                              <1> 	; 24/12/2021
  3916                              <1> FMTDMA_SET:
  3917                              <1> ;; 20/02/2015 modification	
  3918 00001F6C 8B5504              <1> 	mov	edx, [ebp+4] 		; Buffer address
  3919 00001F6F F7C20000F0FF        <1> 	test	edx, 0FFF00000h		; 16 MB limit
  3920 00001F75 75EC                <1> 	jnz	short dma_bnd_err_stc
  3921                              <1> 	;
  3922                              <1> 	;push	dx			; *
  3923                              <1> 	; 24/12/2021
  3924 00001F77 52                  <1> 	push	edx
  3925 00001F78 B204                <1> 	mov	DL, 4			; SECTORS/TRACK VALUE IN PARM TABLE
  3926 00001F7A E8C4020000          <1> 	call	GET_PARM		; "
  3927                              <1> 	;mov	al, ah			; AL = SECTORS/TRACK VALUE
  3928                              <1> 	;sub	ah, ah			; AX = SECTORS/TRACK VALUE
  3929                              <1> 	;shl	ax, 2			; AX = SEC/TRK * 4 (OFFSET C,H,R,N)
  3930                              <1> 	;dec	ax			; -1 FOR DMA VALUE
  3931                              <1> 	;mov	cx, ax
  3932                              <1> 	; 24/12/2021
  3933 00001F7F 29C9                <1> 	sub	ecx, ecx
  3934 00001F81 88E1                <1> 	mov	cl, ah			; SECTORS/TRACK VALUE
  3935 00001F83 D1E1                <1> 	shl	ecx, 1
  3936 00001F85 D1E1                <1> 	shl	ecx, 1			; cx = SEC/TRK * 4 (OFFSET C,H,R,N)
  3937 00001F87 6649                <1> 	dec	cx
  3938                              <1> 	;pop	dx			; *
  3939                              <1> 	; 24/12/2021
  3940 00001F89 5A                  <1> 	pop	edx
  3941 00001F8A 6601CA              <1> 	add	dx, cx			; check for overflow
  3942 00001F8D 72D5                <1> 	jc	short dma_bnd_err
  3943                              <1> 	;
  3944 00001F8F 6629CA              <1> 	sub	dx, cx			; Restore start address
  3945                              <1> 	;
  3946 00001F92 B04A                <1> 	MOV	AL,04AH			; WILL WRITE TO THE DISKETTE
  3947 00001F94 FA                  <1> 	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3948 00001F95 E60C                <1> 	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3949                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001F97 EB00                <2>  jmp short $+2
  2146 00001F99 EB00                <2>  jmp short $+2
  3950 00001F9B E60B                <1> 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3951 00001F9D 89D0                <1> 	mov	eax,edx			; Buffer address
  3952 00001F9F E604                <1> 	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3953                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001FA1 EB00                <2>  jmp short $+2
  2146 00001FA3 EB00                <2>  jmp short $+2
  3954 00001FA5 88E0                <1> 	MOV	AL,AH
  3955 00001FA7 E604                <1> 	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3956 00001FA9 C1E810              <1> 	shr	eax,16
  3957                              <1> 	IODELAY				; I/O WAIT STATE
  2145 00001FAC EB00                <2>  jmp short $+2
  2146 00001FAE EB00                <2>  jmp short $+2
  3958 00001FB0 E681                <1> 	OUT	081H,AL			; OUTPUT highest BITS TO PAGE REGISTER
  3959                              <1> 	IODELAY
  2145 00001FB2 EB00                <2>  jmp short $+2
  2146 00001FB4 EB00                <2>  jmp short $+2
  3960 00001FB6 6689C8              <1> 	mov	ax,cx			; Byte count - 1
  3961 00001FB9 E605                <1> 	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3962                              <1> 	IODELAY				; WAIT FOR I/O
  2145 00001FBB EB00                <2>  jmp short $+2
  2146 00001FBD EB00                <2>  jmp short $+2
  3963 00001FBF 88E0                <1> 	MOV	AL,AH
  3964 00001FC1 E605                <1> 	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3965                              <1> 	IODELAY
  2145 00001FC3 EB00                <2>  jmp short $+2
  2146 00001FC5 EB00                <2>  jmp short $+2
  3966 00001FC7 FB                  <1> 	STI				; RE-ENABLE INTERRUPTS
  3967 00001FC8 B002                <1> 	MOV	AL,2			; MODE FOR 8237
  3968 00001FCA E60A                <1> 	OUT	DMA+10,AL		; INITIALIZE THE DISKETTE CHANNEL
  3969 00001FCC C3                  <1> 	retn
  3970                              <1> 
  3971                              <1> ;; 08/02/2015 - Protected Mode Modification
  3972                              <1> ;;	MOV	AL, 04AH		; WILL WRITE TO THE DISKETTE
  3973                              <1> ;;	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3974                              <1> ;;	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3975                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3976                              <1> ;;	IODELAY
  3977                              <1> ;;	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3978                              <1> ;;	;MOV	AX,ES			; GET THE ES VALUE
  3979                              <1> ;;	;ROL	AX,4			; ROTATE LEFT
  3980                              <1> ;;	;MOV	CH,AL			; GET HIGHEST NIBBLE OF ES TO CH
  3981                              <1> ;;	;AND	AL,11110000B		; ZERO THE LOW NIBBLE FROM SEGMENT
  3982                              <1> ;;	;ADD	AX,[BP+2]		; TEST FOR CARRY FROM ADDITION
  3983                              <1> ;;	;JNC	short J33A
  3984                              <1> ;;	;INC	CH			; CARRY MEANS HIGH 4 BITS MUST BE INC
  3985                              <1> ;;	mov	eax, [ebp+4] ; 08/02/2015
  3986                              <1> ;;;J33A:
  3987                              <1> ;;	PUSH	eAX ; 08/02/2015	; SAVE START ADDRESS
  3988                              <1> ;;	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3989                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3990                              <1> ;;	IODELAY
  3991                              <1> ;;	MOV	AL,AH
  3992                              <1> ;;	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3993                              <1> ;;	shr 	eax, 16 ; 08/02/2015
  3994                              <1> ;;	;MOV	AL,CH			; GET HIGH 4 BITS
  3995                              <1> ;;	;JMP	$+2			; I/O WAIT STATE
  3996                              <1> ;;	IODELAY
  3997                              <1> ;;	;AND	AL,00001111B
  3998                              <1> ;;	OUT	081H,AL			; OUTPUT HIGH 4 BITS TO PAGE REGISTER
  3999                              <1> ;;
  4000                              <1> ;;;----- DETERMINE COUNT
  4001                              <1> ;;	sub	eax, eax ; 08/02/2015
  4002                              <1> ;;	MOV	DL, 4			; SECTORS/TRACK VALUE IN PARM TABLE
  4003                              <1> ;;	CALL	GET_PARM		; "
  4004                              <1> ;;	XCHG	AL, AH			; AL = SECTORS/TRACK VALUE
  4005                              <1> ;;	SUB	AH, AH			; AX = SECTORS/TRACK VALUE
  4006                              <1> ;;	SHL	AX, 2			; AX = SEC/TRK * 4 (OFFSET C,H,R,N)
  4007                              <1> ;;	DEC	AX			; -1 FOR DMA VALUE
  4008                              <1> ;;	PUSH	eAX 	; 08/02/2015	; SAVE # OF BYTES TO BE TRANSFERED
  4009                              <1> ;;	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  4010                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  4011                              <1> ;;	IODELAY
  4012                              <1> ;;	MOV	AL, AH
  4013                              <1> ;;	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  4014                              <1> ;;	STI				; RE-ENABLE INTERRUPTS
  4015                              <1> ;;	POP	eCX	; 08/02/2015	; RECOVER COUNT VALUE
  4016                              <1> ;;	POP	eAX	; 08/02/2015	; RECOVER ADDRESS VALUE
  4017                              <1> ;;	;ADD	AX, CX			; ADD, TEST FOR 64K OVERFLOW
  4018                              <1> ;;	add	ecx, eax ; 08/02/2015
  4019                              <1> ;;	MOV	AL, 2			; MODE FOR 8237
  4020                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  4021                              <1> ;;	SIODELAY
  4022                              <1> ;;	OUT	DMA+10, AL		; INITIALIZE THE DISKETTE CHANNEL
  4023                              <1> ;;	;JNC	short FMTDMA_OK		; CHECK FOR ERROR
  4024                              <1> ;;	jc	short fmtdma_bnd_err ; 08/02/2015
  4025                              <1> ;;	and	ecx, 0FFF00000h  ; 16 MB limit
  4026                              <1> ;;	jz	short FMTDMA_OK
  4027                              <1> ;;	stc	; 20/02/2015
  4028                              <1> ;;fmtdma_bnd_err:
  4029                              <1> ;;	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  4030                              <1> ;;FMTDMA_OK:
  4031                              <1> ;;	RETn				; CY SET BY ABOVE IF ERROR
  4032                              <1> 
  4033                              <1> ;-------------------------------------------------------------------------------
  4034                              <1> ; NEC_INIT	
  4035                              <1> ;	THIS ROUTINE SEEKS TO THE REQUESTED TRACK AND INITIALIZES
  4036                              <1> ;	THE NEC FOR THE READ/WRITE/VERIFY/FORMAT OPERATION.
  4037                              <1> ;
  4038                              <1> ; ON ENTRY:	AH = NEC COMMAND TO BE PERFORMED
  4039                              <1> ;
  4040                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4041                              <1> ;-------------------------------------------------------------------------------
  4042                              <1> NEC_INIT:
  4043                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  4044                              <1> 	; 24/12/2021
  4045 00001FCD 50                  <1> 	push	eax
  4046 00001FCE E8B5020000          <1> 	CALL	MOTOR_ON		; TURN MOTOR ON FOR SPECIFIC DRIVE
  4047                              <1> 
  4048                              <1> ;-----	DO THE SEEK OPERATION
  4049                              <1> 
  4050 00001FD3 8A6D01              <1> 	MOV	CH,[eBP+1]		; CH = TRACK #
  4051 00001FD6 E8A7030000          <1> 	CALL	SEEK			; MOVE TO CORRECT TRACK
  4052                              <1> 	;POP	AX			; RECOVER COMMAND
  4053                              <1> 	; 24/12/2021
  4054 00001FDB 58                  <1> 	pop	eax
  4055 00001FDC 721E                <1> 	JC	short ER_1		; ERROR ON SEEK
  4056 00001FDE BB[FC1F0000]        <1> 	MOV	eBX, ER_1		; LOAD ERROR ADDRESS
  4057 00001FE3 53                  <1> 	PUSH	eBX			; PUSH NEC_OUT ERROR RETURN
  4058                              <1> 
  4059                              <1> ;-----	SEND OUT THE PARAMETERS TO THE CONTROLLER
  4060                              <1> 
  4061 00001FE4 E860030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE OPERATION COMMAND
  4062 00001FE9 6689F0              <1> 	MOV	AX,SI			; AH = HEAD #
  4063 00001FEC 89FB                <1> 	MOV	eBX,eDI			; BL = DRIVE #
  4064 00001FEE C0E402              <1> 	SAL	AH,2			; MOVE IT TO BIT 2
  4065 00001FF1 80E404              <1> 	AND	AH,00000100B		; ISOLATE THAT BIT
  4066 00001FF4 08DC                <1> 	OR	AH,BL			; OR IN THE DRIVE NUMBER
  4067 00001FF6 E84E030000          <1> 	CALL	NEC_OUTPUT		; FALL THRU CY SET IF ERROR
  4068 00001FFB 5B                  <1> 	POP	eBX			; THROW AWAY ERROR RETURN
  4069                              <1> ER_1:
  4070 00001FFC C3                  <1> 	RETn
  4071                              <1> 
  4072                              <1> ;-------------------------------------------------------------------------------
  4073                              <1> ; RWV_COM
  4074                              <1> ;	THIS ROUTINE SENDS PARAMETERS TO THE NEC SPECIFIC TO THE 
  4075                              <1> ;	READ/WRITE/VERIFY OPERATIONS.
  4076                              <1> ;
  4077                              <1> ; ON ENTRY:	CS:BX = ADDRESS OF MEDIA/DRIVE PARAMETER TABLE
  4078                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4079                              <1> ;-------------------------------------------------------------------------------
  4080                              <1> RWV_COM:
  4081 00001FFD B8[48200000]        <1> 	MOV	eAX, ER_2		; LOAD ERROR ADDRESS
  4082 00002002 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  4083 00002003 8A6501              <1> 	MOV	AH,[eBP+1]		; OUTPUT TRACK #
  4084 00002006 E83E030000          <1> 	CALL	NEC_OUTPUT
  4085 0000200B 6689F0              <1> 	MOV	AX,SI			; OUTPUT HEAD #
  4086 0000200E E836030000          <1> 	CALL	NEC_OUTPUT
  4087 00002013 8A6500              <1>         MOV     AH,[eBP]                ; OUTPUT SECTOR #
  4088 00002016 E82E030000          <1> 	CALL	NEC_OUTPUT
  4089 0000201B B203                <1> 	MOV	DL,3			; BYTES/SECTOR PARAMETER FROM BLOCK
  4090 0000201D E821020000          <1> 	CALL	GET_PARM 		; ... TO THE NEC
  4091 00002022 E822030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4092 00002027 B204                <1> 	MOV	DL,4			; EOT PARAMETER FROM BLOCK
  4093 00002029 E815020000          <1> 	CALL	GET_PARM 		; ... TO THE NEC
  4094 0000202E E816030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4095 00002033 8A6305              <1>         MOV     AH, [eBX+MD.GAP]        ; GET GAP LENGTH
  4096                              <1> _R15:
  4097 00002036 E80E030000          <1> 	CALL	NEC_OUTPUT
  4098 0000203B B206                <1> 	MOV	DL,6			; DTL PARAMETER PROM BLOCK
  4099 0000203D E801020000          <1> 	CALL	GET_PARM		;  TO THE NEC
  4100 00002042 E802030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4101 00002047 58                  <1> 	POP	eAX			; THROW AWAY ERROR EXIT
  4102                              <1> ER_2:
  4103 00002048 C3                  <1> 	RETn
  4104                              <1> 
  4105                              <1> ;-------------------------------------------------------------------------------
  4106                              <1> ; NEC_TERM
  4107                              <1> ;	THIS ROUTINE WAITS FOR THE OPERATION THEN ACCEPTS THE STATUS 
  4108                              <1> ;	FROM THE NEC FOR THE READ/WRITE/VERIFY/FORWAT OPERATION.
  4109                              <1> ;
  4110                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4111                              <1> ;-------------------------------------------------------------------------------
  4112                              <1> NEC_TERM:
  4113                              <1> 
  4114                              <1> ;-----	LET THE OPERATION HAPPEN
  4115                              <1> 
  4116 00002049 56                  <1> 	PUSH	eSI			; SAVE HEAD #, # OF SECTORS
  4117 0000204A E804040000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  4118 0000204F 9C                  <1> 	PUSHFd	; 24/12/2021
  4119 00002050 E82E040000          <1> 	CALL	RESULTS			; GET THE NEC STATUS
  4120 00002055 724B                <1> 	JC	short SET_END_POP
  4121 00002057 9D                  <1> 	POPFd	; 24/12/2021
  4122 00002058 723E                <1> 	JC	short SET_END		; LOOK FOR ERROR
  4123                              <1> 
  4124                              <1> ;-----	CHECK THE RESULTS RETURNED BY THE CONTROLLER
  4125                              <1> 
  4126 0000205A FC                  <1> 	CLD				; SET THE CORRECT DIRECTION
  4127 0000205B BE[5D6B0000]        <1> 	MOV	eSI, NEC_STATUS		; POINT TO STATUS FIELD
  4128 00002060 AC                  <1> 	lodsb				; GET ST0
  4129 00002061 24C0                <1> 	AND	AL,11000000B		; TEST FOR NORMAL TERMINATION
  4130 00002063 7433                <1> 	JZ	short SET_END
  4131 00002065 3C40                <1> 	CMP	AL,01000000B		; TEST FOR ABNORMAL TERMINATION
  4132 00002067 7527                <1> 	JNZ	short J18		; NOT ABNORMAL, BAD NEC
  4133                              <1> 
  4134                              <1> ;-----	ABNORMAL TERMINATION, FIND OUT WHY
  4135                              <1> 
  4136 00002069 AC                  <1> 	lodsb				; GET ST1
  4137 0000206A D0E0                <1> 	SAL	AL,1			; TEST FOR EDT FOUND
  4138 0000206C B404                <1> 	MOV	AH,RECORD_NOT_FND
  4139 0000206E 7222                <1> 	JC	short J19
  4140 00002070 C0E002              <1> 	SAL	AL,2
  4141 00002073 B410                <1> 	MOV	AH,BAD_CRC
  4142 00002075 721B                <1> 	JC	short J19
  4143 00002077 D0E0                <1> 	SAL	AL,1			; TEST FOR DMA OVERRUN
  4144 00002079 B408                <1> 	MOV	AH,BAD_DMA
  4145 0000207B 7215                <1> 	JC	short J19
  4146 0000207D C0E002              <1> 	SAL	AL,2			; TEST FOR RECORD NOT FOUND
  4147 00002080 B404                <1> 	MOV	AH,RECORD_NOT_FND
  4148 00002082 720E                <1> 	JC	short J19
  4149 00002084 D0E0                <1> 	SAL	AL,1
  4150 00002086 B403                <1> 	MOV	AH,WRITE_PROTECT	; TEST FOR WRITE_PROTECT
  4151 00002088 7208                <1> 	JC	short J19
  4152 0000208A D0E0                <1> 	SAL	AL,1			; TEST MISSING ADDRESS MARK
  4153 0000208C B402                <1> 	MOV	AH,BAD_ADDR_MARK
  4154 0000208E 7202                <1> 	JC	short J19
  4155                              <1> 
  4156                              <1> ;----- 	NEC MUST HAVE FAILED
  4157                              <1> J18:
  4158 00002090 B420                <1> 	MOV	AH,BAD_NEC
  4159                              <1> J19:
  4160 00002092 0825[5C6B0000]      <1> 	OR	[DSKETTE_STATUS],AH
  4161                              <1> SET_END:
  4162 00002098 803D[5C6B0000]01    <1> 	CMP	byte [DSKETTE_STATUS],1 ; SET ERROR CONDITION
  4163 0000209F F5                  <1> 	CMC
  4164 000020A0 5E                  <1> 	POP	eSI
  4165 000020A1 C3                  <1> 	RETn				; RESTORE HEAD #, # OF SECTORS
  4166                              <1> 
  4167                              <1> SET_END_POP:
  4168 000020A2 9D                  <1> 	POPFd	; 24/12/2021
  4169 000020A3 EBF3                <1> 	JMP	SHORT SET_END
  4170                              <1> 
  4171                              <1> ;-------------------------------------------------------------------------------
  4172                              <1> ; DSTATE:	ESTABLISH STATE UPON SUCCESSFUL OPERATION.
  4173                              <1> ;-------------------------------------------------------------------------------
  4174                              <1> DSTATE:
  4175 000020A5 803D[5C6B0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; CHECK FOR ERROR
  4176 000020AC 753E                <1> 	JNZ	short SETBAC		    ; IF ERROR JUMP
  4177 000020AE 808F[696B0000]10    <1> 	OR	byte [DSK_STATE+eDI],MED_DET ; NO ERROR, MARK MEDIA AS DETERMINED
  4178 000020B5 F687[696B0000]04    <1> 	TEST	byte [DSK_STATE+eDI],DRV_DET ; DRIVE DETERMINED ?
  4179 000020BC 752E                <1> 	JNZ	short SETBAC		; IF DETERMINED NO TRY TO DETERMINE
  4180 000020BE 8A87[696B0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; LOAD STATE
  4181 000020C4 24C0                <1> 	AND	AL,RATE_MSK		; KEEP ONLY RATE
  4182 000020C6 3C80                <1> 	CMP	AL,RATE_250		; RATE 250 ?
  4183 000020C8 751B                <1> 	JNE	short M_12		; NO, MUST BE 1.2M OR 1.44M DRIVE
  4184                              <1> 
  4185                              <1> ;----- 	CHECK IF IT IS 1.44M
  4186                              <1> 
  4187 000020CA E86B010000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  4188                              <1> 	;;20/02/2015
  4189                              <1> 	;;JC	short M_12		; CMOS BAD
  4190 000020CF 7414                <1> 	jz	short M_12 ;; 20/02/2015
  4191 000020D1 3C04                <1> 	CMP	AL, 4			; 1.44MB DRIVE ?
  4192 000020D3 7410                <1> 	JE	short M_12		; YES
  4193                              <1> M_720:
  4194 000020D5 80A7[696B0000]FD    <1> 	AND	byte [DSK_STATE+eDI], ~FMT_CAPA ; TURN OFF FORMAT CAPABILITY
  4195 000020DC 808F[696B0000]04    <1> 	OR	byte [DSK_STATE+eDI],DRV_DET  ; MARK DRIVE DETERMINED
  4196 000020E3 EB07                <1> 	JMP	SHORT SETBAC		; BACK
  4197                              <1> M_12:	
  4198 000020E5 808F[696B0000]06    <1> 	OR	byte [DSK_STATE+eDI],DRV_DET+FMT_CAPA 
  4199                              <1> 					; TURN ON DETERMINED & FMT CAPA
  4200                              <1> SETBAC:
  4201 000020EC C3                  <1> 	RETn
  4202                              <1> 
  4203                              <1> ;-------------------------------------------------------------------------------
  4204                              <1> ; RETRY	
  4205                              <1> ;	DETERMINES WHETHER A RETRY IS NECESSARY. 
  4206                              <1> ;	IF RETRY IS REQUIRED THEN STATE INFORMATION IS UPDATED FOR RETRY.
  4207                              <1> ;
  4208                              <1> ; ON EXIT:	CY = 1 FOR RETRY, CY = 0 FOR NO RETRY
  4209                              <1> ;-------------------------------------------------------------------------------
  4210                              <1> RETRY:
  4211 000020ED 803D[5C6B0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; GET STATUS OF OPERATION
  4212 000020F4 7445                <1> 	JZ	short NO_RETRY		; SUCCESSFUL OPERATION
  4213 000020F6 803D[5C6B0000]80    <1> 	CMP	byte [DSKETTE_STATUS],TIME_OUT ; IF TIME OUT NO RETRY
  4214 000020FD 743C                <1> 	JZ	short NO_RETRY
  4215 000020FF 8AA7[696B0000]      <1> 	MOV	AH,[DSK_STATE+eDI]	; GET MEDIA STATE OF DRIVE
  4216 00002105 F6C410              <1> 	TEST	AH,MED_DET		; ESTABLISHED/DETERMINED ?
  4217 00002108 7531                <1> 	JNZ	short NO_RETRY		; IF ESTABLISHED STATE THEN TRUE ERROR
  4218 0000210A 80E4C0              <1> 	AND	AH,RATE_MSK		; ISOLATE RATE
  4219 0000210D 8A2D[646B0000]      <1> 	MOV	CH,[LASTRATE]		; GET START OPERATION STATE
  4220 00002113 C0C504              <1> 	ROL	CH,4			; TO CORRESPONDING BITS
  4221 00002116 80E5C0              <1> 	AND	CH,RATE_MSK		; ISOLATE RATE BITS
  4222 00002119 38E5                <1> 	CMP	CH,AH			; ALL RATES TRIED
  4223 0000211B 741E                <1> 	JE	short NO_RETRY		; IF YES, THEN TRUE ERROR
  4224                              <1> 
  4225                              <1> ;	SETUP STATE INDICATOR FOR RETRY ATTEMPT TO NEXT RATE
  4226                              <1> ;	 00000000B (500) -> 10000000B	(250)
  4227                              <1> ;	 10000000B (250) -> 01000000B	(300)
  4228                              <1> ;	 01000000B (300) -> 00000000B	(500)
  4229                              <1> 
  4230 0000211D 80FC01              <1> 	CMP	AH,RATE_500+1		; SET CY FOR RATE 500
  4231 00002120 D0DC                <1> 	RCR	AH,1			; TO NEXT STATE
  4232 00002122 80E4C0              <1> 	AND	AH,RATE_MSK		; KEEP ONLY RATE BITS
  4233 00002125 80A7[696B0000]1F    <1> 	AND	byte [DSK_STATE+eDI], ~(RATE_MSK+DBL_STEP)
  4234                              <1> 					; RATE, DBL STEP OFF
  4235 0000212C 08A7[696B0000]      <1> 	OR	[DSK_STATE+eDI],AH	; TURN ON NEW RATE
  4236 00002132 C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; RESET STATUS FOR RETRY
  4237 00002139 F9                  <1> 	STC				; SET CARRY FOR RETRY
  4238 0000213A C3                  <1> 	RETn				; RETRY RETURN
  4239                              <1> 
  4240                              <1> NO_RETRY:
  4241 0000213B F8                  <1> 	CLC				; CLEAR CARRY NO RETRY
  4242 0000213C C3                  <1> 	RETn				; NO RETRY RETURN
  4243                              <1> 
  4244                              <1> ;-------------------------------------------------------------------------------
  4245                              <1> ; NUM_TRANS
  4246                              <1> ;	THIS ROUTINE CALCULATES THE NUMBER OF SECTORS THAT WERE
  4247                              <1> ;	ACTUALLY TRANSFERRED TO/FROM THE DISKETTE.
  4248                              <1> ;
  4249                              <1> ; ON ENTRY:	[BP+1] = TRACK
  4250                              <1> ;		SI-HI  = HEAD
  4251                              <1> ;		[BP]   = START SECTOR
  4252                              <1> ;
  4253                              <1> ; ON EXIT:	AL = NUMBER ACTUALLY TRANSFERRED
  4254                              <1> ;-------------------------------------------------------------------------------
  4255                              <1> NUM_TRANS:
  4256 0000213D 30C0                <1> 	XOR	AL,AL			; CLEAR FOR ERROR
  4257 0000213F 803D[5C6B0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; CHECK FOR ERROR
  4258                              <1> 	; 24/12/2021
  4259 00002146 752C                <1> 	JNZ	short NT_OUT		; IF ERROR 0 TRANSFERRED
  4260 00002148 B204                <1> 	MOV	DL,4			; SECTORS/TRACK OFFSET TO DL
  4261 0000214A E8F4000000          <1> 	CALL	GET_PARM		; AH = SECTORS/TRACK
  4262 0000214F 8A1D[626B0000]      <1> 	MOV	BL, [NEC_STATUS+5]	; GET ENDING SECTOR
  4263 00002155 6689F1              <1> 	MOV	CX,SI			; CH = HEAD # STARTED
  4264 00002158 3A2D[616B0000]      <1> 	CMP	CH, [NEC_STATUS+4]	; GET HEAD ENDED UP ON
  4265 0000215E 750D                <1> 	JNZ	DIF_HD			; IF ON SAME HEAD, THEN NO ADJUST
  4266 00002160 8A2D[606B0000]      <1> 	MOV	CH, [NEC_STATUS+3]	; GET TRACK ENDED UP ON
  4267 00002166 3A6D01              <1> 	CMP	CH,[eBP+1]		; IS IT ASKED FOR TRACK
  4268 00002169 7404                <1> 	JZ	short SAME_TRK		; IF SAME TRACK NO INCREASE
  4269 0000216B 00E3                <1> 	ADD	BL,AH			; ADD SECTORS/TRACK
  4270                              <1> DIF_HD:
  4271 0000216D 00E3                <1> 	ADD	BL,AH			; ADD SECTORS/TRACK
  4272                              <1> SAME_TRK:
  4273 0000216F 2A5D00              <1> 	SUB	BL,[eBP]		; SUBTRACT START FROM END
  4274 00002172 88D8                <1> 	MOV	AL,BL			; TO AL
  4275                              <1> NT_OUT:
  4276 00002174 C3                  <1> 	RETn
  4277                              <1> 
  4278                              <1> ;-------------------------------------------------------------------------------
  4279                              <1> ; SETUP_END
  4280                              <1> ;	RESTORES @MOTOR_COUNT TO PARAMETER PROVIDED IN TABLE 
  4281                              <1> ;	AND LOADS @DSKETTE_STATUS TO AH, AND SETS CY.
  4282                              <1> ;
  4283                              <1> ; ON EXIT:
  4284                              <1> ;	AH, @DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4285                              <1> ;-------------------------------------------------------------------------------
  4286                              <1> SETUP_END:
  4287 00002175 B202                <1> 	MOV	DL,2			; GET THE MOTOR WAIT PARAMETER
  4288                              <1> 	;PUSH	AX			; SAVE NUMBER TRANSFERRED
  4289 00002177 50                  <1> 	push	eax ; 24/12/2021
  4290 00002178 E8C6000000          <1> 	CALL	GET_PARM
  4291 0000217D 8825[5B6B0000]      <1> 	MOV	[MOTOR_COUNT],AH	; STORE UPON RETURN
  4292                              <1> 	;POP	AX			; RESTORE NUMBER TRANSFERRED
  4293 00002183 58                  <1> 	pop	eax ; 24/12/2021
  4294 00002184 8A25[5C6B0000]      <1> 	MOV	AH, [DSKETTE_STATUS]	; GET STATUS OF OPERATION
  4295 0000218A 08E4                <1> 	OR	AH,AH			; CHECK FOR ERROR
  4296 0000218C 7402                <1> 	JZ	short NUN_ERR			; NO ERROR
  4297 0000218E 30C0                <1> 	XOR	AL,AL			; CLEAR NUMBER RETURNED
  4298                              <1> NUN_ERR: 
  4299 00002190 80FC01              <1> 	CMP	AH,1			; SET THE CARRY FLAG TO INDICATE
  4300 00002193 F5                  <1> 	CMC				; SUCCESS OR FAILURE
  4301 00002194 C3                  <1> 	RETn
  4302                              <1> 
  4303                              <1> ;-------------------------------------------------------------------------------
  4304                              <1> ; SETUP_DBL
  4305                              <1> ;	CHECK DOUBLE STEP.
  4306                              <1> ;
  4307                              <1> ; ON ENTRY :	DI = DRIVE
  4308                              <1> ;
  4309                              <1> ; ON EXIT :	CY = 1 MEANS ERROR
  4310                              <1> ;-------------------------------------------------------------------------------
  4311                              <1> SETUP_DBL:
  4312 00002195 8AA7[696B0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; ACCESS STATE
  4313 0000219B F6C410              <1> 	TEST	AH,MED_DET		; ESTABLISHED STATE ?
  4314 0000219E 757A                <1> 	JNZ	short NO_DBL			; IF ESTABLISHED THEN DOUBLE DONE
  4315                              <1> 
  4316                              <1> ;-----	CHECK FOR TRACK 0 TO SPEED UP ACKNOWLEDGE OF UNFORMATTED DISKETTE
  4317                              <1> 
  4318 000021A0 C605[596B0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; SET RECALIBRATE REQUIRED ON ALL DRIVES
  4319 000021A7 E8DC000000          <1> 	CALL	MOTOR_ON		; ENSURE MOTOR STAY ON
  4320 000021AC B500                <1> 	MOV	CH,0			; LOAD TRACK 0
  4321 000021AE E8CF010000          <1> 	CALL	SEEK			; SEEK TO TRACK 0
  4322 000021B3 E864000000          <1> 	CALL	READ_ID			; READ ID FUNCTION
  4323 000021B8 7245                <1> 	JC	short SD_ERR		; IF ERROR NO TRACK 0
  4324                              <1> 
  4325                              <1> ;-----	INITIALIZE START AND MAX TRACKS (TIMES 2 FOR BOTH HEADS)
  4326                              <1> 
  4327 000021BA 66B95004            <1> 	MOV	CX,0450H 		; START, MAX TRACKS
  4328 000021BE F687[696B0000]01    <1> 	TEST	byte [DSK_STATE+eDI],TRK_CAPA ; TEST FOR 80 TRACK CAPABILITY
  4329 000021C5 7402                <1> 	JZ	short CNT_OK		; IF NOT COUNT IS SETUP
  4330 000021C7 B1A0                <1> 	MOV	CL,0A0H			; MAXIMUM TRACK 1.2 MB
  4331                              <1> 
  4332                              <1> ;	ATTEMPT READ ID OF ALL TRACKS, ALL HEADS UNTIL SUCCESS; UPON SUCCESS,
  4333                              <1> ;	MUST SEE IF ASKED FOR TRACK IN SINGLE STEP MODE = TRACK ID READ; IF NOT
  4334                              <1> ;	THEN SET DOUBLE STEP ON.
  4335                              <1> 
  4336                              <1> CNT_OK:
  4337 000021C9 C605[5B6B0000]FF    <1>         MOV     byte [MOTOR_COUNT], 0FFH ; ENSURE MOTOR STAYS ON FOR OPERATION 
  4338                              <1> 	;PUSH	CX			; SAVE TRACK, COUNT
  4339                              <1> 	; 24/12/2021
  4340 000021D0 51                  <1> 	push	ecx
  4341 000021D1 C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; CLEAR STATUS, EXPECT ERRORS
  4342 000021D8 6631C0              <1> 	XOR	AX,AX			; CLEAR AX
  4343 000021DB D0ED                <1> 	SHR	CH,1			; HALVE TRACK, CY = HEAD
  4344 000021DD C0D003              <1> 	RCL	AL,3			; AX = HEAD IN CORRECT BIT
  4345                              <1> 	;PUSH	AX			; SAVE HEAD
  4346                              <1> 	; 24/12/2021
  4347 000021E0 50                  <1> 	push	eax
  4348 000021E1 E89C010000          <1> 	CALL	SEEK			; SEEK TO TRACK
  4349                              <1> 	;POP	AX			; RESTORE HEAD
  4350                              <1> 	; 24/12/2021
  4351 000021E6 58                  <1> 	pop	eax
  4352 000021E7 6609C7              <1> 	OR	DI,AX			; DI = HEAD OR'ED DRIVE
  4353 000021EA E82D000000          <1> 	CALL	READ_ID			; READ ID HEAD 0
  4354 000021EF 9C                  <1> 	PUSHF				; SAVE RETURN FROM READ_ID
  4355 000021F0 6681E7FB00          <1> 	AND	DI,11111011B		; TURN OFF HEAD 1 BIT
  4356 000021F5 9D                  <1> 	POPF				; RESTORE ERROR RETURN
  4357                              <1> 	;POP	CX			; RESTORE COUNT
  4358                              <1> 	; 24/12/2021
  4359 000021F6 59                  <1> 	pop	ecx
  4360 000021F7 7308                <1> 	JNC	short DO_CHK		; IF OK, ASKED = RETURNED TRACK ?
  4361 000021F9 FEC5                <1> 	INC	CH			; INC FOR NEXT TRACK
  4362 000021FB 38CD                <1> 	CMP	CH,CL			; REACHED MAXIMUM YET
  4363 000021FD 75CA                <1> 	JNZ	short CNT_OK		; CONTINUE TILL ALL TRIED
  4364                              <1> 
  4365                              <1> ;-----	FALL THRU, READ ID FAILED FOR ALL TRACKS
  4366                              <1> 
  4367                              <1> SD_ERR:	
  4368 000021FF F9                  <1> 	STC				; SET CARRY FOR ERROR
  4369 00002200 C3                  <1> 	RETn				; SETUP_DBL ERROR EXIT
  4370                              <1> 
  4371                              <1> DO_CHK:
  4372 00002201 8A0D[606B0000]      <1> 	MOV	CL, [NEC_STATUS+3]	; LOAD RETURNED TRACK
  4373 00002207 888F[6D6B0000]      <1> 	MOV	[DSK_TRK+eDI], CL	; STORE TRACK NUMBER
  4374 0000220D D0ED                <1> 	SHR	CH,1			; HALVE TRACK
  4375 0000220F 38CD                <1> 	CMP	CH,CL			; IS IT THE SAME AS ASKED FOR TRACK
  4376 00002211 7407                <1> 	JZ	short NO_DBL		; IF SAME THEN NO DOUBLE STEP
  4377 00002213 808F[696B0000]20    <1> 	OR	byte [DSK_STATE+eDI],DBL_STEP ; TURN ON DOUBLE STEP REQUIRED
  4378                              <1> NO_DBL:
  4379 0000221A F8                  <1> 	CLC				; CLEAR ERROR FLAG
  4380 0000221B C3                  <1> 	RETn
  4381                              <1> 
  4382                              <1> ;-------------------------------------------------------------------------------
  4383                              <1> ; READ_ID
  4384                              <1> ;	READ ID FUNCTION.
  4385                              <1> ;
  4386                              <1> ; ON ENTRY:	DI : BIT 2 = HEAD; BITS 1,0 = DRIVE
  4387                              <1> ;
  4388                              <1> ; ON EXIT: 	DI : BIT 2 IS RESET, BITS 1,0 = DRIVE
  4389                              <1> ;		@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4390                              <1> ;-------------------------------------------------------------------------------
  4391                              <1> READ_ID:
  4392 0000221C B8[39220000]        <1> 	MOV	eAX, ER_3		; MOVE NEC OUTPUT ERROR ADDRESS
  4393 00002221 50                  <1> 	PUSH	eAX
  4394 00002222 B44A                <1> 	MOV	AH,4AH			; READ ID COMMAND
  4395 00002224 E820010000          <1> 	CALL	NEC_OUTPUT		; TO CONTROLLER
  4396 00002229 6689F8              <1> 	MOV	AX,DI			; DRIVE # TO AH, HEAD 0
  4397 0000222C 88C4                <1> 	MOV	AH,AL
  4398 0000222E E816010000          <1> 	CALL	NEC_OUTPUT		; TO CONTROLLER
  4399 00002233 E811FEFFFF          <1> 	CALL	NEC_TERM		; WAIT FOR OPERATION, GET STATUS
  4400 00002238 58                  <1> 	POP	eAX			; THROW AWAY ERROR ADDRESS
  4401                              <1> ER_3:
  4402 00002239 C3                  <1> 	RETn
  4403                              <1> 
  4404                              <1> ;-------------------------------------------------------------------------------
  4405                              <1> ; CMOS_TYPE
  4406                              <1> ;	RETURNS DISKETTE TYPE FROM CMOS
  4407                              <1> ;
  4408                              <1> ; ON ENTRY:	DI = DRIVE #
  4409                              <1> ;
  4410                              <1> ; ON EXIT:	AL = TYPE; CY REFLECTS STATUS
  4411                              <1> ;-------------------------------------------------------------------------------
  4412                              <1> 
  4413                              <1> CMOS_TYPE: ; 11/12/2014
  4414 0000223A 8A87[CE650000]      <1> 	mov	al, [eDI+fd0_type]
  4415 00002240 20C0                <1> 	and 	al, al ; 18/12/2014
  4416 00002242 C3                  <1> 	retn
  4417                              <1> 
  4418                              <1> ;CMOS_TYPE:
  4419                              <1> ;	MOV	AL, CMOS_DIAG		; CMOS DIAGNOSTIC STATUS BYTE ADDRESS
  4420                              <1> ;	CALL	CMOS_READ		; GET CMOS STATUS
  4421                              <1> ;	TEST	AL,BAD_BAT+BAD_CKSUM	; BATTERY GOOD AND CHECKSUM VALID
  4422                              <1> ;	STC				; SET CY = 1 INDICATING ERROR FOR RETURN
  4423                              <1> ;	JNZ	short BAD_CM		; ERROR IF EITHER BIT ON
  4424                              <1> ;	MOV	AL,CMOS_DISKETTE	; ADDRESS OF DISKETTE BYTE IN CMOS
  4425                              <1> ;	CALL	CMOS_READ		; GET DISKETTE BYTE
  4426                              <1> ;	OR	DI,DI			; SEE WHICH DRIVE IN QUESTION
  4427                              <1> ;	JNZ	short TB		; IF DRIVE 1, DATA IN LOW NIBBLE
  4428                              <1> ;	ROR	AL,4			; EXCHANGE NIBBLES IF SECOND DRIVE
  4429                              <1> ;TB:
  4430                              <1> ;	AND	AL,0FH			; KEEP ONLY DRIVE DATA, RESET CY, 0
  4431                              <1> ;BAD_CM:
  4432                              <1> ;	RETn				; CY, STATUS OF READ
  4433                              <1> 
  4434                              <1> ;-------------------------------------------------------------------------------
  4435                              <1> ; GET_PARM
  4436                              <1> ;	THIS ROUTINE FETCHES THE INDEXED POINTER FROM THE DISK_BASE
  4437                              <1> ;	BLOCK POINTED TO BY THE DATA VARIABLE @DISK_POINTER. A BYTE FROM
  4438                              <1> ;	THAT TABLE IS THEN MOVED INTO AH, THE INDEX OF THAT BYTE BEING
  4439                              <1> ;	THE PARAMETER IN DL.
  4440                              <1> ;
  4441                              <1> ; ON ENTRY:	DL = INDEX OF BYTE TO BE FETCHED
  4442                              <1> ;
  4443                              <1> ; ON EXIT:	AH = THAT BYTE FROM BLOCK
  4444                              <1> ;		AL,DH DESTROYED
  4445                              <1> ;-------------------------------------------------------------------------------
  4446                              <1> GET_PARM:
  4447                              <1> 	;PUSH	DS
  4448 00002243 56                  <1> 	PUSH	eSI
  4449                              <1>     	;SUB	AX,AX			; DS = 0, BIOS DATA AREA
  4450                              <1>     	;MOV	DS,AX
  4451                              <1> 	;;mov	ax, cs
  4452                              <1> 	;;mov	ds, ax
  4453                              <1> 	; 08/02/2015 (protected mode modifications, bx -> ebx)
  4454 00002244 87D3                <1> 	XCHG	eDX,eBX			; BL = INDEX
  4455                              <1> 	;SUB	BH,BH			; BX = INDEX
  4456 00002246 81E3FF000000        <1> 	and	ebx, 0FFh
  4457                              <1>     	;LDS	SI, [DISK_POINTER]	; POINT TO BLOCK
  4458                              <1> 	;
  4459                              <1> 	; 17/12/2014
  4460 0000224C 66A1[C1650000]      <1> 	mov	ax, [cfd] ; current (AL) and previous fd (AH)
  4461 00002252 38E0                <1> 	cmp	al, ah
  4462 00002254 7425                <1> 	je	short gpndc
  4463 00002256 A2[C2650000]        <1> 	mov	[pfd], al ; current drive -> previous drive
  4464 0000225B 53                  <1> 	push	ebx ; 08/02/2015
  4465 0000225C 88C3                <1> 	mov	bl, al 
  4466                              <1> 	; 11/12/2014
  4467 0000225E 8A83[CE650000]      <1> 	mov	al, [eBX+fd0_type]	; Drive type (0,1,2,3,4)
  4468                              <1> 	; 18/12/2014
  4469 00002264 20C0                <1> 	and	al, al
  4470 00002266 7507                <1> 	jnz	short gpdtc
  4471 00002268 BB[AB650000]        <1> 	mov	ebx, MD_TBL6		; 1.44 MB param. tbl. (default)
  4472 0000226D EB05                <1>         jmp     short gpdpu
  4473                              <1> gpdtc:	
  4474 0000226F E83EF9FFFF          <1> 	call	DR_TYPE_CHECK
  4475                              <1> 	; cf = 1 -> eBX points to 1.44MB fd parameter table (default)
  4476                              <1> gpdpu:
  4477 00002274 891D[48650000]      <1> 	mov	[DISK_POINTER], ebx
  4478 0000227A 5B                  <1> 	pop	ebx
  4479                              <1> gpndc:
  4480 0000227B 8B35[48650000]      <1> 	mov	esi, [DISK_POINTER] ; 08/02/2015, si -> esi
  4481 00002281 8A241E              <1> 	MOV	AH, [eSI+eBX]		; GET THE WORD
  4482 00002284 87D3                <1> 	XCHG	eDX,eBX			; RESTORE BX
  4483 00002286 5E                  <1> 	POP	eSI
  4484                              <1> 	;POP	DS
  4485 00002287 C3                  <1> 	RETn
  4486                              <1> 
  4487                              <1> ;-------------------------------------------------------------------------------
  4488                              <1> ; MOTOR_ON
  4489                              <1> ;	TURN MOTOR ON AND WAIT FOR MOTOR START UP TIME. THE @MOTOR_COUNT
  4490                              <1> ;	IS REPLACED WITH A SUFFICIENTLY HIGH NUMBER (0FFH) TO ENSURE
  4491                              <1> ;	THAT THE MOTOR DOES NOT GO OFF DURING THE OPERATION. IF THE
  4492                              <1> ;	MOTOR NEEDED TO BE TURNED ON, THE MULTI-TASKING HOOK FUNCTION
  4493                              <1> ;	(AX=90FDH, INT 15) IS CALLED TELLING THE OPERATING SYSTEM
  4494                              <1> ;	THAT THE BIOS IS ABOUT TO WAIT FOR MOTOR START UP. IF THIS
  4495                              <1> ;	FUNCTION RETURNS WITH CY = 1, IT MEANS THAT THE MINIMUM WAIT
  4496                              <1> ;	HAS BEEN COMPLETED. AT THIS POINT A CHECK IS MADE TO ENSURE
  4497                              <1> ;	THAT THE MOTOR WASN'T TURNED OFF BY THE TIMER. IF THE HOOK DID
  4498                              <1> ;	NOT WAIT, THE WAIT FUNCTION (AH=086H) IS CALLED TO WAIT THE
  4499                              <1> ;	PRESCRIBED AMOUNT OF TIME. IF THE CARRY FLAG IS SET ON RETURN,
  4500                              <1> ;	IT MEANS THAT THE FUNCTION IS IN USE AND DID NOT PERFORM THE
  4501                              <1> ;	WAIT. A TIMER 1 WAIT LOOP WILL THEN DO THE WAIT.
  4502                              <1> ;
  4503                              <1> ; ON ENTRY:	DI = DRIVE #
  4504                              <1> ; ON EXIT:	AX,CX,DX DESTROYED
  4505                              <1> ;-------------------------------------------------------------------------------
  4506                              <1> MOTOR_ON:
  4507 00002288 53                  <1> 	PUSH	eBX			; SAVE REG.
  4508 00002289 E82A000000          <1> 	CALL	TURN_ON			; TURN ON MOTOR
  4509 0000228E 7226                <1> 	JC	short MOT_IS_ON		; IF CY=1 NO WAIT
  4510 00002290 E8C0F9FFFF          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  4511 00002295 E88AF9FFFF          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH,
  4512                              <1> 	;CALL	TURN_ON 		; CHECK AGAIN IF MOTOR ON
  4513                              <1> 	;JC	MOT_IS_ON		; IF NO WAIT MEANS IT IS ON
  4514                              <1> M_WAIT:
  4515 0000229A B20A                <1> 	MOV	DL,10			; GET THE MOTOR WAIT PARAMETER
  4516 0000229C E8A2FFFFFF          <1> 	CALL	GET_PARM
  4517                              <1> 	;MOV	AL,AH			; AL = MOTOR WAIT PARAMETER
  4518                              <1> 	;XOR	AH,AH			; AX = MOTOR WAIT PARAMETER
  4519                              <1> 	;CMP	AL,8			; SEE IF AT LEAST A SECOND IS SPECIFIED
  4520 000022A1 80FC08              <1> 	cmp	ah, 8
  4521                              <1> 	;JAE	short GP2		; IF YES, CONTINUE
  4522 000022A4 7702                <1> 	ja	short J13
  4523                              <1> 	;MOV	AL,8			; ONE SECOND WAIT FOR MOTOR START UP
  4524 000022A6 B408                <1> 	mov	ah, 8
  4525                              <1> 
  4526                              <1> ;-----	AS CONTAINS NUMBER OF 1/8 SECONDS (125000 MICROSECONDS) TO WAIT
  4527                              <1> GP2:	
  4528                              <1> ;----- 	FOLLOWING LOOPS REQUIRED WHEN RTC WAIT FUNCTION IS ALREADY IN USE
  4529                              <1> J13:					; WAIT FOR 1/8 SECOND PER (AL)
  4530 000022A8 B95E200000          <1> 	MOV	eCX,8286		; COUNT FOR 1/8 SECOND AT 15.085737 US
  4531 000022AD E80BF2FFFF          <1> 	CALL	WAITF			; GO TO FIXED WAIT ROUTINE
  4532                              <1> 	;DEC	AL			; DECREMENT TIME VALUE
  4533 000022B2 FECC                <1> 	dec	ah
  4534 000022B4 75F2                <1> 	JNZ	short J13		; ARE WE DONE YET
  4535                              <1> MOT_IS_ON:
  4536 000022B6 5B                  <1> 	POP	eBX			; RESTORE REG.
  4537 000022B7 C3                  <1> 	RETn
  4538                              <1> 
  4539                              <1> ;-------------------------------------------------------------------------------
  4540                              <1> ; TURN_ON
  4541                              <1> ;	TURN MOTOR ON AND RETURN WAIT STATE.
  4542                              <1> ;
  4543                              <1> ; ON ENTRY:	DI = DRIVE #
  4544                              <1> ;
  4545                              <1> ; ON EXIT:	CY = 0 MEANS WAIT REQUIRED
  4546                              <1> ;		CY = 1 MEANS NO WAIT REQUIRED
  4547                              <1> ;		AX,BX,CX,DX DESTROYED
  4548                              <1> ;-------------------------------------------------------------------------------
  4549                              <1> TURN_ON:
  4550 000022B8 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4551 000022BA 88D9                <1> 	MOV	CL,BL			; CL = DRIVE #
  4552 000022BC C0C304              <1> 	ROL	BL,4			; BL = DRIVE SELECT
  4553 000022BF FA                  <1> 	CLI				; NO INTERRUPTS WHILE DETERMINING STATUS
  4554 000022C0 C605[5B6B0000]FF    <1> 	MOV	byte [MOTOR_COUNT],0FFH	; ENSURE MOTOR STAYS ON FOR OPERATION
  4555 000022C7 A0[5A6B0000]        <1> 	MOV	AL, [MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  4556 000022CC 2430                <1> 	AND	AL,00110000B		; KEEP ONLY DRIVE SELECT BITS
  4557 000022CE B401                <1> 	MOV	AH,1			; MASK FOR DETERMINING MOTOR BIT
  4558 000022D0 D2E4                <1> 	SHL	AH,CL			; AH = MOTOR ON, A=00000001, B=00000010
  4559                              <1> 
  4560                              <1> ;  AL = DRIVE SELECT FROM @MOTOR_STATUS
  4561                              <1> ;  BL = DRIVE SELECT DESIRED
  4562                              <1> ;  AH = MOTOR ON MASK DESIRED
  4563                              <1> 
  4564 000022D2 38D8                <1> 	CMP	AL,BL			; REQUESTED DRIVE ALREADY SELECTED ?
  4565 000022D4 7508                <1> 	JNZ	short TURN_IT_ON	; IF NOT SELECTED JUMP
  4566 000022D6 8425[5A6B0000]      <1> 	TEST	AH, [MOTOR_STATUS]	; TEST MOTOR ON BIT
  4567 000022DC 7535                <1> 	JNZ	short NO_MOT_WAIT	; JUMP IF MOTOR ON AND SELECTED
  4568                              <1> 
  4569                              <1> TURN_IT_ON:
  4570 000022DE 08DC                <1> 	OR	AH,BL			; AH = DRIVE SELECT AND MOTOR ON
  4571 000022E0 8A3D[5A6B0000]      <1> 	MOV	BH,[MOTOR_STATUS]	; SAVE COPY OF @MOTOR_STATUS BEFORE
  4572 000022E6 80E70F              <1> 	AND	BH,00001111B		; KEEP ONLY MOTOR BITS
  4573 000022E9 8025[5A6B0000]CF    <1> 	AND	byte [MOTOR_STATUS],11001111B ; CLEAR OUT DRIVE SELECT
  4574 000022F0 0825[5A6B0000]      <1> 	OR	[MOTOR_STATUS],AH	; OR IN DRIVE SELECTED AND MOTOR ON
  4575 000022F6 A0[5A6B0000]        <1> 	MOV	AL,[MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  4576 000022FB 88C3                <1> 	MOV	BL,AL			; BL=@MOTOR_STATUS AFTER, BH=BEFORE
  4577 000022FD 80E30F              <1> 	AND	BL,00001111B		; KEEP ONLY MOTOR BITS
  4578 00002300 FB                  <1> 	STI				; ENABLE INTERRUPTS AGAIN
  4579 00002301 243F                <1> 	AND	AL,00111111B		; STRIP AWAY UNWANTED BITS
  4580 00002303 C0C004              <1> 	ROL	AL,4			; PUT BITS IN DESIRED POSITIONS
  4581 00002306 0C0C                <1> 	OR	AL,00001100B		; NO RESET, ENABLE DMA/INTERRUPT
  4582 00002308 66BAF203            <1> 	MOV	DX,03F2H		; SELECT DRIVE AND TURN ON MOTOR
  4583 0000230C EE                  <1> 	OUT	DX,AL
  4584 0000230D 38FB                <1> 	CMP	BL,BH			; NEW MOTOR TURNED ON ?
  4585                              <1> 	;JZ	short NO_MOT_WAIT	; NO WAIT REQUIRED IF JUST SELECT
  4586 0000230F 7403                <1> 	je	short no_mot_w1 ; 27/02/2015 
  4587 00002311 F8                  <1> 	CLC				; (re)SET CARRY MEANING WAIT
  4588 00002312 C3                  <1> 	RETn
  4589                              <1> 
  4590                              <1> NO_MOT_WAIT:
  4591 00002313 FB                  <1> 	sti
  4592                              <1> no_mot_w1: ; 27/02/2015
  4593 00002314 F9                  <1> 	STC				; SET NO WAIT REQUIRED
  4594                              <1> 	;STI				; INTERRUPTS BACK ON
  4595 00002315 C3                  <1> 	RETn
  4596                              <1> 
  4597                              <1> ;-------------------------------------------------------------------------------
  4598                              <1> ; HD_WAIT
  4599                              <1> ;	WAIT FOR HEAD SETTLE TIME.
  4600                              <1> ;
  4601                              <1> ; ON ENTRY:	DI = DRIVE #
  4602                              <1> ;
  4603                              <1> ; ON EXIT:	AX,BX,CX,DX DESTROYED
  4604                              <1> ;-------------------------------------------------------------------------------
  4605                              <1> HD_WAIT:
  4606 00002316 B209                <1> 	MOV	DL,9			; GET HEAD SETTLE PARAMETER
  4607 00002318 E826FFFFFF          <1> 	CALL	GET_PARM
  4608 0000231D 08E4                <1> 	or	ah, ah	; 17/12/2014
  4609 0000231F 7519                <1> 	jnz	short DO_WAT
  4610 00002321 F605[5A6B0000]80    <1>         TEST    byte [MOTOR_STATUS],10000000B ; SEE IF A WRITE OPERATION
  4611                              <1> 	;JZ	short ISNT_WRITE	; IF NOT, DO NOT ENFORCE ANY VALUES
  4612                              <1> 	;OR	AH,AH			; CHECK FOR ANY WAIT?
  4613                              <1> 	;JNZ	short DO_WAT		; IF THERE DO NOT ENFORCE
  4614 00002328 741E                <1> 	jz	short HW_DONE
  4615 0000232A B40F                <1> 	MOV	AH,HD12_SETTLE		; LOAD 1.2M HEAD SETTLE MINIMUM
  4616 0000232C 8A87[696B0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; LOAD STATE
  4617 00002332 24C0                <1> 	AND	AL,RATE_MSK		; KEEP ONLY RATE
  4618 00002334 3C80                <1> 	CMP	AL,RATE_250		; 1.2 M DRIVE ?
  4619 00002336 7502                <1> 	JNZ	short DO_WAT		; DEFAULT HEAD SETTLE LOADED
  4620                              <1> ;GP3:
  4621 00002338 B414                <1> 	MOV	AH,HD320_SETTLE		; USE 320/360 HEAD SETTLE
  4622                              <1> ;	JMP	SHORT DO_WAT
  4623                              <1> 
  4624                              <1> ;ISNT_WRITE:
  4625                              <1> ;	OR	AH,AH			; CHECK FOR NO WAIT
  4626                              <1> ;	JZ	short HW_DONE		; IF NOT WRITE AND 0 ITS OK
  4627                              <1> 
  4628                              <1> ;-----	AH CONTAINS NUMBER OF MILLISECONDS TO WAIT
  4629                              <1> DO_WAT:
  4630                              <1> ;	MOV	AL,AH			; AL = # MILLISECONDS
  4631                              <1> ;	;XOR	AH,AH			; AX = # MILLISECONDS
  4632                              <1> J29:					; 	1 MILLISECOND LOOP
  4633                              <1> 	;mov	cx, WAIT_FDU_HEAD_SETTLE ; 33 ; 1 ms in 30 micro units.
  4634 0000233A B942000000          <1> 	MOV	eCX,66			; COUNT AT 15.085737 US PER COUNT
  4635 0000233F E879F1FFFF          <1> 	CALL	WAITF			; DELAY FOR 1 MILLISECOND
  4636                              <1> 	;DEC	AL			; DECREMENT THE COUNT
  4637 00002344 FECC                <1> 	dec	ah
  4638 00002346 75F2                <1> 	JNZ	short J29		; DO AL MILLISECOND # OF TIMES
  4639                              <1> HW_DONE:
  4640 00002348 C3                  <1> 	RETn
  4641                              <1> 
  4642                              <1> ;-------------------------------------------------------------------------------
  4643                              <1> ; NEC_OUTPUT
  4644                              <1> ;	THIS ROUTINE SENDS A BYTE TO THE NEC CONTROLLER AFTER TESTING
  4645                              <1> ;	FOR CORRECT DIRECTION AND CONTROLLER READY THIS ROUTINE WILL
  4646                              <1> ;	TIME OUT IF THE BYTE IS NOT ACCEPTED WITHIN A REASONABLE AMOUNT
  4647                              <1> ;	OF TIME, SETTING THE DISKETTE STATUS ON COMPLETION.
  4648                              <1> ; 
  4649                              <1> ; ON ENTRY: 	AH = BYTE TO BE OUTPUT
  4650                              <1> ;
  4651                              <1> ; ON EXIT:	CY = 0  SUCCESS
  4652                              <1> ;		CY = 1  FAILURE -- DISKETTE STATUS UPDATED
  4653                              <1> ;		        IF A FAILURE HAS OCCURRED, THE RETURN IS MADE ONE LEVEL
  4654                              <1> ;		        HIGHER THAN THE CALLER OF NEC OUTPUT. THIS REMOVES THE
  4655                              <1> ;		        REQUIREMENT OF TESTING AFTER EVERY CALL OF NEC_OUTPUT.
  4656                              <1> ;		AX,CX,DX DESTROYED
  4657                              <1> ;-------------------------------------------------------------------------------
  4658                              <1> 
  4659                              <1> ; 09/12/2014 [Erdogan Tan] 
  4660                              <1> ;	(from 'PS2 Hardware Interface Tech. Ref. May 88', Page 09-05.)
  4661                              <1> ; Diskette Drive Controller Status Register (3F4h)
  4662                              <1> ;	This read only register facilitates the transfer of data between
  4663                              <1> ;	the system microprocessor and the controller.
  4664                              <1> ; Bit 7 - When set to 1, the Data register is ready to transfer data 
  4665                              <1> ;	  with the system micrprocessor.
  4666                              <1> ; Bit 6 - The direction of data transfer. If this bit is set to 0,
  4667                              <1> ;	  the transfer is to the controller.
  4668                              <1> ; Bit 5 - When this bit is set to 1, the controller is in the non-DMA mode.
  4669                              <1> ; Bit 4 - When this bit is set to 1, a Read or Write command is being executed.
  4670                              <1> ; Bit 3 - Reserved.
  4671                              <1> ; Bit 2 - Reserved.
  4672                              <1> ; Bit 1 - When this bit is set to 1, dskette drive 1 is in the seek mode.
  4673                              <1> ; Bit 0 - When this bit is set to 1, dskette drive 1 is in the seek mode.
  4674                              <1> 
  4675                              <1> ; Data Register (3F5h)
  4676                              <1> ; This read/write register passes data, commands and parameters, and provides
  4677                              <1> ; diskette status information.
  4678                              <1>   		
  4679                              <1> NEC_OUTPUT:
  4680                              <1> 	;PUSH	BX			; SAVE REG.
  4681 00002349 66BAF403            <1> 	MOV	DX,03F4H		; STATUS PORT
  4682                              <1> 	;MOV	BL,2			; HIGH ORDER COUNTER
  4683                              <1> 	;XOR	CX,CX			; COUNT FOR TIME OUT
  4684                              <1> 	; 16/12/2014
  4685                              <1> 	; waiting for (max.) 0.5 seconds
  4686                              <1>         ;;mov	byte [wait_count], 0 ;; 27/02/2015
  4687                              <1> 	;
  4688                              <1> 	; 17/12/2014
  4689                              <1> 	; Modified from AWARD BIOS 1999 - ADISK.ASM - SEND_COMMAND
  4690                              <1> 	;
  4691                              <1> 	;WAIT_FOR_PORT:	Waits for a bit at a port pointed to by DX to
  4692                              <1> 	;		go on.
  4693                              <1> 	;INPUT:
  4694                              <1> 	;	AH=Mask for isolation bits.
  4695                              <1> 	;	AL=pattern to look for.
  4696                              <1> 	;	DX=Port to test for
  4697                              <1> 	;	BH:CX=Number of memory refresh periods to delay.
  4698                              <1> 	;	     (normally 30 microseconds per period.)
  4699                              <1> 	;
  4700                              <1> 	;WFP_SHORT:  
  4701                              <1> 	;	Wait for port if refresh cycle is short (15-80 Us range).
  4702                              <1> 	;
  4703                              <1> 
  4704                              <1> ;	mov	bl, WAIT_FDU_SEND_HI+1	; 0+1
  4705                              <1> ;	mov	cx, WAIT_FDU_SEND_LO	; 16667
  4706 0000234D B91B410000          <1> 	mov	ecx, WAIT_FDU_SEND_LH   ; 16667 (27/02/2015)
  4707                              <1> ;
  4708                              <1> ;WFPS_OUTER_LP:
  4709                              <1> ;	;
  4710                              <1> ;WFPS_CHECK_PORT:
  4711                              <1> J23:
  4712 00002352 EC                  <1> 	IN	AL,DX			; GET STATUS
  4713 00002353 24C0                <1> 	AND	AL,11000000B		; KEEP STATUS AND DIRECTION
  4714 00002355 3C80                <1> 	CMP	AL,10000000B		; STATUS 1 AND DIRECTION 0 ?
  4715 00002357 7418                <1> 	JZ	short J27		; STATUS AND DIRECTION OK
  4716                              <1> WFPS_HI:
  4717 00002359 E461                <1> 	IN	AL, PORT_B	;061h	; SYS1	; wait for hi to lo
  4718 0000235B A810                <1> 	TEST	AL,010H			; transition on memory
  4719 0000235D 75FA                <1> 	JNZ	SHORT WFPS_HI		; refresh.
  4720                              <1> WFPS_LO:
  4721 0000235F E461                <1> 	IN	AL, PORT_B		; SYS1
  4722 00002361 A810                <1> 	TEST	AL,010H
  4723 00002363 74FA                <1> 	JZ	SHORT WFPS_LO
  4724                              <1> 	;LOOP	SHORT WFPS_CHECK_PORT
  4725 00002365 E2EB                <1> 	loop	J23	; 27/02/2015
  4726                              <1> ;	;
  4727                              <1> ;	dec	bl
  4728                              <1> ;	jnz	short WFPS_OUTER_LP
  4729                              <1> ;	jmp	short WFPS_TIMEOUT	; fail
  4730                              <1> ;J23:
  4731                              <1> ;	IN	AL,DX			; GET STATUS
  4732                              <1> ;	AND	AL,11000000B		; KEEP STATUS AND DIRECTION
  4733                              <1> ;	CMP	AL,10000000B		; STATUS 1 AND DIRECTION 0 ?
  4734                              <1> ;	JZ	short J27		; STATUS AND DIRECTION OK
  4735                              <1> 	;LOOP	J23			; CONTINUE TILL CX EXHAUSTED
  4736                              <1> 	;DEC	BL			; DECREMENT COUNTER
  4737                              <1> 	;JNZ	short J23		; REPEAT TILL DELAY FINISHED, CX = 0
  4738                              <1>    
  4739                              <1> 	;;27/02/2015
  4740                              <1> 	;16/12/2014
  4741                              <1>         ;;cmp	byte [wait_count], 10   ; (10/18.2 seconds)
  4742                              <1> 	;;jb	short J23
  4743                              <1> 
  4744                              <1> ;WFPS_TIMEOUT:
  4745                              <1> 
  4746                              <1> ;-----	FALL THRU TO ERROR RETURN
  4747                              <1> 
  4748 00002367 800D[5C6B0000]80    <1> 	OR	byte [DSKETTE_STATUS],TIME_OUT
  4749                              <1> 	;POP	BX			; RESTORE REG.
  4750 0000236E 58                  <1> 	POP	eAX ; 08/02/2015	; DISCARD THE RETURN ADDRESS
  4751 0000236F F9                  <1> 	STC				; INDICATE ERROR TO CALLER
  4752 00002370 C3                  <1> 	RETn
  4753                              <1> 
  4754                              <1> ;-----	DIRECTION AND STATUS OK; OUTPUT BYTE
  4755                              <1> 
  4756                              <1> J27:	
  4757 00002371 88E0                <1> 	MOV	AL,AH			; GET BYTE TO OUTPUT
  4758 00002373 6642                <1> 	INC	DX			; DATA PORT = STATUS PORT + 1
  4759 00002375 EE                  <1> 	OUT	DX,AL			; OUTPUT THE BYTE
  4760                              <1> 	;;NEWIODELAY  ;; 27/02/2015
  4761                              <1> 	; 27/02/2015
  4762 00002376 9C                  <1> 	PUSHFd	; 24/12/2021		; SAVE FLAGS
  4763                              <1> 	;MOV	eCX, 3			; 30 TO 45 MICROSECONDS WAIT FOR
  4764 00002377 29C9                <1> 	sub	ecx, ecx
  4765 00002379 B103                <1> 	mov	cl, 3 ; 24/12/2021
  4766 0000237B E83DF1FFFF          <1> 	CALL 	WAITF			; NEC FLAGS UPDATE CYCLE
  4767 00002380 9D                  <1> 	POPFd	; 24/12/2021			; RESTORE FLAGS FOR EXIT
  4768                              <1> 	;POP	BX			; RESTORE REG
  4769 00002381 C3                  <1> 	RETn				; CY = 0 FROM TEST INSTRUCTION
  4770                              <1> 
  4771                              <1> ;-------------------------------------------------------------------------------
  4772                              <1> ; SEEK
  4773                              <1> ;	THIS ROUTINE WILL MOVE THE HEAD ON THE NAMED DRIVE TO THE NAMED
  4774                              <1> ;	TRACK. IF THE DRIVE HAS NOT BEEN ACCESSED SINCE THE DRIVE
  4775                              <1> ;	RESET COMMAND WAS ISSUED, THE DRIVE WILL BE RECALIBRATED.
  4776                              <1> ;
  4777                              <1> ; ON ENTRY:	DI = DRIVE #
  4778                              <1> ;		CH = TRACK #
  4779                              <1> ;
  4780                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4781                              <1> ;		AX,BX,CX DX DESTROYED
  4782                              <1> ;-------------------------------------------------------------------------------
  4783                              <1> SEEK:
  4784 00002382 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4785 00002384 B001                <1> 	MOV	AL,1			; ESTABLISH MASK FOR RECALIBRATE TEST
  4786 00002386 86CB                <1> 	XCHG	CL,BL			; SET DRIVE VALULE INTO CL
  4787 00002388 D2C0                <1> 	ROL	AL,CL			; SHIFT MASK BY THE DRIVE VALUE
  4788 0000238A 86CB                <1> 	XCHG	CL,BL			; RECOVER TRACK VALUE
  4789 0000238C 8405[596B0000]      <1> 	TEST	AL,[SEEK_STATUS]	; TEST FOR RECALIBRATE REQUIRED
  4790 00002392 7526                <1> 	JNZ	short J28A		; JUMP IF RECALIBRATE NOT REQUIRED
  4791                              <1> 
  4792 00002394 0805[596B0000]      <1> 	OR	[SEEK_STATUS],AL	; TURN ON THE NO RECALIBRATE BIT IN FLAG
  4793 0000239A E862000000          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  4794 0000239F 730E                <1> 	JNC	short AFT_RECAL		; RECALIBRATE DONE
  4795                              <1> 
  4796                              <1> ;-----	ISSUE RECALIBRATE FOR 80 TRACK DISKETTES
  4797                              <1> 
  4798 000023A1 C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; CLEAR OUT INVALID STATUS
  4799 000023A8 E854000000          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  4800 000023AD 7251                <1> 	JC	short RB		; IF RECALIBRATE FAILS TWICE THEN ERROR
  4801                              <1> 
  4802                              <1> AFT_RECAL:
  4803 000023AF C687[6D6B0000]00    <1>         MOV     byte [DSK_TRK+eDI],0    ; SAVE NEW CYLINDER AS PRESENT POSITION
  4804 000023B6 08ED                <1> 	OR	CH,CH			; CHECK FOR SEEK TO TRACK 0
  4805 000023B8 743F                <1> 	JZ	short DO_WAIT		; HEAD SETTLE, CY = 0 IF JUMP
  4806                              <1> 
  4807                              <1> ;-----	DRIVE IS IN SYNCHRONIZATION WITH CONTROLLER, SEEK TO TRACK
  4808                              <1> 
  4809 000023BA F687[696B0000]20    <1> J28A:	TEST	byte [DSK_STATE+eDI],DBL_STEP ; CHECK FOR DOUBLE STEP REQUIRED
  4810 000023C1 7402                <1> 	JZ	short _R7		; SINGLE STEP REQUIRED BYPASS DOUBLE
  4811 000023C3 D0E5                <1> 	SHL	CH,1			; DOUBLE NUMBER OF STEP TO TAKE
  4812                              <1> 
  4813 000023C5 3AAF[6D6B0000]      <1> _R7:	CMP	CH, [DSK_TRK+eDI]	; SEE IF ALREADY AT THE DESIRED TRACK
  4814 000023CB 7433                <1> 	JE	short RB		; IF YES, DO NOT NEED TO SEEK
  4815                              <1> 
  4816 000023CD BA[00240000]        <1> 	MOV	eDX, NEC_ERR		; LOAD RETURN ADDRESS
  4817 000023D2 52                  <1> 	PUSH	eDX ; (*)		; ON STACK FOR NEC OUTPUT ERROR
  4818 000023D3 88AF[6D6B0000]      <1> 	MOV	[DSK_TRK+eDI],CH	; SAVE NEW CYLINDER AS PRESENT POSITION
  4819 000023D9 B40F                <1> 	MOV	AH,0FH			; SEEK COMMAND TO NEC
  4820 000023DB E869FFFFFF          <1> 	CALL	NEC_OUTPUT
  4821 000023E0 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4822 000023E2 88DC                <1> 	MOV	AH,BL			; OUTPUT DRIVE NUMBER
  4823 000023E4 E860FFFFFF          <1> 	CALL	NEC_OUTPUT
  4824 000023E9 8AA7[6D6B0000]      <1> 	MOV	AH, [DSK_TRK+eDI]	; GET CYLINDER NUMBER
  4825 000023EF E855FFFFFF          <1> 	CALL	NEC_OUTPUT
  4826 000023F4 E827000000          <1> 	CALL	CHK_STAT_2		; ENDING INTERRUPT AND SENSE STATUS
  4827                              <1> 
  4828                              <1> ;-----	WAIT FOR HEAD SETTLE
  4829                              <1> 
  4830                              <1> DO_WAIT:
  4831 000023F9 9C                  <1> 	PUSHFd	; 24/12/2021		; SAVE STATUS
  4832 000023FA E817FFFFFF          <1> 	CALL	HD_WAIT			; WAIT FOR HEAD SETTLE TIME
  4833 000023FF 9D                  <1> 	POPFd	; 24/12/2021		; RESTORE STATUS
  4834                              <1> RB:
  4835                              <1> NEC_ERR:
  4836                              <1> 	; 08/02/2015 (code trick here from original IBM PC/AT DISKETTE.ASM)
  4837                              <1> 	; (*) nec_err -> retn (push edx -> pop edx) -> nec_err -> retn
  4838 00002400 C3                  <1> 	RETn				; RETURN TO CALLER
  4839                              <1> 
  4840                              <1> ;-------------------------------------------------------------------------------
  4841                              <1> ; RECAL
  4842                              <1> ;	RECALIBRATE DRIVE
  4843                              <1> ;
  4844                              <1> ; ON ENTRY:	DI = DRIVE #
  4845                              <1> ;
  4846                              <1> ; ON EXIT:	CY REFLECTS STATUS OF OPERATION.
  4847                              <1> ;-------------------------------------------------------------------------------
  4848                              <1> RECAL:
  4849                              <1> 	;PUSH	CX
  4850                              <1> 	; 24/12/2021
  4851 00002401 51                  <1> 	push	ecx
  4852 00002402 B8[1E240000]        <1> 	MOV	eAX, RC_BACK		; LOAD NEC_OUTPUT ERROR
  4853 00002407 50                  <1> 	PUSH	eAX
  4854 00002408 B407                <1> 	MOV	AH,07H			; RECALIBRATE COMMAND
  4855 0000240A E83AFFFFFF          <1> 	CALL	NEC_OUTPUT
  4856 0000240F 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4857 00002411 88DC                <1> 	MOV	AH,BL
  4858 00002413 E831FFFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE DRIVE NUMBER
  4859 00002418 E803000000          <1> 	CALL	CHK_STAT_2		; GET THE INTERRUPT AND SENSE INT STATUS
  4860 0000241D 58                  <1> 	POP	eAX			; THROW AWAY ERROR
  4861                              <1> RC_BACK:
  4862                              <1> 	;POP	CX
  4863                              <1> 	; 24/12/2021
  4864 0000241E 59                  <1> 	pop	ecx
  4865 0000241F C3                  <1> 	RETn
  4866                              <1> 
  4867                              <1> ;-------------------------------------------------------------------------------
  4868                              <1> ; CHK_STAT_2
  4869                              <1> ;	THIS ROUTINE HANDLES THE INTERRUPT RECEIVED AFTER RECALIBRATE,
  4870                              <1> ;	OR SEEK TO THE ADAPTER. THE INTERRUPT IS WAITED FOR, THE
  4871                              <1> ;	INTERRUPT STATUS SENSED, AND THE RESULT RETURNED TO THE CALLER.
  4872                              <1> ;
  4873                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4874                              <1> ;-------------------------------------------------------------------------------
  4875                              <1> CHK_STAT_2:
  4876 00002420 B8[48240000]        <1>         MOV     eAX, CS_BACK            ; LOAD NEC_OUTPUT ERROR ADDRESS
  4877 00002425 50                  <1> 	PUSH	eAX
  4878 00002426 E828000000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  4879 0000242B 721A                <1> 	JC	short J34		; IF ERROR, RETURN IT
  4880 0000242D B408                <1> 	MOV	AH,08H			; SENSE INTERRUPT STATUS COMMAND
  4881 0000242F E815FFFFFF          <1> 	CALL	NEC_OUTPUT
  4882 00002434 E84A000000          <1> 	CALL	RESULTS			; READ IN THE RESULTS
  4883 00002439 720C                <1> 	JC	short J34
  4884 0000243B A0[5D6B0000]        <1> 	MOV	AL,[NEC_STATUS]		; GET THE FIRST STATUS BYTE
  4885 00002440 2460                <1> 	AND	AL,01100000B		; ISOLATE THE BITS
  4886 00002442 3C60                <1> 	CMP	AL,01100000B		; TEST FOR CORRECT VALUE
  4887 00002444 7403                <1> 	JZ	short J35		; IF ERROR, GO MARK IT
  4888 00002446 F8                  <1> 	CLC				; GOOD RETURN
  4889                              <1> J34:
  4890 00002447 58                  <1> 	POP	eAX			; THROW AWAY ERROR RETURN
  4891                              <1> CS_BACK:
  4892 00002448 C3                  <1> 	RETn
  4893                              <1> J35:
  4894 00002449 800D[5C6B0000]40    <1> 	OR	byte [DSKETTE_STATUS], BAD_SEEK
  4895 00002450 F9                  <1> 	STC				; ERROR RETURN CODE
  4896 00002451 EBF4                <1> 	JMP	SHORT J34
  4897                              <1> 
  4898                              <1> ;-------------------------------------------------------------------------------
  4899                              <1> ; WAIT_INT
  4900                              <1> ;	THIS ROUTINE WAITS FOR AN INTERRUPT TO OCCUR A TIME OUT ROUTINE
  4901                              <1> ;	TAKES PLACE DURING THE WAIT, SO THAT AN ERROR MAY BE RETURNED
  4902                              <1> ;	IF THE DRIVE IS NOT READY.
  4903                              <1> ;
  4904                              <1> ; ON EXIT: 	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4905                              <1> ;-------------------------------------------------------------------------------
  4906                              <1> 
  4907                              <1> ; 17/12/2014
  4908                              <1> ; 2.5 seconds waiting !
  4909                              <1> ;(AWARD BIOS - 1999, WAIT_FDU_INT_LOW, WAIT_FDU_INT_HI)
  4910                              <1> ; amount of time to wait for completion interrupt from NEC.
  4911                              <1> 
  4912                              <1> 
  4913                              <1> WAIT_INT:
  4914 00002453 FB                  <1> 	STI				; TURN ON INTERRUPTS, JUST IN CASE
  4915 00002454 F8                  <1> 	CLC				; CLEAR TIMEOUT INDICATOR
  4916                              <1>        ;MOV	BL,10			; CLEAR THE COUNTERS
  4917                              <1>        ;XOR	CX,CX			; FOR 2 SECOND WAIT
  4918                              <1> 
  4919                              <1> 	; Modification from AWARD BIOS - 1999 (ATORGS.ASM, WAIT
  4920                              <1> 	;
  4921                              <1> 	;WAIT_FOR_MEM:	
  4922                              <1> 	;	Waits for a bit at a specified memory location pointed
  4923                              <1> 	;	to by ES:[DI] to become set.
  4924                              <1> 	;INPUT:
  4925                              <1> 	;	AH=Mask to test with.
  4926                              <1> 	;	ES:[DI] = memory location to watch.
  4927                              <1> 	;	BH:CX=Number of memory refresh periods to delay.
  4928                              <1> 	;	     (normally 30 microseconds per period.)
  4929                              <1> 
  4930                              <1> 	; waiting for (max.) 2.5 secs in 30 micro units.
  4931                              <1> ;	mov 	cx, WAIT_FDU_INT_LO		; 017798
  4932                              <1> ;;	mov 	bl, WAIT_FDU_INT_HI
  4933                              <1> ;	mov 	bl, WAIT_FDU_INT_HI + 1
  4934                              <1> 	; 27/02/2015
  4935 00002455 B986450100          <1> 	mov 	ecx, WAIT_FDU_INT_LH	; 83334 (2.5 seconds)		
  4936                              <1> WFMS_CHECK_MEM:
  4937 0000245A F605[596B0000]80    <1> 	test	byte [SEEK_STATUS],INT_FLAG ; TEST FOR INTERRUPT OCCURRING
  4938 00002461 7516                <1>         jnz     short J37
  4939                              <1> WFMS_HI:
  4940 00002463 E461                <1> 	IN	AL,PORT_B  ; 061h	; SYS1, wait for lo to hi
  4941 00002465 A810                <1> 	TEST	AL,010H			; transition on memory
  4942 00002467 75FA                <1> 	JNZ	SHORT WFMS_HI		; refresh.
  4943                              <1> WFMS_LO:
  4944 00002469 E461                <1> 	IN	AL,PORT_B		;SYS1
  4945 0000246B A810                <1> 	TEST	AL,010H
  4946 0000246D 74FA                <1> 	JZ	SHORT WFMS_LO
  4947 0000246F E2E9                <1>         LOOP    WFMS_CHECK_MEM
  4948                              <1> ;WFMS_OUTER_LP:
  4949                              <1> ;;	or	bl, bl			; check outer counter
  4950                              <1> ;;	jz	short J36A		; WFMS_TIMEOUT
  4951                              <1> ;	dec	bl
  4952                              <1> ;	jz	short J36A	
  4953                              <1> ;	jmp	short WFMS_CHECK_MEM
  4954                              <1> 
  4955                              <1> 	;17/12/2014
  4956                              <1> 	;16/12/2014
  4957                              <1> ;	mov     byte [wait_count], 0    ; Reset (INT 08H) counter
  4958                              <1> ;J36:
  4959                              <1> ;	TEST	byte [SEEK_STATUS],INT_FLAG ; TEST FOR INTERRUPT OCCURRING
  4960                              <1> ;	JNZ	short J37
  4961                              <1> 	;16/12/2014
  4962                              <1> 	;LOOP	J36			; COUNT DOWN WHILE WAITING
  4963                              <1> 	;DEC	BL			; SECOND LEVEL COUNTER
  4964                              <1> 	;JNZ	short J36
  4965                              <1> ;       cmp     byte [wait_count], 46   ; (46/18.2 seconds)
  4966                              <1> ;	jb	short J36
  4967                              <1> 
  4968                              <1> ;WFMS_TIMEOUT:
  4969                              <1> ;J36A:
  4970 00002471 800D[5C6B0000]80    <1> 	OR	byte [DSKETTE_STATUS], TIME_OUT ; NOTHING HAPPENED
  4971 00002478 F9                  <1> 	STC				; ERROR RETURN
  4972                              <1> J37:
  4973 00002479 9C                  <1> 	PUSHF				; SAVE CURRENT CARRY
  4974 0000247A 8025[596B0000]7F    <1> 	AND	byte [SEEK_STATUS], ~INT_FLAG ; TURN OFF INTERRUPT FLAG
  4975 00002481 9D                  <1> 	POPF				; RECOVER CARRY
  4976 00002482 C3                  <1> 	RETn				; GOOD RETURN CODE
  4977                              <1> 
  4978                              <1> ;-------------------------------------------------------------------------------
  4979                              <1> ; RESULTS
  4980                              <1> ;	THIS ROUTINE WILL READ ANYTHING THAT THE NEC CONTROLLER RETURNS 
  4981                              <1> ;	FOLLOWING AN INTERRUPT.
  4982                              <1> ;
  4983                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4984                              <1> ;		AX,BX,CX,DX DESTROYED
  4985                              <1> ;-------------------------------------------------------------------------------
  4986                              <1> RESULTS:
  4987 00002483 57                  <1> 	PUSH	eDI
  4988 00002484 BF[5D6B0000]        <1> 	MOV	eDI, NEC_STATUS		; POINTER TO DATA AREA
  4989 00002489 B307                <1> 	MOV	BL,7			; MAX STATUS BYTES
  4990 0000248B 66BAF403            <1> 	MOV	DX,03F4H		; STATUS PORT
  4991                              <1> 
  4992                              <1> ;-----	WAIT FOR REQUEST FOR MASTER
  4993                              <1> 
  4994                              <1> _R10: 
  4995                              <1> 	; 16/12/2014
  4996                              <1> 	; wait for (max) 0.5 seconds
  4997                              <1> 	;MOV	BH,2			; HIGH ORDER COUNTER
  4998                              <1> 	;XOR	CX,CX			; COUNTER
  4999                              <1> 
  5000                              <1> 	;Time to wait while waiting for each byte of NEC results = .5
  5001                              <1> 	;seconds.  .5 seconds = 500,000 micros.  500,000/30 = 16,667.
  5002                              <1> 	; 27/02/2015
  5003 0000248F B91B410000          <1> 	mov 	ecx, WAIT_FDU_RESULTS_LH ; 16667  
  5004                              <1> 	;mov	cx, WAIT_FDU_RESULTS_LO  ; 16667
  5005                              <1> 	;mov	bh, WAIT_FDU_RESULTS_HI+1 ; 0+1
  5006                              <1> 
  5007                              <1> WFPSR_OUTER_LP:
  5008                              <1> 	;
  5009                              <1> WFPSR_CHECK_PORT:
  5010                              <1> J39:					; WAIT FOR MASTER
  5011 00002494 EC                  <1> 	IN	AL,DX			; GET STATUS
  5012 00002495 24C0                <1> 	AND	AL,11000000B		; KEEP ONLY STATUS AND DIRECTION
  5013 00002497 3CC0                <1> 	CMP	AL,11000000B		; STATUS 1 AND DIRECTION 1 ?
  5014 00002499 7418                <1> 	JZ	short J42		; STATUS AND DIRECTION OK
  5015                              <1> WFPSR_HI:
  5016 0000249B E461                <1> 	IN	AL, PORT_B	;061h	; SYS1	; wait for hi to lo
  5017 0000249D A810                <1> 	TEST	AL,010H			; transition on memory
  5018 0000249F 75FA                <1> 	JNZ	SHORT WFPSR_HI		; refresh.
  5019                              <1> WFPSR_LO:
  5020 000024A1 E461                <1> 	IN	AL, PORT_B		; SYS1
  5021 000024A3 A810                <1> 	TEST	AL,010H
  5022 000024A5 74FA                <1> 	JZ	SHORT WFPSR_LO
  5023 000024A7 E2EB                <1>         LOOP    WFPSR_CHECK_PORT
  5024                              <1> 	;; 27/02/2015
  5025                              <1> 	;;dec	bh
  5026                              <1> 	;;jnz	short WFPSR_OUTER_LP
  5027                              <1> 	;jmp	short WFPSR_TIMEOUT	; fail
  5028                              <1> 
  5029                              <1> 	;;mov	byte [wait_count], 0
  5030                              <1> ;J39:					; WAIT FOR MASTER
  5031                              <1> ;	IN	AL,DX			; GET STATUS
  5032                              <1> ;	AND	AL,11000000B		; KEEP ONLY STATUS AND DIRECTION
  5033                              <1> ;	CMP	AL,11000000B		; STATUS 1 AND DIRECTION 1 ?
  5034                              <1> ;	JZ	short J42		; STATUS AND DIRECTION OK
  5035                              <1> 	;LOOP	J39			; LOOP TILL TIMEOUT
  5036                              <1> 	;DEC	BH			; DECREMENT HIGH ORDER COUNTER
  5037                              <1> 	;JNZ	short J39		; REPEAT TILL DELAY DONE
  5038                              <1> 	;
  5039                              <1> 	;;cmp	byte [wait_count], 10  ; (10/18.2 seconds)
  5040                              <1> 	;;jb	short J39	
  5041                              <1> 
  5042                              <1> ;WFPSR_TIMEOUT:
  5043 000024A9 800D[5C6B0000]80    <1> 	OR	byte [DSKETTE_STATUS],TIME_OUT
  5044 000024B0 F9                  <1> 	STC				; SET ERROR RETURN
  5045 000024B1 EB29                <1> 	JMP	SHORT POPRES		; POP REGISTERS AND RETURN
  5046                              <1> 
  5047                              <1> ;-----	READ IN THE STATUS
  5048                              <1> 
  5049                              <1> J42:
  5050 000024B3 EB00                <1> 	JMP	$+2			; I/O DELAY
  5051 000024B5 6642                <1> 	INC	DX			; POINT AT DATA PORT
  5052 000024B7 EC                  <1> 	IN	AL,DX			; GET THE DATA
  5053                              <1> 	; 16/12/2014
  5054                              <1> 	NEWIODELAY
  2150 000024B8 E6EB                <2>  out 0EBh,al
  5055 000024BA 8807                <1>         MOV     [eDI],AL                ; STORE THE BYTE
  5056 000024BC 47                  <1> 	INC	eDI			; INCREMENT THE POINTER
  5057                              <1> 	; 16/12/2014
  5058                              <1> ;	push	cx
  5059                              <1> ;	mov	cx, 30
  5060                              <1> ;wdw2:
  5061                              <1> ;	NEWIODELAY
  5062                              <1> ;	loop	wdw2
  5063                              <1> ;	pop	cx
  5064                              <1> 
  5065 000024BD B903000000          <1> 	MOV	eCX,3			; MINIMUM 24 MICROSECONDS FOR NEC
  5066 000024C2 E8F6EFFFFF          <1> 	CALL	WAITF			; WAIT 30 TO 45 MICROSECONDS
  5067 000024C7 664A                <1> 	DEC	DX			; POINT AT STATUS PORT
  5068 000024C9 EC                  <1> 	IN	AL,DX			; GET STATUS
  5069                              <1> 	; 16/12/2014
  5070                              <1> 	NEWIODELAY
  2150 000024CA E6EB                <2>  out 0EBh,al
  5071                              <1> 	;
  5072 000024CC A810                <1> 	TEST	AL,00010000B		; TEST FOR NEC STILL BUSY
  5073 000024CE 740C                <1> 	JZ	short POPRES		; RESULTS DONE ?
  5074                              <1> 
  5075 000024D0 FECB                <1> 	DEC	BL			; DECREMENT THE STATUS COUNTER
  5076 000024D2 75BB                <1>         JNZ     short _R10              ; GO BACK FOR MORE
  5077 000024D4 800D[5C6B0000]20    <1> 	OR	byte [DSKETTE_STATUS],BAD_NEC ; TOO MANY STATUS BYTES
  5078 000024DB F9                  <1> 	STC				; SET ERROR FLAG
  5079                              <1> 
  5080                              <1> ;-----	RESULT OPERATION IS DONE
  5081                              <1> POPRES:
  5082 000024DC 5F                  <1> 	POP	eDI
  5083 000024DD C3                  <1> 	RETn				; RETURN WITH CARRY SET
  5084                              <1> 
  5085                              <1> ;-------------------------------------------------------------------------------
  5086                              <1> ; READ_DSKCHNG
  5087                              <1> ;	READS THE STATE OF THE DISK CHANGE LINE.
  5088                              <1> ;
  5089                              <1> ; ON ENTRY:	DI = DRIVE #
  5090                              <1> ;
  5091                              <1> ; ON EXIT:	DI = DRIVE #
  5092                              <1> ;		ZF = 0 : DISK CHANGE LINE INACTIVE
  5093                              <1> ;		ZF = 1 : DISK CHANGE LINE ACTIVE
  5094                              <1> ;		AX,CX,DX DESTROYED
  5095                              <1> ;-------------------------------------------------------------------------------
  5096                              <1> READ_DSKCHNG:
  5097 000024DE E8A5FDFFFF          <1> 	CALL	MOTOR_ON		; TURN ON THE MOTOR IF OFF
  5098 000024E3 66BAF703            <1> 	MOV	DX,03F7H		; ADDRESS DIGITAL INPUT REGISTER
  5099 000024E7 EC                  <1> 	IN	AL,DX			; INPUT DIGITAL INPUT REGISTER
  5100 000024E8 A880                <1> 	TEST	AL,DSK_CHG		; CHECK FOR DISK CHANGE LINE ACTIVE
  5101 000024EA C3                  <1> 	RETn				; RETURN TO CALLER WITH ZERO FLAG SET
  5102                              <1> 
  5103                              <1> ;-------------------------------------------------------------------------------
  5104                              <1> ; DRIVE_DET
  5105                              <1> ;	DETERMINES WHETHER DRIVE IS 80 OR 40 TRACKS AND
  5106                              <1> ;	UPDATES STATE INFORMATION ACCORDINGLY.
  5107                              <1> ; ON ENTRY:	DI = DRIVE #
  5108                              <1> ;-------------------------------------------------------------------------------
  5109                              <1> DRIVE_DET:
  5110 000024EB E898FDFFFF          <1> 	CALL	MOTOR_ON		; TURN ON MOTOR IF NOT ALREADY ON
  5111 000024F0 E80CFFFFFF          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  5112 000024F5 724F                <1> 	JC	short DD_BAC		; ASSUME NO DRIVE PRESENT
  5113 000024F7 B530                <1> 	MOV	CH,TRK_SLAP		; SEEK TO TRACK 48
  5114 000024F9 E884FEFFFF          <1> 	CALL	SEEK
  5115 000024FE 7246                <1> 	JC	short DD_BAC		; ERROR NO DRIVE
  5116 00002500 B50B                <1> 	MOV	CH,QUIET_SEEK+1		; SEEK TO TRACK 10
  5117                              <1> SK_GIN:
  5118 00002502 FECD                <1> 	DEC	CH			; DECREMENT TO NEXT TRACK
  5119                              <1> 	;PUSH	CX			; SAVE TRACK
  5120                              <1> 	; 24/12/2021
  5121 00002504 51                  <1> 	push	ecx
  5122 00002505 E878FEFFFF          <1> 	CALL	SEEK
  5123 0000250A 723B                <1> 	JC	short POP_BAC		; POP AND RETURN
  5124 0000250C B8[47250000]        <1> 	MOV	eAX, POP_BAC		; LOAD NEC OUTPUT ERROR ADDRESS
  5125 00002511 50                  <1> 	PUSH	eAX
  5126 00002512 B404                <1> 	MOV	AH,SENSE_DRV_ST		; SENSE DRIVE STATUS COMMAND BYTE
  5127 00002514 E830FEFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO NEC
  5128 00002519 6689F8              <1> 	MOV	AX,DI			; AL = DRIVE
  5129 0000251C 88C4                <1> 	MOV	AH,AL			; AH = DRIVE
  5130 0000251E E826FEFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO NEC
  5131 00002523 E85BFFFFFF          <1> 	CALL	RESULTS			; GO GET STATUS
  5132 00002528 58                  <1> 	POP	eAX			; THROW AWAY ERROR ADDRESS
  5133                              <1> 	;POP	CX			; RESTORE TRACK
  5134                              <1> 	; 24/12/2021
  5135 00002529 59                  <1> 	pop	ecx
  5136 0000252A F605[5D6B0000]10    <1> 	TEST	byte [NEC_STATUS], HOME	; TRACK 0 ?
  5137 00002531 74CF                <1> 	JZ	short SK_GIN		; GO TILL TRACK 0
  5138 00002533 08ED                <1> 	OR	CH,CH			; IS HOME AT TRACK 0
  5139 00002535 7408                <1> 	JZ	short IS_80		; MUST BE 80 TRACK DRIVE
  5140                              <1> 
  5141                              <1> ;	DRIVE IS A 360; SET DRIVE TO DETERMINED;
  5142                              <1> ;	SET MEDIA TO DETERMINED AT RATE 250.
  5143                              <1> 
  5144 00002537 808F[696B0000]94    <1> 	OR	byte [DSK_STATE+eDI], DRV_DET+MED_DET+RATE_250
  5145 0000253E C3                  <1> 	RETn				; ALL INFORMATION SET
  5146                              <1> IS_80:
  5147 0000253F 808F[696B0000]01    <1> 	OR	byte [DSK_STATE+eDI], TRK_CAPA ; SETUP 80 TRACK CAPABILITY
  5148                              <1> DD_BAC:
  5149 00002546 C3                  <1> 	RETn
  5150                              <1> POP_BAC:
  5151                              <1> 	;POP	CX			; THROW AWAY
  5152                              <1> 	; 24/12/2021
  5153 00002547 59                  <1> 	pop	ecx
  5154 00002548 C3                  <1> 	RETn
  5155                              <1> 
  5156                              <1> fdc_int:  
  5157                              <1> 	  ; 30/07/2015	
  5158                              <1> 	  ; 16/02/2015
  5159                              <1> ;int_0Eh: ; 11/12/2014
  5160                              <1> 
  5161                              <1> ;--- HARDWARE INT 0EH -- ( IRQ LEVEL  6 ) --------------------------------------
  5162                              <1> ; DISK_INT
  5163                              <1> ;	THIS ROUTINE HANDLES THE DISKETTE INTERRUPT.
  5164                              <1> ;
  5165                              <1> ; ON EXIT:	THE INTERRUPT FLAG IS SET IN @SEEK_STATUS.
  5166                              <1> ;-------------------------------------------------------------------------------
  5167                              <1> DISK_INT_1:
  5168                              <1> 
  5169                              <1> 	;PUSH	AX			; SAVE WORK REGISTER
  5170                              <1> 	; 24/12/2021
  5171 00002549 50                  <1> 	push	eax
  5172 0000254A 1E                  <1> 	push	ds
  5173 0000254B 66B81000            <1> 	mov	ax, KDATA
  5174 0000254F 8ED8                <1> 	mov 	ds, ax
  5175 00002551 800D[596B0000]80    <1>         OR      byte [SEEK_STATUS], INT_FLAG ; TURN ON INTERRUPT OCCURRED
  5176 00002558 B020                <1> 	MOV     AL,EOI                  ; END OF INTERRUPT MARKER
  5177 0000255A E620                <1> 	OUT	INTA00,AL		; INTERRUPT CONTROL PORT
  5178 0000255C 1F                  <1> 	pop	ds
  5179                              <1> 	;POP	AX			; RECOVER REGISTER
  5180                              <1> 	; 24/12/2021
  5181 0000255D 58                  <1> 	pop	eax
  5182 0000255E CF                  <1> 	IRETd				; RETURN FROM INTERRUPT
  5183                              <1> 
  5184                              <1> ;-------------------------------------------------------------------------------
  5185                              <1> ; DSKETTE_SETUP
  5186                              <1> ;	THIS ROUTINE DOES A PRELIMINARY CHECK TO SEE WHAT TYPE OF
  5187                              <1> ;	DISKETTE DRIVES ARE ATTACH TO THE SYSTEM.
  5188                              <1> ;-------------------------------------------------------------------------------
  5189                              <1> DSKETTE_SETUP:
  5190                              <1> 	;PUSH	AX			; SAVE REGISTERS
  5191                              <1> 	;PUSH	BX
  5192                              <1> 	;PUSH	CX
  5193 0000255F 52                  <1> 	PUSH	eDX
  5194                              <1> 	;PUSH	DI
  5195                              <1> 	;;PUSH	DS
  5196                              <1> 	; 14/12/2014
  5197                              <1> 	;mov	word [DISK_POINTER], MD_TBL6
  5198                              <1> 	;mov	[DISK_POINTER+2], cs
  5199                              <1> 	;
  5200                              <1> 	;OR	byte [RTC_WAIT_FLAG], 1	; NO RTC WAIT, FORCE USE OF LOOP
  5201 00002560 31FF                <1> 	XOR	eDI,eDI			; INITIALIZE DRIVE POINTER
  5202 00002562 66C705[696B0000]00- <1> 	MOV	WORD [DSK_STATE],0	; INITIALIZE STATES
  5202 0000256A 00                  <1>
  5203 0000256B 8025[646B0000]33    <1> 	AND	byte [LASTRATE],~(STRT_MSK+SEND_MSK) ; CLEAR START & SEND
  5204 00002572 800D[646B0000]C0    <1> 	OR	byte [LASTRATE],SEND_MSK ; INITIALIZE SENT TO IMPOSSIBLE
  5205 00002579 C605[596B0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; INDICATE RECALIBRATE NEEDED
  5206 00002580 C605[5B6B0000]00    <1> 	MOV	byte [MOTOR_COUNT],0	; INITIALIZE MOTOR COUNT
  5207 00002587 C605[5A6B0000]00    <1> 	MOV	byte [MOTOR_STATUS],0	; INITIALIZE DRIVES TO OFF STATE
  5208 0000258E C605[5C6B0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; NO ERRORS
  5209                              <1> 	;
  5210                              <1> 	; 28/02/2015
  5211                              <1> 	;mov	word [cfd], 100h 
  5212 00002595 E89DF2FFFF          <1> 	call	DSK_RESET
  5213 0000259A 5A                  <1> 	pop	edx
  5214 0000259B C3                  <1> 	retn
  5215                              <1> 
  5216                              <1> ;SUP0:
  5217                              <1> ;	CALL	DRIVE_DET		; DETERMINE DRIVE
  5218                              <1> ;	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  5219                              <1> ;	; 02/01/2015
  5220                              <1> ;	;INC	DI			; POINT TO NEXT DRIVE
  5221                              <1> ;	;CMP	DI,MAX_DRV		; SEE IF DONE
  5222                              <1> ;	;JNZ	short SUP0		; REPEAT FOR EACH ORIVE
  5223                              <1> ;       cmp     byte [fd1_type], 0	
  5224                              <1> ;	jna	short sup1
  5225                              <1> ;	or	di, di
  5226                              <1> ;	jnz	short sup1
  5227                              <1> ;	inc	di
  5228                              <1> ;       jmp     short SUP0
  5229                              <1> ;sup1:
  5230                              <1> ;	MOV	byte [SEEK_STATUS],0	; FORCE RECALIBRATE
  5231                              <1> ;	;AND	byte [RTC_WAIT_FLAG],0FEH ; ALLOW FOR RTC WAIT
  5232                              <1> ;	CALL	SETUP_END		; VARIOUS CLEANUPS
  5233                              <1> ;	;;POP	DS			; RESTORE CALLERS REGISTERS
  5234                              <1> ;	;POP	DI
  5235                              <1> ;	POP	eDX
  5236                              <1> ;	;POP	CX
  5237                              <1> ;	;POP	BX
  5238                              <1> ;	;POP	AX
  5239                              <1> ;	RETn
  5240                              <1> 
  5241                              <1> ;//////////////////////////////////////////////////////
  5242                              <1> ;; END OF DISKETTE I/O ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  5243                              <1> ;
  5244                              <1> 
  5245                              <1> int13h: ; 21/02/2015
  5246 0000259C 9C                  <1> 	pushfd
  5247 0000259D 0E                  <1> 	push 	cs
  5248 0000259E E858000000          <1> 	call 	DISK_IO
  5249 000025A3 C3                  <1> 	retn
  5250                              <1> 
  5251                              <1> ;;;;;; DISK I/O ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 21/02/2015 ;;;
  5252                              <1> ;/////////////////////////////////////////////////////////////////////
  5253                              <1> 
  5254                              <1> ; DISK I/O - Erdogan Tan (Retro UNIX 386 v1 project)
  5255                              <1> ; 23/02/2015
  5256                              <1> ; 21/02/2015 (unix386.s)
  5257                              <1> ; 22/12/2014 - 14/02/2015 (dsectrm2.s)
  5258                              <1> ;
  5259                              <1> ; Original Source Code:
  5260                              <1> ; DISK ----- 09/25/85 FIXED DISK BIOS
  5261                              <1> ; (IBM PC XT Model 286 System BIOS Source Code, 04-21-86)
  5262                              <1> ;
  5263                              <1> ; Modifications: by reference of AWARD BIOS 1999 (D1A0622) 
  5264                              <1> ;		 Source Code - ATORGS.ASM, AHDSK.ASM
  5265                              <1> ;
  5266                              <1> 
  5267                              <1> ;The wait for controller to be not busy is 10 seconds.
  5268                              <1> ;10,000,000 / 30 = 333,333.  333,333 decimal = 051615h
  5269                              <1> ;;WAIT_HDU_CTLR_BUSY_LO	equ	1615h		
  5270                              <1> ;;WAIT_HDU_CTLR_BUSY_HI	equ	  05h
  5271                              <1> WAIT_HDU_CTRL_BUSY_LH	equ	51615h	 ;21/02/2015		
  5272                              <1> 
  5273                              <1> ;The wait for controller to issue completion interrupt is 10 seconds.
  5274                              <1> ;10,000,000 / 30 = 333,333.  333,333 decimal = 051615h
  5275                              <1> ;;WAIT_HDU_INT_LO	equ	1615h
  5276                              <1> ;;WAIT_HDU_INT_HI	equ	  05h
  5277                              <1> WAIT_HDU_INT_LH		equ	51615h	; 21/02/2015
  5278                              <1> 
  5279                              <1> ;The wait for Data request on read and write longs is
  5280                              <1> ;2000 us. (?)
  5281                              <1> ;;WAIT_HDU_DRQ_LO	equ	1000	; 03E8h
  5282                              <1> ;;WAIT_HDU_DRQ_HI	equ	0
  5283                              <1> WAIT_HDU_DRQ_LH		equ	1000	; 21/02/2015
  5284                              <1> 
  5285                              <1> ; Port 61h (PORT_B)
  5286                              <1> SYS1		equ	61h	; PORT_B  (diskette.inc)
  5287                              <1> 
  5288                              <1> ; 23/12/2014
  5289                              <1> %define CMD_BLOCK       eBP-8  ; 21/02/2015
  5290                              <1> 
  5291                              <1> ;--- INT 13H -------------------------------------------------------------------
  5292                              <1> ;									       :
  5293                              <1> ; FIXED DISK I/O INTERFACE						       :
  5294                              <1> ;									       :
  5295                              <1> ;	THIS INTERFACE PROVIDES ACCESS TO 5 1/4" FIXED DISKS THROUGH           :
  5296                              <1> ;	THE IBM FIXED DISK CONTROLLER.					       :
  5297                              <1> ;									       :
  5298                              <1> ;	THE  BIOS  ROUTINES  ARE  MEANT  TO  BE  ACCESSED  THROUGH	       :
  5299                              <1> ;	SOFTWARE  INTERRUPTS  ONLY.    ANY  ADDRESSES  PRESENT	IN	       :
  5300                              <1> ;	THESE  LISTINGS  ARE  INCLUDED	 ONLY	FOR  COMPLETENESS,	       :
  5301                              <1> ;	NOT  FOR  REFERENCE.  APPLICATIONS   WHICH  REFERENCE  ANY	       :
  5302                              <1> ;	ABSOLUTE  ADDRESSES  WITHIN  THE  CODE	SEGMENTS  OF  BIOS	       :
  5303                              <1> ;	VIOLATE  THE  STRUCTURE  AND  DESIGN  OF  BIOS. 		       :
  5304                              <1> ;									       :
  5305                              <1> ;------------------------------------------------------------------------------:
  5306                              <1> ;									       :
  5307                              <1> ; INPUT  (AH)= HEX COMMAND VALUE					       :
  5308                              <1> ;									       :
  5309                              <1> ;	(AH)= 00H  RESET DISK (DL = 80H,81H) / DISKETTE 		       :
  5310                              <1> ;	(AH)= 01H  READ THE STATUS OF THE LAST DISK OPERATION INTO (AL)        :
  5311                              <1> ;		    NOTE: DL < 80H - DISKETTE				       :
  5312                              <1> ;			  DL > 80H - DISK				       :
  5313                              <1> ;	(AH)= 02H  READ THE DESIRED SECTORS INTO MEMORY 		       :
  5314                              <1> ;	(AH)= 03H  WRITE THE DESIRED SECTORS FROM MEMORY		       :
  5315                              <1> ;	(AH)= 04H  VERIFY THE DESIRED SECTORS				       :
  5316                              <1> ;	(AH)= 05H  FORMAT THE DESIRED TRACK				       :
  5317                              <1> ;	(AH)= 06H  UNUSED						       :
  5318                              <1> ;	(AH)= 07H  UNUSED						       :
  5319                              <1> ;	(AH)= 08H  RETURN THE CURRENT DRIVE PARAMETERS			       :
  5320                              <1> ;	(AH)= 09H  INITIALIZE DRIVE PAIR CHARACTERISTICS		       :
  5321                              <1> ;		    INTERRUPT 41 POINTS TO DATA BLOCK FOR DRIVE 0	       :
  5322                              <1> ;		    INTERRUPT 46 POINTS TO DATA BLOCK FOR DRIVE 1	       :
  5323                              <1> ;	(AH)= 0AH  READ LONG						       :
  5324                              <1> ;	(AH)= 0BH  WRITE LONG  (READ & WRITE LONG ENCOMPASS 512 + 4 BYTES ECC) :
  5325                              <1> ;	(AH)= 0CH  SEEK 						       :
  5326                              <1> ;	(AH)= 0DH  ALTERNATE DISK RESET (SEE DL)			       :
  5327                              <1> ;	(AH)= 0EH  UNUSED						       :
  5328                              <1> ;	(AH)= 0FH  UNUSED						       :
  5329                              <1> ;	(AH)= 10H  TEST DRIVE READY					       :
  5330                              <1> ;	(AH)= 11H  RECALIBRATE						       :
  5331                              <1> ;	(AH)= 12H  UNUSED						       :
  5332                              <1> ;	(AH)= 13H  UNUSED						       :
  5333                              <1> ;	(AH)= 14H  CONTROLLER INTERNAL DIAGNOSTIC			       :
  5334                              <1> ;	(AH)= 15H  READ DASD TYPE					       :
  5335                              <1> ;									       :
  5336                              <1> ;-------------------------------------------------------------------------------
  5337                              <1> ;									       :
  5338                              <1> ;	REGISTERS USED FOR FIXED DISK OPERATIONS			       :
  5339                              <1> ;									       :
  5340                              <1> ;		(DL)	-  DRIVE NUMBER     (80H-81H FOR DISK. VALUE CHECKED)  :
  5341                              <1> ;		(DH)	-  HEAD NUMBER	    (0-15 ALLOWED, NOT VALUE CHECKED)  :
  5342                              <1> ;		(CH)	-  CYLINDER NUMBER  (0-1023, NOT VALUE CHECKED)(SEE CL):
  5343                              <1> ;		(CL)	-  SECTOR NUMBER    (1-17, NOT VALUE CHECKED)	       :
  5344                              <1> ;									       :
  5345                              <1> ;			   NOTE: HIGH 2 BITS OF CYLINDER NUMBER ARE PLACED     :
  5346                              <1> ;				 IN THE HIGH 2 BITS OF THE CL REGISTER	       :
  5347                              <1> ;				 (10 BITS TOTAL)			       :
  5348                              <1> ;									       :
  5349                              <1> ;		(AL)	-  NUMBER OF SECTORS (MAXIMUM POSSIBLE RANGE 1-80H,    :
  5350                              <1> ;					      FOR READ/WRITE LONG 1-79H)       :
  5351                              <1> ;									       :
  5352                              <1> ;		(ES:BX) -  ADDRESS OF BUFFER FOR READS AND WRITES,	       :
  5353                              <1> ;			   (NOT REQUIRED FOR VERIFY)			       :
  5354                              <1> ;									       :
  5355                              <1> ;		FORMAT (AH=5) ES:BX POINTS TO A 512 BYTE BUFFER. THE FIRST     :
  5356                              <1> ;			   2*(SECTORS/TRACK) BYTES CONTAIN F,N FOR EACH SECTOR.:
  5357                              <1> ;			   F = 00H FOR A GOOD SECTOR			       :
  5358                              <1> ;			       80H FOR A BAD SECTOR			       :
  5359                              <1> ;			   N = SECTOR NUMBER				       :
  5360                              <1> ;			   FOR AN INTERLEAVE OF 2 AND 17 SECTORS/TRACK	       :
  5361                              <1> ;			   THE TABLE SHOULD BE: 			       :
  5362                              <1> ;									       :
  5363                              <1> ;		   DB	   00H,01H,00H,0AH,00H,02H,00H,0BH,00H,03H,00H,0CH     :
  5364                              <1> ;		   DB	   00H,04H,00H,0DH,00H,05H,00H,0EH,00H,06H,00H,0FH     :
  5365                              <1> ;		   DB	   00H,07H,00H,10H,00H,08H,00H,11H,00H,09H	       :
  5366                              <1> ;									       :
  5367                              <1> ;-------------------------------------------------------------------------------
  5368                              <1> 
  5369                              <1> ;-------------------------------------------------------------------------------
  5370                              <1> ; OUTPUT								       :
  5371                              <1> ;	AH = STATUS OF CURRENT OPERATION				       :
  5372                              <1> ;	     STATUS BITS ARE DEFINED IN THE EQUATES BELOW		       :
  5373                              <1> ;	CY = 0	SUCCESSFUL OPERATION (AH=0 ON RETURN)			       :
  5374                              <1> ;	CY = 1	FAILED OPERATION (AH HAS ERROR REASON)			       :
  5375                              <1> ;									       :
  5376                              <1> ;	NOTE:	ERROR 11H  INDICATES THAT THE DATA READ HAD A RECOVERABLE      :
  5377                              <1> ;		ERROR WHICH WAS CORRECTED BY THE ECC ALGORITHM.  THE DATA      :
  5378                              <1> ;		IS PROBABLY GOOD,   HOWEVER THE BIOS ROUTINE INDICATES AN      :
  5379                              <1> ;		ERROR TO ALLOW THE CONTROLLING PROGRAM A CHANCE TO DECIDE      :
  5380                              <1> ;		FOR ITSELF.  THE  ERROR  MAY  NOT  RECUR  IF  THE DATA IS      :
  5381                              <1> ;		REWRITTEN.						       :
  5382                              <1> ;									       :
  5383                              <1> ;	IF DRIVE PARAMETERS WERE REQUESTED (DL >= 80H), 		       :
  5384                              <1> ;	   INPUT:							       :
  5385                              <1> ;	     (DL) = DRIVE NUMBER					       :
  5386                              <1> ;	   OUTPUT:							       :
  5387                              <1> ;	     (DL) = NUMBER OF CONSECUTIVE ACKNOWLEDGING DRIVES ATTACHED (1-2)  :
  5388                              <1> ;		    (CONTROLLER CARD ZERO TALLY ONLY)			       :
  5389                              <1> ;	     (DH) = MAXIMUM USEABLE VALUE FOR HEAD NUMBER		       :
  5390                              <1> ;	     (CH) = MAXIMUM USEABLE VALUE FOR CYLINDER NUMBER		       :
  5391                              <1> ;	     (CL) = MAXIMUM USEABLE VALUE FOR SECTOR NUMBER		       :
  5392                              <1> ;		    AND CYLINDER NUMBER HIGH BITS			       :
  5393                              <1> ;									       :
  5394                              <1> ;	IF READ DASD TYPE WAS REQUESTED,				       :
  5395                              <1> ;									       :
  5396                              <1> ;	AH = 0 - NOT PRESENT						       :
  5397                              <1> ;	     1 - DISKETTE - NO CHANGE LINE AVAILABLE			       :
  5398                              <1> ;	     2 - DISKETTE - CHANGE LINE AVAILABLE			       :
  5399                              <1> ;	     3 - FIXED DISK						       :
  5400                              <1> ;									       :
  5401                              <1> ;	CX,DX = NUMBER OF 512 BYTE BLOCKS WHEN AH = 3			       :
  5402                              <1> ;									       :
  5403                              <1> ;	REGISTERS WILL BE PRESERVED EXCEPT WHEN THEY ARE USED TO RETURN        :
  5404                              <1> ;	INFORMATION.							       :
  5405                              <1> ;									       :
  5406                              <1> ;	NOTE: IF AN ERROR IS REPORTED BY THE DISK CODE, THE APPROPRIATE        :
  5407                              <1> ;		ACTION IS TO RESET THE DISK, THEN RETRY THE OPERATION.	       :
  5408                              <1> ;									       :
  5409                              <1> ;-------------------------------------------------------------------------------
  5410                              <1> 
  5411                              <1> SENSE_FAIL	EQU	0FFH		; NOT IMPLEMENTED
  5412                              <1> NO_ERR		EQU	0E0H		; STATUS ERROR/ERROR REGISTER=0
  5413                              <1> WRITE_FAULT	EQU	0CCH		; WRITE FAULT ON SELECTED DRIVE
  5414                              <1> UNDEF_ERR	EQU	0BBH		; UNDEFINED ERROR OCCURRED
  5415                              <1> NOT_RDY 	EQU	0AAH		; DRIVE NOT READY
  5416                              <1> TIME_OUT	EQU	80H		; ATTACHMENT FAILED TO RESPOND
  5417                              <1> BAD_SEEK	EQU	40H		; SEEK OPERATION FAILED
  5418                              <1> BAD_CNTLR	EQU	20H		; CONTROLLER HAS FAILED
  5419                              <1> DATA_CORRECTED	EQU	11H		; ECC CORRECTED DATA ERROR
  5420                              <1> BAD_ECC 	EQU	10H		; BAD ECC ON DISK READ
  5421                              <1> BAD_TRACK	EQU	0BH		; NOT IMPLEMENTED
  5422                              <1> BAD_SECTOR	EQU	0AH		; BAD SECTOR FLAG DETECTED
  5423                              <1> ;DMA_BOUNDARY	EQU	09H		; DATA EXTENDS TOO FAR
  5424                              <1> INIT_FAIL	EQU	07H		; DRIVE PARAMETER ACTIVITY FAILED
  5425                              <1> BAD_RESET	EQU	05H		; RESET FAILED
  5426                              <1> ;RECORD_NOT_FND	EQU	04H		; REQUESTED SECTOR NOT FOUND
  5427                              <1> ;BAD_ADDR_MARK	EQU	02H		; ADDRESS MARK NOT FOUND
  5428                              <1> ;BAD_CMD 	EQU	01H		; BAD COMMAND PASSED TO DISK I/O
  5429                              <1> 
  5430                              <1> ;--------------------------------------------------------
  5431                              <1> ;							:
  5432                              <1> ; FIXED DISK PARAMETER TABLE				:
  5433                              <1> ;  -  THE TABLE IS COMPOSED OF A BLOCK DEFINED AS:	:
  5434                              <1> ;							:
  5435                              <1> ;  +0	(1 WORD) - MAXIMUM NUMBER OF CYLINDERS		:
  5436                              <1> ;  +2	(1 BYTE) - MAXIMUM NUMBER OF HEADS		:
  5437                              <1> ;  +3	(1 WORD) - NOT USED/SEE PC-XT			:
  5438                              <1> ;  +5	(1 WORD) - STARTING WRITE PRECOMPENSATION CYL	:
  5439                              <1> ;  +7	(1 BYTE) - MAXIMUM ECC DATA BURST LENGTH	:
  5440                              <1> ;  +8	(1 BYTE) - CONTROL BYTE 			:
  5441                              <1> ;		   BIT	  7 DISABLE RETRIES -OR-	:
  5442                              <1> ;		   BIT	  6 DISABLE RETRIES		:
  5443                              <1> ;		   BIT	  3 MORE THAN 8 HEADS		:
  5444                              <1> ;  +9	(3 BYTES)- NOT USED/SEE PC-XT			:
  5445                              <1> ; +12	(1 WORD) - LANDING ZONE 			:
  5446                              <1> ; +14	(1 BYTE) - NUMBER OF SECTORS/TRACK		:
  5447                              <1> ; +15	(1 BYTE) - RESERVED FOR FUTURE USE		:
  5448                              <1> ;							:
  5449                              <1> ;	 - TO DYNAMICALLY DEFINE A SET OF PARAMETERS	:
  5450                              <1> ;	   BUILD A TABLE FOR UP TO 15 TYPES AND PLACE	:
  5451                              <1> ;	   THE CORRESPONDING VECTOR INTO INTERRUPT 41	:
  5452                              <1> ;	   FOR DRIVE 0 AND INTERRUPT 46 FOR DRIVE 1.	:
  5453                              <1> ;							:
  5454                              <1> ;--------------------------------------------------------
  5455                              <1> 
  5456                              <1> ;--------------------------------------------------------
  5457                              <1> ;							:
  5458                              <1> ; HARDWARE SPECIFIC VALUES				:
  5459                              <1> ;							:
  5460                              <1> ;  -  CONTROLLER I/O PORT				:
  5461                              <1> ;							:
  5462                              <1> ;     > WHEN READ FROM: 				:
  5463                              <1> ;	HF_PORT+0 - READ DATA (FROM CONTROLLER TO CPU)	:
  5464                              <1> ;	HF_PORT+1 - GET ERROR REGISTER			:
  5465                              <1> ;	HF_PORT+2 - GET SECTOR COUNT			:
  5466                              <1> ;	HF_PORT+3 - GET SECTOR NUMBER			:
  5467                              <1> ;	HF_PORT+4 - GET CYLINDER LOW			:
  5468                              <1> ;	HF_PORT+5 - GET CYLINDER HIGH (2 BITS)		:
  5469                              <1> ;	HF_PORT+6 - GET SIZE/DRIVE/HEAD 		:
  5470                              <1> ;	HF_PORT+7 - GET STATUS REGISTER 		:
  5471                              <1> ;							:
  5472                              <1> ;     > WHEN WRITTEN TO:				:
  5473                              <1> ;	HF_PORT+0 - WRITE DATA (FROM CPU TO CONTROLLER) :
  5474                              <1> ;	HF_PORT+1 - SET PRECOMPENSATION CYLINDER	:
  5475                              <1> ;	HF_PORT+2 - SET SECTOR COUNT			:
  5476                              <1> ;	HF_PORT+3 - SET SECTOR NUMBER			:
  5477                              <1> ;	HF_PORT+4 - SET CYLINDER LOW			:
  5478                              <1> ;	HF_PORT+5 - SET CYLINDER HIGH (2 BITS)		:
  5479                              <1> ;	HF_PORT+6 - SET SIZE/DRIVE/HEAD 		:
  5480                              <1> ;	HF_PORT+7 - SET COMMAND REGISTER		:
  5481                              <1> ;							:
  5482                              <1> ;--------------------------------------------------------
  5483                              <1> 
  5484                              <1> ;HF_PORT 	EQU	01F0H	; DISK PORT
  5485                              <1> ;HF1_PORT	equ	0170h	
  5486                              <1> ;HF_REG_PORT	EQU	03F6H
  5487                              <1> ;HF1_REG_PORT	equ	0376h
  5488                              <1> 
  5489                              <1> HDC1_BASEPORT	equ	1F0h
  5490                              <1> HDC2_BASEPORT	equ	170h		
  5491                              <1> 
  5492                              <1> align 2
  5493                              <1> 
  5494                              <1> ;-----		STATUS REGISTER
  5495                              <1> 
  5496                              <1> ST_ERROR	EQU	00000001B	;
  5497                              <1> ST_INDEX	EQU	00000010B	;
  5498                              <1> ST_CORRCTD	EQU	00000100B	; ECC CORRECTION SUCCESSFUL
  5499                              <1> ST_DRQ		EQU	00001000B	;
  5500                              <1> ST_SEEK_COMPL	EQU	00010000B	; SEEK COMPLETE
  5501                              <1> ST_WRT_FLT	EQU	00100000B	; WRITE FAULT
  5502                              <1> ST_READY	EQU	01000000B	;
  5503                              <1> ST_BUSY 	EQU	10000000B	;
  5504                              <1> 
  5505                              <1> ;-----		ERROR REGISTER
  5506                              <1> 
  5507                              <1> ERR_DAM 	EQU	00000001B	; DATA ADDRESS MARK NOT FOUND
  5508                              <1> ERR_TRK_0	EQU	00000010B	; TRACK 0 NOT FOUND ON RECAL
  5509                              <1> ERR_ABORT	EQU	00000100B	; ABORTED COMMAND
  5510                              <1> ;		EQU	00001000B	; NOT USED
  5511                              <1> ERR_ID		EQU	00010000B	; ID NOT FOUND
  5512                              <1> ;		EQU	00100000B	; NOT USED
  5513                              <1> ERR_DATA_ECC	EQU	01000000B
  5514                              <1> ERR_BAD_BLOCK	EQU	10000000B
  5515                              <1> 
  5516                              <1> 
  5517                              <1> RECAL_CMD	EQU	00010000B	; DRIVE RECAL	(10H)
  5518                              <1> READ_CMD	EQU	00100000B	;	READ	(20H)
  5519                              <1> WRITE_CMD	EQU	00110000B	;	WRITE	(30H)
  5520                              <1> VERIFY_CMD	EQU	01000000B	;	VERIFY	(40H)
  5521                              <1> FMTTRK_CMD	EQU	01010000B	; FORMAT TRACK	(50H)
  5522                              <1> INIT_CMD	EQU	01100000B	;   INITIALIZE	(60H)
  5523                              <1> SEEK_CMD	EQU	01110000B	;	SEEK	(70H)
  5524                              <1> DIAG_CMD	EQU	10010000B	; DIAGNOSTIC	(90H)
  5525                              <1> SET_PARM_CMD	EQU	10010001B	; DRIVE PARMS	(91H)
  5526                              <1> NO_RETRIES	EQU	00000001B	; CHD MODIFIER	(01H)
  5527                              <1> ECC_MODE	EQU	00000010B	; CMD MODIFIER	(02H)
  5528                              <1> BUFFER_MODE	EQU	00001000B	; CMD MODIFIER	(08H)
  5529                              <1> 
  5530                              <1> ;MAX_FILE	EQU	2
  5531                              <1> ;S_MAX_FILE	EQU	2
  5532                              <1> MAX_FILE	equ	4		; 22/12/2014
  5533                              <1> S_MAX_FILE	equ	4		; 22/12/2014
  5534                              <1> 
  5535                              <1> DELAY_1 	EQU	25H		; DELAY FOR OPERATION COMPLETE
  5536                              <1> DELAY_2 	EQU	0600H		; DELAY FOR READY
  5537                              <1> DELAY_3 	EQU	0100H		; DELAY FOR DATA REQUEST
  5538                              <1> 
  5539                              <1> HF_FAIL 	EQU	08H		; CMOS FLAG IN BYTE 0EH
  5540                              <1> 
  5541                              <1> ;-----		COMMAND BLOCK REFERENCE
  5542                              <1> 
  5543                              <1> ;CMD_BLOCK      EQU     BP-8            ; @CMD_BLOCK REFERENCES BLOCK HEAD IN SS
  5544                              <1> 					;  (BP) POINTS TO COMMAND BLOCK TAIL
  5545                              <1> 					;	AS DEFINED BY THE "ENTER" PARMS
  5546                              <1> ; 19/12/2014
  5547                              <1> ORG_VECTOR	equ	4*13h		; INT 13h vector
  5548                              <1> DISK_VECTOR	equ	4*40h		; INT 40h vector (for floppy disks)
  5549                              <1> ;HDISK_INT	equ	4*76h		; Primary HDC - Hardware interrupt (IRQ14)
  5550                              <1> ;HDISK_INT1	equ	4*76h		; Primary HDC - Hardware interrupt (IRQ14)
  5551                              <1> ;HDISK_INT2	equ	4*77h		; Secondary HDC - Hardware interrupt (IRQ15)
  5552                              <1> ;HF_TBL_VEC	equ	4*41h		; Pointer to 1st fixed disk parameter table
  5553                              <1> ;HF1_TBL_VEC	equ	4*46h		; Pointer to 2nd fixed disk parameter table
  5554                              <1> 
  5555                              <1> align 2
  5556                              <1> 
  5557                              <1> ;----------------------------------------------------------------
  5558                              <1> ; FIXED DISK I/O SETUP						:
  5559                              <1> ;								:
  5560                              <1> ;  -  ESTABLISH TRANSFER VECTORS FOR THE FIXED DISK		:
  5561                              <1> ;  -  PERFORM POWER ON DIAGNOSTICS				:
  5562                              <1> ;     SHOULD AN ERROR OCCUR A "1701" MESSAGE IS DISPLAYED       :
  5563                              <1> ;								:
  5564                              <1> ;----------------------------------------------------------------
  5565                              <1> 
  5566                              <1> DISK_SETUP:
  5567                              <1> 	;CLI
  5568                              <1> 	;;MOV	AX,ABS0 			; GET ABSOLUTE SEGMENT
  5569                              <1> 	;xor	ax,ax
  5570                              <1> 	;MOV	DS,AX				; SET SEGMENT REGISTER
  5571                              <1> 	;MOV	AX, [ORG_VECTOR] 		; GET DISKETTE VECTOR
  5572                              <1> 	;MOV	[DISK_VECTOR],AX		;  INTO INT 40H
  5573                              <1> 	;MOV	AX, [ORG_VECTOR+2]
  5574                              <1> 	;MOV	[DISK_VECTOR+2],AX
  5575                              <1> 	;MOV	word [ORG_VECTOR],DISK_IO	; FIXED DISK HANDLER
  5576                              <1> 	;MOV	[ORG_VECTOR+2],CS
  5577                              <1> 	; 1st controller (primary master, slave)   - IRQ 14
  5578                              <1> 	;;MOV	word [HDISK_INT],HD_INT		; FIXED DISK INTERRUPT
  5579                              <1> 	;mov	word [HDISK_INT1],HD_INT	;
  5580                              <1> 	;;MOV	[HDISK_INT+2],CS
  5581                              <1> 	;mov	[HDISK_INT1+2],CS
  5582                              <1> 	; 2nd controller (secondary master, slave) - IRQ 15
  5583                              <1> 	;mov	word [HDISK_INT2],HD1_INT	;
  5584                              <1> 	;mov	[HDISK_INT2+2],CS
  5585                              <1> 	;
  5586                              <1> 	;;MOV	word [HF_TBL_VEC],HD0_DPT	; PARM TABLE DRIVE 80
  5587                              <1> 	;;MOV	word [HF_TBL_VEC+2],DPT_SEGM
  5588                              <1> 	;;MOV	word [HF1_TBL_VEC],HD1_DPT	; PARM TABLE DRIVE 81
  5589                              <1> 	;;MOV	word [HF1_TBL_VEC+2],DPT_SEGM
  5590                              <1> 	;push	cs
  5591                              <1> 	;pop	ds
  5592                              <1> 	;mov	word [HDPM_TBL_VEC],HD0_DPT	; PARM TABLE DRIVE 80h
  5593                              <1> 	;mov	word [HDPM_TBL_VEC+2],DPT_SEGM
  5594 000025A4 C705[746B0000]0000- <1> 	mov 	dword [HDPM_TBL_VEC], (DPT_SEGM*16)+HD0_DPT
  5594 000025AC 0900                <1>
  5595                              <1> 	;mov	word [HDPS_TBL_VEC],HD1_DPT	; PARM TABLE DRIVE 81h
  5596                              <1> 	;mov	word [HDPS_TBL_VEC+2],DPT_SEGM
  5597 000025AE C705[786B0000]2000- <1> 	mov 	dword [HDPS_TBL_VEC], (DPT_SEGM*16)+HD1_DPT
  5597 000025B6 0900                <1>
  5598                              <1> 	;mov	word [HDSM_TBL_VEC],HD2_DPT	; PARM TABLE DRIVE 82h
  5599                              <1> 	;mov	word [HDSM_TBL_VEC+2],DPT_SEGM
  5600 000025B8 C705[7C6B0000]4000- <1> 	mov 	dword [HDSM_TBL_VEC], (DPT_SEGM*16)+HD2_DPT
  5600 000025C0 0900                <1>
  5601                              <1> 	;mov	word [HDSS_TBL_VEC],HD3_DPT	; PARM TABLE DRIVE 83h
  5602                              <1> 	;mov	word [HDSS_TBL_VEC+2],DPT_SEGM
  5603 000025C2 C705[806B0000]6000- <1> 	mov 	dword [HDSS_TBL_VEC], (DPT_SEGM*16)+HD3_DPT
  5603 000025CA 0900                <1>
  5604                              <1> 	;
  5605                              <1> 	;;IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  5606                              <1> 	;;;AND	AL,0BFH
  5607                              <1> 	;;and	al, 3Fh			; enable IRQ 14 and IRQ 15
  5608                              <1> 	;;;JMP	$+2
  5609                              <1> 	;;IODELAY
  5610                              <1> 	;;OUT	INTB01,AL
  5611                              <1> 	;;IODELAY
  5612                              <1> 	;;IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  5613                              <1> 	;;AND	AL,0FBH 		;  SECOND CHIP
  5614                              <1> 	;;;JMP	$+2
  5615                              <1> 	;;IODELAY
  5616                              <1> 	;;OUT	INTA01,AL
  5617                              <1> 	;
  5618                              <1> 	;STI
  5619                              <1> 	;;PUSH	DS			; MOVE ABS0 POINTER TO
  5620                              <1> 	;;POP	ES			; EXTRA SEGMENT POINTER
  5621                              <1> 	;;;CALL	DDS			; ESTABLISH DATA SEGMENT
  5622                              <1> 	;;MOV	byte [DISK_STATUS1],0 	; RESET THE STATUS INDICATOR
  5623                              <1> 	;;MOV	byte [HF_NUM],0		; ZERO NUMBER OF FIXED DISKS
  5624                              <1> 	;;MOV	byte [CONTROL_BYTE],0
  5625                              <1> 	;;MOV	byte [PORT_OFF],0	; ZERO CARD OFFSET
  5626                              <1> 	; 20/12/2014 - private code by Erdogan Tan
  5627                              <1> 		      ; (out of original PC-AT, PC-XT BIOS code)
  5628                              <1> 	;mov	si, hd0_type
  5629 000025CC BE[D0650000]        <1> 	mov	esi, hd0_type
  5630                              <1> 	;mov	cx, 4
  5631 000025D1 B904000000          <1> 	mov	ecx, 4
  5632                              <1> hde_l:
  5633 000025D6 AC                  <1> 	lodsb
  5634 000025D7 3C80                <1> 	cmp	al, 80h			; 8?h = existing
  5635 000025D9 7206                <1> 	jb	short _L4
  5636 000025DB FE05[706B0000]      <1> 	inc	byte [HF_NUM]		; + 1 hard (fixed) disk drives
  5637                              <1> _L4: ; 26/02/2015
  5638 000025E1 E2F3                <1> 	loop	hde_l	
  5639                              <1> ;_L4:					; 0 <= [HF_NUM] =< 4
  5640                              <1> ;L4:
  5641                              <1> 	; 
  5642                              <1> 	;; 31/12/2014 - cancel controller diagnostics here
  5643                              <1> 	;;;mov 	cx, 3  ; 26/12/2014 (Award BIOS 1999)
  5644                              <1> 	;;mov 	cl, 3
  5645                              <1> 	;;
  5646                              <1> 	;;MOV	DL,80H			; CHECK THE CONTROLLER
  5647                              <1> ;;hdc_dl:
  5648                              <1> 	;;MOV	AH,14H			; USE CONTROLLER DIAGNOSTIC COMMAND
  5649                              <1> 	;;INT	13H			; CALL BIOS WITH DIAGNOSTIC COMMAND
  5650                              <1> 	;;;JC	short CTL_ERRX		; DISPLAY ERROR MESSAGE IF BAD RETURN
  5651                              <1> 	;;;jc	short POD_DONE ;22/12/2014
  5652                              <1> 	;;jnc	short hdc_reset0
  5653                              <1> 	;;loop	hdc_dl
  5654                              <1> 	;;; 27/12/2014
  5655                              <1> 	;;stc
  5656                              <1> 	;;retn
  5657                              <1> 	;
  5658                              <1> ;;hdc_reset0:
  5659                              <1> 	; 18/01/2015
  5660 000025E3 8A0D[706B0000]      <1> 	mov	cl, [HF_NUM]
  5661 000025E9 20C9                <1> 	and	cl, cl
  5662 000025EB 740D                <1> 	jz	short POD_DONE
  5663                              <1> 	;
  5664 000025ED B27F                <1> 	mov	dl, 7Fh
  5665                              <1> hdc_reset1:
  5666 000025EF FEC2                <1> 	inc	dl
  5667                              <1> 	;; 31/12/2015
  5668                              <1> 	;;push	dx
  5669                              <1> 	;;push	cx
  5670                              <1> 	;;push	ds
  5671                              <1> 	;;sub	ax, ax
  5672                              <1> 	;;mov	ds, ax
  5673                              <1> 	;;MOV	AX, [TIMER_LOW]		; GET START TIMER COUNTS
  5674                              <1> 	;;pop	ds
  5675                              <1> 	;;MOV	BX,AX
  5676                              <1> 	;;ADD	AX,6*182		; 60 SECONDS* 18.2
  5677                              <1> 	;;MOV	CX,AX
  5678                              <1> 	;;mov	word [wait_count], 0	; 22/12/2014 (reset wait counter)
  5679                              <1> 	;;
  5680                              <1> 	;; 31/12/2014 - cancel HD_RESET_1
  5681                              <1> 	;;CALL	HD_RESET_1		; SET UP DRIVE 0, (1,2,3)
  5682                              <1> 	;;pop	cx
  5683                              <1> 	;;pop	dx
  5684                              <1> 	;;
  5685                              <1> 	; 18/01/2015
  5686 000025F1 B40D                <1> 	mov	ah, 0Dh ; ALTERNATE RESET
  5687                              <1> 	;int	13h
  5688 000025F3 E8A4FFFFFF          <1> 	call	int13h
  5689 000025F8 E2F5                <1> 	loop	hdc_reset1
  5690                              <1> POD_DONE:
  5691 000025FA C3                  <1> 	RETn
  5692                              <1> 
  5693                              <1> ;;-----	POD_ERROR
  5694                              <1> 
  5695                              <1> ;;CTL_ERRX:
  5696                              <1> ;	;MOV	SI,OFFSET F1782 	; CONTROLLER ERROR
  5697                              <1> ;	;CALL	SET_FAIL		; DO NOT IPL FROM DISK
  5698                              <1> ;	;CALL	E_MSG			; DISPLAY ERROR AND SET (BP) ERROR FLAG
  5699                              <1> ;	;JMP	short POD_DONE
  5700                              <1> 
  5701                              <1> ;;HD_RESET_1:
  5702                              <1> ;;	;PUSH	BX			; SAVE TIMER LIMITS
  5703                              <1> ;;	;PUSH	CX
  5704                              <1> ;;RES_1: MOV	AH,09H			; SET DRIVE PARAMETERS
  5705                              <1> ;;	INT	13H
  5706                              <1> ;;	JC	short RES_2
  5707                              <1> ;;	MOV	AH,11H			; RECALIBRATE DRIVE
  5708                              <1> ;;	INT	13H
  5709                              <1> ;;	JNC	short RES_CK		; DRIVE OK
  5710                              <1> ;;RES_2: ;CALL	POD_TCHK		; CHECK TIME OUT
  5711                              <1> ;;	cmp	word [wait_count], 6*182 ; waiting time (in timer ticks)
  5712                              <1> ;;					; (30 seconds)		
  5713                              <1> ;;	;cmc
  5714                              <1> ;;	;JNC	short RES_1
  5715                              <1> ;;	jb	short RES_1
  5716                              <1> ;;;RES_FL: ;MOV	SI,OFFSET F1781 	; INDICATE DISK 1 FAILURE;
  5717                              <1> ;;	;TEST	DL,1
  5718                              <1> ;;	;JNZ	RES_E1
  5719                              <1> ;;	;MOV	SI,OFFSET F1780 	; INDICATE DISK 0 FAILURE
  5720                              <1> ;;	;CALL	SET_FAIL		; DO NOT TRY TO IPL DISK 0
  5721                              <1> ;;	;JMP	SHORT RES_E1
  5722                              <1> ;;RES_ER: ; 22/12/2014
  5723                              <1> ;;RES_OK:
  5724                              <1> ;;	;POP	CX			; RESTORE TIMER LIMITS
  5725                              <1> ;;	;POP	BX
  5726                              <1> ;;	RETn
  5727                              <1> ;;
  5728                              <1> ;;RES_RS: MOV	AH,00H			; RESET THE DRIVE
  5729                              <1> ;;	INT	13H
  5730                              <1> ;;RES_CK: MOV	AH,08H			; GET MAX CYLINDER,HEAD,SECTOR
  5731                              <1> ;;	MOV	BL,DL			; SAVE DRIVE CODE
  5732                              <1> ;;	INT	13H
  5733                              <1> ;;	JC	short RES_ER
  5734                              <1> ;;	MOV	[NEC_STATUS],CX 	; SAVE MAX CYLINDER, SECTOR
  5735                              <1> ;;	MOV	DL,BL			; RESTORE DRIVE CODE
  5736                              <1> ;;RES_3: MOV	AX,0401H		; VERIFY THE LAST SECTOR
  5737                              <1> ;;	INT	13H
  5738                              <1> ;;	JNC	short RES_OK		; VERIFY OK
  5739                              <1> ;;	CMP	AH,BAD_SECTOR		; OK ALSO IF JUST ID READ
  5740                              <1> ;;	JE	short RES_OK
  5741                              <1> ;;	CMP	AH,DATA_CORRECTED
  5742                              <1> ;;	JE	short RES_OK
  5743                              <1> ;;	CMP	AH,BAD_ECC
  5744                              <1> ;;	JE	short RES_OK
  5745                              <1> ;;	;CALL	POD_TCHK		; CHECK FOR TIME OUT
  5746                              <1> ;;	cmp	word [wait_count], 6*182 ; waiting time (in timer ticks)
  5747                              <1> ;;					; (60 seconds)		
  5748                              <1> ;;	cmc
  5749                              <1> ;;	JC	short RES_ER		; FAILED
  5750                              <1> ;;	MOV	CX,[NEC_STATUS] 	; GET SECTOR ADDRESS, AND CYLINDER
  5751                              <1> ;;	MOV	AL,CL			; SEPARATE OUT SECTOR NUMBER
  5752                              <1> ;;	AND	AL,3FH
  5753                              <1> ;;	DEC	AL			; TRY PREVIOUS ONE
  5754                              <1> ;;	JZ	short RES_RS		; WE'VE TRIED ALL SECTORS ON TRACK
  5755                              <1> ;;	AND	CL,0C0H 		; KEEP CYLINDER BITS
  5756                              <1> ;;	OR	CL,AL			; MERGE SECTOR WITH CYLINDER BITS
  5757                              <1> ;;	MOV	[NEC_STATUS],CX 	; SAVE CYLINDER, NEW SECTOR NUMBER
  5758                              <1> ;;	JMP	short RES_3		; TRY AGAIN
  5759                              <1> ;;;RES_ER: MOV	SI,OFFSET F1791 	; INDICATE DISK 1 ERROR
  5760                              <1> ;;	;TEST	DL,1
  5761                              <1> ;;	;JNZ	short RES_E1
  5762                              <1> ;;	;MOV	SI,OFFSET F1790 	; INDICATE DISK 0 ERROR
  5763                              <1> ;;;RES_E1:
  5764                              <1> ;;	;CALL	E_MSG			; DISPLAY ERROR AND SET (BP) ERROR FLAG
  5765                              <1> ;;;RES_OK:
  5766                              <1> ;;	;POP	CX			; RESTORE TIMER LIMITS
  5767                              <1> ;;	;POP	BX
  5768                              <1> ;;	;RETn
  5769                              <1> ;
  5770                              <1> ;;SET_FAIL:
  5771                              <1> ;	;MOV	AX,X*(CMOS_DIAG+NMI)	; GET CMOS ERROR BYTE
  5772                              <1> ;	;CALL	CMOS_READ
  5773                              <1> ;	;OR	AL,HF_FAIL		; SET DO NOT IPL FROM DISK FLAG
  5774                              <1> ;	;XCHG	AH,AL			; SAVE IT
  5775                              <1> ;	;CALL	CMOS_WRITE		; PUT IT OUT
  5776                              <1> ;	;RETn
  5777                              <1> ;
  5778                              <1> ;;POD_TCHK:				; CHECK FOR 30 SECOND TIME OUT
  5779                              <1> ;	;POP	AX			; SAVE RETURN
  5780                              <1> ;	;POP	CX			; GET TIME OUT LIMITS
  5781                              <1> ;	;POP	BX
  5782                              <1> ;	;PUSH	BX			; AND SAVE THEM AGAIN
  5783                              <1> ;	;PUSH	CX
  5784                              <1> ;	;PUSH	AX
  5785                              <1> ;	;push	ds
  5786                              <1> ;	;xor	ax, ax
  5787                              <1> ;	;mov	ds, ax			; RESTORE RETURN
  5788                              <1> ;	;MOV	AX, [TIMER_LOW]		; AX = CURRENT TIME
  5789                              <1> ;	;				; BX = START TIME
  5790                              <1> ;	;				; CX = END TIME
  5791                              <1> ;	;pop	ds
  5792                              <1> ;	;CMP	BX,CX
  5793                              <1> ;	;JB	short TCHK1		; START < END
  5794                              <1> ;	;CMP	BX,AX
  5795                              <1> ;	;JB	short TCHKG		; END < START < CURRENT
  5796                              <1> ;	;JMP	SHORT TCHK2		; END, CURRENT < START
  5797                              <1> ;;TCHK1: CMP	AX,BX
  5798                              <1> ;;	JB	short TCHKNG		; CURRENT < START < END
  5799                              <1> ;;TCHK2: CMP	AX,CX
  5800                              <1> ;;	JB	short TCHKG		; START < CURRENT < END
  5801                              <1> ;;					; OR CURRENT < END < START
  5802                              <1> ;;TCHKNG: STC				; CARRY SET INDICATES TIME OUT
  5803                              <1> ;;	RETn
  5804                              <1> ;;TCHKG: CLC				; INDICATE STILL TIME
  5805                              <1> ;;	RETn
  5806                              <1> ;;
  5807                              <1> ;;int_13h:
  5808                              <1> 
  5809                              <1> ;----------------------------------------
  5810                              <1> ;	FIXED DISK BIOS ENTRY POINT	:
  5811                              <1> ;----------------------------------------
  5812                              <1> 
  5813                              <1> DISK_IO:
  5814 000025FB 80FA80              <1> 	CMP	DL,80H			; TEST FOR FIXED DISK DRIVE
  5815                              <1> 	;JAE	short A1		; YES, HANDLE HERE
  5816                              <1> 	;;;INT	40H			; DISKETTE HANDLER
  5817                              <1> 	;;call	int40h
  5818                              <1> 	;jb	DISKETTE_IO_1
  5819                              <1> 	; 24/12/2021
  5820 000025FE 7305                <1> 	jnb	short A1
  5821 00002600 E960F1FFFF          <1> 	jmp	DISKETTE_IO_1
  5822                              <1> ;RET_2:
  5823                              <1> 	;RETf	2			; BACK TO CALLER
  5824                              <1> ;	retf	4
  5825                              <1> A1:
  5826 00002605 FB                  <1> 	STI				; ENABLE INTERRUPTS
  5827                              <1> 	;; 04/01/2015
  5828                              <1> 	;;OR	AH,AH
  5829                              <1> 	;;JNZ	short A2
  5830                              <1> 	;;INT	40H			; RESET NEC WHEN AH=0
  5831                              <1> 	;;SUB	AH,AH
  5832 00002606 80FA83              <1> 	CMP	DL,(80H + S_MAX_FILE - 1)
  5833 00002609 772E                <1> 	JA	short RET_2
  5834                              <1> 	; 18/01/2015
  5835 0000260B 08E4                <1> 	or	ah,ah
  5836 0000260D 742D                <1> 	jz	short A4
  5837 0000260F 80FC0D              <1> 	cmp	ah, 0Dh	; Alternate reset
  5838 00002612 7504                <1> 	jne	short A2
  5839 00002614 28E4                <1> 	sub	ah,ah	; Reset
  5840 00002616 EB24                <1> 	jmp	short A4
  5841                              <1> A2:
  5842 00002618 80FC08              <1> 	CMP	AH,08H			; GET PARAMETERS IS A SPECIAL CASE
  5843                              <1> 	;JNZ	short A3
  5844                              <1>         ;JMP    GET_PARM_N
  5845                              <1> 	;je	GET_PARM_N
  5846                              <1> 	; 24/12/2021
  5847 0000261B 7505                <1> 	jne	short A3
  5848 0000261D E90D030000          <1> 	jmp	GET_PARM_N
  5849                              <1> A3:	
  5850 00002622 80FC15              <1> 	CMP	AH,15H			; READ DASD TYPE IS ALSO
  5851                              <1> 	;JNZ	short A4
  5852                              <1>         ;JMP    READ_DASD_TYPE
  5853                              <1> 	;je	READ_DASD_TYPE
  5854                              <1> 	; 24/12/2021
  5855 00002625 7505                <1> 	jne	short A3_A4
  5856 00002627 E9BA020000          <1> 	jmp	READ_DASD_TYPE
  5857                              <1> A3_A4:
  5858                              <1> 	; 02/02/2015
  5859 0000262C 80FC1D              <1> 	cmp	ah, 1Dh			; (Temporary for Retro UNIX 386 v1)
  5860                              <1> 	; 12/01/2015
  5861 0000262F F5                  <1> 	cmc
  5862 00002630 730A                <1> 	jnc	short A4
  5863                              <1> 	; 30/01/2015
  5864                              <1> 	;mov	byte [CS:DISK_STATUS1],BAD_CMD  ; COMMAND ERROR
  5865 00002632 C605[6F6B0000]01    <1>         mov     byte [DISK_STATUS1], BAD_CMD
  5866                              <1> 	;jmp	short RET_2
  5867                              <1> RET_2:
  5868 00002639 CA0400              <1> 	retf	4
  5869                              <1> A4:					; SAVE REGISTERS DURING OPERATION
  5870 0000263C C8080000            <1> 	ENTER	8,0			; SAVE (BP) AND MAKE ROOM FOR @CMD_BLOCK
  5871 00002640 53                  <1> 	PUSH	eBX			;  IN THE STACK, THE COMMAND BLOCK IS:
  5872 00002641 51                  <1> 	PUSH	eCX			;   @CMD_BLOCK == BYTE PTR [BP]-8
  5873 00002642 52                  <1> 	PUSH	eDX
  5874 00002643 1E                  <1> 	PUSH	DS
  5875 00002644 06                  <1> 	PUSH	ES
  5876 00002645 56                  <1> 	PUSH	eSI
  5877 00002646 57                  <1> 	PUSH	eDI
  5878                              <1> 	;;04/01/2015
  5879                              <1> 	;;OR	AH,AH			; CHECK FOR RESET
  5880                              <1> 	;;JNZ	short A5
  5881                              <1> 	;;MOV	DL,80H			; FORCE DRIVE 80 FOR RESET
  5882                              <1> ;;A5:	
  5883                              <1> 	;push	cs
  5884                              <1> 	;pop	ds
  5885                              <1> 	; 21/02/2015
  5886                              <1> 	;push	ax
  5887                              <1> 	; 24/12/2021
  5888 00002647 50                  <1> 	push	eax
  5889 00002648 66B81000            <1> 	mov	ax, KDATA
  5890 0000264C 8ED8                <1> 	mov	ds, ax
  5891 0000264E 8EC0                <1> 	mov	es, ax	
  5892                              <1> 	;pop	ax
  5893                              <1> 	; 24/12/2021
  5894 00002650 58                  <1> 	pop	eax
  5895 00002651 E889000000          <1> 	CALL	DISK_IO_CONT		; PERFORM THE OPERATION
  5896                              <1> 	;;CALL	DDS			; ESTABLISH SEGMENT
  5897 00002656 8A25[6F6B0000]      <1> 	MOV	AH,[DISK_STATUS1]	; GET STATUS FROM OPERATION
  5898 0000265C 80FC01              <1> 	CMP	AH,1			; SET THE CARRY FLAG TO INDICATE
  5899 0000265F F5                  <1> 	CMC				; SUCCESS OR FAILURE
  5900 00002660 5F                  <1> 	POP	eDI			; RESTORE REGISTERS
  5901 00002661 5E                  <1> 	POP	eSI
  5902 00002662 07                  <1>         POP     ES
  5903 00002663 1F                  <1>         POP     DS
  5904 00002664 5A                  <1> 	POP	eDX
  5905 00002665 59                  <1> 	POP	eCX
  5906 00002666 5B                  <1> 	POP	eBX
  5907 00002667 C9                  <1> 	LEAVE				; ADJUST (SP) AND RESTORE (BP)
  5908                              <1> 	;RETf	2			; THROW AWAY SAVED FLAGS
  5909 00002668 CA0400              <1> 	retf	4
  5910                              <1> ; 21/02/2015
  5911                              <1> ;       dw --> dd
  5912                              <1> M1:					; FUNCTION TRANSFER TABLE
  5913 0000266B [24280000]          <1> 	dd	DISK_RESET		; 000H
  5914 0000266F [99280000]          <1> 	dd	RETURN_STATUS		; 001H
  5915 00002673 [A6280000]          <1> 	dd	DISK_READ		; 002H
  5916 00002677 [AF280000]          <1> 	dd	DISK_WRITE		; 003H
  5917 0000267B [B8280000]          <1> 	dd	DISK_VERF		; 004H
  5918 0000267F [D0280000]          <1> 	dd	FMT_TRK 		; 005H
  5919 00002683 [1A280000]          <1> 	dd	BAD_COMMAND		; 006H	FORMAT BAD SECTORS
  5920 00002687 [1A280000]          <1> 	dd	BAD_COMMAND		; 007H	FORMAT DRIVE
  5921 0000268B [1A280000]          <1> 	dd	BAD_COMMAND		; 008H	RETURN PARAMETERS
  5922 0000268F [91290000]          <1> 	dd	INIT_DRV		; 009H
  5923 00002693 [F0290000]          <1> 	dd	RD_LONG 		; 00AH
  5924 00002697 [F9290000]          <1> 	dd	WR_LONG 		; 00BH
  5925 0000269B [022A0000]          <1> 	dd	DISK_SEEK		; 00CH
  5926 0000269F [24280000]          <1> 	dd	DISK_RESET		; 00DH
  5927 000026A3 [1A280000]          <1> 	dd	BAD_COMMAND		; 00EH	READ BUFFER
  5928 000026A7 [1A280000]          <1> 	dd	BAD_COMMAND		; 00FH	WRITE BUFFER
  5929 000026AB [2A2A0000]          <1> 	dd	TST_RDY 		; 010H
  5930 000026AF [4E2A0000]          <1> 	dd	HDISK_RECAL		; 011H
  5931 000026B3 [1A280000]          <1> 	dd	BAD_COMMAND		; 012H	MEMORY DIAGNOSTIC
  5932 000026B7 [1A280000]          <1> 	dd	BAD_COMMAND		; 013H	DRIVE DIAGNOSTIC
  5933 000026BB [842A0000]          <1> 	dd	CTLR_DIAGNOSTIC 	; 014H	CONTROLLER DIAGNOSTIC
  5934                              <1> 	; 02/02/2015 (Temporary - Retro UNIX 386 v1 - DISK I/O test)
  5935 000026BF [1A280000]          <1> 	dd	BAD_COMMAND		; 015h
  5936 000026C3 [1A280000]          <1> 	dd	BAD_COMMAND		; 016h
  5937 000026C7 [1A280000]          <1> 	dd	BAD_COMMAND		; 017h
  5938 000026CB [1A280000]          <1> 	dd	BAD_COMMAND		; 018h
  5939 000026CF [1A280000]          <1> 	dd	BAD_COMMAND		; 019h
  5940 000026D3 [1A280000]          <1> 	dd	BAD_COMMAND		; 01Ah
  5941 000026D7 [A6280000]          <1> 	dd	DISK_READ		; 01Bh ; LBA read
  5942 000026DB [AF280000]          <1> 	dd	DISK_WRITE		; 01Ch ; LBA write
  5943                              <1> M1L     EQU    $-M1
  5944                              <1> 
  5945                              <1> DISK_IO_CONT:
  5946                              <1> 	;;CALL	DDS			; ESTABLISH SEGMENT
  5947 000026DF 80FC01              <1> 	CMP	AH,01H			; RETURN STATUS
  5948                              <1> 	;;JNZ	short SU0
  5949                              <1>         ;;JMP	RETURN_STATUS
  5950                              <1> 	;je	RETURN_STATUS
  5951                              <1> 	; 24/12/2021
  5952 000026E2 7505                <1> 	jne	short SU0
  5953 000026E4 E9B0010000          <1> 	jmp	RETURN_STATUS
  5954                              <1> SU0:
  5955 000026E9 C605[6F6B0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; RESET THE STATUS INDICATOR
  5956                              <1> 	;;PUSH	BX			; SAVE DATA ADDRESS
  5957                              <1> 	;mov	si, bx ;; 14/02/2015
  5958 000026F0 89DE                <1> 	mov	esi, ebx ; 21/02/2015
  5959 000026F2 8A1D[706B0000]      <1> 	MOV	BL,[HF_NUM]		; GET NUMBER OF DRIVES
  5960                              <1> 	;; 04/01/2015
  5961                              <1> 	;;PUSH	AX
  5962 000026F8 80E27F              <1> 	AND	DL,7FH			; GET DRIVE AS 0 OR 1
  5963                              <1> 					; (get drive number as 0 to 3)
  5964 000026FB 38D3                <1> 	CMP	BL,DL
  5965                              <1>         ;;JBE   BAD_COMMAND_POP         ; INVALID DRIVE
  5966                              <1>         ;jbe    BAD_COMMAND ;; 14/02/2015
  5967                              <1> 	; 24/12/2021
  5968 000026FD 7705                <1> 	ja	short su0_su1
  5969 000026FF E916010000          <1> 	jmp	BAD_COMMAND
  5970                              <1> su0_su1:
  5971                              <1>         ;;03/01/2015
  5972 00002704 29DB                <1> 	sub	ebx, ebx
  5973 00002706 88D3                <1> 	mov	bl, dl
  5974                              <1> 	;sub	bh, bh
  5975 00002708 883D[846B0000]      <1> 	mov	[LBAMode], bh 	; 0
  5976                              <1> 	;;test	byte [bx+hd0_type], 1	; LBA ready ?
  5977                              <1> 	;test	byte [ebx+hd0_type], 1
  5978                              <1> 	;jz	short su1		; no
  5979                              <1> 	;inc	byte [LBAMode]
  5980                              <1> ;su1:
  5981                              <1> 	; 21/02/2015 (32 bit modification)
  5982                              <1> 	; 04/01/2015
  5983                              <1> 	;push	ax ; ***
  5984                              <1> 	; 24/12/2021
  5985 0000270E 50                  <1> 	push	eax ; ***
  5986                              <1> 	;PUSH	ES ; **
  5987                              <1> 	;PUSH	DX ; *
  5988                              <1> 	; 24/12/2021
  5989 0000270F 52                  <1> 	push	edx ; *
  5990                              <1> 	;push	ax
  5991 00002710 50                  <1> 	push	eax
  5992 00002711 E849060000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETERS
  5993                              <1> 	; 02/02/2015
  5994                              <1> 	;mov	ax, [ES:BX+16] ; I/O port base address (1F0h, 170h)
  5995 00002716 668B4310            <1> 	mov	ax, [ebx+16]
  5996 0000271A 66A3[C4650000]      <1> 	mov	[HF_PORT], ax
  5997                              <1> 	;mov	dx, [ES:BX+18] ; control port address (3F6h, 376h)
  5998 00002720 668B5312            <1> 	mov	dx, [ebx+18]
  5999 00002724 668915[C6650000]    <1> 	mov	[HF_REG_PORT], dx
  6000                              <1> 	;mov	al, [ES:BX+20] ; head register upper nibble (A0h,B0h,E0h,F0h)
  6001 0000272B 8A4314              <1> 	mov	al, [ebx+20]
  6002                              <1> 	; 23/02/2015
  6003 0000272E A840                <1> 	test	al, 40h	 ; LBA bit (bit 6)
  6004 00002730 7406                <1> 	jz 	short su1
  6005 00002732 FE05[846B0000]      <1> 	inc	byte [LBAMode] ; 1 
  6006                              <1> su1: 	 
  6007 00002738 C0E804              <1> 	shr 	al, 4
  6008 0000273B 2401                <1> 	and	al, 1			
  6009 0000273D A2[C8650000]        <1> 	mov	[hf_m_s], al 
  6010                              <1> 	;
  6011                              <1> 	; 03/01/2015
  6012                              <1> 	;MOV	AL,byte [ES:BX+8]	; GET CONTROL BYTE MODIFIER
  6013 00002742 8A4308              <1> 	mov	al, [ebx+8]
  6014                              <1> 	;MOV	DX,[HF_REG_PORT]	; Device Control register	
  6015 00002745 EE                  <1> 	OUT	DX,AL			; SET EXTRA HEAD OPTION
  6016                              <1> 					; Control Byte:  (= 08h, here)
  6017                              <1> 					; bit 0 - 0
  6018                              <1> 					; bit 1 - nIEN (1 = disable irq)
  6019                              <1> 					; bit 2 - SRST (software RESET)
  6020                              <1> 					; bit 3 - use extra heads (8 to 15)
  6021                              <1> 					;         -always set to 1-	
  6022                              <1> 					; (bits 3 to 7 are reserved
  6023                              <1> 					;          for ATA devices)
  6024 00002746 8A25[716B0000]      <1> 	MOV	AH,[CONTROL_BYTE]	; SET EXTRA HEAD OPTION IN
  6025 0000274C 80E4C0              <1> 	AND	AH,0C0H 		; CONTROL BYTE
  6026 0000274F 08C4                <1> 	OR	AH,AL
  6027 00002751 8825[716B0000]      <1> 	MOV	[CONTROL_BYTE],AH	
  6028                              <1> 	; 04/01/2015
  6029                              <1> 	;pop	ax
  6030                              <1> 	; 24/12/2021
  6031 00002757 58                  <1> 	pop	eax
  6032                              <1> 	;pop	dx ; * ;; 14/02/2015
  6033                              <1> 	; 24/12/2021
  6034 00002758 5A                  <1> 	pop	edx ; *
  6035 00002759 20E4                <1> 	and	ah, ah	; Reset function ?
  6036 0000275B 7506                <1> 	jnz	short su2
  6037                              <1> 	;;pop	dx ; * ;; 14/02/2015
  6038                              <1> 	;pop	es ; **
  6039                              <1> 	;pop	ax ; ***
  6040                              <1> 	; 24/12/2021
  6041 0000275D 58                  <1> 	pop	eax ; ***	
  6042                              <1> 	;;pop	bx
  6043 0000275E E9C1000000          <1>         jmp     DISK_RESET
  6044                              <1> su2:
  6045 00002763 803D[846B0000]00    <1> 	cmp	byte [LBAMode], 0
  6046 0000276A 765E                <1> 	jna	short su3
  6047                              <1> 	;
  6048                              <1> 	; 02/02/2015 (LBA read/write function calls)
  6049 0000276C 80FC1B              <1> 	cmp	ah, 1Bh
  6050 0000276F 720B                <1> 	jb	short lbarw1
  6051 00002771 80FC1C              <1> 	cmp	ah, 1Ch
  6052 00002774 7759                <1> 	ja 	short invldfnc
  6053                              <1> 	;;pop	dx ; * ; 14/02/2015
  6054                              <1> 	;mov	ax, cx ; Lower word of LBA address (bits 0-15)
  6055 00002776 89C8                <1> 	mov	eax, ecx ; LBA address (21/02/2015)
  6056                              <1> 	;; 14/02/2015
  6057 00002778 88D1                <1> 	mov	cl, dl ; 14/02/2015
  6058                              <1> 	;;mov	dx, bx
  6059                              <1> 	;mov	dx, si ; higher word of LBA address (bits 16-23)
  6060                              <1> 	;;mov	bx, di
  6061                              <1> 	;mov	si, di ; Buffer offset
  6062 0000277A EB2E                <1> 	jmp	short lbarw2
  6063                              <1> lbarw1:
  6064                              <1> 	; convert CHS to LBA
  6065                              <1> 	;
  6066                              <1> 	; LBA calculation - AWARD BIOS - 1999 - AHDSK.ASM
  6067                              <1> 	; LBA = "# of Heads" * Sectors/Track * Cylinder + Head * Sectors/Track
  6068                              <1> 	;	+ Sector - 1
  6069                              <1> 	;push	dx ; * ;; 14/02/2015
  6070                              <1> 	; 24/12/2021
  6071 0000277C 52                  <1> 	push	edx ; *
  6072                              <1> 	;xor	dh, dh
  6073 0000277D 31D2                <1> 	xor	edx, edx
  6074                              <1> 	;mov	dl, [ES:BX+14]	; sectors per track (logical)
  6075 0000277F 8A530E              <1> 	mov	dl, [ebx+14]
  6076                              <1> 	;xor	ah, ah
  6077 00002782 31C0                <1> 	xor	eax, eax
  6078                              <1> 	;mov	al, [ES:BX+2]	; heads (logical) 	
  6079 00002784 8A4302              <1> 	mov	al, [ebx+2]
  6080 00002787 FEC8                <1> 	dec	al
  6081                              <1> 	;inc	ax		; 0 =  256
  6082 00002789 40                  <1> 	inc	eax ; 24/12/2021
  6083 0000278A 66F7E2              <1> 	mul 	dx
  6084                              <1> 		; AX = # of Heads" * Sectors/Track
  6085 0000278D 6689CA              <1> 	mov	dx, cx
  6086                              <1> 	;and	cx, 3Fh	 ; sector  (1 to 63)
  6087 00002790 83E13F              <1> 	and	ecx, 3fh
  6088 00002793 86D6                <1> 	xchg	dl, dh
  6089 00002795 C0EE06              <1> 	shr	dh, 6
  6090                              <1> 		; DX = cylinder (0 to 1023)
  6091                              <1> 	;mul 	dx
  6092                              <1> 		; DX:AX = # of Heads" * Sectors/Track * Cylinder
  6093 00002798 F7E2                <1> 	mul	edx
  6094 0000279A FEC9                <1> 	dec	cl  ; sector - 1
  6095                              <1> 	;add	ax, cx
  6096                              <1> 	;adc	dx, 0
  6097                              <1> 		; DX:AX = # of Heads" * Sectors/Track * Cylinder + Sector -1
  6098 0000279C 01C8                <1> 	add	eax, ecx
  6099                              <1> 	;pop	cx ; * ; ch = head, cl = drive number (zero based)
  6100                              <1> 	; 24/12/2021
  6101 0000279E 59                  <1> 	pop	ecx ; * ; ch = head, cl = drive number (zero based)
  6102                              <1> 	;push	dx
  6103                              <1> 	;push	ax
  6104 0000279F 50                  <1> 	push	eax
  6105                              <1> 	;mov	al, [ES:BX+14]	; sectors per track (logical)	
  6106 000027A0 8A430E              <1> 	mov	al, [ebx+14]
  6107 000027A3 F6E5                <1> 	mul	ch
  6108                              <1> 		; AX = Head * Sectors/Track
  6109 000027A5 6699                <1>         cwd
  6110                              <1> 	;pop	dx
  6111 000027A7 5A                  <1> 	pop	edx
  6112                              <1> 	;add	ax, dx
  6113                              <1> 	;pop	dx
  6114                              <1> 	;adc	dx, 0 ; add carry bit
  6115 000027A8 01D0                <1> 	add	eax, edx
  6116                              <1> lbarw2:
  6117 000027AA 29D2                <1> 	sub	edx, edx ; 21/02/2015
  6118 000027AC 88CA                <1> 	mov	dl, cl ; 21/02/2015
  6119 000027AE C645F800            <1>         mov     byte [CMD_BLOCK], 0 ; Features Register
  6120                              <1> 				; NOTE: Features register (1F1h, 171h)
  6121                              <1> 				; is not used for ATA device R/W functions. 
  6122                              <1> 				; It is old/obsolete 'write precompensation'
  6123                              <1> 				; register and error register
  6124                              <1> 				; for old ATA/IDE devices.
  6125                              <1> 	; 18/01/2014
  6126                              <1> 	;mov	ch, [hf_m_s]	; Drive 0 (master) or 1 (slave)
  6127 000027B2 8A0D[C8650000]      <1> 	mov	cl, [hf_m_s]
  6128                              <1> 	;shl	ch, 4		; bit 4 (drive bit)
  6129                              <1> 	;or	ch, 0E0h	; bit 5 = 1
  6130                              <1> 				; bit 6 = 1 = LBA mode
  6131                              <1> 				; bit 7 = 1
  6132 000027B8 80C90E              <1> 	or	cl, 0Eh ; 1110b
  6133                              <1> 	;and	dh, 0Fh		; LBA byte 4 (bits 24 to 27)
  6134 000027BB 25FFFFFF0F          <1> 	and	eax, 0FFFFFFFh
  6135 000027C0 C1E11C              <1> 	shl	ecx, 28 ; 21/02/2015
  6136                              <1> 	;or	dh, ch
  6137 000027C3 09C8                <1> 	or	eax, ecx	
  6138                              <1> 	;;mov	[CMD_BLOCK+2], al ; LBA byte 1 (bits 0 to 7)
  6139                              <1> 				  ; (Sector Number Register)
  6140                              <1> 	;;mov	[CMD_BLOCK+3], ah ; LBA byte 2 (bits 8 to 15)
  6141                              <1> 				  ; (Cylinder Low Register)
  6142                              <1> 	;mov	[CMD_BLOCK+2], ax ; LBA byte 1, 2
  6143                              <1> 	;mov	[CMD_BLOCK+4], dl ; LBA byte 3 (bits 16 to 23)
  6144                              <1> 				  ; (Cylinder High Register)
  6145                              <1> 	;;mov	[CMD_BLOCK+5], dh ; LBA byte 4 (bits 24 to 27)
  6146                              <1> 				  ; (Drive/Head Register)
  6147                              <1> 	
  6148                              <1> 	;mov	[CMD_BLOCK+4], dx ; LBA byte 4, LBA & DEV select bits
  6149 000027C5 8945FA              <1> 	mov	[CMD_BLOCK+2], eax ; 21/02/2015
  6150                              <1> 	;14/02/2015
  6151                              <1> 	;mov	dl, cl ; Drive number (INIT_DRV)		
  6152 000027C8 EB37                <1> 	jmp	short su4
  6153                              <1> su3:
  6154                              <1> 	; 02/02/2015 
  6155                              <1> 	; (Temporary functions 1Bh & 1Ch are not valid for CHS mode) 
  6156 000027CA 80FC14              <1> 	cmp 	ah, 14h
  6157 000027CD 7603                <1> 	jna 	short chsfnc
  6158                              <1> invldfnc:
  6159                              <1>         ; 14/02/2015  
  6160                              <1> 	;pop	es ; **
  6161                              <1>         ;pop	ax ; ***
  6162                              <1>         ; 24/12/2021
  6163 000027CF 58                  <1> 	pop	eax ; ***
  6164                              <1> 	;jmp	short BAD_COMMAND_POP
  6165 000027D0 EB48                <1>         jmp     short BAD_COMMAND
  6166                              <1> chsfnc:	
  6167                              <1> 	;MOV	AX,[ES:BX+5]		; GET WRITE PRE-COMPENSATION CYLINDER
  6168 000027D2 668B4305            <1> 	mov	ax, [ebx+5]
  6169 000027D6 66C1E802            <1> 	SHR	AX,2
  6170 000027DA 8845F8              <1> 	MOV	[CMD_BLOCK],AL
  6171                              <1> 	;;MOV	AL,[ES:BX+8]		; GET CONTROL BYTE MODIFIER
  6172                              <1> 	;;PUSH	DX
  6173                              <1> 	;;MOV	DX,[HF_REG_PORT]
  6174                              <1> 	;;OUT	DX,AL			; SET EXTRA HEAD OPTION
  6175                              <1> 	;;POP	DX ; * 
  6176                              <1> 	;;POP	ES ; **
  6177                              <1> 	;;MOV	AH,[CONTROL_BYTE]	; SET EXTRA HEAD OPTION IN
  6178                              <1> 	;;AND	AH,0C0H 		; CONTROL BYTE	
  6179                              <1> 	;;OR	AH,AL
  6180                              <1> 	;;MOV	[CONTROL_BYTE],AH
  6181                              <1> 	;
  6182 000027DD 88C8                <1> 	MOV	AL,CL			; GET SECTOR NUMBER
  6183 000027DF 243F                <1> 	AND	AL,3FH
  6184 000027E1 8845FA              <1> 	MOV	[CMD_BLOCK+2],AL
  6185 000027E4 886DFB              <1> 	MOV	[CMD_BLOCK+3],CH 	; GET CYLINDER NUMBER
  6186 000027E7 88C8                <1> 	MOV	AL,CL
  6187 000027E9 C0E806              <1> 	SHR	AL,6
  6188 000027EC 8845FC              <1> 	MOV	[CMD_BLOCK+4],AL 	; CYLINDER HIGH ORDER 2 BITS
  6189                              <1> 	;;05/01/2015
  6190                              <1> 	;;MOV	AL,DL			; DRIVE NUMBER
  6191 000027EF A0[C8650000]        <1> 	mov	al, [hf_m_s]
  6192 000027F4 C0E004              <1> 	SHL	AL,4
  6193 000027F7 80E60F              <1> 	AND	DH,0FH			; HEAD NUMBER
  6194 000027FA 08F0                <1> 	OR	AL,DH
  6195                              <1> 	;OR	AL,80H or 20H
  6196 000027FC 0CA0                <1> 	OR	AL,80h+20h		; ECC AND 512 BYTE SECTORS
  6197 000027FE 8845FD              <1> 	MOV	[CMD_BLOCK+5],AL 	; ECC/SIZE/DRIVE/HEAD
  6198                              <1> su4:
  6199                              <1> 	;POP	ES ; **
  6200                              <1>         ;; 14/02/2015
  6201                              <1>         ;;POP   AX
  6202                              <1>         ;;MOV   [CMD_BLOCK+1],AL        ; SECTOR COUNT
  6203                              <1>         ;;PUSH  AX
  6204                              <1>         ;;MOV   AL,AH                   ; GET INTO LOW BYTE
  6205                              <1>         ;;XOR   AH,AH                   ; ZERO HIGH BYTE
  6206                              <1>         ;;SAL   AX,1                    ; *2 FOR TABLE LOOKUP
  6207                              <1> 	;pop     ax ; ***
  6208                              <1> 	; 24/12/2021
  6209 00002801 58                  <1> 	pop	eax ; ***
  6210 00002802 8845F9              <1> 	mov     [CMD_BLOCK+1], al
  6211 00002805 29DB                <1>         sub	ebx, ebx
  6212 00002807 88E3                <1> 	mov     bl, ah
  6213                              <1>         ;xor	bh, bh
  6214                              <1>         ;sal	bx, 1
  6215 00002809 66C1E302            <1>         sal	bx, 2	; 32 bit offset (21/02/2015)
  6216                              <1> 	;;MOV   SI,AX                   ; PUT INTO SI FOR BRANCH
  6217                              <1>         ;;CMP   AX,M1L                  ; TEST WITHIN RANGE
  6218                              <1>         ;;JNB   short BAD_COMMAND_POP
  6219                              <1>         ;cmp	bx, M1L
  6220 0000280D 83FB74              <1> 	cmp	ebx, M1L
  6221 00002810 7308                <1> 	jnb	short BAD_COMMAND
  6222                              <1>         ;xchg	bx, si
  6223 00002812 87DE                <1>         xchg	ebx, esi
  6224                              <1> 	;;;POP	AX			; RESTORE AX
  6225                              <1> 	;;;POP	BX			; AND DATA ADDRESS
  6226                              <1> 	
  6227                              <1> 	;;PUSH	CX
  6228                              <1> 	;;PUSH	AX			; ADJUST ES:BX
  6229                              <1> 	;MOV	CX,BX			; GET 3 HIGH ORDER NIBBLES OF BX
  6230                              <1> 	;SHR	CX,4
  6231                              <1> 	;MOV	AX,ES
  6232                              <1> 	;ADD	AX,CX
  6233                              <1> 	;MOV	ES,AX
  6234                              <1> 	;AND	BX,000FH		; ES:BX CHANGED TO ES:000X
  6235                              <1> 	;;POP	AX
  6236                              <1> 	;;POP	CX
  6237                              <1> 	;;JMP	word [CS:SI+M1]
  6238                              <1> 	;jmp	word [SI+M1]
  6239 00002814 FFA6[6B260000]      <1> 	jmp	dword [esi+M1]
  6240                              <1> ;;BAD_COMMAND_POP:
  6241                              <1> ;;	POP	AX
  6242                              <1> ;;	POP	BX
  6243                              <1> BAD_COMMAND:
  6244 0000281A C605[6F6B0000]01    <1>         MOV     byte [DISK_STATUS1],BAD_CMD  ; COMMAND ERROR
  6245 00002821 B000                <1> 	MOV	AL,0
  6246 00002823 C3                  <1> 	RETn
  6247                              <1> 
  6248                              <1> ;----------------------------------------
  6249                              <1> ;	RESET THE DISK SYSTEM  (AH=00H) :
  6250                              <1> ;----------------------------------------
  6251                              <1> 
  6252                              <1> ; 18-1-2015 : one controller reset (not other one)
  6253                              <1> 
  6254                              <1> DISK_RESET:
  6255 00002824 FA                  <1> 	CLI
  6256 00002825 E4A1                <1> 	IN	AL,INTB01		; GET THE MASK REGISTER
  6257                              <1> 	;JMP	$+2
  6258                              <1> 	IODELAY
  2145 00002827 EB00                <2>  jmp short $+2
  2146 00002829 EB00                <2>  jmp short $+2
  6259                              <1> 	;AND	AL,0BFH 		; ENABLE FIXED DISK INTERRUPT
  6260 0000282B 243F                <1> 	and	al,3Fh			; 22/12/2014 (IRQ 14 & IRQ 15)
  6261 0000282D E6A1                <1> 	OUT	INTB01,AL
  6262 0000282F FB                  <1> 	STI				; START INTERRUPTS
  6263                              <1> 	; 14/02/2015
  6264                              <1> 	;mov	di, dx
  6265                              <1> 	; 24/12/2021
  6266 00002830 89D7                <1> 	mov	edi, edx	
  6267                              <1> 	; 04/01/2015
  6268                              <1> 	;xor	di,di
  6269                              <1> drst0:
  6270 00002832 B004                <1> 	MOV	AL,04H  ; bit 2 - SRST 
  6271                              <1> 	;MOV	DX,HF_REG_PORT
  6272 00002834 668B15[C6650000]    <1> 	MOV	DX,[HF_REG_PORT]
  6273 0000283B EE                  <1> 	OUT	DX,AL			; RESET
  6274                              <1> ;	MOV	CX,10			; DELAY COUNT
  6275                              <1> ;DRD:	DEC	CX
  6276                              <1> ;	JNZ	short DRD		; WAIT 4.8 MICRO-SEC
  6277                              <1> 	;mov	cx,2			; wait for 30 micro seconds	
  6278 0000283C B902000000          <1>         mov	ecx, 2 ; 21/02/2015
  6279 00002841 E877ECFFFF          <1> 	call    WAITF                   ; (Award Bios 1999 - WAIT_REFRESH,
  6280                              <1>                                         ; 40 micro seconds)
  6281 00002846 A0[716B0000]        <1> 	mov	al,[CONTROL_BYTE]
  6282 0000284B 240F                <1> 	AND	AL,0FH			; SET HEAD OPTION
  6283 0000284D EE                  <1> 	OUT	DX,AL			; TURN RESET OFF
  6284 0000284E E807040000          <1> 	CALL	NOT_BUSY
  6285 00002853 7515                <1> 	JNZ	short DRERR		; TIME OUT ON RESET
  6286 00002855 668B15[C4650000]    <1> 	MOV	DX,[HF_PORT]
  6287 0000285C FEC2                <1> 	inc	dl  ; HF_PORT+1
  6288                              <1> 	; 02/01/2015 - Award BIOS 1999 - AHDSK.ASM
  6289                              <1>         ;mov	cl, 10
  6290 0000285E B90A000000          <1>         mov     ecx, 10 ; 21/02/2015 
  6291                              <1> drst1:
  6292 00002863 EC                  <1> 	IN	AL,DX			; GET RESET STATUS
  6293 00002864 3C01                <1> 	CMP	AL,1
  6294                              <1> 	; 04/01/2015
  6295 00002866 740A                <1> 	jz	short drst2
  6296                              <1> 	;JNZ	short DRERR		; BAD RESET STATUS
  6297                              <1>         	; Drive/Head Register - bit 4
  6298 00002868 E2F9                <1> 	loop	drst1
  6299                              <1> DRERR:	
  6300 0000286A C605[6F6B0000]05    <1> 	MOV	byte [DISK_STATUS1],BAD_RESET ; CARD FAILED
  6301 00002871 C3                  <1> 	RETn
  6302                              <1> drst2:
  6303                              <1> 	; 14/02/2015
  6304                              <1> 	;mov	dx, di
  6305                              <1> 	; 24/12/2021
  6306 00002872 89FA                <1> 	mov	edx, edi
  6307                              <1> ;drst3:
  6308                              <1> ;	; 05/01/2015
  6309                              <1> ;	shl 	di,1
  6310                              <1> ;	; 04/01/2015
  6311                              <1> ;	mov	ax,[di+hd_cports]
  6312                              <1> ;	cmp	ax,[HF_REG_PORT]
  6313                              <1> ;	je	short drst4
  6314                              <1> ;	mov	[HF_REG_PORT], ax
  6315                              <1> ;	; 03/01/2015
  6316                              <1> ;	mov	ax,[di+hd_ports]
  6317                              <1> ;       mov     [HF_PORT], ax
  6318                              <1> ;	; 05/01/2014
  6319                              <1> ;	shr	di,1
  6320                              <1> ;	; 04/01/2015
  6321                              <1> ;	jmp	short drst0	; reset other controller
  6322                              <1> ;drst4:
  6323                              <1> ;	; 05/01/2015
  6324                              <1> ;	shr	di,1
  6325                              <1> ;	mov	al,[di+hd_dregs]
  6326                              <1> ;	and	al,10h ; bit 4 only
  6327                              <1> ;	shr	al,4 ; bit 4  -> bit 0
  6328                              <1> ;	mov	[hf_m_s], al ; (0 = master, 1 = slave)
  6329                              <1> 	;
  6330 00002874 A0[C8650000]        <1> 	mov	al, [hf_m_s] ; 18/01/2015
  6331 00002879 A801                <1> 	test	al,1
  6332                              <1> ;	jnz	short drst6
  6333 0000287B 7516                <1>         jnz     short drst4
  6334 0000287D 8065FDEF            <1> 	AND     byte [CMD_BLOCK+5],0EFH ; SET TO DRIVE 0
  6335                              <1> ;drst5:
  6336                              <1> drst3:
  6337 00002881 E80B010000          <1> 	CALL	INIT_DRV		; SET MAX HEADS
  6338                              <1> 	;mov	dx,di
  6339 00002886 E8C3010000          <1> 	CALL	HDISK_RECAL		; RECAL TO RESET SEEK SPEED
  6340                              <1> 	; 04/01/2014
  6341                              <1> ;	inc	di
  6342                              <1> ;	mov	dx,di
  6343                              <1> ;	cmp	dl,[HF_NUM]
  6344                              <1> ;	jb	short drst3
  6345                              <1> ;DRE:
  6346 0000288B C605[6F6B0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; IGNORE ANY SET UP ERRORS
  6347 00002892 C3                  <1> 	RETn
  6348                              <1> ;drst6:
  6349                              <1> drst4:		; Drive/Head Register - bit 4
  6350 00002893 804DFD10            <1> 	OR      byte [CMD_BLOCK+5],010H ; SET TO DRIVE 1     
  6351                              <1>         ;jmp    short drst5
  6352 00002897 EBE8                <1>         jmp     short drst3
  6353                              <1> 
  6354                              <1> ;----------------------------------------
  6355                              <1> ;	DISK STATUS ROUTINE  (AH = 01H) :
  6356                              <1> ;----------------------------------------
  6357                              <1> 
  6358                              <1> RETURN_STATUS:
  6359 00002899 A0[6F6B0000]        <1> 	MOV	AL,[DISK_STATUS1]	; OBTAIN PREVIOUS STATUS
  6360 0000289E C605[6F6B0000]00    <1>         MOV     byte [DISK_STATUS1],0   ; RESET STATUS
  6361 000028A5 C3                  <1> 	RETn
  6362                              <1> 
  6363                              <1> ;----------------------------------------
  6364                              <1> ;	DISK READ ROUTINE    (AH = 02H) :
  6365                              <1> ;----------------------------------------
  6366                              <1> 
  6367                              <1> DISK_READ:
  6368 000028A6 C645FE20            <1> 	MOV	byte [CMD_BLOCK+6],READ_CMD
  6369 000028AA E92A020000          <1>         JMP     COMMANDI
  6370                              <1> 
  6371                              <1> ;----------------------------------------
  6372                              <1> ;	DISK WRITE ROUTINE   (AH = 03H) :
  6373                              <1> ;----------------------------------------
  6374                              <1> 
  6375                              <1> DISK_WRITE:
  6376 000028AF C645FE30            <1> 	MOV	byte [CMD_BLOCK+6],WRITE_CMD
  6377 000028B3 E976020000          <1>         JMP     COMMANDO
  6378                              <1> 
  6379                              <1> ;----------------------------------------
  6380                              <1> ;	DISK VERIFY	     (AH = 04H) :
  6381                              <1> ;----------------------------------------
  6382                              <1> 
  6383                              <1> DISK_VERF:
  6384 000028B8 C645FE40            <1> 	MOV	byte [CMD_BLOCK+6],VERIFY_CMD
  6385 000028BC E8E4020000          <1> 	CALL	COMMAND
  6386 000028C1 750C                <1> 	JNZ	short VERF_EXIT		; CONTROLLER STILL BUSY
  6387 000028C3 E856030000          <1> 	CALL	_WAIT			; (Original: CALL WAIT)	
  6388 000028C8 7505                <1> 	JNZ	short VERF_EXIT		; TIME OUT
  6389 000028CA E8E3030000          <1> 	CALL	CHECK_STATUS
  6390                              <1> VERF_EXIT:
  6391 000028CF C3                  <1> 	RETn
  6392                              <1> 
  6393                              <1> ;----------------------------------------
  6394                              <1> ;	FORMATTING	     (AH = 05H) :
  6395                              <1> ;----------------------------------------
  6396                              <1> 
  6397                              <1> FMT_TRK:				; FORMAT TRACK	(AH = 005H)
  6398 000028D0 C645FE50            <1> 	MOV	byte [CMD_BLOCK+6],FMTTRK_CMD
  6399                              <1> 	;PUSH	ES
  6400                              <1> 	;PUSH	BX
  6401 000028D4 53                  <1> 	push	ebx
  6402 000028D5 E885040000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETERS ADDRESS
  6403                              <1> 	;MOV	AL,[ES:BX+14]		; GET SECTORS/TRACK
  6404 000028DA 8A430E              <1> 	mov	al, [ebx+14]
  6405 000028DD 8845F9              <1> 	MOV	[CMD_BLOCK+1],AL 	; SET SECTOR COUNT IN COMMAND
  6406 000028E0 5B                  <1> 	pop	ebx
  6407                              <1> 	;POP	BX
  6408                              <1> 	;POP	ES
  6409 000028E1 E94F020000          <1>         JMP     CMD_OF                  ; GO EXECUTE THE COMMAND
  6410                              <1> 
  6411                              <1> ;----------------------------------------
  6412                              <1> ;	READ DASD TYPE	     (AH = 15H) :
  6413                              <1> ;----------------------------------------
  6414                              <1> 
  6415                              <1> READ_DASD_TYPE:
  6416                              <1> READ_D_T:				; GET DRIVE PARAMETERS
  6417 000028E6 1E                  <1> 	PUSH	DS			; SAVE REGISTERS
  6418                              <1> 	;PUSH	ES
  6419 000028E7 53                  <1> 	PUSH	eBX
  6420                              <1> 	;CALL	DDS			; ESTABLISH ADDRESSING
  6421                              <1> 	;push	cs
  6422                              <1> 	;pop	ds
  6423 000028E8 66BB1000            <1>         mov	bx, KDATA
  6424 000028EC 8EDB                <1> 	mov	ds, bx
  6425                              <1> 	;mov	es, bx
  6426 000028EE C605[6F6B0000]00    <1> 	MOV     byte [DISK_STATUS1],0
  6427 000028F5 8A1D[706B0000]      <1> 	MOV	BL,[HF_NUM]		; GET NUMBER OF DRIVES
  6428 000028FB 80E27F              <1> 	AND	DL,7FH			; GET DRIVE NUMBER
  6429 000028FE 38D3                <1> 	CMP	BL,DL
  6430 00002900 7625                <1> 	JBE	short RDT_NOT_PRESENT 	; RETURN DRIVE NOT PRESENT
  6431 00002902 E858040000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETER ADDRESS
  6432                              <1> 	;MOV	AL,[ES:BX+2]		; HEADS
  6433 00002907 8A4302              <1> 	mov	al, [ebx+2]
  6434                              <1> 	;MOV	CL,[ES:BX+14]
  6435 0000290A 8A4B0E              <1> 	mov	cl, [ebx+14]
  6436 0000290D F6E9                <1> 	IMUL	CL			; * NUMBER OF SECTORS
  6437                              <1> 	;MOV	CX,[ES:BX]		; MAX NUMBER OF CYLINDERS
  6438 0000290F 668B0B              <1> 	mov	cx, [ebx]
  6439                              <1> 	;
  6440                              <1> 	; 02/01/2015 
  6441                              <1> 	; ** leave the last cylinder as reserved for diagnostics **
  6442                              <1> 	; (Also in Award BIOS - 1999, AHDSK.ASM, FUN15 -> sub ax, 1)
  6443 00002912 6649                <1> 	DEC	CX			; LEAVE ONE FOR DIAGNOSTICS
  6444                              <1> 	;
  6445 00002914 66F7E9              <1> 	IMUL	CX			; NUMBER OF SECTORS
  6446 00002917 6689D1              <1> 	MOV	CX,DX			; HIGH ORDER HALF
  6447 0000291A 6689C2              <1> 	MOV	DX,AX			; LOW ORDER HALF
  6448                              <1> 	;SUB	AX,AX
  6449 0000291D 28C0                <1> 	sub	al, al
  6450 0000291F B403                <1> 	MOV	AH,03H			; INDICATE FIXED DISK
  6451 00002921 5B                  <1> RDT2:	POP	eBX			; RESTORE REGISTERS
  6452                              <1> 	;POP	ES
  6453 00002922 1F                  <1> 	POP	DS
  6454 00002923 F8                  <1> 	CLC				; CLEAR CARRY
  6455                              <1> 	;RETf	2
  6456 00002924 CA0400              <1> 	retf	4
  6457                              <1> RDT_NOT_PRESENT:
  6458                              <1> 	;SUB	AX,AX			; DRIVE NOT PRESENT RETURN
  6459                              <1> 	; 24/12/2021
  6460 00002927 29C0                <1> 	sub	eax, eax
  6461                              <1> 	;MOV	CX,AX			; ZERO BLOCK COUNT
  6462                              <1> 	;MOV	DX,AX
  6463 00002929 89C1                <1> 	mov	ecx, eax
  6464 0000292B 89C2                <1> 	mov	edx, eax
  6465 0000292D EBF2                <1> 	JMP	short RDT2
  6466                              <1> 
  6467                              <1> ;----------------------------------------
  6468                              <1> ;	GET PARAMETERS	     (AH = 08H) :
  6469                              <1> ;----------------------------------------
  6470                              <1> 
  6471                              <1> GET_PARM_N:
  6472                              <1> ;GET_PARM:				; GET DRIVE PARAMETERS
  6473 0000292F 1E                  <1> 	PUSH	DS			; SAVE REGISTERS
  6474                              <1> 	;PUSH	ES
  6475 00002930 53                  <1> 	PUSH	eBX
  6476                              <1> 	;MOV	AX,ABS0 		; ESTABLISH ADDRESSING
  6477                              <1> 	;MOV	DS,AX
  6478                              <1> 	;TEST	DL,1			; CHECK FOR DRIVE 1
  6479                              <1> 	;JZ	short G0
  6480                              <1> 	;LES	BX,@HF1_TBL_VEC
  6481                              <1> 	;JMP	SHORT G1
  6482                              <1> ;G0:	LES	BX,@HF_TBL_VEC
  6483                              <1> ;G1:
  6484                              <1> 	;CALL	DDS			; ESTABLISH SEGMENT
  6485                              <1> 	; 22/12/2014
  6486                              <1> 	;push	cs
  6487                              <1> 	;pop	ds
  6488 00002931 66BB1000            <1> 	mov	bx, KDATA
  6489 00002935 8EDB                <1> 	mov	ds, bx
  6490                              <1> 	;mov	es, bx
  6491                              <1> 	;
  6492 00002937 80EA80              <1> 	SUB	DL,80H
  6493 0000293A 80FA04              <1> 	CMP	DL,MAX_FILE		; TEST WITHIN RANGE
  6494 0000293D 7340                <1> 	JAE	short G4
  6495                              <1> 	;
  6496 0000293F 31DB                <1> 	xor	ebx, ebx ; 21/02/2015
  6497                              <1> 	; 22/12/2014
  6498 00002941 88D3                <1> 	mov	bl, dl
  6499                              <1> 	;xor	bh, bh  
  6500 00002943 C0E302              <1> 	shl	bl, 2			; convert index to offset
  6501                              <1> 	;add	bx, HF_TBL_VEC
  6502 00002946 81C3[746B0000]      <1> 	add	ebx, HF_TBL_VEC
  6503                              <1> 	;mov	ax, [bx+2]
  6504                              <1> 	;mov	es, ax			; dpt segment
  6505                              <1> 	;mov	bx, [bx]		; dpt offset
  6506 0000294C 8B1B                <1> 	mov	ebx, [ebx] ; 32 bit offset	
  6507                              <1> 
  6508 0000294E C605[6F6B0000]00    <1> 	MOV	byte [DISK_STATUS1],0
  6509                              <1>         ;MOV     AX,[ES:BX]              ; MAX NUMBER OF CYLINDERS
  6510 00002955 668B03              <1> 	mov	ax, [ebx]
  6511                              <1> 	;;SUB	AX,2			; ADJUST FOR 0-N
  6512 00002958 6648                <1> 	dec	ax			; max. cylinder number
  6513 0000295A 88C5                <1> 	MOV	CH,AL
  6514 0000295C 66250003            <1> 	AND	AX,0300H		; HIGH TWO BITS OF CYLINDER
  6515 00002960 66D1E8              <1> 	SHR	AX,1
  6516 00002963 66D1E8              <1> 	SHR	AX,1
  6517                              <1> 	;OR	AL,[ES:BX+14]		; SECTORS
  6518 00002966 0A430E              <1> 	or	al, [ebx+14]
  6519 00002969 88C1                <1> 	MOV	CL,AL
  6520                              <1> 	;MOV	DH,[ES:BX+2]		; HEADS
  6521 0000296B 8A7302              <1> 	mov	dh, [ebx+2]
  6522 0000296E FECE                <1> 	DEC	DH			; 0-N RANGE
  6523 00002970 8A15[706B0000]      <1> 	MOV	DL,[HF_NUM]		; DRIVE COUNT
  6524                              <1> 	;SUB	AX,AX
  6525                              <1> 	; 24/12/2021
  6526 00002976 29C0                <1> 	sub	eax, eax
  6527                              <1> 	; 27/12/2014 
  6528                              <1> 	; ES:DI = Address of disk parameter table from BIOS
  6529                              <1> 	; (Programmer's Guide to the AMIBIOS - 1993)
  6530                              <1> 	;mov	di, bx			; HDPT offset
  6531 00002978 89DF                <1> 	mov	edi, ebx
  6532                              <1> G5:
  6533 0000297A 5B                  <1> 	POP	eBX			; RESTORE REGISTERS
  6534                              <1> 	;POP	ES
  6535 0000297B 1F                  <1> 	POP	DS
  6536                              <1> 	;RETf	2
  6537 0000297C CA0400              <1> 	retf	4
  6538                              <1> G4:
  6539 0000297F C605[6F6B0000]07    <1> 	MOV     byte [DISK_STATUS1],INIT_FAIL ; OPERATION FAILED
  6540                              <1> 	; 24/12/2021
  6541 00002986 29C0                <1> 	sub	eax, eax
  6542 00002988 B407                <1> 	MOV	AH,INIT_FAIL
  6543                              <1> 	;SUB	AL,AL
  6544                              <1> 	;SUB	DX,DX
  6545 0000298A 29D2                <1> 	sub	edx, edx
  6546                              <1> 	;SUB	CX,CX
  6547 0000298C 29C9                <1> 	sub	ecx, ecx
  6548 0000298E F9                  <1> 	STC				; SET ERROR FLAG
  6549 0000298F EBE9                <1> 	JMP	short G5
  6550                              <1> 
  6551                              <1> ;----------------------------------------
  6552                              <1> ;	INITIALIZE DRIVE     (AH = 09H) :
  6553                              <1> ;----------------------------------------
  6554                              <1> 	; 03/01/2015
  6555                              <1> 	; According to ATA-ATAPI specification v2.0 to v5.0
  6556                              <1> 	; logical sector per logical track
  6557                              <1> 	; and logical heads - 1 would be set but
  6558                              <1> 	; it is seen as it will be good
  6559                              <1> 	; if physical parameters will be set here
  6560                              <1> 	; because, number of heads <= 16.
  6561                              <1> 	; (logical heads usually more than 16)
  6562                              <1> 	; NOTE: ATA logical parameters (software C, H, S)
  6563                              <1> 	;	== INT 13h physical parameters
  6564                              <1> 
  6565                              <1> ;INIT_DRV:
  6566                              <1> ;	MOV	byte [CMD_BLOCK+6],SET_PARM_CMD
  6567                              <1> ;	CALL	GET_VEC 		; ES:BX -> PARAMETER BLOCK
  6568                              <1> ;	MOV	AL,[ES:BX+2]		; GET NUMBER OF HEADS
  6569                              <1> ;	DEC	AL			; CONVERT TO 0-INDEX
  6570                              <1> ;	MOV	AH,[CMD_BLOCK+5] 	; GET SDH REGISTER
  6571                              <1> ;	AND	AH,0F0H 		; CHANGE HEAD NUMBER
  6572                              <1> ;	OR	AH,AL			; TO MAX HEAD
  6573                              <1> ;	MOV	[CMD_BLOCK+5],AH
  6574                              <1> ;	MOV	AL,[ES:BX+14]		; MAX SECTOR NUMBER
  6575                              <1> ;	MOV	[CMD_BLOCK+1],AL
  6576                              <1> ;	SUB	AX,AX
  6577                              <1> ;	MOV	[CMD_BLOCK+3],AL 	; ZERO FLAGS
  6578                              <1> ;	CALL	COMMAND 		; TELL CONTROLLER
  6579                              <1> ;	JNZ	short INIT_EXIT		; CONTROLLER BUSY ERROR
  6580                              <1> ;	CALL	NOT_BUSY		; WAIT FOR IT TO BE DONE
  6581                              <1> ;	JNZ	short INIT_EXIT		; TIME OUT
  6582                              <1> ;	CALL	CHECK_STATUS
  6583                              <1> ;INIT_EXIT:
  6584                              <1> ;	RETn
  6585                              <1> 
  6586                              <1> ; 04/01/2015
  6587                              <1> ; 02/01/2015 - Derived from from AWARD BIOS 1999
  6588                              <1> ;				 AHDSK.ASM - INIT_DRIVE
  6589                              <1> INIT_DRV:
  6590                              <1> 	;xor	ah,ah
  6591 00002991 31C0                <1> 	xor	eax,eax ; 21/02/2015
  6592 00002993 B00B                <1> 	mov	al,11 ; Physical heads from translated HDPT
  6593 00002995 3825[846B0000]      <1>         cmp     [LBAMode], ah   ; 0
  6594 0000299B 7702                <1> 	ja	short idrv0
  6595 0000299D B002                <1> 	mov	al,2  ; Physical heads from standard HDPT
  6596                              <1> idrv0:
  6597                              <1> 	; DL = drive number (0 based)
  6598 0000299F E8BB030000          <1> 	call	GET_VEC
  6599                              <1> 	;push	bx
  6600 000029A4 53                  <1> 	push	ebx ; 21/02/2015
  6601                              <1> 	;add	bx,ax
  6602 000029A5 01C3                <1> 	add	ebx,eax
  6603                              <1> 	;; 05/01/2015
  6604 000029A7 8A25[C8650000]      <1> 	mov	ah,[hf_m_s] ; drive number (0= master, 1= slave)
  6605                              <1> 	;;and 	ah,1 
  6606 000029AD C0E404              <1> 	shl	ah,4
  6607 000029B0 80CCA0              <1> 	or	ah,0A0h  ; Drive/Head register - 10100000b (A0h)	
  6608                              <1> 	;mov	al,[es:bx]
  6609 000029B3 8A03                <1> 	mov	al,[ebx] ; 21/02/2015
  6610 000029B5 FEC8                <1> 	dec	al	 ; last head number 
  6611                              <1> 	;and	al,0Fh
  6612 000029B7 08E0                <1> 	or	al,ah	 ; lower 4 bits for head number
  6613                              <1> 	;
  6614 000029B9 C645FE91            <1> 	mov	byte [CMD_BLOCK+6],SET_PARM_CMD
  6615 000029BD 8845FD              <1> 	mov	[CMD_BLOCK+5],al
  6616                              <1> 	;pop	bx
  6617 000029C0 5B                  <1> 	pop	ebx
  6618 000029C1 29C0                <1> 	sub	eax,eax ; 21/02/2015
  6619 000029C3 B004                <1> 	mov	al,4 ; Physical sec per track from translated HDPT
  6620 000029C5 803D[846B0000]00    <1> 	cmp	byte [LBAMode],0
  6621 000029CC 7702                <1> 	ja	short idrv1
  6622 000029CE B00E                <1> 	mov	al,14 ; Physical sec per track from standard HDPT
  6623                              <1> idrv1:
  6624                              <1> 	;xor	ah,ah
  6625                              <1> 	;add	bx,ax
  6626 000029D0 01C3                <1> 	add	ebx,eax ; 21/02/2015
  6627                              <1> 	;mov	al,[es:bx]
  6628                              <1> 			; sector number
  6629 000029D2 8A03                <1> 	mov	al,[ebx]
  6630 000029D4 8845F9              <1> 	mov	[CMD_BLOCK+1],al
  6631 000029D7 28C0                <1> 	sub	al,al
  6632 000029D9 8845FB              <1> 	mov	[CMD_BLOCK+3],al  ; ZERO FLAGS
  6633 000029DC E8C4010000          <1> 	call	COMMAND 	  ; TELL CONTROLLER
  6634 000029E1 750C                <1> 	jnz	short INIT_EXIT	  ; CONTROLLER BUSY ERROR
  6635 000029E3 E872020000          <1> 	call	NOT_BUSY	  ; WAIT FOR IT TO BE DONE
  6636 000029E8 7505                <1> 	jnz	short INIT_EXIT	  ; TIME OUT
  6637 000029EA E8C3020000          <1> 	call	CHECK_STATUS
  6638                              <1> INIT_EXIT:
  6639 000029EF C3                  <1> 	RETn
  6640                              <1> 
  6641                              <1> ;----------------------------------------
  6642                              <1> ;	READ LONG	     (AH = 0AH) :
  6643                              <1> ;----------------------------------------
  6644                              <1> 
  6645                              <1> RD_LONG:
  6646                              <1> 	;MOV	@CMD_BLOCK+6,READ_CMD OR ECC_MODE
  6647 000029F0 C645FE22            <1>         mov     byte [CMD_BLOCK+6],READ_CMD + ECC_MODE 
  6648 000029F4 E9E0000000          <1>         JMP     COMMANDI
  6649                              <1> 
  6650                              <1> ;----------------------------------------
  6651                              <1> ;	WRITE LONG	     (AH = 0BH) :
  6652                              <1> ;----------------------------------------
  6653                              <1> 
  6654                              <1> WR_LONG:
  6655                              <1> 	;MOV	@CMD_BLOCK+6,WRITE_CMD OR ECC_MODE
  6656 000029F9 C645FE32            <1>         MOV     byte [CMD_BLOCK+6],WRITE_CMD + ECC_MODE
  6657 000029FD E92C010000          <1>         JMP     COMMANDO
  6658                              <1> 
  6659                              <1> ;----------------------------------------
  6660                              <1> ;	SEEK		     (AH = 0CH) :
  6661                              <1> ;----------------------------------------
  6662                              <1> 
  6663                              <1> DISK_SEEK:
  6664 00002A02 C645FE70            <1>         MOV     byte [CMD_BLOCK+6],SEEK_CMD
  6665 00002A06 E89A010000          <1> 	CALL	COMMAND
  6666 00002A0B 751C                <1> 	JNZ	short DS_EXIT 		; CONTROLLER BUSY ERROR
  6667 00002A0D E80C020000          <1> 	CALL	_WAIT
  6668 00002A12 7515                <1>         JNZ     DS_EXIT                 ; TIME OUT ON SEEK
  6669 00002A14 E899020000          <1> 	CALL	CHECK_STATUS
  6670 00002A19 803D[6F6B0000]40    <1>         CMP     byte [DISK_STATUS1],BAD_SEEK
  6671 00002A20 7507                <1> 	JNE	short DS_EXIT
  6672 00002A22 C605[6F6B0000]00    <1>         MOV     byte [DISK_STATUS1],0
  6673                              <1> DS_EXIT:
  6674 00002A29 C3                  <1> 	RETn
  6675                              <1> 
  6676                              <1> ;----------------------------------------
  6677                              <1> ;	TEST DISK READY      (AH = 10H) :
  6678                              <1> ;----------------------------------------
  6679                              <1> 
  6680                              <1> TST_RDY:				; WAIT FOR CONTROLLER
  6681 00002A2A E82B020000          <1> 	CALL	NOT_BUSY
  6682 00002A2F 751C                <1> 	JNZ	short TR_EX
  6683 00002A31 8A45FD              <1> 	MOV	AL,[CMD_BLOCK+5] 	; SELECT DRIVE
  6684 00002A34 668B15[C4650000]    <1> 	MOV	DX,[HF_PORT]
  6685 00002A3B 80C206              <1> 	add	dl,6
  6686 00002A3E EE                  <1> 	OUT	DX,AL
  6687 00002A3F E886020000          <1> 	CALL	CHECK_ST		; CHECK STATUS ONLY
  6688 00002A44 7507                <1> 	JNZ	short TR_EX
  6689 00002A46 C605[6F6B0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; WIPE OUT DATA CORRECTED ERROR
  6690                              <1> TR_EX:	
  6691 00002A4D C3                  <1> 	RETn
  6692                              <1> 
  6693                              <1> ;----------------------------------------
  6694                              <1> ;	RECALIBRATE	     (AH = 11H) :
  6695                              <1> ;----------------------------------------
  6696                              <1> 
  6697                              <1> HDISK_RECAL:
  6698 00002A4E C645FE10            <1>         MOV     byte [CMD_BLOCK+6],RECAL_CMD ; 10h, 16
  6699 00002A52 E84E010000          <1> 	CALL	COMMAND 		; START THE OPERATION
  6700 00002A57 7523                <1> 	JNZ	short RECAL_EXIT	; ERROR
  6701 00002A59 E8C0010000          <1> 	CALL	_WAIT			; WAIT FOR COMPLETION
  6702 00002A5E 7407                <1> 	JZ	short RECAL_X 		; TIME OUT ONE OK ?
  6703 00002A60 E8B9010000          <1> 	CALL	_WAIT			; WAIT FOR COMPLETION LONGER
  6704 00002A65 7515                <1> 	JNZ	short RECAL_EXIT	; TIME OUT TWO TIMES IS ERROR
  6705                              <1> RECAL_X:
  6706 00002A67 E846020000          <1> 	CALL	CHECK_STATUS
  6707 00002A6C 803D[6F6B0000]40    <1> 	CMP	byte [DISK_STATUS1],BAD_SEEK ; SEEK NOT COMPLETE
  6708 00002A73 7507                <1> 	JNE	short RECAL_EXIT	; IS OK
  6709 00002A75 C605[6F6B0000]00    <1> 	MOV	byte [DISK_STATUS1],0
  6710                              <1> RECAL_EXIT:
  6711 00002A7C 803D[6F6B0000]00    <1>         CMP     byte [DISK_STATUS1],0
  6712 00002A83 C3                  <1> 	RETn
  6713                              <1> 
  6714                              <1> ;----------------------------------------
  6715                              <1> ;      CONTROLLER DIAGNOSTIC (AH = 14H) :
  6716                              <1> ;----------------------------------------
  6717                              <1> 
  6718                              <1> CTLR_DIAGNOSTIC:
  6719 00002A84 FA                  <1>         CLI                             ; DISABLE INTERRUPTS WHILE CHANGING MASK
  6720 00002A85 E4A1                <1> 	IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  6721                              <1> 	;AND	AL,0BFH
  6722 00002A87 243F                <1> 	and	al, 3Fh			; enable IRQ 14 & IRQ 15
  6723                              <1> 	;JMP	$+2
  6724                              <1> 	IODELAY
  2145 00002A89 EB00                <2>  jmp short $+2
  2146 00002A8B EB00                <2>  jmp short $+2
  6725 00002A8D E6A1                <1> 	OUT	INTB01,AL
  6726                              <1> 	IODELAY
  2145 00002A8F EB00                <2>  jmp short $+2
  2146 00002A91 EB00                <2>  jmp short $+2
  6727 00002A93 E421                <1> 	IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  6728 00002A95 24FB                <1> 	AND	AL,0FBH 		;  SECOND CHIP
  6729                              <1> 	;JMP	$+2
  6730                              <1> 	IODELAY
  2145 00002A97 EB00                <2>  jmp short $+2
  2146 00002A99 EB00                <2>  jmp short $+2
  6731 00002A9B E621                <1> 	OUT	INTA01,AL
  6732 00002A9D FB                  <1> 	STI
  6733 00002A9E E8B7010000          <1> 	CALL	NOT_BUSY		; WAIT FOR CARD
  6734 00002AA3 752B                <1> 	JNZ	short CD_ERR		; BAD CARD
  6735                              <1> 	;MOV	DX, HF_PORT+7
  6736 00002AA5 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6737 00002AAC 80C207              <1> 	add	dl, 7
  6738 00002AAF B090                <1> 	MOV	AL,DIAG_CMD		; START DIAGNOSE
  6739 00002AB1 EE                  <1> 	OUT	DX,AL
  6740 00002AB2 E8A3010000          <1> 	CALL	NOT_BUSY		; WAIT FOR IT TO COMPLETE
  6741 00002AB7 B480                <1> 	MOV	AH,TIME_OUT
  6742 00002AB9 7517                <1> 	JNZ	short CD_EXIT 		; TIME OUT ON DIAGNOSTIC
  6743                              <1> 	;MOV	DX,HF_PORT+1		; GET ERROR REGISTER
  6744 00002ABB 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6745 00002AC2 FEC2                <1> 	inc	dl
  6746 00002AC4 EC                  <1> 	IN	AL,DX
  6747 00002AC5 A2[666B0000]        <1> 	MOV	[HF_ERROR],AL		; SAVE IT
  6748 00002ACA B400                <1> 	MOV	AH,0
  6749 00002ACC 3C01                <1> 	CMP	AL,1			; CHECK FOR ALL OK
  6750 00002ACE 7402                <1> 	JE	SHORT CD_EXIT
  6751 00002AD0 B420                <1> CD_ERR: MOV	AH,BAD_CNTLR
  6752                              <1> CD_EXIT:
  6753 00002AD2 8825[6F6B0000]      <1> 	MOV	[DISK_STATUS1],AH
  6754 00002AD8 C3                  <1> 	RETn
  6755                              <1> 
  6756                              <1> ;----------------------------------------
  6757                              <1> ; COMMANDI				:
  6758                              <1> ;	REPEATEDLY INPUTS DATA TILL	:
  6759                              <1> ;	NSECTOR RETURNS ZERO		:
  6760                              <1> ;----------------------------------------
  6761                              <1> COMMANDI:
  6762 00002AD9 E85A020000          <1> 	CALL	CHECK_DMA		; CHECK 64K BOUNDARY ERROR
  6763 00002ADE 724D                <1> 	JC	short CMD_ABORT
  6764                              <1> 	;MOV	DI,BX
  6765 00002AE0 89DF                <1> 	mov	edi, ebx ; 21/02/2015
  6766 00002AE2 E8BE000000          <1> 	CALL	COMMAND 		; OUTPUT COMMAND
  6767 00002AE7 7544                <1> 	JNZ	short CMD_ABORT
  6768                              <1> CMD_I1:
  6769 00002AE9 E830010000          <1> 	CALL	_WAIT			; WAIT FOR DATA REQUEST INTERRUPT
  6770 00002AEE 753D                <1> 	JNZ	short TM_OUT		; TIME OUT
  6771                              <1> 	;MOV	CX,256			; SECTOR SIZE IN WORDS
  6772 00002AF0 B900010000          <1> 	mov	ecx, 256 ; 21/02/2015	
  6773                              <1> 	;MOV	DX,HF_PORT
  6774 00002AF5 668B15[C4650000]    <1> 	mov	dx,[HF_PORT]
  6775 00002AFC FA                  <1> 	CLI
  6776 00002AFD FC                  <1> 	CLD
  6777 00002AFE F3666D              <1> 	REP	INSW			; GET THE SECTOR
  6778 00002B01 FB                  <1> 	STI
  6779 00002B02 F645FE02            <1> 	TEST	byte [CMD_BLOCK+6],ECC_MODE ; CHECK FOR NORMAL INPUT
  6780 00002B06 7419                <1> 	JZ	CMD_I3
  6781 00002B08 E87A010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6782 00002B0D 721E                <1> 	JC	short TM_OUT
  6783                              <1> 	;MOV	DX,HF_PORT
  6784 00002B0F 668B15[C4650000]    <1> 	mov	dx,[HF_PORT]
  6785                              <1> 	;MOV	CX,4			; GET ECC BYTES
  6786 00002B16 B904000000          <1> 	mov 	ecx, 4 ; mov cx, 4 
  6787 00002B1B EC                  <1> CMD_I2: IN	AL,DX
  6788                              <1> 	;MOV	[ES:DI],AL		; GO SLOW FOR BOARD
  6789 00002B1C 8807                <1> 	mov 	[edi], al ; 21/02/2015
  6790 00002B1E 47                  <1> 	INC	eDI
  6791 00002B1F E2FA                <1> 	LOOP	CMD_I2
  6792 00002B21 E88C010000          <1> CMD_I3: CALL	CHECK_STATUS
  6793 00002B26 7505                <1> 	JNZ	short CMD_ABORT		; ERROR RETURNED
  6794 00002B28 FE4DF9              <1> 	DEC	byte [CMD_BLOCK+1]	; CHECK FOR MORE
  6795 00002B2B 75BC                <1> 	JNZ	SHORT CMD_I1
  6796                              <1> CMD_ABORT:
  6797 00002B2D C3                  <1> TM_OUT: RETn
  6798                              <1> 
  6799                              <1> ;----------------------------------------
  6800                              <1> ; COMMANDO				:
  6801                              <1> ;	REPEATEDLY OUTPUTS DATA TILL	:
  6802                              <1> ;	NSECTOR RETURNS ZERO		:
  6803                              <1> ;----------------------------------------
  6804                              <1> COMMANDO:
  6805 00002B2E E805020000          <1> 	CALL	CHECK_DMA		; CHECK 64K BOUNDARY ERROR
  6806 00002B33 72F8                <1> 	JC	short CMD_ABORT
  6807 00002B35 89DE                <1> CMD_OF: MOV	eSI,eBX ; 21/02/2015
  6808 00002B37 E869000000          <1> 	CALL	COMMAND 		; OUTPUT COMMAND
  6809 00002B3C 75EF                <1> 	JNZ	short CMD_ABORT
  6810 00002B3E E844010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6811 00002B43 72E8                <1> 	JC	short TM_OUT			; TOO LONG
  6812                              <1> CMD_O1: ;PUSH	DS
  6813                              <1> 	;PUSH	ES			; MOVE ES TO DS
  6814                              <1> 	;POP	DS
  6815                              <1> 	;MOV	CX,256			; PUT THE DATA OUT TO THE CARD
  6816                              <1> 	;MOV	DX,HF_PORT
  6817                              <1> 	; 01/02/2015
  6818 00002B45 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6819                              <1> 	;push	es
  6820                              <1> 	;pop	ds
  6821                              <1> 	;mov	cx, 256
  6822 00002B4C B900010000          <1> 	mov	ecx, 256 ; 21/02/2015
  6823 00002B51 FA                  <1> 	CLI
  6824 00002B52 FC                  <1> 	CLD
  6825 00002B53 F3666F              <1> 	REP	OUTSW
  6826 00002B56 FB                  <1> 	STI
  6827                              <1> 	;POP	DS			; RESTORE DS
  6828 00002B57 F645FE02            <1> 	TEST	byte [CMD_BLOCK+6],ECC_MODE ; CHECK FOR NORMAL OUTPUT
  6829 00002B5B 7419                <1> 	JZ	short CMD_O3
  6830 00002B5D E825010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6831 00002B62 72C9                <1> 	JC	short TM_OUT
  6832                              <1> 	;MOV	DX,HF_PORT
  6833 00002B64 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6834                              <1> 	;MOV	CX,4			; OUTPUT THE ECC BYTES
  6835 00002B6B B904000000          <1> 	mov	ecx, 4  ; mov cx, 4
  6836                              <1> CMD_O2: ;MOV	AL,[ES:SI]
  6837 00002B70 8A06                <1> 	mov	al, [esi]
  6838 00002B72 EE                  <1> 	OUT	DX,AL
  6839 00002B73 46                  <1> 	INC	eSI
  6840 00002B74 E2FA                <1> 	LOOP	CMD_O2
  6841                              <1> CMD_O3:
  6842 00002B76 E8A3000000          <1> 	CALL	_WAIT			; WAIT FOR SECTOR COMPLETE INTERRUPT
  6843 00002B7B 75B0                <1> 	JNZ	short TM_OUT		; ERROR RETURNED
  6844 00002B7D E830010000          <1> 	CALL	CHECK_STATUS
  6845 00002B82 75A9                <1> 	JNZ	short CMD_ABORT
  6846 00002B84 F605[656B0000]08    <1> 	TEST	byte [HF_STATUS],ST_DRQ	; CHECK FOR MORE
  6847 00002B8B 75B8                <1> 	JNZ	SHORT CMD_O1
  6848                              <1> 	;MOV	DX,HF_PORT+2		; CHECK RESIDUAL SECTOR COUNT
  6849 00002B8D 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6850                              <1> 	;add	dl, 2
  6851 00002B94 FEC2                <1> 	inc	dl
  6852 00002B96 FEC2                <1> 	inc	dl
  6853 00002B98 EC                  <1> 	IN	AL,DX			;
  6854 00002B99 A8FF                <1> 	TEST	AL,0FFH 		;
  6855 00002B9B 7407                <1> 	JZ	short CMD_O4			; COUNT = 0  OK
  6856 00002B9D C605[6F6B0000]BB    <1> 	MOV	byte [DISK_STATUS1],UNDEF_ERR 
  6857                              <1> 					; OPERATION ABORTED - PARTIAL TRANSFER
  6858                              <1> CMD_O4:
  6859 00002BA4 C3                  <1> 	RETn
  6860                              <1> 
  6861                              <1> ;--------------------------------------------------------
  6862                              <1> ; COMMAND						:
  6863                              <1> ;	THIS ROUTINE OUTPUTS THE COMMAND BLOCK		:
  6864                              <1> ; OUTPUT						:
  6865                              <1> ;	BL = STATUS					:
  6866                              <1> ;	BH = ERROR REGISTER				:
  6867                              <1> ;--------------------------------------------------------
  6868                              <1> 
  6869                              <1> COMMAND:
  6870 00002BA5 53                  <1> 	PUSH	eBX			; WAIT FOR SEEK COMPLETE AND READY
  6871                              <1> 	;;MOV	CX,DELAY_2		; SET INITIAL DELAY BEFORE TEST
  6872                              <1> COMMAND1:
  6873                              <1> 	;;PUSH	CX			; SAVE LOOP COUNT
  6874 00002BA6 E87FFEFFFF          <1> 	CALL	TST_RDY 		; CHECK DRIVE READY
  6875                              <1> 	;;POP	CX
  6876 00002BAB 7419                <1> 	JZ	short COMMAND2		; DRIVE IS READY
  6877 00002BAD 803D[6F6B0000]80    <1>         CMP     byte [DISK_STATUS1],TIME_OUT ; TST_RDY TIMED OUT--GIVE UP
  6878                              <1> 	;JZ	short CMD_TIMEOUT
  6879                              <1> 	;;LOOP	COMMAND1		; KEEP TRYING FOR A WHILE
  6880                              <1> 	;JMP	SHORT COMMAND4		; ITS NOT GOING TO GET READY
  6881 00002BB4 7507                <1> 	jne	short COMMAND4
  6882                              <1> CMD_TIMEOUT:
  6883 00002BB6 C605[6F6B0000]20    <1> 	MOV	byte [DISK_STATUS1],BAD_CNTLR
  6884                              <1> COMMAND4:
  6885 00002BBD 5B                  <1> 	POP	eBX
  6886 00002BBE 803D[6F6B0000]00    <1>         CMP     byte [DISK_STATUS1],0   ; SET CONDITION CODE FOR CALLER
  6887 00002BC5 C3                  <1> 	RETn
  6888                              <1> COMMAND2:
  6889 00002BC6 5B                  <1> 	POP	eBX
  6890 00002BC7 57                  <1> 	PUSH	eDI
  6891 00002BC8 C605[676B0000]00    <1> 	MOV	byte [HF_INT_FLAG],0	; RESET INTERRUPT FLAG
  6892 00002BCF FA                  <1> 	CLI				; INHIBIT INTERRUPTS WHILE CHANGING MASK
  6893 00002BD0 E4A1                <1> 	IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  6894                              <1> 	;AND	AL,0BFH
  6895 00002BD2 243F                <1> 	and	al, 3Fh			; Enable IRQ 14 & 15
  6896                              <1> 	;JMP	$+2
  6897                              <1> 	IODELAY
  2145 00002BD4 EB00                <2>  jmp short $+2
  2146 00002BD6 EB00                <2>  jmp short $+2
  6898 00002BD8 E6A1                <1> 	OUT	INTB01,AL
  6899 00002BDA E421                <1> 	IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  6900 00002BDC 24FB                <1> 	AND	AL,0FBH 		;  SECOND CHIP
  6901                              <1> 	;JMP	$+2
  6902                              <1> 	IODELAY
  2145 00002BDE EB00                <2>  jmp short $+2
  2146 00002BE0 EB00                <2>  jmp short $+2
  6903 00002BE2 E621                <1> 	OUT	INTA01,AL
  6904 00002BE4 FB                  <1> 	STI
  6905 00002BE5 31FF                <1> 	XOR	eDI,eDI			; INDEX THE COMMAND TABLE
  6906                              <1> 	;MOV	DX,HF_PORT+1		; DISK ADDRESS
  6907 00002BE7 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  6908 00002BEE FEC2                <1> 	inc	dl
  6909 00002BF0 F605[716B0000]C0    <1> 	TEST	byte [CONTROL_BYTE],0C0H ; CHECK FOR RETRY SUPPRESSION
  6910 00002BF7 7411                <1> 	JZ	short COMMAND3
  6911 00002BF9 8A45FE              <1> 	MOV	AL, [CMD_BLOCK+6] 	; YES-GET OPERATION CODE
  6912 00002BFC 24F0                <1> 	AND	AL,0F0H 		; GET RID OF MODIFIERS
  6913 00002BFE 3C20                <1> 	CMP	AL,20H			; 20H-40H IS READ, WRITE, VERIFY
  6914 00002C00 7208                <1> 	JB	short COMMAND3
  6915 00002C02 3C40                <1> 	CMP	AL,40H
  6916 00002C04 7704                <1> 	JA	short COMMAND3
  6917 00002C06 804DFE01            <1> 	OR	byte [CMD_BLOCK+6],NO_RETRIES 
  6918                              <1> 					; VALID OPERATION FOR RETRY SUPPRESS
  6919                              <1> COMMAND3:
  6920 00002C0A 8A443DF8            <1> 	MOV	AL,[CMD_BLOCK+eDI]	; GET THE COMMAND STRING BYTE
  6921 00002C0E EE                  <1> 	OUT	DX,AL			; GIVE IT TO CONTROLLER
  6922                              <1> 	IODELAY
  2145 00002C0F EB00                <2>  jmp short $+2
  2146 00002C11 EB00                <2>  jmp short $+2
  6923 00002C13 47                  <1> 	INC	eDI			; NEXT BYTE IN COMMAND BLOCK
  6924 00002C14 6642                <1> 	INC	DX			; NEXT DISK ADAPTER REGISTER
  6925 00002C16 6683FF07            <1> 	cmp	di, 7	; 1/1/2015	; ALL DONE?
  6926 00002C1A 75EE                <1> 	JNZ	short COMMAND3		; NO--GO DO NEXT ONE
  6927 00002C1C 5F                  <1> 	POP	eDI
  6928 00002C1D C3                  <1> 	RETn				; ZERO FLAG IS SET
  6929                              <1> 
  6930                              <1> ;CMD_TIMEOUT:
  6931                              <1> ;	MOV	byte [DISK_STATUS1],BAD_CNTLR
  6932                              <1> ;COMMAND4:
  6933                              <1> ;	POP	BX
  6934                              <1> ;	CMP	[DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  6935                              <1> ;	RETn
  6936                              <1> 
  6937                              <1> ;----------------------------------------
  6938                              <1> ;	WAIT FOR INTERRUPT		:
  6939                              <1> ;----------------------------------------
  6940                              <1> ;WAIT:
  6941                              <1> _WAIT:
  6942 00002C1E FB                  <1> 	STI				; MAKE SURE INTERRUPTS ARE ON
  6943                              <1> 	;SUB	CX,CX			; SET INITIAL DELAY BEFORE TEST
  6944                              <1> 	;CLC
  6945                              <1> 	;MOV	AX,9000H		; DEVICE WAIT INTERRUPT
  6946                              <1> 	;INT	15H
  6947                              <1> 	;JC	WT2			; DEVICE TIMED OUT
  6948                              <1> 	;MOV	BL,DELAY_1		; SET DELAY COUNT
  6949                              <1> 
  6950                              <1> 	;mov	bl, WAIT_HDU_INT_HI
  6951                              <1> 	;; 21/02/2015
  6952                              <1> 	;;mov	bl, WAIT_HDU_INT_HI + 1
  6953                              <1> 	;;mov	cx, WAIT_HDU_INT_LO
  6954 00002C1F B915160500          <1> 	mov	ecx, WAIT_HDU_INT_LH
  6955                              <1> 					; (AWARD BIOS -> WAIT_FOR_MEM)
  6956                              <1> ;-----	WAIT LOOP
  6957                              <1> 
  6958                              <1> WT1:	
  6959                              <1> 	;TEST	byte [HF_INT_FLAG],80H	; TEST FOR INTERRUPT
  6960 00002C24 F605[676B0000]C0    <1> 	test 	byte [HF_INT_FLAG],0C0h
  6961                              <1> 	;LOOPZ	WT1
  6962 00002C2B 7517                <1> 	JNZ	short WT3		; INTERRUPT--LETS GO
  6963                              <1> 	;DEC	BL
  6964                              <1> 	;JNZ	short WT1		; KEEP TRYING FOR A WHILE
  6965                              <1> 
  6966                              <1> WT1_hi:
  6967 00002C2D E461                <1> 	in	al, SYS1 ; 61h (PORT_B)	; wait for lo to hi
  6968 00002C2F A810                <1> 	test	al, 10h			; transition on memory
  6969 00002C31 75FA                <1> 	jnz	short WT1_hi		; refresh.
  6970                              <1> WT1_lo:
  6971 00002C33 E461                <1> 	in	al, SYS1 		; 061h (PORT_B)	
  6972 00002C35 A810                <1> 	test	al, 10h			
  6973 00002C37 74FA                <1> 	jz	short WT1_lo
  6974 00002C39 E2E9                <1> 	loop	WT1
  6975                              <1> 	;;or	bl, bl
  6976                              <1> 	;;jz	short WT2	
  6977                              <1> 	;;dec	bl
  6978                              <1> 	;;jmp	short WT1
  6979                              <1> 	;dec	bl
  6980                              <1> 	;jnz	short WT1	
  6981                              <1> 
  6982 00002C3B C605[6F6B0000]80    <1> WT2:	MOV	byte [DISK_STATUS1],TIME_OUT ; REPORT TIME OUT ERROR
  6983 00002C42 EB0E                <1> 	JMP	SHORT WT4
  6984 00002C44 C605[6F6B0000]00    <1> WT3:	MOV	byte [DISK_STATUS1],0
  6985 00002C4B C605[676B0000]00    <1> 	MOV	byte [HF_INT_FLAG],0
  6986 00002C52 803D[6F6B0000]00    <1> WT4:	CMP	byte [DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  6987 00002C59 C3                  <1> 	RETn
  6988                              <1> 
  6989                              <1> ;----------------------------------------
  6990                              <1> ;	WAIT FOR CONTROLLER NOT BUSY	:
  6991                              <1> ;----------------------------------------
  6992                              <1> NOT_BUSY:
  6993 00002C5A FB                  <1> 	STI				; MAKE SURE INTERRUPTS ARE ON
  6994                              <1> 	;PUSH	eBX
  6995                              <1> 	;SUB	CX,CX			; SET INITIAL DELAY BEFORE TEST
  6996 00002C5B 668B15[C4650000]    <1> 	mov	DX, [HF_PORT]
  6997 00002C62 80C207              <1> 	add	dl, 7			; Status port (HF_PORT+7)
  6998                              <1> 	;MOV	BL,DELAY_1
  6999                              <1> 					; wait for 10 seconds
  7000                              <1> 	;mov 	cx, WAIT_HDU_INT_LO	; 1615h
  7001                              <1> 	;;mov 	bl, WAIT_HDU_INT_HI	;   05h
  7002                              <1> 	;mov	bl, WAIT_HDU_INT_HI + 1
  7003 00002C65 B915160500          <1> 	mov	ecx, WAIT_HDU_INT_LH  ; 21/02/2015
  7004                              <1> 	;
  7005                              <1> ;;      mov     byte [wait_count], 0    ; Reset wait counter
  7006                              <1> NB1:	
  7007 00002C6A EC                  <1> 	IN	AL,DX			; CHECK STATUS
  7008                              <1> 	;TEST	AL,ST_BUSY
  7009 00002C6B 2480                <1> 	and	al, ST_BUSY
  7010                              <1> 	;LOOPNZ	NB1
  7011 00002C6D 7410                <1> 	JZ	short NB2		; NOT BUSY--LETS GO
  7012                              <1> 	;DEC	BL			
  7013                              <1> 	;JNZ	short NB1		; KEEP TRYING FOR A WHILE
  7014                              <1> 
  7015 00002C6F E461                <1> NB1_hi: IN	AL,SYS1			; wait for hi to lo
  7016 00002C71 A810                <1> 	TEST	AL,010H			; transition on memory
  7017 00002C73 75FA                <1> 	JNZ	SHORT NB1_hi		; refresh.
  7018 00002C75 E461                <1> NB1_lo: IN	AL,SYS1
  7019 00002C77 A810                <1> 	TEST	AL,010H
  7020 00002C79 74FA                <1> 	JZ	short NB1_lo
  7021 00002C7B E2ED                <1> 	LOOP	NB1
  7022                              <1> 	;dec	bl
  7023                              <1> 	;jnz	short NB1
  7024                              <1> 	;
  7025                              <1> ;;      cmp     byte [wait_count], 182  ; 10 seconds (182 timer ticks)
  7026                              <1> ;;	jb	short NB1
  7027                              <1> 	;
  7028                              <1> 	;MOV	[DISK_STATUS1],TIME_OUT	; REPORT TIME OUT ERROR
  7029                              <1> 	;JMP	SHORT NB3
  7030 00002C7D B080                <1> 	mov	al, TIME_OUT
  7031                              <1> NB2:	
  7032                              <1> 	;MOV	byte [DISK_STATUS1],0
  7033                              <1> ;NB3:	
  7034                              <1> 	;POP	eBX
  7035 00002C7F A2[6F6B0000]        <1> 	mov	[DISK_STATUS1], al	;;; will be set after return
  7036                              <1> 	;CMP	byte [DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  7037 00002C84 08C0                <1> 	or	al, al			; (zf = 0 --> timeout)
  7038 00002C86 C3                  <1> 	RETn
  7039                              <1> 
  7040                              <1> ;----------------------------------------
  7041                              <1> ;	WAIT FOR DATA REQUEST		:
  7042                              <1> ;----------------------------------------
  7043                              <1> WAIT_DRQ:
  7044                              <1> 	;MOV	CX,DELAY_3
  7045                              <1> 	;MOV	DX,HF_PORT+7
  7046 00002C87 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  7047 00002C8E 80C207              <1> 	add	dl, 7
  7048                              <1> 	;;MOV	bl, WAIT_HDU_DRQ_HI	; 0
  7049                              <1> 	;MOV	cx, WAIT_HDU_DRQ_LO	; 1000 (30 milli seconds)
  7050                              <1> 					; (but it is written as 2000
  7051                              <1> 					; micro seconds in ATORGS.ASM file
  7052                              <1> 					; of Award Bios - 1999, D1A0622)
  7053 00002C91 B9E8030000          <1> 	mov 	ecx, WAIT_HDU_DRQ_LH ; 21/02/2015 
  7054 00002C96 EC                  <1> WQ_1:	IN	AL,DX			; GET STATUS
  7055 00002C97 A808                <1> 	TEST	AL,ST_DRQ		; WAIT FOR DRQ
  7056 00002C99 7516                <1> 	JNZ	short WQ_OK
  7057                              <1> 	;LOOP	WQ_1			; KEEP TRYING FOR A SHORT WHILE
  7058                              <1> WQ_hi:	
  7059 00002C9B E461                <1> 	IN	AL,SYS1			; wait for hi to lo
  7060 00002C9D A810                <1> 	TEST	AL,010H			; transition on memory
  7061 00002C9F 75FA                <1> 	JNZ	SHORT WQ_hi		; refresh.
  7062 00002CA1 E461                <1> WQ_lo:  IN      AL,SYS1
  7063 00002CA3 A810                <1> 	TEST	AL,010H
  7064 00002CA5 74FA                <1> 	JZ	SHORT WQ_lo
  7065 00002CA7 E2ED                <1> 	LOOP	WQ_1
  7066                              <1> 
  7067 00002CA9 C605[6F6B0000]80    <1>         MOV     byte [DISK_STATUS1],TIME_OUT ; ERROR
  7068 00002CB0 F9                  <1> 	STC
  7069                              <1> WQ_OK:
  7070 00002CB1 C3                  <1> 	RETn
  7071                              <1> ;WQ_OK:	;CLC
  7072                              <1> ;	RETn
  7073                              <1> 
  7074                              <1> ;----------------------------------------
  7075                              <1> ;	CHECK FIXED DISK STATUS 	:
  7076                              <1> ;----------------------------------------
  7077                              <1> CHECK_STATUS:
  7078 00002CB2 E813000000          <1> 	CALL	CHECK_ST		; CHECK THE STATUS BYTE
  7079 00002CB7 7509                <1> 	JNZ	short CHECK_S1		; AN ERROR WAS FOUND
  7080 00002CB9 A801                <1> 	TEST	AL,ST_ERROR		; WERE THERE ANY OTHER ERRORS
  7081 00002CBB 7405                <1> 	JZ	short CHECK_S1		; NO ERROR REPORTED
  7082 00002CBD E847000000          <1> 	CALL	CHECK_ER		; ERROR REPORTED
  7083                              <1> CHECK_S1:
  7084 00002CC2 803D[6F6B0000]00    <1> 	CMP	byte [DISK_STATUS1],0 	; SET STATUS FOR CALLER
  7085 00002CC9 C3                  <1> 	RETn
  7086                              <1> 
  7087                              <1> ;----------------------------------------
  7088                              <1> ;	CHECK FIXED DISK STATUS BYTE	:
  7089                              <1> ;----------------------------------------
  7090                              <1> CHECK_ST:
  7091                              <1> 	;MOV	DX,HF_PORT+7		; GET THE STATUS
  7092 00002CCA 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]
  7093 00002CD1 80C207              <1> 	add	dl, 7
  7094 00002CD4 EC                  <1> 	IN	AL,DX
  7095 00002CD5 A2[656B0000]        <1> 	MOV	[HF_STATUS],AL
  7096 00002CDA B400                <1> 	MOV	AH,0
  7097 00002CDC A880                <1> 	TEST	AL,ST_BUSY		; IF STILL BUSY
  7098 00002CDE 751A                <1> 	JNZ	short CKST_EXIT		;  REPORT OK
  7099 00002CE0 B4CC                <1> 	MOV	AH,WRITE_FAULT
  7100 00002CE2 A820                <1> 	TEST	AL,ST_WRT_FLT		; CHECK FOR WRITE FAULT
  7101 00002CE4 7514                <1> 	JNZ	short CKST_EXIT
  7102 00002CE6 B4AA                <1> 	MOV	AH,NOT_RDY
  7103 00002CE8 A840                <1> 	TEST	AL,ST_READY		; CHECK FOR NOT READY
  7104 00002CEA 740E                <1> 	JZ	short CKST_EXIT
  7105 00002CEC B440                <1> 	MOV	AH,BAD_SEEK
  7106 00002CEE A810                <1> 	TEST	AL,ST_SEEK_COMPL	; CHECK FOR SEEK NOT COMPLETE
  7107 00002CF0 7408                <1> 	JZ	short CKST_EXIT
  7108 00002CF2 B411                <1> 	MOV	AH,DATA_CORRECTED
  7109 00002CF4 A804                <1> 	TEST	AL,ST_CORRCTD		; CHECK FOR CORRECTED ECC
  7110 00002CF6 7502                <1> 	JNZ	short CKST_EXIT
  7111 00002CF8 B400                <1> 	MOV	AH,0
  7112                              <1> CKST_EXIT:
  7113 00002CFA 8825[6F6B0000]      <1> 	MOV	[DISK_STATUS1],AH	; SET ERROR FLAG
  7114 00002D00 80FC11              <1> 	CMP	AH,DATA_CORRECTED	; KEEP GOING WITH DATA CORRECTED
  7115 00002D03 7403                <1> 	JZ	short CKST_EX1
  7116 00002D05 80FC00              <1> 	CMP	AH,0
  7117                              <1> CKST_EX1:
  7118 00002D08 C3                  <1> 	RETn
  7119                              <1> 
  7120                              <1> ;----------------------------------------
  7121                              <1> ;	CHECK FIXED DISK ERROR REGISTER :
  7122                              <1> ;----------------------------------------
  7123                              <1> CHECK_ER:
  7124                              <1> 	;MOV	DX, HF_PORT+1		; GET THE ERROR REGISTER
  7125 00002D09 668B15[C4650000]    <1> 	mov	dx, [HF_PORT]		;
  7126 00002D10 FEC2                <1> 	inc	dl
  7127 00002D12 EC                  <1> 	IN	AL,DX
  7128 00002D13 A2[666B0000]        <1> 	MOV	[HF_ERROR],AL
  7129 00002D18 53                  <1> 	PUSH	eBX ; 21/02/2015
  7130 00002D19 B908000000          <1> 	MOV	eCX,8			; TEST ALL 8 BITS
  7131 00002D1E D0E0                <1> CK1:	SHL	AL,1			; MOVE NEXT ERROR BIT TO CARRY
  7132 00002D20 7202                <1> 	JC	short CK2		; FOUND THE ERROR
  7133 00002D22 E2FA                <1> 	LOOP	CK1			; KEEP TRYING
  7134 00002D24 BB[B8650000]        <1> CK2:	MOV	eBX, ERR_TBL		; COMPUTE ADDRESS OF
  7135 00002D29 01CB                <1> 	ADD	eBX,eCX			; ERROR CODE
  7136                              <1> 	;;MOV	AH,BYTE [CS:BX]		; GET ERROR CODE
  7137                              <1> 	;mov	ah, [bx]
  7138 00002D2B 8A23                <1> 	mov	ah, [ebx] ; 21/02/2015	
  7139 00002D2D 8825[6F6B0000]      <1> CKEX:	MOV	[DISK_STATUS1],AH	; SAVE ERROR CODE
  7140 00002D33 5B                  <1> 	POP	eBX
  7141 00002D34 80FC00              <1> 	CMP	AH,0
  7142 00002D37 C3                  <1> 	RETn
  7143                              <1> 
  7144                              <1> ;--------------------------------------------------------
  7145                              <1> ; CHECK_DMA						:
  7146                              <1> ;  -CHECK ES:BX AND # SECTORS TO MAKE SURE THAT IT WILL :
  7147                              <1> ;   FIT WITHOUT SEGMENT OVERFLOW.			:
  7148                              <1> ;  -ES:BX HAS BEEN REVISED TO THE FORMAT SSSS:000X	:
  7149                              <1> ;  -OK IF # SECTORS < 80H (7FH IF LONG READ OR WRITE)	:
  7150                              <1> ;  -OK IF # SECTORS = 80H (7FH) AND BX <= 00H (04H)	:
  7151                              <1> ;  -ERROR OTHERWISE					:
  7152                              <1> ;--------------------------------------------------------
  7153                              <1> CHECK_DMA:
  7154                              <1> 	;PUSH	AX			; SAVE REGISTERS
  7155                              <1> 	; 24/12/2021
  7156 00002D38 50                  <1> 	push	eax
  7157 00002D39 66B80080            <1> 	MOV	AX,8000H		; AH = MAX # SECTORS AL = MAX OFFSET
  7158 00002D3D F645FE02            <1>         TEST    byte [CMD_BLOCK+6],ECC_MODE
  7159 00002D41 7404                <1> 	JZ	short CKD1
  7160 00002D43 66B8047F            <1> 	MOV	AX,7F04H		; ECC IS 4 MORE BYTES
  7161 00002D47 3A65F9              <1> CKD1:	CMP	AH, [CMD_BLOCK+1] 	; NUMBER OF SECTORS
  7162 00002D4A 7706                <1> 	JA	short CKDOK		; IT WILL FIT
  7163 00002D4C 7207                <1> 	JB	short CKDERR		; TOO MANY
  7164 00002D4E 38D8                <1> 	CMP	AL,BL			; CHECK OFFSET ON MAX SECTORS
  7165 00002D50 7203                <1> 	JB	short CKDERR		; ERROR
  7166 00002D52 F8                  <1> CKDOK:	CLC				; CLEAR CARRY
  7167                              <1> 	;POP	AX
  7168                              <1> 	; 24/12/2021
  7169 00002D53 58                  <1> 	pop	eax
  7170 00002D54 C3                  <1> 	RETn				; NORMAL RETURN
  7171 00002D55 F9                  <1> CKDERR: STC				; INDICATE ERROR
  7172 00002D56 C605[6F6B0000]09    <1>         MOV     byte [DISK_STATUS1],DMA_BOUNDARY
  7173                              <1> 	;POP	AX
  7174                              <1> 	; 24/12/2021
  7175 00002D5D 58                  <1> 	pop	eax	
  7176 00002D5E C3                  <1> 	RETn
  7177                              <1> 
  7178                              <1> ;----------------------------------------
  7179                              <1> ;	SET UP ES:BX-> DISK PARMS	:
  7180                              <1> ;----------------------------------------
  7181                              <1> 					
  7182                              <1> ; INPUT -> DL = 0 based drive number
  7183                              <1> ; OUTPUT -> ES:BX = disk parameter table address
  7184                              <1> 
  7185                              <1> GET_VEC:
  7186                              <1> 	;SUB	AX,AX			; GET DISK PARAMETER ADDRESS
  7187                              <1> 	;MOV	ES,AX
  7188                              <1> 	;TEST	DL,1
  7189                              <1> 	;JZ	short GV_0
  7190                              <1> ;	LES	BX,[HF1_TBL_VEC] 	; ES:BX -> DRIVE PARAMETERS
  7191                              <1> ;	JMP	SHORT GV_EXIT
  7192                              <1> ;GV_0:
  7193                              <1> ;	LES	BX,[HF_TBL_VEC]		; ES:BX -> DRIVE PARAMETERS
  7194                              <1> ;
  7195                              <1> 	;xor	bh, bh
  7196 00002D5F 31DB                <1> 	xor	ebx, ebx
  7197 00002D61 88D3                <1> 	mov	bl, dl
  7198                              <1> 	;;02/01/2015
  7199                              <1> 	;;shl	bl, 1			; port address offset
  7200                              <1> 	;;mov	ax, [bx+hd_ports]	; Base port address (1F0h, 170h)
  7201                              <1> 	;;shl	bl, 1			; dpt pointer offset
  7202 00002D63 C0E302              <1> 	shl	bl, 2	;;
  7203                              <1> 	;add	bx, HF_TBL_VEC		; Disk parameter table pointer
  7204 00002D66 81C3[746B0000]      <1> 	add	ebx, HF_TBL_VEC ; 21/02/2015
  7205                              <1> 	;push	word [bx+2]		; dpt segment
  7206                              <1> 	;pop	es
  7207                              <1> 	;mov	bx, [bx]		; dpt offset
  7208 00002D6C 8B1B                <1> 	mov	ebx, [ebx]		
  7209                              <1> ;GV_EXIT:
  7210 00002D6E C3                  <1> 	RETn
  7211                              <1> 
  7212                              <1> 	; 24/12/2021 - Retro UNIX 386 v1.1
  7213                              <1> hdc1_int: ; 21/02/2015
  7214                              <1> ;--- HARDWARE INT 76H -- ( IRQ LEVEL  14 ) ----------------------
  7215                              <1> ;								:
  7216                              <1> ;	FIXED DISK INTERRUPT ROUTINE				:
  7217                              <1> ;								:
  7218                              <1> ;----------------------------------------------------------------
  7219                              <1> 
  7220                              <1> ; 22/12/2014
  7221                              <1> ; IBM PC-XT Model 286 System BIOS Source Code - DISK.ASM (HD_INT)
  7222                              <1> ;	 '11/15/85'
  7223                              <1> ; AWARD BIOS 1999 (D1A0622) 
  7224                              <1> ;	Source Code - ATORGS.ASM (INT_HDISK, INT_HDISK1)
  7225                              <1> 
  7226                              <1> ;int_76h:
  7227                              <1> HD_INT:
  7228                              <1> 	;push	ax
  7229                              <1> 	; 24/12/2021
  7230 00002D6F 50                  <1> 	push	eax
  7231 00002D70 1E                  <1> 	push	ds
  7232                              <1> 	;CALL	DDS
  7233                              <1> 	; 21/02/2015 (32 bit, 386 pm modification)
  7234 00002D71 66B81000            <1> 	mov	ax, KDATA
  7235 00002D75 8ED8                <1> 	mov 	ds, ax
  7236                              <1> 	;
  7237                              <1> 	;;MOV	@HF_INT_FLAG,0FFH	; ALL DONE
  7238                              <1>         ;mov     byte [CS:HF_INT_FLAG], 0FFh
  7239 00002D77 C605[676B0000]FF    <1> 	mov	byte [HF_INT_FLAG], 0FFh
  7240                              <1> 	;
  7241                              <1> 	;push	dx
  7242                              <1> 	; 24/12/2021
  7243 00002D7E 52                  <1> 	push	edx
  7244 00002D7F 66BAF701            <1> 	mov	dx, HDC1_BASEPORT+7	; Status Register (1F7h)
  7245                              <1> 					; Clear Controller
  7246                              <1> Clear_IRQ1415:				; (Award BIOS - 1999)
  7247 00002D83 EC                  <1> 	in	al, dx			;
  7248                              <1> 	;pop	dx
  7249                              <1> 	; 24/12/2021
  7250 00002D84 5A                  <1> 	pop	edx
  7251                              <1> 	NEWIODELAY
  2150 00002D85 E6EB                <2>  out 0EBh,al
  7252                              <1> 	;
  7253 00002D87 B020                <1> 	MOV	AL,EOI			; NON-SPECIFIC END OF INTERRUPT
  7254 00002D89 E6A0                <1> 	OUT	INTB00,AL		; FOR CONTROLLER #2
  7255                              <1> 	;JMP	$+2			; WAIT
  7256                              <1> 	NEWIODELAY
  2150 00002D8B E6EB                <2>  out 0EBh,al
  7257 00002D8D E620                <1> 	OUT	INTA00,AL		; FOR CONTROLLER #1
  7258 00002D8F 1F                  <1> 	pop	ds
  7259                              <1> 	;STI				; RE-ENABLE INTERRUPTS
  7260                              <1> 	;MOV	AX,9100H		; DEVICE POST
  7261                              <1> 	;INT	15H			;  INTERRUPT
  7262                              <1> irq15_iret: ; 25/02/2015
  7263                              <1> 	;pop	ax
  7264                              <1> 	; 24/12/2021
  7265 00002D90 58                  <1> 	pop	eax
  7266 00002D91 CF                  <1> 	iretd			; RETURN FROM INTERRUPT
  7267                              <1> 
  7268                              <1> 	; 24/12/2021 - Retro UNIX 386 v1.1
  7269                              <1> hdc2_int: ; 21/02/2015
  7270                              <1> ;++++ HARDWARE INT 77H ++ ( IRQ LEVEL  15 ) +++++++++++++++++++++
  7271                              <1> ;								:
  7272                              <1> ;	FIXED DISK INTERRUPT ROUTINE				:
  7273                              <1> ;								:
  7274                              <1> ;++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  7275                              <1> 
  7276                              <1> ;int_77h:
  7277                              <1> HD1_INT:
  7278                              <1> 	;push	ax
  7279                              <1> 	; 24/12/2021
  7280 00002D92 50                  <1> 	push	eax
  7281                              <1> 	; Check if that is a spurious IRQ (from slave PIC)
  7282                              <1> 	; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  7283 00002D93 B00B                <1> 	mov	al, 0Bh  ; In-Service Register
  7284 00002D95 E6A0                <1> 	out	0A0h, al
  7285 00002D97 EB00                <1>         jmp short $+2
  7286 00002D99 EB00                <1> 	jmp short $+2
  7287 00002D9B E4A0                <1> 	in	al, 0A0h
  7288 00002D9D 2480                <1> 	and 	al, 80h ; bit 7 (is it real IRQ 15 or fake?)
  7289 00002D9F 74EF                <1> 	jz	short irq15_iret ; Fake (spurious)IRQ, do not send EOI)
  7290                              <1> 	;
  7291 00002DA1 1E                  <1> 	push	ds
  7292                              <1> 	;CALL	DDS
  7293                              <1> 	; 21/02/2015 (32 bit, 386 pm modification)
  7294 00002DA2 66B81000            <1> 	mov	ax, KDATA
  7295 00002DA6 8ED8                <1> 	mov 	ds, ax
  7296                              <1> 	;
  7297                              <1> 	;;MOV	@HF_INT_FLAG,0FFH	; ALL DONE
  7298                              <1>         ;or	byte [CS:HF_INT_FLAG],0C0h 
  7299 00002DA8 800D[676B0000]C0    <1> 	or	byte [HF_INT_FLAG], 0C0h
  7300                              <1> 	;
  7301                              <1> 	;push	dx
  7302                              <1> 	; 24/12/2021
  7303 00002DAF 52                  <1> 	push	edx
  7304 00002DB0 66BA7701            <1> 	mov	dx, HDC2_BASEPORT+7	; Status Register (177h)
  7305                              <1> 					; Clear Controller (Award BIOS 1999)
  7306 00002DB4 EBCD                <1> 	jmp	short Clear_IRQ1415
  7307                              <1> 
  7308                              <1> ;%include 'diskdata.inc' ; 11/03/2015
  7309                              <1> ;%include 'diskbss.inc' ; 11/03/2015
  7310                              <1> 
  7311                              <1> ;////////////////////////////////////////////////////////////////////
  7312                              <1> ;; END OF DISK I/O SYTEM ///
  2089                                  %include 'memory.inc'  ; 09/03/2015
  2090                              <1> ; MEMORY.ASM - Retro UNIX 386 v1.1 MEMORY MANAGEMENT FUNCTIONS (PROCEDURES)
  2091                              <1> ; Retro UNIX 386 v1.1 Kernel (unix386.s, v0.2.1.1) - MEMORY.INC
  2092                              <1> ; Last Modification: 31/12/2021
  2093                              <1> ;
  2094                              <1> ; Source code for NASM - Netwide Assembler (2.15)
  2095                              <1> 
  2096                              <1> ; ///////// MEMORY MANAGEMENT FUNCTIONS (PROCEDURES) ///////////////
  2097                              <1> 
  2098                              <1> ;;04/11/2014 (unix386.s)	
  2099                              <1> ;PDE_A_PRESENT	equ 1		; Present flag for PDE
  2100                              <1> ;PDE_A_WRITE	equ 2		; Writable (write permission) flag
  2101                              <1> ;PDE_A_USER	equ 4		; User (non-system/kernel) page flag
  2102                              <1> ;;
  2103                              <1> ;PTE_A_PRESENT	equ 1		; Present flag for PTE (bit 0)
  2104                              <1> ;PTE_A_WRITE	equ 2		; Writable (write permission) flag (bit 1)
  2105                              <1> ;PTE_A_USER	equ 4		; User (non-system/kernel) page flag (bit 2)
  2106                              <1> ;PTE_A_ACCESS   equ 32		; Accessed flag (bit 5) ; 09/03/2015
  2107                              <1> 
  2108                              <1> ; 27/04/2015
  2109                              <1> ; 09/03/2015
  2110                              <1> PAGE_SIZE 	equ 4096	; page size in bytes
  2111                              <1> PAGE_SHIFT 	equ 12		; page table shift count
  2112                              <1> PAGE_D_SHIFT 	equ 22 ; 12+10	; page directory shift count
  2113                              <1> PAGE_OFF	equ 0FFFh	; 12 bit byte offset in page frame
  2114                              <1> PTE_MASK 	equ 03FFh	; page table entry mask
  2115                              <1> PTE_DUPLICATED  equ 200h	; duplicated page sign (AVL bit 0)
  2116                              <1> PDE_A_CLEAR	equ 0F000h	; to clear PDE attribute bits
  2117                              <1> PTE_A_CLEAR	equ 0F000h	; to clear PTE attribute bits
  2118                              <1> LOGIC_SECT_SIZE equ 512		; logical sector size
  2119                              <1> ERR_MAJOR_PF	equ 0E0h	; major error: page fault
  2120                              <1> ; 15/10/2016 (TRDOS 386 v2)
  2121                              <1> ERR_MINOR_IM	equ 4 ;15/10/2016 (1->4); insufficient (out of) memory
  2122                              <1> ERR_MINOR_PV	equ 6 ;15/10/2016 (3->6); protection violation
  2123                              <1> SWP_DISK_READ_ERR 	   equ 40
  2124                              <1> SWP_DISK_NOT_PRESENT_ERR   equ 41
  2125                              <1> SWP_SECTOR_NOT_PRESENT_ERR equ 42
  2126                              <1> SWP_NO_FREE_SPACE_ERR      equ 43
  2127                              <1> SWP_DISK_WRITE_ERR         equ 44
  2128                              <1> SWP_NO_PAGE_TO_SWAP_ERR    equ 45
  2129                              <1> PTE_A_ACCESS_BIT equ 5	; Bit 5 (accessed flag)        
  2130                              <1> SECTOR_SHIFT     equ 3	; sector shift (to convert page block number)
  2131                              <1> ; 10/06/2021 (Retro UNIX 386 v2)
  2132                              <1> ; 12/07/2016 (TRDOS 386 v2) 
  2133                              <1> PTE_SHARED	 equ 400h		; AVL bit 1, direct memory access bit	
  2134                              <1> 					; (Indicates that the page is not allocated
  2135                              <1> 					; for the process, it is a shared or system
  2136                              <1>                                         ; page, it must not be deallocated!)
  2137                              <1> ; 14/12/2020
  2138                              <1> ; (Linear Frame Buffer - video memory mark : AVL bit 1, outside M.A.T.)
  2139                              <1> PDE_EXTERNAL	equ 400h	; Page directory entry for external memory blocks
  2140                              <1> PTE_EXTERNAL	equ 400h	; Allocated kernel pages for Linear Frame Buffer
  2141                              <1> 				; (Out of memory allocation table)	
  2142                              <1> ;
  2143                              <1> ;; Retro Unix 386 v1 - paging method/principles
  2144                              <1> ;;
  2145                              <1> ;; 10/10/2014
  2146                              <1> ;; RETRO UNIX 386 v1 - PAGING METHOD/PRINCIPLES
  2147                              <1> ;;
  2148                              <1> ;; KERNEL PAGE MAP: 1 to 1 physical memory page map
  2149                              <1> ;;	(virtual address = physical address)
  2150                              <1> ;; KERNEL PAGE TABLES:
  2151                              <1> ;;	Kernel page directory and all page tables are
  2152                              <1> ;;	on memory as initialized, as equal to physical memory
  2153                              <1> ;;	layout. Kernel pages can/must not be swapped out/in.
  2154                              <1> ;;
  2155                              <1> ;;	what for: User pages may be swapped out, when accessing
  2156                              <1> ;;	a page in kernel/system mode, if it would be swapped out,
  2157                              <1> ;;	kernel would have to swap it in! But it is also may be
  2158                              <1> ;;	in use by a user process. (In system/kernel mode
  2159                              <1> ;;	kernel can access all memory pages even if they are
  2160                              <1> ;;	reserved/allocated for user processes. Swap out/in would
  2161                              <1> ;;	cause conflicts.) 
  2162                              <1> ;;	
  2163                              <1> ;;	As result of these conditions,
  2164                              <1> ;;	all kernel pages must be initialized as equal to 
  2165                              <1> ;;	physical layout for preventing page faults. 
  2166                              <1> ;;	Also, calling "allocate page" procedure after
  2167                              <1> ;;	a page fault can cause another page fault (double fault)
  2168                              <1> ;;	if all kernel page tables would not be initialized.
  2169                              <1> ;;
  2170                              <1> ;;	[first_page] = Beginning of users space, as offset to 
  2171                              <1> ;;	memory allocation table. (double word aligned)
  2172                              <1> ;;
  2173                              <1> ;;	[next_page] = first/next free space to be searched
  2174                              <1> ;;	as offset to memory allocation table. (dw aligned)
  2175                              <1> ;;
  2176                              <1> ;;	[last_page] = End of memory (users space), as offset
  2177                              <1> ;;	to memory allocation table. (double word aligned)
  2178                              <1> ;;
  2179                              <1> ;; USER PAGE TABLES:
  2180                              <1> ;;	Demand paging (& 'copy on write' allocation method) ...
  2181                              <1> ;;		'ready only' marked copies of the 
  2182                              <1> ;;		parent process's page table entries (for
  2183                              <1> ;;		same physical memory).
  2184                              <1> ;;		(A page will be copied to a new page after
  2185                              <1> ;;		 if it causes R/W page fault.)
  2186                              <1> ;;
  2187                              <1> ;;	Every user process has own (different)
  2188                              <1> ;;	page directory and page tables.	
  2189                              <1> ;;
  2190                              <1> ;;	Code starts at virtual address 0, always.
  2191                              <1> ;;	(Initial value of EIP is 0 in user mode.)
  2192                              <1> ;;	(Programs can be written/developed as simple
  2193                              <1> ;;	 flat memory programs.)
  2194                              <1> ;;
  2195                              <1> ;; MEMORY ALLOCATION STRATEGY:
  2196                              <1> ;;	Memory page will be allocated by kernel only 
  2197                              <1> ;;		(in kernel/system mode only).
  2198                              <1> ;;	* After a
  2199                              <1> ;;	  - 'not present' page fault
  2200                              <1> ;;	  - 'writing attempt on read only page' page fault 	 	
  2201                              <1> ;;	* For loading (opening, reading) a file or disk/drive
  2202                              <1> ;;	* As responce to 'allocate additional memory blocks' 
  2203                              <1> ;;	  request by running process.
  2204                              <1> ;;	* While creating a process, allocating a new buffer,
  2205                              <1> ;;	  new page tables etc.
  2206                              <1> ;;
  2207                              <1> ;;	At first,
  2208                              <1> ;;	- 'allocate page' procedure will be called;
  2209                              <1> ;,	   if it will return with a valid (>0) physical address
  2210                              <1> ;;	   (that means the relevant M.A.T. bit has been RESET)	
  2211                              <1> ;;	   relevant memory page/block will be cleared (zeroed).
  2212                              <1> ;;	- 'allocate page' will be called for allocating page
  2213                              <1> ;;	   directory, page table and running space (data/code).
  2214                              <1> ;;	- every successful 'allocate page' call will decrease
  2215                              <1> ;;	  'free_pages' count (pointer).
  2216                              <1> ;;	- 'out of (insufficient) memory error' will be returned
  2217                              <1> ;;	  if 'free_pages' points to a ZERO.
  2218                              <1> ;;	- swapping out and swapping in (if it is not a new page)
  2219                              <1> ;;	  procedures will be called as responce to 'out of memory'
  2220                              <1> ;;	  error except errors caused by attribute conflicts.
  2221                              <1> ;;	 (swapper functions)	 
  2222                              <1> ;;					
  2223                              <1> ;;	At second,
  2224                              <1> ;;	- page directory entry will be updated then page table
  2225                              <1> ;;	  entry will be updated.		
  2226                              <1> ;;
  2227                              <1> ;; MEMORY ALLOCATION TABLE FORMAT:
  2228                              <1> ;;	- M.A.T. has a size according to available memory as
  2229                              <1> ;;	  follows:
  2230                              <1> ;;		  - 1 (allocation) bit per 1 page (4096 bytes)
  2231                              <1> ;;		  - a bit with value of 0 means allocated page
  2232                              <1> ;;		  - a bit with value of 1 means a free page
  2233                              <1> ;,	- 'free_pages' pointer holds count of free pages
  2234                              <1> ;;	  depending on M.A.T.
  2235                              <1> ;;		(NOTE: Free page count will not be checked
  2236                              <1> ;;		again -on M.A.T.- after initialization. 
  2237                              <1> ;;		Kernel will trust on initial count.)
  2238                              <1> ;,	- 'free_pages' count will be decreased by allocation
  2239                              <1> ;;	  and it will be increased by deallocation procedures.
  2240                              <1> ;;	
  2241                              <1> ;;	- Available memory will be calculated during
  2242                              <1> ;;	  the kernel's initialization stage (in real mode).
  2243                              <1> ;;	  Memory allocation table and kernel page tables 
  2244                              <1> ;;	  will be formatted/sized as result of available
  2245                              <1> ;;	  memory calculation before paging is enabled.
  2246                              <1> ;;
  2247                              <1> ;; For 4GB Available/Present Memory: (max. possible memory size)
  2248                              <1> ;;	- Memory Allocation Table size will be 128 KB.
  2249                              <1> ;;	- Memory allocation for kernel page directory size 
  2250                              <1> ;;	  is always 4 KB. (in addition to total allocation size
  2251                              <1> ;;	  for page tables)
  2252                              <1> ;;	- Memory allocation for kernel page tables (1024 tables)
  2253                              <1> ;;	  is 4 MB (1024*4*1024 bytes).
  2254                              <1> ;;	- User (available) space will be started 
  2255                              <1> ;;	  at 6th MB of the memory (after 1MB+4MB).
  2256                              <1> ;;	- The first 640 KB is for kernel's itself plus
  2257                              <1> ;;	  memory allocation table and kernel's page directory
  2258                              <1> ;;	  (D0000h-EFFFFh may be used as kernel space...)	
  2259                              <1> ;;	- B0000h to B7FFFh address space (32 KB) will be used
  2260                              <1> ;; 	  for buffers.
  2261                              <1> ;;	- ROMBIOS, VIDEO BUFFER and VIDEO ROM space are reserved.
  2262                              <1> ;,	  (A0000h-AFFFFh, C0000h-CFFFFh, F0000h-FFFFFh)
  2263                              <1> ;;	- Kernel page tables start at 100000h (2nd MB)
  2264                              <1> ;;
  2265                              <1> ;; For 1GB Available Memory:
  2266                              <1> ;;	- Memory Allocation Table size will be 32 KB.
  2267                              <1> ;;	- Memory allocation for kernel page directory size 
  2268                              <1> ;;	  is always 4 KB. (in addition to total allocation size
  2269                              <1> ;;	  for page tables)
  2270                              <1> ;;	- Memory allocation for kernel page tables (256 tables)
  2271                              <1> ;;	  is 1 MB (256*4*1024 bytes).
  2272                              <1> ;;	- User (available) space will be started 
  2273                              <1> ;;	  at 3th MB of the memory (after 1MB+1MB).
  2274                              <1> ;;	- The first 640 KB is for kernel's itself plus
  2275                              <1> ;;	  memory allocation table and kernel's page directory
  2276                              <1> ;;	  (D0000h-EFFFFh may be used as kernel space...)	
  2277                              <1> ;;	- B0000h to B7FFFh address space (32 KB) will be used
  2278                              <1> ;; 	  for buffers.
  2279                              <1> ;;	- ROMBIOS, VIDEO BUFFER and VIDEO ROM space are reserved.
  2280                              <1> ;,	  (A0000h-AFFFFh, C0000h-CFFFFh, F0000h-FFFFFh)
  2281                              <1> ;;	- Kernel page tables start at 100000h (2nd MB).	
  2282                              <1> ;;
  2283                              <1> ;;
  2284                              <1> 
  2285                              <1> ;;************************************************************************************
  2286                              <1> ;; 
  2287                              <1> ;; RETRO UNIX 386 v1 - Paging (Method for Copy On Write paging principle)
  2288                              <1> ;; DEMAND PAGING - PARENT&CHILD PAGE TABLE DUPLICATION PRINCIPLES (23/04/2015)
  2289                              <1> 
  2290                              <1> ;; Main factor: "sys fork" system call 
  2291                              <1> ;;	
  2292                              <1> ;; 		FORK
  2293                              <1> ;;                      |----> parent - duplicated PTEs, read only pages
  2294                              <1> ;;  writable pages ---->|
  2295                              <1> ;;                      |----> child - duplicated PTEs, read only pages
  2296                              <1> ;; 
  2297                              <1> ;; AVL bit (0) of Page Table Entry is used as duplication sign 
  2298                              <1> ;; 
  2299                              <1> ;; AVL Bit 0 [PTE Bit 9] = 'Duplicated PTE belongs to child' sign/flag (if it is set)
  2300                              <1> ;; Note: Dirty bit (PTE bit 6) may be used instead of AVL bit 0 (PTE bit 9)
  2301                              <1> ;;       -while R/W bit is 0-. 
  2302                              <1> ;; 
  2303                              <1> ;; Duplicate page tables with writable pages (the 1st sys fork in the process):
  2304                              <1> ;; # Parent's Page Table Entries are updated to point same pages as read only, 
  2305                              <1> ;;   as duplicated PTE bit  -AVL bit 0, PTE bit 9- are reset/clear.
  2306                              <1> ;; # Then Parent's Page Table is copied to Child's Page Table.
  2307                              <1> ;; # Child's Page Table Entries are updated as duplicated child bit
  2308                              <1> ;;   -AVL bit 0, PTE bit 9- is set.	  
  2309                              <1> ;; 
  2310                              <1> ;; Duplicate page tables with read only pages (several sys fork system calls):
  2311                              <1> ;; # Parent's read only pages are copied to new child pages. 
  2312                              <1> ;;   Parent's PTE attributes are not changed.
  2313                              <1> ;;   (Because, there is another parent-child fork before this fork! We must not
  2314                              <1> ;;    destroy/mix previous fork result).
  2315                              <1> ;; # Child's Page Table Entries (which are corresponding to Parent's 
  2316                              <1> ;;   read only pages) are set as writable (while duplicated PTE bit is clear). 
  2317                              <1> ;; # Parent's PTEs with writable page attribute are updated to point same pages 
  2318                              <1> ;;   as read only, (while) duplicated PTE bit is reset (clear).
  2319                              <1> ;; # Parent's Page Table Entries (with writable page attribute) are duplicated 
  2320                              <1> ;;   as Child's Page Table Entries without copying actual page.
  2321                              <1> ;; # Child 's Page Table Entries (which are corresponding to Parent's writable 
  2322                              <1> ;;   pages) are updated as duplicated PTE bit (AVL bit 0, PTE bit 9- is set.
  2323                              <1> ;; 
  2324                              <1> ;; !? WHAT FOR (duplication after duplication):
  2325                              <1> ;; In UNIX method for sys fork (a typical 'fork' application in /etc/init)
  2326                              <1> ;; program/executable code continues from specified location as child process, 
  2327                              <1> ;; returns back previous code location as parent process, every child after 
  2328                              <1> ;; every sys fork uses last image of code and data just prior the fork.
  2329                              <1> ;; Even if the parent code changes data, the child will not see the changed data 
  2330                              <1> ;; after the fork. In Retro UNIX 8086 v1, parent's process segment (32KB)
  2331                              <1> ;; was copied to child's process segment (all of code and data) according to
  2332                              <1> ;; original UNIX v1 which copies all of parent process code and data -core- 
  2333                              <1> ;; to child space -core- but swaps that core image -of child- on to disk.
  2334                              <1> ;; If I (Erdogan Tan) would use a method of to copy parent's core
  2335                              <1> ;; (complete running image of parent process) to the child process; 
  2336                              <1> ;; for big sizes, i would force Retro UNIX 386 v1 to spend many memory pages 
  2337                              <1> ;; and times only for a sys fork. (It would excessive reservation for sys fork,
  2338                              <1> ;; because sys fork usually is prior to sys exec; sys exec always establishes
  2339                              <1> ;; a new/fresh core -running space-, by clearing all code/data content). 
  2340                              <1> ;; 'Read Only' page flag ensures page fault handler is needed only for a few write
  2341                              <1> ;; attempts between sys fork and sys exec, not more... (I say so by thinking 
  2342                              <1> ;; of "/etc/init" content, specially.) sys exec will clear page tables and
  2343                              <1> ;; new/fresh pages will be used to load and run new executable/program.
  2344                              <1> ;; That is what for i have preferred "copy on write", "duplication" method
  2345                              <1> ;; for sharing same read only pages between parent and child processes.
  2346                              <1> ;; That is a pitty i have to use new private flag (AVL bit 0, "duplicated PTE 
  2347                              <1> ;; belongs to child" sign) for cooperation on duplicated pages between a parent 
  2348                              <1> ;; and it's child processes; otherwise parent process would destroy data belongs
  2349                              <1> ;; to its child or vice versa; or some pages would remain unclaimed 
  2350                              <1> ;; -deallocation problem-.
  2351                              <1> ;; Note: to prevent conflicts, read only pages must not be swapped out... 
  2352                              <1> ;; 
  2353                              <1> ;; WHEN PARENT TRIES TO WRITE IT'S READ ONLY (DUPLICATED) PAGE:
  2354                              <1> ;; # Page fault handler will do those:
  2355                              <1> ;;   - 'Duplicated PTE' flag (PTE bit 9) is checked (on the failed PTE).
  2356                              <1> ;;   - If it is reset/clear, there is a child uses same page.
  2357                              <1> ;;   - Parent's read only page -previous page- is copied to a new writable page. 
  2358                              <1> ;;   - Parent's PTE is updated as writable page, as unique page (AVL=0)
  2359                              <1> ;;   - (Page fault handler whill check this PTE later, if child process causes to
  2360                              <1> ;;     page fault due to write attempt on read only page. Of course, the previous 
  2361                              <1> ;;     read only page will be converted to writable and unique page which belongs
  2362                              <1> ;;     to child process.)	
  2363                              <1> ;; WHEN CHILD TRIES TO WRITE IT'S READ ONLY (DUPLICATED) PAGE:
  2364                              <1> ;; # Page fault handler will do those:
  2365                              <1> ;;   - 'Duplicated PTE' flag (PTE bit 9) is checked (on the failed PTE).
  2366                              <1> ;;   - If it is set, there is a parent uses -or was using- same page.
  2367                              <1> ;;   - Same PTE address within parent's page table is checked if it has same page
  2368                              <1> ;;     address or not. 
  2369                              <1> ;;   - If parent's PTE has same address, child will continue with a new writable page.
  2370                              <1> ;;     Parent's PTE will point to same (previous) page as writable, unique (AVL=0).	
  2371                              <1> ;;   - If parent's PTE has different address, child will continue with it's 
  2372                              <1> ;;     own/same page but read only flag (0) will be changed to writable flag (1) and
  2373                              <1> ;;     'duplicated PTE (belongs to child)' flag/sign will be cleared/reset. 	  	
  2374                              <1> ;; 
  2375                              <1> ;; NOTE: When a child process is terminated, read only flags of parent's page tables
  2376                              <1> ;;       will be set as writable (and unique) in case of child process was using 
  2377                              <1> ;;       same pages with duplicated child PTE sign... Depending on sys fork and 
  2378                              <1> ;;       duplication method details, it is not possible multiple child processes
  2379                              <1> ;;       were using same page with duplicated PTEs.
  2380                              <1> ;; 
  2381                              <1> ;;************************************************************************************   
  2382                              <1> 
  2383                              <1> ;; 08/10/2014
  2384                              <1> ;; 11/09/2014 - Retro UNIX 386 v1 PAGING (further) draft
  2385                              <1> ;;		by Erdogan Tan (Based on KolibriOS 'memory.inc')
  2386                              <1> 
  2387                              <1> ;; 'allocate_page' code is derived and modified from KolibriOS
  2388                              <1> ;; 'alloc_page' procedure in 'memory.inc' 
  2389                              <1> ;; (25/08/2014, Revision: 5057) file 
  2390                              <1> ;; by KolibriOS Team (2004-2012)
  2391                              <1> 
  2392                              <1> allocate_page:
  2393                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2394                              <1> 	; 01/07/2015
  2395                              <1> 	; 05/05/2015
  2396                              <1> 	; 30/04/2015
  2397                              <1> 	; 16/10/2014
  2398                              <1> 	; 08/10/2014
  2399                              <1> 	; 09/09/2014 (Retro UNIX 386 v1 - beginning)
  2400                              <1> 	;
  2401                              <1> 	; INPUT -> none
  2402                              <1> 	;
  2403                              <1> 	; OUTPUT ->
  2404                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  2405                              <1> 	;	(corresponding MEMORY ALLOCATION TABLE bit is RESET)
  2406                              <1> 	;
  2407                              <1> 	;	CF = 1 and EAX = 0 
  2408                              <1> 	; 		   if there is not a free page to be allocated	
  2409                              <1> 	;
  2410                              <1> 	; Modified Registers -> none (except EAX)
  2411                              <1> 	;
  2412 00002DB6 A1[E06A0000]        <1> 	mov	eax, [free_pages]
  2413 00002DBB 21C0                <1> 	and	eax, eax
  2414 00002DBD 7438                <1> 	jz	short out_of_memory
  2415                              <1> 	;
  2416 00002DBF 53                  <1> 	push	ebx
  2417 00002DC0 51                  <1> 	push	ecx
  2418                              <1> 	;
  2419 00002DC1 BB00001000          <1> 	mov	ebx, MEM_ALLOC_TBL   ; Memory Allocation Table offset
  2420 00002DC6 89D9                <1> 	mov	ecx, ebx
  2421                              <1>  				     ; NOTE: 32 (first_page) is initial
  2422                              <1> 				     ; value of [next_page].
  2423                              <1> 				     ; It points to the first available
  2424                              <1> 				     ; page block for users (ring 3) ...	
  2425                              <1> 				     ; (MAT offset 32 = 1024/32)	
  2426                              <1> 				     ; (at the of the first 4 MB)		
  2427 00002DC8 031D[E46A0000]      <1> 	add	ebx, [next_page] ; Free page searching starts from here
  2428                              <1> 				 ; next_free_page >> 5
  2429 00002DCE 030D[E86A0000]      <1> 	add	ecx, [last_page] ; Free page searching ends here
  2430                              <1> 				 ; (total_pages - 1) >> 5
  2431                              <1> al_p_scan:
  2432 00002DD4 39CB                <1> 	cmp	ebx, ecx
  2433 00002DD6 770A                <1> 	ja	short al_p_notfound
  2434                              <1> 	;
  2435                              <1> 	; 01/07/2015
  2436                              <1> 	; AMD64 Architecture Programmers Manual
  2437                              <1> 	; Volume 3:
  2438                              <1> 	; General-Purpose and System Instructions
  2439                              <1> 	;
  2440                              <1> 	; BSF - Bit Scan Forward
  2441                              <1> 	;
  2442                              <1> 	;   Searches the value in a register or a memory location
  2443                              <1> 	;   (second operand) for the least-significant set bit. 
  2444                              <1> 	;   If a set bit is found, the instruction clears the zero flag (ZF)
  2445                              <1> 	;   and stores the index of the least-significant set bit in a destination
  2446                              <1> 	;   register (first operand). If the second operand contains 0, 
  2447                              <1> 	;   the instruction sets ZF to 1 and does not change the contents of the 
  2448                              <1> 	;   destination register. The bit index is an unsigned offset from bit 0 
  2449                              <1> 	;   of the searched value
  2450                              <1> 	;
  2451 00002DD8 0FBC03              <1> 	bsf	eax, [ebx] ; Scans source operand for first bit set (1).
  2452                              <1> 			   ; Clear ZF if a bit is found set (1) and 
  2453                              <1> 			   ; loads the destination with an index to
  2454                              <1> 			   ; first set bit. (0 -> 31) 
  2455                              <1> 			   ; Sets ZF to 1 if no bits are found set.
  2456 00002DDB 751C                <1> 	jnz	short al_p_found ; ZF = 0 -> a free page has been found
  2457                              <1> 			 ;
  2458                              <1> 			 ; NOTE:  a Memory Allocation Table bit 
  2459                              <1> 			 ;	  with value of 1 means 
  2460                              <1> 			 ;	  the corresponding page is free 
  2461                              <1> 			 ;	  (Retro UNIX 386 v1 feature only!)
  2462 00002DDD 83C304              <1> 	add	ebx, 4
  2463                              <1> 			 ; We return back for searching next page block
  2464                              <1> 			 ; NOTE: [free_pages] is not ZERO; so, 
  2465                              <1> 			 ;	 we always will find at least 1 free page here.
  2466 00002DE0 EBF2                <1>         jmp     short al_p_scan
  2467                              <1> 	;
  2468                              <1> al_p_notfound:
  2469 00002DE2 81E900001000        <1> 	sub	ecx, MEM_ALLOC_TBL
  2470 00002DE8 890D[E46A0000]      <1> 	mov	[next_page], ecx ; next/first free page = last page 
  2471                              <1> 				 ; (deallocate_page procedure will change it)
  2472 00002DEE 31C0                <1> 	xor	eax, eax
  2473 00002DF0 A3[E06A0000]        <1> 	mov	[free_pages], eax ; 0
  2474 00002DF5 59                  <1> 	pop	ecx
  2475 00002DF6 5B                  <1> 	pop	ebx
  2476                              <1> 	;
  2477                              <1> ; 24/12/2021
  2478                              <1> ; ('swap_out' procedure call is disabled)
  2479                              <1> 
  2480                              <1> out_of_memory:
  2481                              <1> ;	call	swap_out
  2482                              <1> ;	jnc	short al_p_ok  ; [free_pages] = 0, re-allocation by swap_out
  2483                              <1> ;	;
  2484                              <1> ;	sub 	eax, eax ; 0
  2485 00002DF7 F9                  <1> 	stc
  2486 00002DF8 C3                  <1> 	retn
  2487                              <1> 
  2488                              <1> al_p_found:
  2489 00002DF9 89D9                <1> 	mov	ecx, ebx
  2490 00002DFB 81E900001000        <1> 	sub	ecx, MEM_ALLOC_TBL
  2491 00002E01 890D[E46A0000]      <1> 	mov	[next_page], ecx ; Set first free page searching start
  2492                              <1> 				 ; address/offset (to the next)
  2493 00002E07 FF0D[E06A0000]      <1>         dec     dword [free_pages] ; 1 page has been allocated (X = X-1) 
  2494                              <1> 	;
  2495 00002E0D 0FB303              <1> 	btr	[ebx], eax	 ; The destination bit indexed by the source value
  2496                              <1> 				 ; is copied into the Carry Flag and then cleared
  2497                              <1> 				 ; in the destination.
  2498                              <1> 				 ;
  2499                              <1> 				 ; Reset the bit which is corresponding to the 
  2500                              <1> 				 ; (just) allocated page.
  2501                              <1> 	; 01/07/2015 (4*8 = 32, 1 allocation byte = 8 pages)	
  2502 00002E10 C1E103              <1> 	shl	ecx, 3		 ; (page block offset * 32) + page index
  2503 00002E13 01C8                <1> 	add	eax, ecx	 ; = page number
  2504 00002E15 C1E00C              <1> 	shl	eax, 12		 ; physical address of the page (flat/real value)
  2505                              <1> 	; EAX = physical address of memory page
  2506                              <1> 	;
  2507                              <1> 	; NOTE: The relevant page directory and page table entry will be updated
  2508                              <1> 	;       according to this EAX value...
  2509 00002E18 59                  <1> 	pop	ecx
  2510 00002E19 5B                  <1> 	pop	ebx
  2511                              <1> al_p_ok:
  2512 00002E1A C3                  <1> 	retn
  2513                              <1> 
  2514                              <1> make_page_dir:
  2515                              <1> 	; 18/04/2015
  2516                              <1> 	; 12/04/2015
  2517                              <1> 	; 23/10/2014
  2518                              <1> 	; 16/10/2014
  2519                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2520                              <1> 	;
  2521                              <1> 	; INPUT ->
  2522                              <1> 	;	none
  2523                              <1> 	; OUTPUT ->
  2524                              <1> 	;	(EAX = 0)
  2525                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2526                              <1> 	;	cf = 0 ->
  2527                              <1> 	;	u.pgdir = page directory (physical) address of the current
  2528                              <1> 	;		  process/user.
  2529                              <1> 	;
  2530                              <1> 	; Modified Registers -> EAX
  2531                              <1> 	;
  2532 00002E1B E896FFFFFF          <1> 	call	allocate_page
  2533 00002E20 7216                <1> 	jc	short mkpd_error
  2534                              <1> 	;
  2535 00002E22 A3[F16E0000]        <1> 	mov	[u.pgdir], eax    ; Page dir address for current user/process
  2536                              <1> 				  ; (Physical address)
  2537                              <1> clear_page:
  2538                              <1> 	; 18/04/2015
  2539                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2540                              <1> 	;
  2541                              <1> 	; INPUT ->
  2542                              <1> 	;	EAX = physical address of the page
  2543                              <1> 	; OUTPUT ->
  2544                              <1> 	;	all bytes of the page will be cleared
  2545                              <1> 	;
  2546                              <1> 	; Modified Registers -> none
  2547                              <1> 	;
  2548 00002E27 57                  <1> 	push	edi
  2549 00002E28 51                  <1> 	push	ecx
  2550 00002E29 50                  <1> 	push	eax
  2551 00002E2A B900040000          <1> 	mov	ecx, PAGE_SIZE / 4
  2552 00002E2F 89C7                <1> 	mov	edi, eax
  2553 00002E31 31C0                <1> 	xor	eax, eax
  2554 00002E33 F3AB                <1> 	rep	stosd
  2555 00002E35 58                  <1> 	pop	eax
  2556 00002E36 59                  <1> 	pop	ecx
  2557 00002E37 5F                  <1> 	pop	edi
  2558                              <1> mkpd_error:
  2559                              <1> mkpt_error:
  2560 00002E38 C3                  <1> 	retn
  2561                              <1> 
  2562                              <1> make_page_table:
  2563                              <1> 	; 23/06/2015
  2564                              <1> 	; 18/04/2015
  2565                              <1> 	; 12/04/2015
  2566                              <1> 	; 16/10/2014
  2567                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2568                              <1> 	;
  2569                              <1> 	; INPUT ->
  2570                              <1> 	;	EBX = virtual (linear) address
  2571                              <1> 	;	ECX = page table attributes (lower 12 bits)
  2572                              <1> 	;	      (higher 20 bits must be ZERO)
  2573                              <1> 	;	      (bit 0 must be 1)	 
  2574                              <1> 	;	u.pgdir = page directory (physical) address
  2575                              <1> 	; OUTPUT ->
  2576                              <1> 	;	EDX = Page directory entry address
  2577                              <1> 	;	EAX = Page table address
  2578                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2579                              <1> 	;	cf = 0 -> page table address in the PDE (EDX)
  2580                              <1> 	;
  2581                              <1> 	; Modified Registers -> EAX, EDX
  2582                              <1> 	;
  2583 00002E39 E878FFFFFF          <1> 	call	allocate_page
  2584 00002E3E 72F8                <1> 	jc	short mkpt_error
  2585 00002E40 E811000000          <1> 	call	set_pde	
  2586 00002E45 EBE0                <1> 	jmp	short clear_page
  2587                              <1> 
  2588                              <1> make_page:
  2589                              <1> 	; 24/07/2015
  2590                              <1> 	; 23/06/2015 ; (Retro UNIX 386 v1 - beginning)
  2591                              <1> 	;
  2592                              <1> 	; INPUT ->
  2593                              <1> 	;	EBX = virtual (linear) address
  2594                              <1> 	;	ECX = page attributes (lower 12 bits)
  2595                              <1> 	;	      (higher 20 bits must be ZERO)
  2596                              <1> 	;	      (bit 0 must be 1)	 
  2597                              <1> 	;	u.pgdir = page directory (physical) address
  2598                              <1> 	; OUTPUT ->
  2599                              <1> 	;	EBX = Virtual address
  2600                              <1> 	;	(EDX = PTE value)
  2601                              <1> 	;	EAX = Physical address
  2602                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2603                              <1> 	;
  2604                              <1> 	; Modified Registers -> EAX, EDX
  2605                              <1> 	;
  2606 00002E47 E86AFFFFFF          <1> 	call	allocate_page
  2607 00002E4C 7207                <1> 	jc	short mkp_err
  2608 00002E4E E821000000          <1> 	call	set_pte	
  2609 00002E53 73D2                <1> 	jnc	short clear_page ; 18/04/2015
  2610                              <1> mkp_err:
  2611 00002E55 C3                  <1> 	retn
  2612                              <1> 
  2613                              <1> set_pde:	; Set page directory entry (PDE)
  2614                              <1> 	; 20/07/2015
  2615                              <1> 	; 18/04/2015
  2616                              <1> 	; 12/04/2015
  2617                              <1> 	; 23/10/2014
  2618                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2619                              <1> 	;
  2620                              <1> 	; INPUT ->
  2621                              <1> 	;	EAX = physical address
  2622                              <1> 	;	      (use present value if EAX = 0)
  2623                              <1> 	;	EBX = virtual (linear) address
  2624                              <1> 	;	ECX = page table attributes (lower 12 bits)
  2625                              <1> 	;	      (higher 20 bits must be ZERO)
  2626                              <1> 	;	      (bit 0 must be 1)	 
  2627                              <1> 	;	u.pgdir = page directory (physical) address
  2628                              <1> 	; OUTPUT ->
  2629                              <1> 	;	EDX = PDE address
  2630                              <1> 	;	EAX = page table address (physical)
  2631                              <1> 	;	;(CF=1 -> Invalid page address)
  2632                              <1> 	;
  2633                              <1> 	; Modified Registers -> EDX
  2634                              <1> 	;
  2635 00002E56 89DA                <1> 	mov	edx, ebx
  2636 00002E58 C1EA16              <1> 	shr	edx, PAGE_D_SHIFT ; 22
  2637 00002E5B C1E202              <1> 	shl	edx, 2 ; offset to page directory (1024*4)
  2638 00002E5E 0315[F16E0000]      <1> 	add	edx, [u.pgdir]
  2639                              <1> 	;
  2640 00002E64 21C0                <1> 	and	eax, eax
  2641 00002E66 7506                <1> 	jnz	short spde_1
  2642                              <1> 	;
  2643 00002E68 8B02                <1> 	mov	eax, [edx]  ; old PDE value
  2644                              <1> 	;test	al, 1
  2645                              <1> 	;jz	short spde_2
  2646 00002E6A 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h  ; clear lower 12 bits
  2647                              <1> spde_1:
  2648                              <1> 	;and	cx, 0FFFh
  2649 00002E6E 8902                <1> 	mov	[edx], eax
  2650 00002E70 66090A              <1> 	or	[edx], cx
  2651 00002E73 C3                  <1> 	retn
  2652                              <1> ;spde_2: ; error
  2653                              <1> ;	stc
  2654                              <1> ;	retn
  2655                              <1> 
  2656                              <1> set_pte:	; Set page table entry (PTE)
  2657                              <1> 	; 24/07/2015
  2658                              <1> 	; 20/07/2015
  2659                              <1> 	; 23/06/2015
  2660                              <1> 	; 18/04/2015
  2661                              <1> 	; 12/04/2015
  2662                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2663                              <1> 	;
  2664                              <1> 	; INPUT ->
  2665                              <1> 	;	EAX = physical page address
  2666                              <1> 	;	      (use present value if EAX = 0)
  2667                              <1> 	;	EBX = virtual (linear) address
  2668                              <1> 	;	ECX = page attributes (lower 12 bits)
  2669                              <1> 	;	      (higher 20 bits must be ZERO)
  2670                              <1> 	;	      (bit 0 must be 1)	 
  2671                              <1> 	;	u.pgdir = page directory (physical) address
  2672                              <1> 	; OUTPUT ->
  2673                              <1> 	;	EAX = physical page address
  2674                              <1> 	;	(EDX = PTE value)
  2675                              <1> 	;	EBX = virtual address
  2676                              <1> 	;
  2677                              <1> 	;	CF = 1 -> error
  2678                              <1> 	;
  2679                              <1> 	; Modified Registers -> EAX, EDX
  2680                              <1> 	;
  2681 00002E74 50                  <1> 	push	eax
  2682 00002E75 A1[F16E0000]        <1> 	mov	eax, [u.pgdir] ; 20/07/2015
  2683 00002E7A E837000000          <1> 	call 	get_pde
  2684                              <1> 		; EDX = PDE address
  2685                              <1> 		; EAX = PDE value
  2686 00002E7F 5A                  <1> 	pop	edx ; physical page address
  2687 00002E80 722A                <1> 	jc	short spte_err ; PDE not present
  2688                              <1> 	;
  2689 00002E82 53                  <1> 	push	ebx ; 24/07/2015
  2690 00002E83 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2691                              <1> 			    ; EDX = PT address (physical)	
  2692 00002E87 C1EB0C              <1> 	shr	ebx, PAGE_SHIFT ; 12
  2693 00002E8A 81E3FF030000        <1> 	and	ebx, PTE_MASK	; 03FFh
  2694                              <1> 			 ; clear higher 10 bits (PD bits)
  2695 00002E90 C1E302              <1> 	shl	ebx, 2   ; offset to page table (1024*4)
  2696 00002E93 01C3                <1> 	add	ebx, eax
  2697                              <1> 	;
  2698 00002E95 8B03                <1> 	mov	eax, [ebx] ; Old PTE value
  2699 00002E97 A801                <1> 	test	al, 1
  2700 00002E99 740C                <1> 	jz	short spte_0
  2701 00002E9B 09D2                <1> 	or	edx, edx
  2702 00002E9D 750F                <1> 	jnz	short spte_1
  2703 00002E9F 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2704 00002EA3 89C2                <1> 	mov	edx, eax
  2705 00002EA5 EB09                <1> 	jmp	short spte_2	
  2706                              <1> spte_0:
  2707                              <1> 	; If this PTE contains a swap (disk) address,
  2708                              <1> 	; it can be updated by using 'swap_in' procedure
  2709                              <1> 	; only!
  2710 00002EA7 21C0                <1> 	and	eax, eax
  2711 00002EA9 7403                <1> 	jz	short spte_1
  2712                              <1> 	; 24/07/2015
  2713                              <1> 	; swapped page ! (on disk)
  2714 00002EAB 5B                  <1> 	pop	ebx
  2715                              <1> spte_err:
  2716 00002EAC F9                  <1> 	stc
  2717 00002EAD C3                  <1> 	retn
  2718                              <1> spte_1: 
  2719 00002EAE 89D0                <1> 	mov	eax, edx
  2720                              <1> spte_2:
  2721 00002EB0 09CA                <1> 	or	edx, ecx
  2722                              <1> 	; 23/06/2015
  2723 00002EB2 8913                <1> 	mov	[ebx], edx ; PTE value in EDX
  2724                              <1> 	; 24/07/2015
  2725 00002EB4 5B                  <1> 	pop	ebx
  2726 00002EB5 C3                  <1> 	retn
  2727                              <1> 
  2728                              <1> get_pde:	; Get present value of the relevant PDE
  2729                              <1> 	; 20/07/2015
  2730                              <1> 	; 18/04/2015
  2731                              <1> 	; 12/04/2015
  2732                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2733                              <1> 	;
  2734                              <1> 	; INPUT ->
  2735                              <1> 	;	EBX = virtual (linear) address
  2736                              <1> 	;	EAX = page directory (physical) address
  2737                              <1> 	; OUTPUT ->
  2738                              <1> 	;	EDX = Page directory entry address
  2739                              <1> 	;	EAX = Page directory entry value
  2740                              <1> 	;	CF = 1 -> PDE not present or invalid ? 
  2741                              <1> 	; Modified Registers -> EDX, EAX
  2742                              <1> 	;
  2743 00002EB6 89DA                <1> 	mov	edx, ebx
  2744 00002EB8 C1EA16              <1> 	shr	edx, PAGE_D_SHIFT ; 22  (12+10)
  2745 00002EBB C1E202              <1> 	shl 	edx, 2 ; offset to page directory (1024*4)
  2746 00002EBE 01C2                <1> 	add	edx, eax ; page directory address (physical)
  2747 00002EC0 8B02                <1> 	mov	eax, [edx]
  2748 00002EC2 A801                <1> 	test	al, PDE_A_PRESENT ; page table is present or not !
  2749 00002EC4 751F                <1> 	jnz	short gpte_retn
  2750 00002EC6 F9                  <1> 	stc
  2751                              <1> gpde_retn:	
  2752 00002EC7 C3                  <1> 	retn
  2753                              <1> 
  2754                              <1> get_pte:
  2755                              <1> 		; Get present value of the relevant PTE
  2756                              <1> 	; 29/07/2015
  2757                              <1> 	; 20/07/2015
  2758                              <1> 	; 18/04/2015
  2759                              <1> 	; 12/04/2015
  2760                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2761                              <1> 	;
  2762                              <1> 	; INPUT ->
  2763                              <1> 	;	EBX = virtual (linear) address
  2764                              <1> 	;	EAX = page directory (physical) address
  2765                              <1> 	; OUTPUT ->
  2766                              <1> 	;	EDX = Page table entry address (if CF=0)
  2767                              <1> 	;	      Page directory entry address (if CF=1)
  2768                              <1> 	;            (Bit 0 value is 0 if PT is not present)
  2769                              <1> 	;	EAX = Page table entry value (page address)
  2770                              <1> 	;	CF = 1 -> PDE not present or invalid ? 
  2771                              <1> 	; Modified Registers -> EAX, EDX
  2772                              <1> 	;
  2773 00002EC8 E8E9FFFFFF          <1> 	call 	get_pde
  2774 00002ECD 72F8                <1> 	jc	short gpde_retn	; page table is not present
  2775                              <1> 	;jnc	short gpte_1
  2776                              <1> 	;retn
  2777                              <1> ;gpte_1:
  2778 00002ECF 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2779 00002ED3 89DA                <1> 	mov	edx, ebx
  2780 00002ED5 C1EA0C              <1> 	shr	edx, PAGE_SHIFT ; 12
  2781 00002ED8 81E2FF030000        <1> 	and	edx, PTE_MASK	; 03FFh
  2782                              <1> 			 ; clear higher 10 bits (PD bits)
  2783 00002EDE C1E202              <1> 	shl	edx, 2 ; offset from start of page table (1024*4)
  2784 00002EE1 01C2                <1> 	add	edx, eax
  2785 00002EE3 8B02                <1> 	mov	eax, [edx]
  2786                              <1> gpte_retn:
  2787 00002EE5 C3                  <1> 	retn
  2788                              <1> 
  2789                              <1> deallocate_page_dir:
  2790                              <1> 	; 15/09/2015
  2791                              <1> 	; 05/08/2015
  2792                              <1> 	; 30/04/2015
  2793                              <1> 	; 28/04/2015
  2794                              <1> 	; 17/10/2014
  2795                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2796                              <1> 	;
  2797                              <1> 	; INPUT ->
  2798                              <1> 	;	EAX = PHYSICAL ADDRESS OF THE PAGE DIRECTORY (CHILD)
  2799                              <1> 	;	EBX = PHYSICAL ADDRESS OF THE PARENT'S PAGE DIRECTORY
  2800                              <1> 	; OUTPUT ->
  2801                              <1> 	;	All of page tables in the page directory
  2802                              <1> 	;	and page dir's itself will be deallocated
  2803                              <1> 	;	except 'read only' duplicated pages (will be converted
  2804                              <1> 	;	to writable pages).
  2805                              <1> 	;
  2806                              <1> 	; Modified Registers -> EAX
  2807                              <1> 	;
  2808                              <1> 	;
  2809 00002EE6 56                  <1> 	push	esi
  2810 00002EE7 51                  <1> 	push	ecx
  2811 00002EE8 50                  <1> 	push	eax
  2812 00002EE9 89C6                <1> 	mov	esi, eax 
  2813 00002EEB 31C9                <1> 	xor	ecx, ecx
  2814                              <1> 	; The 1st PDE points to Kernel Page Table 0 (the 1st 4MB),
  2815                              <1> 	; it must not be deallocated
  2816 00002EED 890E                <1> 	mov	[esi], ecx ; 0 ; clear PDE 0
  2817                              <1> dapd_0:
  2818 00002EEF AD                  <1> 	lodsd
  2819 00002EF0 A801                <1> 	test	al, PDE_A_PRESENT ; bit 0, present flag (must be 1)
  2820 00002EF2 7409                <1> 	jz	short dapd_1	
  2821 00002EF4 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 (attribute) bits
  2822 00002EF8 E812000000          <1> 	call	deallocate_page_table			
  2823                              <1> dapd_1:
  2824 00002EFD 41                  <1> 	inc	ecx ; page directory entry index
  2825 00002EFE 81F900040000        <1> 	cmp	ecx, PAGE_SIZE / 4 ; 1024
  2826 00002F04 72E9                <1> 	jb	short dapd_0
  2827                              <1> dapd_2:
  2828 00002F06 58                  <1> 	pop	eax
  2829 00002F07 E872000000          <1> 	call	deallocate_page	; deallocate the page dir's itself
  2830 00002F0C 59                  <1> 	pop	ecx
  2831 00002F0D 5E                  <1> 	pop	esi
  2832 00002F0E C3                  <1> 	retn
  2833                              <1> 
  2834                              <1> deallocate_page_table:
  2835                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2836                              <1> 	; 12/07/2016 (TRDOS 386 v2)
  2837                              <1> 	; 19/09/2015
  2838                              <1> 	; 15/09/2015
  2839                              <1> 	; 05/08/2015
  2840                              <1> 	; 30/04/2015
  2841                              <1> 	; 28/04/2015
  2842                              <1> 	; 24/10/2014
  2843                              <1> 	; 23/10/2014
  2844                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2845                              <1> 	;
  2846                              <1> 	; INPUT ->
  2847                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE PAGE TABLE
  2848                              <1> 	;	EBX = PHYSICAL ADDRESS OF THE PARENT'S PAGE DIRECTORY
  2849                              <1> 	;	(ECX = page directory entry index)
  2850                              <1> 	; OUTPUT ->
  2851                              <1> 	;	All of pages in the page table and page table's itself
  2852                              <1> 	;	will be deallocated except 'read only' duplicated pages
  2853                              <1> 	;	(will be converted to writable pages).
  2854                              <1> 	;
  2855                              <1> 	; Modified Registers -> EAX
  2856                              <1> 	;
  2857 00002F0F 56                  <1> 	push	esi
  2858 00002F10 57                  <1> 	push	edi
  2859 00002F11 52                  <1> 	push	edx
  2860 00002F12 50                  <1> 	push	eax ; *
  2861 00002F13 89C6                <1> 	mov	esi, eax 
  2862 00002F15 31FF                <1> 	xor	edi, edi ; 0
  2863                              <1> dapt_0:
  2864 00002F17 AD                  <1> 	lodsd
  2865 00002F18 A801                <1> 	test	al, PTE_A_PRESENT ; bit 0, present flag (must be 1)
  2866 00002F1A 7455                <1> 	jz	short dapt_1
  2867                              <1> 	;
  2868 00002F1C A802                <1> 	test	al, PTE_A_WRITE   ; bit 1, writable (r/w) flag
  2869                              <1> 				  ; (must be 1)
  2870 00002F1E 753F                <1> 	jnz	short dapt_3
  2871                              <1> 	; Read only -duplicated- page (belongs to a parent or a child)
  2872 00002F20 66A90002            <1>         test    ax, PTE_DUPLICATED ; Was this page duplicated 
  2873                              <1> 				   ; as child's page ?
  2874 00002F24 7444                <1> 	jz	short dapt_4 ; Clear PTE but don't deallocate the page!
  2875                              <1> 	; check the parent's PTE value is read only & same page or not.. 
  2876                              <1> 	; ECX = page directory entry index (0-1023)
  2877 00002F26 53                  <1> 	push	ebx
  2878 00002F27 51                  <1> 	push	ecx
  2879 00002F28 66C1E102            <1> 	shl	cx, 2 ; *4 
  2880 00002F2C 01CB                <1> 	add	ebx, ecx ; PDE offset (for the parent)
  2881 00002F2E 8B0B                <1> 	mov	ecx, [ebx]
  2882 00002F30 F6C101              <1> 	test	cl, PDE_A_PRESENT ; present (valid) or not ?
  2883 00002F33 7428                <1> 	jz	short dapt_2	; parent process does not use this page
  2884 00002F35 6681E100F0          <1> 	and	cx, PDE_A_CLEAR ; 0F000h ; Clear attribute bits
  2885                              <1> 	; EDI = page table entry index (0-1023)
  2886 00002F3A 89FA                <1> 	mov	edx, edi 
  2887 00002F3C 66C1E202            <1> 	shl	dx, 2 ; *4 
  2888 00002F40 01CA                <1> 	add	edx, ecx ; PTE offset (for the parent)
  2889 00002F42 8B1A                <1> 	mov	ebx, [edx]
  2890 00002F44 F6C301              <1> 	test	bl, PTE_A_PRESENT ; present or not ?
  2891 00002F47 7414                <1> 	jz	short dapt_2	; parent process does not use this page
  2892 00002F49 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; Clear attribute bits 
  2893 00002F4D 6681E300F0          <1> 	and	bx, PTE_A_CLEAR ; 0F000h ; Clear attribute bits
  2894 00002F52 39D8                <1> 	cmp	eax, ebx	; parent's and child's pages are same ?
  2895 00002F54 7507                <1> 	jne	short dapt_2	; not same page
  2896                              <1> 				; deallocate the child's page
  2897 00002F56 800A02              <1>         or      byte [edx], PTE_A_WRITE ; convert to writable page (parent)
  2898 00002F59 59                  <1> 	pop	ecx
  2899 00002F5A 5B                  <1> 	pop	ebx
  2900 00002F5B EB0D                <1> 	jmp	short dapt_4
  2901                              <1> 
  2902                              <1> ; 24/12/2021
  2903                              <1> ; ('dapt_1' is disabled)
  2904                              <1> ;
  2905                              <1> ;dapt_1:
  2906                              <1> ;	or	eax, eax	; swapped page ?
  2907                              <1> ;	jz	short dapt_5	; no
  2908                              <1> ;				; yes
  2909                              <1> ;	shr	eax, 1
  2910                              <1> ;	call	unlink_swap_block ; Deallocate swapped page block
  2911                              <1> ;				  ; on the swap disk (or in file)
  2912                              <1> ;	jmp	short dapt_5
  2913                              <1> dapt_2:
  2914 00002F5D 59                  <1> 	pop	ecx
  2915 00002F5E 5B                  <1> 	pop	ebx
  2916                              <1> dapt_3:	
  2917                              <1> 	; 12/07/2016
  2918 00002F5F 66A90004            <1> 	test	ax, PTE_SHARED ; shared or direct memory access indicator
  2919 00002F63 7505                <1> 	jnz	short dapt_4   ; AVL bit 1 = 1, do not deallocate this page!
  2920                              <1> 	;
  2921                              <1> 	;and	ax, PTE_A_CLEAR ; 0F000h ; clear lower 12 (attribute) bits
  2922 00002F65 E814000000          <1> 	call	deallocate_page ; set the mem allocation bit of this page
  2923                              <1> dapt_4:
  2924 00002F6A C746FC00000000      <1> 	mov	dword [esi-4], 0 ; clear/reset PTE (child, dupl. as parent)
  2925                              <1> dapt_1:	; 24/12/2021
  2926                              <1> dapt_5:
  2927 00002F71 47                  <1> 	inc	edi ; page table entry index
  2928 00002F72 81FF00040000        <1> 	cmp	edi, PAGE_SIZE / 4 ; 1024
  2929 00002F78 729D                <1> 	jb	short dapt_0
  2930                              <1> 	;
  2931 00002F7A 58                  <1> 	pop	eax ; *
  2932 00002F7B 5A                  <1> 	pop	edx
  2933 00002F7C 5F                  <1> 	pop	edi	
  2934 00002F7D 5E                  <1> 	pop	esi
  2935                              <1> 	;
  2936                              <1> 	;call	deallocate_page	; deallocate the page table's itself
  2937                              <1> 	;retn
  2938                              <1> 
  2939                              <1> deallocate_page:
  2940                              <1> 	; 15/09/2015
  2941                              <1> 	; 28/04/2015
  2942                              <1> 	; 10/03/2015
  2943                              <1> 	; 17/10/2014
  2944                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2945                              <1> 	;
  2946                              <1> 	; INPUT -> 
  2947                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  2948                              <1> 	; OUTPUT ->
  2949                              <1> 	;	[free_pages] is increased
  2950                              <1> 	;	(corresponding MEMORY ALLOCATION TABLE bit is SET)
  2951                              <1> 	;	CF = 1 if the page is already deallocated
  2952                              <1> 	; 	       (or not allocated) before.  
  2953                              <1> 	;
  2954                              <1> 	; Modified Registers -> EAX
  2955                              <1> 	;
  2956 00002F7E 53                  <1> 	push	ebx
  2957 00002F7F 52                  <1> 	push	edx
  2958                              <1> 	;
  2959 00002F80 C1E80C              <1> 	shr	eax, PAGE_SHIFT      ; shift physical address to 
  2960                              <1> 				     ; 12 bits right
  2961                              <1> 				     ; to get page number
  2962 00002F83 89C2                <1> 	mov	edx, eax
  2963                              <1> 	; 15/09/2015
  2964 00002F85 C1EA03              <1> 	shr	edx, 3		     ; to get offset to M.A.T.
  2965                              <1> 				     ; (1 allocation bit = 1 page)
  2966                              <1> 				     ; (1 allocation bytes = 8 pages)
  2967 00002F88 80E2FC              <1> 	and	dl, 0FCh 	     ; clear lower 2 bits
  2968                              <1> 				     ; (to get 32 bit position)			
  2969                              <1> 	;
  2970 00002F8B BB00001000          <1> 	mov	ebx, MEM_ALLOC_TBL   ; Memory Allocation Table address
  2971 00002F90 01D3                <1> 	add	ebx, edx
  2972 00002F92 83E01F              <1> 	and	eax, 1Fh	     ; lower 5 bits only
  2973                              <1> 				     ; (allocation bit position)	 
  2974 00002F95 3B15[E46A0000]      <1> 	cmp 	edx, [next_page]     ; is the new free page address lower
  2975                              <1> 				     ; than the address in 'next_page' ?
  2976                              <1> 				     ; (next/first free page value)		
  2977 00002F9B 7306                <1> 	jnb	short dap_1	     ; no	
  2978 00002F9D 8915[E46A0000]      <1> 	mov	[next_page], edx     ; yes
  2979                              <1> dap_1:
  2980 00002FA3 0FAB03              <1> 	bts	[ebx], eax	     ; unlink/release/deallocate page
  2981                              <1> 				     ; set relevant bit to 1.
  2982                              <1> 				     ; set CF to the previous bit value	
  2983                              <1> 	;cmc			     ; complement carry flag	
  2984                              <1> 	;jc	short dap_2	     ; do not increase free_pages count
  2985                              <1> 				     ; if the page is already deallocated
  2986                              <1> 				     ; before.	
  2987 00002FA6 FF05[E06A0000]      <1>         inc     dword [free_pages]
  2988                              <1> dap_2:
  2989 00002FAC 5A                  <1> 	pop	edx
  2990 00002FAD 5B                  <1> 	pop	ebx
  2991 00002FAE C3                  <1> 	retn
  2992                              <1> 
  2993                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2994                              <1> ;;                                                              ;;
  2995                              <1> ;; Copyright (C) KolibriOS team 2004-2012. All rights reserved. ;;
  2996                              <1> ;; Distributed under terms of the GNU General Public License    ;;
  2997                              <1> ;;                                                              ;;
  2998                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2999                              <1> 
  3000                              <1> ;;$Revision: 5057 $
  3001                              <1> 
  3002                              <1> 
  3003                              <1> ;;align 4
  3004                              <1> ;;proc alloc_page
  3005                              <1> 
  3006                              <1> ;;        pushfd
  3007                              <1> ;;        cli
  3008                              <1> ;;        push    ebx
  3009                              <1> ;;;//-
  3010                              <1> ;;        cmp     [pg_data.pages_free], 1
  3011                              <1> ;;        jle     .out_of_memory
  3012                              <1> ;;;//-
  3013                              <1> ;;
  3014                              <1> ;;        mov     ebx, [page_start]
  3015                              <1> ;;        mov     ecx, [page_end]
  3016                              <1> ;;.l1:
  3017                              <1> ;;        bsf     eax, [ebx];
  3018                              <1> ;;        jnz     .found
  3019                              <1> ;;        add     ebx, 4
  3020                              <1> ;;        cmp     ebx, ecx
  3021                              <1> ;;        jb      .l1
  3022                              <1> ;;        pop     ebx
  3023                              <1> ;;        popfd
  3024                              <1> ;;        xor     eax, eax
  3025                              <1> ;;        ret
  3026                              <1> ;;.found:
  3027                              <1> ;;;//-
  3028                              <1> ;;        dec     [pg_data.pages_free]
  3029                              <1> ;;        jz      .out_of_memory
  3030                              <1> ;;;//-
  3031                              <1> ;;        btr     [ebx], eax
  3032                              <1> ;;        mov     [page_start], ebx
  3033                              <1> ;;        sub     ebx, sys_pgmap
  3034                              <1> ;;        lea     eax, [eax+ebx*8]
  3035                              <1> ;;        shl     eax, 12
  3036                              <1> ;;;//-       dec [pg_data.pages_free]
  3037                              <1> ;;        pop     ebx
  3038                              <1> ;;        popfd
  3039                              <1> ;;        ret
  3040                              <1> ;;;//-
  3041                              <1> ;;.out_of_memory:
  3042                              <1> ;;        mov     [pg_data.pages_free], 1
  3043                              <1> ;;        xor     eax, eax
  3044                              <1> ;;        pop     ebx
  3045                              <1> ;;        popfd
  3046                              <1> ;;        ret
  3047                              <1> ;;;//-
  3048                              <1> ;;endp
  3049                              <1> 
  3050                              <1> duplicate_page_dir:
  3051                              <1> 	; 21/09/2015
  3052                              <1> 	; 31/08/2015
  3053                              <1> 	; 20/07/2015
  3054                              <1> 	; 28/04/2015
  3055                              <1> 	; 27/04/2015
  3056                              <1> 	; 18/04/2015
  3057                              <1> 	; 12/04/2015
  3058                              <1> 	; 18/10/2014
  3059                              <1> 	; 16/10/2014 (Retro UNIX 386 v1 - beginning)
  3060                              <1> 	;
  3061                              <1> 	; INPUT -> 
  3062                              <1> 	;	[u.pgdir] = PHYSICAL (real/flat) ADDRESS of the parent's
  3063                              <1> 	;		    page directory.
  3064                              <1> 	; OUTPUT ->
  3065                              <1> 	;	EAX =  PHYSICAL (real/flat) ADDRESS of the child's
  3066                              <1> 	;	       page directory.
  3067                              <1> 	;	(New page directory with new page table entries.)
  3068                              <1> 	;	(New page tables with read only copies of the parent's
  3069                              <1> 	;	pages.)
  3070                              <1> 	;	EAX = 0 -> Error (CF = 1)
  3071                              <1> 	;
  3072                              <1> 	; Modified Registers -> none (except EAX)
  3073                              <1> 	;
  3074 00002FAF E802FEFFFF          <1> 	call	allocate_page
  3075 00002FB4 723E                <1> 	jc	short dpd_err
  3076                              <1> 	;
  3077 00002FB6 55                  <1> 	push	ebp ; 20/07/2015
  3078 00002FB7 56                  <1> 	push	esi
  3079 00002FB8 57                  <1> 	push	edi
  3080 00002FB9 53                  <1> 	push	ebx
  3081 00002FBA 51                  <1> 	push	ecx
  3082 00002FBB 8B35[F16E0000]      <1> 	mov	esi, [u.pgdir]
  3083 00002FC1 89C7                <1> 	mov	edi, eax
  3084 00002FC3 50                  <1> 	push	eax ; save child's page directory address
  3085                              <1> 	; 31/08/2015
  3086                              <1> 	; copy PDE 0 from the parent's page dir to the child's page dir
  3087                              <1> 	; (use same system space for all user page tables) 
  3088 00002FC4 A5                  <1> 	movsd
  3089 00002FC5 BD00004000          <1> 	mov	ebp, 1024*4096 ; pass the 1st 4MB (system space)
  3090 00002FCA B9FF030000          <1> 	mov	ecx, (PAGE_SIZE / 4) - 1 ; 1023
  3091                              <1> dpd_0:	
  3092 00002FCF AD                  <1> 	lodsd
  3093                              <1> 	;or	eax, eax
  3094                              <1>         ;jnz     short dpd_1
  3095 00002FD0 A801                <1> 	test	al, PDE_A_PRESENT ;  bit 0 =  1
  3096 00002FD2 7508                <1> 	jnz	short dpd_1
  3097                              <1>  	; 20/07/2015 (virtual address at the end of the page table)	
  3098 00002FD4 81C500004000        <1> 	add	ebp, 1024*4096 ; page size * PTE count
  3099 00002FDA EB0F                <1> 	jmp	short dpd_2
  3100                              <1> dpd_1:	
  3101 00002FDC 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear attribute bits
  3102 00002FE0 89C3                <1> 	mov	ebx, eax
  3103                              <1> 	; EBX = Parent's page table address
  3104 00002FE2 E81F000000          <1> 	call	duplicate_page_table
  3105 00002FE7 720C                <1> 	jc	short dpd_p_err
  3106                              <1> 	; EAX = Child's page table address
  3107 00002FE9 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER
  3108                              <1> 			 ; set bit 0, bit 1 and bit 2 to 1
  3109                              <1> 			 ; (present, writable, user)
  3110                              <1> dpd_2:
  3111 00002FEB AB                  <1> 	stosd
  3112 00002FEC E2E1                <1> 	loop	dpd_0
  3113                              <1> 	;
  3114 00002FEE 58                  <1> 	pop	eax  ; restore child's page directory address
  3115                              <1> dpd_3:
  3116 00002FEF 59                  <1> 	pop	ecx
  3117 00002FF0 5B                  <1> 	pop	ebx
  3118 00002FF1 5F                  <1> 	pop	edi
  3119 00002FF2 5E                  <1> 	pop	esi
  3120 00002FF3 5D                  <1> 	pop	ebp ; 20/07/2015
  3121                              <1> dpd_err:
  3122 00002FF4 C3                  <1> 	retn
  3123                              <1> dpd_p_err:
  3124                              <1> 	; release the allocated pages missing (recover free space)
  3125 00002FF5 58                  <1> 	pop	eax  ; the new page directory address (physical)
  3126 00002FF6 8B1D[F16E0000]      <1> 	mov	ebx, [u.pgdir] ; parent's page directory address 
  3127 00002FFC E8E5FEFFFF          <1> 	call 	deallocate_page_dir
  3128 00003001 29C0                <1> 	sub	eax, eax ; 0
  3129 00003003 F9                  <1> 	stc
  3130 00003004 EBE9                <1> 	jmp	short dpd_3	
  3131                              <1> 
  3132                              <1> duplicate_page_table:
  3133                              <1> 	; 31/12/2021
  3134                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3135                              <1> 	; 20/02/2017 (TRDOS 386 v2)
  3136                              <1> 	; 21/09/2015
  3137                              <1> 	; 20/07/2015
  3138                              <1> 	; 05/05/2015
  3139                              <1> 	; 28/04/2015
  3140                              <1> 	; 27/04/2015
  3141                              <1> 	; 18/04/2015
  3142                              <1> 	; 18/10/2014
  3143                              <1> 	; 16/10/2014 (Retro UNIX 386 v1 - beginning)
  3144                              <1> 	;
  3145                              <1> 	; INPUT -> 
  3146                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS of the parent's page table.
  3147                              <1> 	;       20/02/2017		 
  3148                              <1> 	;	EBP = Linear address of the page (from 'duplicate_page_dir')
  3149                              <1> 	;	      (Linear address = CORE + user's virtual address) 	
  3150                              <1> 	; OUTPUT ->
  3151                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS of the child's page table.
  3152                              <1> 	;	      (with 'read only' attribute of page table entries)
  3153                              <1> 	;	20/02/2017
  3154                              <1> 	;	EBP = Next linear page address (for 'duplicate_page_dir')
  3155                              <1> 	;	
  3156                              <1> 	;	CF = 1 -> error 
  3157                              <1> 	;
  3158                              <1> 	; Modified Registers -> EBP (except EAX)
  3159                              <1> 	;
  3160 00003006 E8ABFDFFFF          <1> 	call	allocate_page
  3161 0000300B 725B                <1> 	jc	short dpt_err
  3162                              <1> 	;
  3163 0000300D 50                  <1> 	push	eax ; *
  3164 0000300E 56                  <1> 	push	esi
  3165 0000300F 57                  <1> 	push	edi
  3166 00003010 52                  <1> 	push	edx
  3167 00003011 51                  <1> 	push	ecx
  3168                              <1> 	;
  3169 00003012 89DE                <1> 	mov	esi, ebx
  3170 00003014 89C7                <1> 	mov	edi, eax
  3171 00003016 89C2                <1> 	mov	edx, eax
  3172 00003018 81C200100000        <1> 	add	edx, PAGE_SIZE 	
  3173                              <1> dpt_0:
  3174 0000301E AD                  <1> 	lodsd
  3175 0000301F 21C0                <1> 	and	eax, eax
  3176 00003021 7435                <1> 	jz	short dpt_3
  3177 00003023 A801                <1> 	test	al, PTE_A_PRESENT ;  bit 0 =  1
  3178                              <1> 	; 24/12/2021
  3179 00003025 7503                <1> 	jnz	short dpt_1
  3180                              <1> 	;jz	short dpt_p_err
  3181                              <1> 	; 31/12/2021
  3182 00003027 F9                  <1> 	stc
  3183 00003028 EB39                <1> 	jmp	short dpt_p_err
  3184                              <1> 
  3185                              <1> ; 24/12/2021
  3186                              <1> ; ('reload_page' procedure call is disabled)
  3187                              <1> ;
  3188                              <1> ;	; 20/07/2015
  3189                              <1> ;	; ebp = virtual (linear) address of the memory page
  3190                              <1> ;	call	reload_page ; 28/04/2015
  3191                              <1> ;	jc	short dpt_p_err
  3192                              <1> dpt_1:
  3193                              <1> 	; 21/09/2015
  3194 0000302A 89C1                <1> 	mov	ecx, eax
  3195 0000302C 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3196 00003030 F6C102              <1> 	test	cl, PTE_A_WRITE ; writable page ?
  3197 00003033 751A                <1> 	jnz	short dpt_2
  3198                              <1> 	; Read only (parent) page
  3199                              <1> 	; 	- there is a third process which uses this page -
  3200                              <1> 	; Allocate a new page for the child process
  3201 00003035 E87CFDFFFF          <1> 	call	allocate_page
  3202 0000303A 7227                <1> 	jc	short dpt_p_err
  3203 0000303C 57                  <1> 	push	edi
  3204 0000303D 56                  <1> 	push	esi
  3205 0000303E 89CE                <1> 	mov	esi, ecx
  3206 00003040 89C7                <1> 	mov	edi, eax
  3207 00003042 B900040000          <1> 	mov	ecx, PAGE_SIZE/4
  3208 00003047 F3A5                <1> 	rep	movsd	; copy page (4096 bytes)
  3209 00003049 5E                  <1> 	pop	esi
  3210 0000304A 5F                  <1> 	pop	edi
  3211                              <1> 	;
  3212                              <1> 
  3213                              <1> ; 24/12/2021
  3214                              <1> ; ('add_to_swap_queue' procedure call is disabled)
  3215                              <1> ; 
  3216                              <1> ;	push	ebx
  3217                              <1> ;	push	eax
  3218                              <1> ;	; 20/07/2015
  3219                              <1> ;	mov	ebx, ebp
  3220                              <1> ;	; ebx = virtual (linear) address of the memory page
  3221                              <1> ;	call	add_to_swap_queue
  3222                              <1> ;	pop	eax
  3223                              <1> ;	pop	ebx
  3224                              <1> 
  3225                              <1> 	; 21/09/2015
  3226 0000304B 0C07                <1> 	or	al, PTE_A_USER+PTE_A_WRITE+PTE_A_PRESENT 
  3227                              <1> 		; user + writable + present page
  3228 0000304D EB09                <1> 	jmp	short dpt_3
  3229                              <1> dpt_2:
  3230                              <1> 	;or	ax, PTE_A_USER+PTE_A_PRESENT 
  3231 0000304F 0C05                <1> 	or	al, PTE_A_USER+PTE_A_PRESENT 
  3232                              <1> 		    ; (read only page!)
  3233 00003051 8946FC              <1> 	mov	[esi-4], eax ; update parent's PTE
  3234 00003054 660D0002            <1> 	or      ax, PTE_DUPLICATED  ; (read only page & duplicated PTE!)
  3235                              <1> dpt_3:
  3236 00003058 AB                  <1> 	stosd  ; EDI points to child's PTE  	 
  3237                              <1> 	;
  3238 00003059 81C500100000        <1> 	add	ebp, 4096 ; 20/07/2015 (next page)
  3239                              <1> 	;
  3240 0000305F 39D7                <1> 	cmp	edi, edx
  3241 00003061 72BB                <1> 	jb	short dpt_0
  3242                              <1> dpt_p_err:
  3243 00003063 59                  <1> 	pop	ecx
  3244 00003064 5A                  <1> 	pop	edx
  3245 00003065 5F                  <1> 	pop	edi
  3246 00003066 5E                  <1> 	pop	esi
  3247 00003067 58                  <1> 	pop	eax ; *
  3248                              <1> dpt_err:
  3249 00003068 C3                  <1> 	retn
  3250                              <1> 
  3251                              <1> page_fault_handler: ; CPU EXCEPTION 0Eh (14) : Page Fault !
  3252                              <1> 	; 31/12/2021
  3253                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3254                              <1> 	; 21/09/2015
  3255                              <1> 	; 19/09/2015
  3256                              <1> 	; 17/09/2015
  3257                              <1> 	; 28/08/2015
  3258                              <1> 	; 20/07/2015
  3259                              <1> 	; 28/06/2015
  3260                              <1> 	; 03/05/2015
  3261                              <1> 	; 30/04/2015
  3262                              <1> 	; 18/04/2015
  3263                              <1> 	; 12/04/2015
  3264                              <1> 	; 30/10/2014
  3265                              <1> 	; 11/09/2014
  3266                              <1> 	; 10/09/2014 (Retro UNIX 386 v1 - beginning)
  3267                              <1> 	;
  3268                              <1> 	; Note: This is not an interrupt/exception handler.
  3269                              <1> 	;	This is a 'page fault remedy' subroutine 
  3270                              <1> 	;	which will be called by standard/uniform
  3271                              <1> 	;	exception handler.
  3272                              <1> 	;
  3273                              <1> 	; INPUT -> 
  3274                              <1> 	;	[error_code] = 32 bit ERROR CODE (lower 5 bits are valid)
  3275                              <1> 	;
  3276                              <1> 	;	cr2 = the virtual (linear) address 
  3277                              <1> 	;	      which has caused to page fault (19/09/2015)
  3278                              <1> 	;
  3279                              <1> 	; OUTPUT ->
  3280                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3281                              <1> 	;	EAX = 0 -> no error
  3282                              <1> 	;	EAX > 0 -> error code in EAX (also CF = 1)
  3283                              <1> 	;
  3284                              <1> 	; Modified Registers -> none (except EAX)
  3285                              <1> 	;	
  3286                              <1>         ;
  3287                              <1>         ; ERROR CODE:
  3288                              <1> 	;	 31  .....	4   3	2   1	0
  3289                              <1> 	;	+---+-- --+---+---+---+---+---+---+
  3290                              <1> 	;	|   Reserved  | I | R | U | W | P |
  3291                              <1> 	;	+---+-- --+---+---+---+---+---+---+
  3292                              <1> 	;
  3293                              <1> 	; P : PRESENT -	When set, the page fault was caused by 
  3294                              <1>     	;		a page-protection violation. When not set,
  3295                              <1> 	;		it was caused by a non-present page.
  3296                              <1> 	; W : WRITE   -	When set, the page fault was caused by
  3297                              <1> 	;		a page write. When not set, it was caused
  3298                              <1> 	;		by a page read.
  3299                              <1> 	; U : USER    -	When set, the page fault was caused 
  3300                              <1> 	;		while CPL = 3. 
  3301                              <1> 	;		This does not necessarily mean that
  3302                              <1> 	;		the page fault was a privilege violation.
  3303                              <1> 	; R : RESERVD -	When set, the page fault was caused by
  3304                              <1> 	;     WRITE	reading a 1 in a reserved field.
  3305                              <1> 	; I : INSTRUC -	When set, the page fault was caused by
  3306                              <1> 	;     FETCH	an instruction fetch
  3307                              <1> 	;
  3308                              <1> 	;; x86 (32 bit) VIRTUAL ADDRESS TRANSLATION
  3309                              <1> 	;  31               22                  12 11                    0
  3310                              <1> 	; +-------------------+-------------------+-----------------------+
  3311                              <1>        	; | PAGE DIR. ENTRY # | PAGE TAB. ENTRY # |        OFFSET         |
  3312                              <1>        	; +-------------------+-------------------+-----------------------+
  3313                              <1> 	;
  3314                              <1> 
  3315                              <1> 	;; CR3 REGISTER (Control Register 3)
  3316                              <1> 	;  31                                   12             5 4 3 2   0
  3317                              <1> 	; +---------------------------------------+-------------+---+-----+
  3318                              <1>       	; |                                       |  		|P|P|     |
  3319                              <1>       	; |   PAGE DIRECTORY TABLE BASE ADDRESS   |  reserved	|C|W|rsvrd|
  3320                              <1>       	; |                                       | 		|D|T|     |
  3321                              <1>    	; +---------------------------------------+-------------+---+-----+
  3322                              <1> 	;
  3323                              <1> 	;	PWT    - WRITE THROUGH
  3324                              <1> 	;	PCD    - CACHE DISABLE		
  3325                              <1> 	;
  3326                              <1> 	;
  3327                              <1> 	;; x86 PAGE DIRECTORY ENTRY (4 KByte Page)
  3328                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3329                              <1> 	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3330                              <1>       	; |                                       |     | | | | |P|P|U|R| |
  3331                              <1>       	; |     PAGE TABLE BASE ADDRESS 31..12    | AVL |G|0|D|A|C|W|/|/|P|
  3332                              <1>       	; |                                       |     | | | | |D|T|S|W| |
  3333                              <1>    	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3334                              <1> 	;
  3335                              <1>         ;       P      - PRESENT
  3336                              <1>         ;       R/W    - READ/WRITE
  3337                              <1>         ;       U/S    - USER/SUPERVISOR
  3338                              <1> 	;	PWT    - WRITE THROUGH
  3339                              <1> 	;	PCD    - CACHE DISABLE	
  3340                              <1> 	;	A      - ACCESSED	
  3341                              <1>         ;       D      - DIRTY (IGNORED)
  3342                              <1> 	;	PAT    - PAGE ATTRIBUTE TABLE INDEX (CACHE BEHAVIOR)
  3343                              <1> 	;	G      - GLOBAL	(IGNORED) 
  3344                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3345                              <1> 	;
  3346                              <1> 	;
  3347                              <1> 	;; x86 PAGE TABLE ENTRY (4 KByte Page)
  3348                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3349                              <1> 	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3350                              <1>       	; |                                       |     | |P| | |P|P|U|R| |
  3351                              <1>       	; |     PAGE FRAME BASE ADDRESS 31..12    | AVL |G|A|D|A|C|W|/|/|P|
  3352                              <1>       	; |                                       |     | |T| | |D|T|S|W| |
  3353                              <1>    	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3354                              <1> 	;
  3355                              <1>         ;       P      - PRESENT
  3356                              <1>         ;       R/W    - READ/WRITE
  3357                              <1>         ;       U/S    - USER/SUPERVISOR
  3358                              <1> 	;	PWT    - WRITE THROUGH
  3359                              <1> 	;	PCD    - CACHE DISABLE	
  3360                              <1> 	;	A      - ACCESSED	
  3361                              <1>         ;       D      - DIRTY
  3362                              <1> 	;	PAT    - PAGE ATTRIBUTE TABLE INDEX (CACHE BEHAVIOR)
  3363                              <1> 	;	G      - GLOBAL	 
  3364                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3365                              <1> 	;
  3366                              <1> 	;
  3367                              <1> 	;; 80386 PAGE TABLE ENTRY (4 KByte Page)
  3368                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3369                              <1> 	; +---------------------------------------+-----+-+-+-+-+---+-+-+-+
  3370                              <1>       	; |                                       |     | | | | | | |U|R| |
  3371                              <1>       	; |     PAGE FRAME BASE ADDRESS 31..12    | AVL |0|0|D|A|0|0|/|/|P|
  3372                              <1>       	; |                                       |     | | | | | | |S|W| |
  3373                              <1>       	; +---------------------------------------+-----+-+-+-+-+---+-+-+-+
  3374                              <1> 	;
  3375                              <1>         ;       P      - PRESENT
  3376                              <1>         ;       R/W    - READ/WRITE
  3377                              <1>         ;       U/S    - USER/SUPERVISOR
  3378                              <1>         ;       D      - DIRTY
  3379                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3380                              <1> 	;
  3381                              <1>         ;       NOTE: 0 INDICATES INTEL RESERVED. DO NOT DEFINE.
  3382                              <1> 	;
  3383                              <1> 	;
  3384                              <1> 	;; Invalid Page Table Entry
  3385                              <1> 	; 31                                                           1 0
  3386                              <1>       	; +-------------------------------------------------------------+-+
  3387                              <1>       	; |                                                             | |
  3388                              <1>       	; |                          AVAILABLE                          |0|
  3389                              <1>       	; |                                                             | |
  3390                              <1>       	; +-------------------------------------------------------------+-+
  3391                              <1> 	;
  3392                              <1> 
  3393 00003069 53                  <1> 	push	ebx
  3394 0000306A 52                  <1> 	push	edx
  3395 0000306B 51                  <1> 	push	ecx
  3396                              <1> 	;
  3397                              <1> 	; 21/09/2015 (debugging)
  3398 0000306C FF05[016F0000]      <1> 	inc	dword [u.pfcount] ; page fault count for running process
  3399 00003072 FF05[906B0000]      <1> 	inc	dword [PF_Count]  ; total page fault count	
  3400                              <1> 	; 28/06/2015
  3401                              <1> 	;mov	edx, [error_code] ; Lower 5 bits are valid
  3402 00003078 8A15[886B0000]      <1> 	mov	dl, [error_code]
  3403                              <1> 	;
  3404 0000307E F6C201              <1> 	test	dl, 1	; page fault was caused by a non-present page
  3405                              <1> 			; sign
  3406 00003081 7425                <1> 	jz	short pfh_alloc_np
  3407                              <1> 	; 
  3408                              <1> 	; If it is not a 'write on read only page' type page fault
  3409                              <1> 	; major page fault error with minor reason must be returned without 
  3410                              <1> 	; fixing the problem. 'sys_exit with error' will be needed
  3411                              <1> 	; after return here!
  3412                              <1> 	; Page fault will be remedied, by copying page contents
  3413                              <1> 	; to newly allocated page with write permission;
  3414                              <1> 	; sys_fork -> sys_exec -> copy on write, demand paging method is 
  3415                              <1> 	; used for working with minimum possible memory usage. 
  3416                              <1> 	; sys_fork will duplicate page directory and tables of parent  
  3417                              <1> 	; process with 'read only' flag. If the child process attempts to
  3418                              <1> 	; write on these read only pages, page fault will be directed here
  3419                              <1> 	; for allocating a new page with same data/content. 
  3420                              <1> 	;
  3421                              <1> 	; IMPORTANT : Retro UNIX 386 v1 (and SINGLIX and TR-DOS)
  3422                              <1> 	; will not force to separate CODE and DATA space 
  3423                              <1> 	; in a process/program... 
  3424                              <1> 	; CODE segment/section may contain DATA!
  3425                              <1> 	; It is flat, smoth and simplest programming method already as in 
  3426                              <1> 	; Retro UNIX 8086 v1 and MS-DOS programs.
  3427                              <1> 	;	
  3428 00003083 F6C202              <1> 	test	dl, 2	; page fault was caused by a page write
  3429                              <1> 			; sign
  3430 00003086 7418                <1>         jz      pfh_p_err
  3431                              <1> 	; 31/08/2015
  3432 00003088 F6C204              <1> 	test	dl, 4	; page fault was caused while CPL = 3 (user mode)
  3433                              <1> 			; sign.  (U+W+P = 4+2+1 = 7)
  3434 0000308B 7413                <1>         jz	short pfh_pv_err
  3435                              <1> 	;
  3436                              <1> 	; make a new page and copy the parent's page content
  3437                              <1> 	; as the child's new page content
  3438                              <1> 	;
  3439 0000308D 0F20D3              <1> 	mov	ebx, cr2 ; CR2 contains the linear address 
  3440                              <1> 			 ; which has caused to page fault
  3441 00003090 E87C000000          <1> 	call 	copy_page
  3442 00003095 7202                <1>         jc	short pfh_im_err ; insufficient memory
  3443                              <1> 	;
  3444 00003097 EB72                <1>         jmp     pfh_cpp_ok
  3445                              <1> 
  3446                              <1> 	; 31/12/2021 (short jump)
  3447                              <1> pfh_im_err:
  3448 00003099 B8E4000000          <1> 	mov	eax, ERR_MAJOR_PF + ERR_MINOR_IM ; Error code in AX
  3449                              <1> 			; Major (Primary) Error: Page Fault
  3450                              <1> 			; Minor (Secondary) Error: Insufficient Memory !
  3451 0000309E EB6D                <1> 	jmp	short pfh_err_retn
  3452                              <1> 
  3453                              <1> 	; 31/12/2021
  3454                              <1> pfh_p_err: ; 09/03/2015
  3455                              <1> pfh_pv_err:
  3456                              <1> 	; Page fault was caused by a protection-violation
  3457 000030A0 B8E6000000          <1> 	mov	eax, ERR_MAJOR_PF + ERR_MINOR_PV ; Error code in AX
  3458                              <1> 			; Major (Primary) Error: Page Fault
  3459                              <1> 			; Minor (Secondary) Error: Protection violation !
  3460 000030A5 F9                  <1> 	stc
  3461 000030A6 EB65                <1> 	jmp	short pfh_err_retn
  3462                              <1> 	
  3463                              <1> pfh_alloc_np:
  3464 000030A8 E809FDFFFF          <1> 	call	allocate_page	; (allocate a new page)
  3465 000030AD 72EA                <1>         jc	short pfh_im_err ; 'insufficient memory' error
  3466                              <1> pfh_chk_cpl:
  3467                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  3468                              <1> 		; (Lower 12 bits are ZERO, because 
  3469                              <1> 		;	the address is on a page boundary)
  3470 000030AF 80E204              <1> 	and	dl, 4	; CPL = 3 ?
  3471 000030B2 7505                <1> 	jnz	short pfh_um
  3472                              <1> 			; Page fault handler for kernel/system mode (CPL=0)		
  3473 000030B4 0F20DB              <1> 	mov	ebx, cr3 ; CR3 (Control Register 3) contains physical address
  3474                              <1> 			 ; of the current/active page directory
  3475                              <1> 			 ; (Always kernel/system mode page directory, here!)
  3476                              <1> 			 ; Note: Lower 12 bits are 0. (page boundary)
  3477 000030B7 EB06                <1> 	jmp	short pfh_get_pde
  3478                              <1> 	;
  3479                              <1> pfh_um:			; Page fault handler for user/appl. mode (CPL=3)
  3480 000030B9 8B1D[F16E0000]      <1>  	mov	ebx, [u.pgdir] ; Page directory of current/active process
  3481                              <1> 			; Physical address of the USER's page directory
  3482                              <1> 			; Note: Lower 12 bits are 0. (page boundary)
  3483                              <1> pfh_get_pde:
  3484 000030BF 80CA03              <1> 	or	dl, 3	; USER + WRITE + PRESENT or SYSTEM + WRITE + PRESENT
  3485 000030C2 0F20D1              <1> 	mov	ecx, cr2 ; CR2 contains the virtual address 
  3486                              <1> 			 ; which has been caused to page fault
  3487                              <1> 			 ;
  3488 000030C5 C1E914              <1> 	shr	ecx, 20	 ; shift 20 bits right
  3489 000030C8 80E1FC              <1> 	and	cl, 0FCh ; mask lower 2 bits to get PDE offset		
  3490                              <1> 	;
  3491 000030CB 01CB                <1> 	add	ebx, ecx ; now, EBX points to the relevant page dir entry 
  3492 000030CD 8B0B                <1> 	mov	ecx, [ebx] ; physical (base) address of the page table 	
  3493 000030CF F6C101              <1> 	test	cl, 1	 ; check bit 0 is set (1) or not (0).
  3494 000030D2 740B                <1> 	jz	short pfh_set_pde ; Page directory entry is not valid,
  3495                              <1> 			  	  ; set/validate page directory entry
  3496 000030D4 6681E100F0          <1> 	and	cx, PDE_A_CLEAR ; 0F000h ; Clear attribute bits
  3497 000030D9 89CB                <1> 	mov	ebx, ecx ; Physical address of the page table
  3498 000030DB 89C1                <1> 	mov	ecx, eax ; new page address (physical) 	
  3499 000030DD EB16                <1> 	jmp	short pfh_get_pte
  3500                              <1> pfh_set_pde:
  3501                              <1> 	;; NOTE: Page directories and page tables never be swapped out!
  3502                              <1> 	;;	 (So, we know this PDE is empty or invalid)
  3503                              <1> 	;
  3504 000030DF 08D0                <1> 	or	al, dl	 ; lower 3 bits are used as U/S, R/W, P flags
  3505 000030E1 8903                <1> 	mov	[ebx], eax ; Let's put the new page directory entry here !
  3506 000030E3 30C0                <1> 	xor	al, al	 ; clear lower (3..8) bits
  3507 000030E5 89C3                <1> 	mov	ebx, eax
  3508 000030E7 E8CAFCFFFF          <1> 	call	allocate_page	 ; (allocate a new page)
  3509 000030EC 72AB                <1> 	jc	short pfh_im_err   ; 'insufficient memory' error
  3510                              <1> pfh_spde_1:
  3511                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  3512 000030EE 89C1                <1> 	mov	ecx, eax
  3513 000030F0 E832FDFFFF          <1> 	call	clear_page ; Clear page content
  3514                              <1> pfh_get_pte:
  3515 000030F5 0F20D0              <1> 	mov	eax, cr2 ; virtual address
  3516                              <1> 			 ; which has been caused to page fault
  3517 000030F8 89C7                <1> 	mov	edi, eax ; 20/07/2015
  3518 000030FA C1E80C              <1> 	shr	eax, 12	 ; shift 12 bit right to get 
  3519                              <1> 			 ; higher 20 bits of the page fault address 
  3520 000030FD 25FF030000          <1> 	and	eax, 3FFh ; mask PDE# bits, the result is PTE# (0 to 1023)
  3521 00003102 C1E002              <1> 	shl	eax, 2	; shift 2 bits left to get PTE offset
  3522 00003105 01C3                <1> 	add	ebx, eax ; now, EBX points to the relevant page table entry 
  3523                              <1> ; 24/12/2021
  3524                              <1> ;	mov	eax, [ebx] ; get previous value of pte
  3525                              <1> ;		; bit 0 of EAX is always 0 (otherwise we would not be here)
  3526                              <1> ; 24/12/2021
  3527                              <1> ; ('swap_in' procedure call has been disabled)
  3528                              <1> ;
  3529                              <1> ;	and	eax, eax
  3530                              <1> ;	jz	short pfh_gpte_1
  3531                              <1> ;	; 20/07/2015
  3532                              <1> ;	xchg	ebx, ecx ; new page address (physical)
  3533                              <1> ;	push	ebp ; 20/07/2015
  3534                              <1> ;	mov	ebp, cr2
  3535                              <1> ;		; ECX = physical address of the page table entry
  3536                              <1> ;		; EBX = Memory page address (physical!)
  3537                              <1> ;		; EAX = Swap disk (offset) address
  3538                              <1> ;		; EBP = virtual address (page fault address)
  3539                              <1> ;	call	swap_in
  3540                              <1> ;	pop	ebp
  3541                              <1> ;	jc      short pfh_err_retn
  3542                              <1> ;	xchg	ecx, ebx
  3543                              <1> ;		; EBX = physical address of the page table entry
  3544                              <1> ;		; ECX = new page
  3545                              <1> pfh_gpte_1:
  3546 00003107 08D1                <1> 	or	cl, dl	; lower 3 bits are used as U/S, R/W, P flags
  3547 00003109 890B                <1> 	mov	[ebx], ecx ; Let's put the new page table entry here !
  3548                              <1> pfh_cpp_ok:
  3549                              <1> ; 24/12/2021
  3550                              <1> ; ('add_to_swap_queue' procedure call has been disabled)
  3551                              <1> ;
  3552                              <1> ;	; 20/07/2015
  3553                              <1> ;	mov	ebx, cr2
  3554                              <1> ;	call 	add_to_swap_queue
  3555                              <1> 	;
  3556                              <1> 	; The new PTE (which contains the new page) will be added to 
  3557                              <1> 	; the swap queue, here. 
  3558                              <1> 	; (Later, if memory will become insufficient, 
  3559                              <1> 	; one page will be swapped out which is at the head of 
  3560                              <1> 	; the swap queue by using FIFO and access check methods.)
  3561                              <1> 	;
  3562 0000310B 31C0                <1> 	xor	eax, eax  ; 0
  3563                              <1> 	;
  3564                              <1> pfh_err_retn:
  3565 0000310D 59                  <1> 	pop	ecx
  3566 0000310E 5A                  <1> 	pop	edx
  3567 0000310F 5B                  <1> 	pop	ebx
  3568 00003110 C3                  <1> 	retn 
  3569                              <1> 	
  3570                              <1> copy_page:
  3571                              <1> 	; 24/12/2021 - Retro UNIX 386 v1.1
  3572                              <1> 	; 16/04/2021
  3573                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3574                              <1> 	; 22/09/2015
  3575                              <1> 	; 21/09/2015
  3576                              <1> 	; 19/09/2015
  3577                              <1> 	; 07/09/2015
  3578                              <1> 	; 31/08/2015
  3579                              <1> 	; 20/07/2015
  3580                              <1> 	; 05/05/2015
  3581                              <1> 	; 03/05/2015
  3582                              <1> 	; 18/04/2015
  3583                              <1> 	; 12/04/2015
  3584                              <1> 	; 30/10/2014
  3585                              <1> 	; 18/10/2014 (Retro UNIX 386 v1 - beginning)
  3586                              <1> 	;
  3587                              <1> 	; INPUT -> 
  3588                              <1> 	;	EBX = Virtual (linear) address of source page
  3589                              <1> 	;	     (Page fault address)
  3590                              <1> 	; OUTPUT ->
  3591                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  3592                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3593                              <1> 	;	EAX = 0 (CF = 1) 
  3594                              <1> 	;		if there is not a free page to be allocated
  3595                              <1> 	;	(page content of the source page will be copied
  3596                              <1> 	;	onto the target/new page) 	
  3597                              <1> 	;
  3598                              <1> 	; Modified Registers -> ecx, ebx (except EAX)
  3599                              <1> 	;
  3600                              <1> 
  3601                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3602                              <1> 	; INPUT: 
  3603                              <1> 	;	EBX = Virtual (linear) address of source page
  3604                              <1> 	;	     (Page fault address)
  3605                              <1> 	; OUTPUT:
  3606                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  3607                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3608                              <1> 	;	EAX = 0 (CF = 1) 
  3609                              <1> 	;		if there is not a free page to be allocated
  3610                              <1> 	;	(page content of the source page will be copied
  3611                              <1> 	;	onto the target/new page) 	
  3612                              <1> 	;
  3613                              <1> 	; Modified Registers -> ecx, ebx (except EAX) ; 16/04/2021
  3614                              <1> 	
  3615 00003111 56                  <1> 	push	esi ; *
  3616 00003112 57                  <1> 	push	edi ; **
  3617                              <1> 	; 16/04/2021
  3618                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3619                              <1> 	;push	ebx ; ***
  3620                              <1> 	;push	ecx ; ****
  3621 00003113 31F6                <1> 	xor 	esi, esi
  3622 00003115 C1EB0C              <1> 	shr	ebx, 12 ; shift 12 bits right to get PDE & PTE numbers
  3623 00003118 89D9                <1> 	mov	ecx, ebx ; save page fault address (as 12 bit shifted)
  3624 0000311A C1EB08              <1> 	shr	ebx, 8	 ; shift 8 bits right and then
  3625 0000311D 80E3FC              <1> 	and	bl, 0FCh ; mask lower 2 bits to get PDE offset	
  3626 00003120 89DF                <1> 	mov 	edi, ebx ; save it for the parent of current process
  3627 00003122 031D[F16E0000]      <1> 	add	ebx, [u.pgdir] ; EBX points to the relevant page dir entry 
  3628 00003128 8B03                <1> 	mov	eax, [ebx] ; physical (base) address of the page table
  3629 0000312A 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits 	
  3630 0000312E 89CB                <1> 	mov	ebx, ecx   ; (restore higher 20 bits of page fault address)
  3631 00003130 81E3FF030000        <1> 	and	ebx, 3FFh  ; mask PDE# bits, the result is PTE# (0 to 1023)
  3632 00003136 66C1E302            <1> 	shl	bx, 2	   ; shift 2 bits left to get PTE offset
  3633 0000313A 01C3                <1> 	add	ebx, eax   ; EBX points to the relevant page table entry 
  3634                              <1> 	; 07/09/2015
  3635 0000313C 66F7030002          <1>         test    word [ebx], PTE_DUPLICATED ; (Does current process share this
  3636                              <1> 				     ; read only page as a child process?)	
  3637 00003141 7509                <1> 	jnz	short cpp_0 ; yes
  3638 00003143 8B0B                <1> 	mov	ecx, [ebx] ; PTE value
  3639 00003145 6681E100F0          <1> 	and	cx, PTE_A_CLEAR ; 0F000h  ; clear page attributes
  3640 0000314A EB32                <1> 	jmp	short cpp_1
  3641                              <1> cpp_0:
  3642 0000314C 89FE                <1> 	mov	esi, edi
  3643 0000314E 0335[F56E0000]      <1> 	add	esi, [u.ppgdir] ; the parent's page directory entry
  3644 00003154 8B06                <1> 	mov	eax, [esi] ; physical (base) address of the page table
  3645 00003156 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3646 0000315A 89CE                <1> 	mov	esi, ecx   ; (restore higher 20 bits of page fault address)	
  3647 0000315C 81E6FF030000        <1> 	and	esi, 3FFh  ; mask PDE# bits, the result is PTE# (0 to 1023)
  3648 00003162 66C1E602            <1> 	shl	si, 2	   ; shift 2 bits left to get PTE offset
  3649 00003166 01C6                <1> 	add	esi, eax   ; EDX points to the relevant page table entry  	
  3650 00003168 8B0E                <1> 	mov	ecx, [esi] ; PTE value of the parent process
  3651                              <1> 	; 21/09/2015
  3652 0000316A 8B03                <1> 	mov	eax, [ebx] ; PTE value of the child process
  3653 0000316C 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear page attributes	
  3654                              <1> 	;
  3655 00003170 F6C101              <1> 	test	cl, PTE_A_PRESENT ; is it a present/valid page ?
  3656 00003173 7424                <1> 	jz	short cpp_3 ; the parent's page is not same page  	
  3657                              <1> 	;
  3658 00003175 6681E100F0          <1> 	and	cx, PTE_A_CLEAR ; 0F000h ; clear page attributes
  3659 0000317A 39C8                <1> 	cmp	eax, ecx   ; Same page?	
  3660 0000317C 751B                <1> 	jne	short cpp_3 ; Parent page and child page are not same 
  3661                              <1> 			    ; Convert child's page to writable page
  3662                              <1> cpp_1:
  3663 0000317E E833FCFFFF          <1> 	call	allocate_page
  3664 00003183 721A                <1> 	jc	short cpp_4 ; 'insufficient memory' error
  3665 00003185 21F6                <1> 	and	esi, esi    ; check ESI is valid or not
  3666 00003187 7405                <1> 	jz	short cpp_2
  3667                              <1> 		; Convert read only page to writable page 
  3668                              <1> 		;(for the parent of the current process)
  3669                              <1> 	;and	word [esi], PTE_A_CLEAR ; 0F000h
  3670                              <1> 	; 22/09/2015
  3671 00003189 890E                <1> 	mov	[esi], ecx
  3672 0000318B 800E07              <1> 	or	byte [esi], PTE_A_PRESENT + PTE_A_WRITE + PTE_A_USER
  3673                              <1> 				 ; 1+2+4 = 7
  3674                              <1> cpp_2:
  3675 0000318E 89C7                <1> 	mov	edi, eax ; new page address of the child process
  3676                              <1> 	; 07/09/2015
  3677 00003190 89CE                <1> 	mov	esi, ecx ; the page address of the parent process
  3678 00003192 B900040000          <1> 	mov	ecx, PAGE_SIZE / 4
  3679 00003197 F3A5                <1> 	rep	movsd ; 31/08/2015
  3680                              <1> cpp_3:		
  3681 00003199 0C07                <1> 	or	al, PTE_A_PRESENT + PTE_A_WRITE + PTE_A_USER ; 1+2+4 = 7
  3682 0000319B 8903                <1> 	mov	[ebx], eax ; Update PTE
  3683 0000319D 28C0                <1> 	sub	al, al ; clear attributes
  3684                              <1> cpp_4:
  3685                              <1> 	; 16/04/2021
  3686                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3687                              <1> 	;pop	ecx ; ****
  3688                              <1> 	;pop	ebx ; ***
  3689 0000319F 5F                  <1> 	pop	edi ; **
  3690 000031A0 5E                  <1> 	pop	esi ; *
  3691 000031A1 C3                  <1> 	retn
  3692                              <1> 
  3693                              <1> ;; 28/04/2015
  3694                              <1> ;; 24/10/2014
  3695                              <1> ;; 21/10/2014 (Retro UNIX 386 v1 - beginning)
  3696                              <1> ;; SWAP_PAGE_QUEUE (4096 bytes)
  3697                              <1> ;;
  3698                              <1> ;;   0000   0001   0002   0003   ....   1020   1021   1022   1023	
  3699                              <1> ;; +------+------+------+------+-    -+------+------+------+------+
  3700                              <1> ;; |  pg1 |  pg2 |  pg3 |  pg4 | .... |pg1021|pg1022|pg1023|pg1024|
  3701                              <1> ;; +------+------+------+------+-    -+------+------+------+------+    
  3702                              <1> ;;
  3703                              <1> ;; [swpq_last] = 0 to 4096 (step 4) -> the last position on the queue
  3704                              <1> ;;
  3705                              <1> ;; Method:
  3706                              <1> ;;	Swap page queue is a list of allocated pages with physical
  3707                              <1> ;;	addresses (system mode virtual adresses = physical addresses).
  3708                              <1> ;;	It is used for 'swap_in' and 'swap_out' procedures.
  3709                              <1> ;;	When a new page is being allocated, swap queue is updated
  3710                              <1> ;;	by 'swap_queue_shift' procedure, header of the queue (offset 0)
  3711                              <1> ;;	is checked for 'accessed' flag. If the 1st page on the queue
  3712                              <1> ;;	is 'accessed' or 'read only', it is dropped from the list;
  3713                              <1> ;;	other pages from the 2nd to the last (in [swpq_last]) shifted
  3714                              <1> ;; 	to head then the 2nd page becomes the 1st and '[swpq_last]' 
  3715                              <1> ;;	offset value becomes it's previous offset value - 4.
  3716                              <1> ;;	If the 1st page of the swap page queue is not 'accessed'	
  3717                              <1> ;;	the queue/list is not shifted.
  3718                              <1> ;;	After the queue/list shift, newly allocated page is added
  3719                              <1> ;;	to the tail of the queue at the [swpq_count*4] position.
  3720                              <1> ;;	But, if [swpq_count] > 1023, the newly allocated page
  3721                              <1> ;;	will not be added to the tail of swap page queue.  		 
  3722                              <1> ;;	
  3723                              <1> ;;	During 'swap_out' procedure, swap page queue is checked for
  3724                              <1> ;;	the first non-accessed, writable page in the list, 
  3725                              <1> ;;	from the head to the tail. The list is shifted to left 
  3726                              <1> ;;	(to the head) till a non-accessed page will be found in the list.
  3727                              <1> ;;	Then, this page	is swapped out (to disk) and then it is dropped
  3728                              <1> ;;	from the list by a final swap queue shift. [swpq_count] value
  3729                              <1> ;;	is changed. If all pages on the queue' are 'accessed', 
  3730                              <1> ;;	'insufficient memory' error will be returned ('swap_out' 
  3731                              <1> ;;	procedure will be failed)...
  3732                              <1> ;;
  3733                              <1> ;;	Note: If the 1st page of the queue is an 'accessed' page,
  3734                              <1> ;;	'accessed' flag of the page will be reset (0) and that page
  3735                              <1> ;;	(PTE) will be added to the tail of the queue after
  3736                              <1> ;;	the check, if [swpq_count] < 1023. If [swpq_count] = 1024
  3737                              <1> ;;	the queue will be rotated and the PTE in the head will be
  3738                              <1> ;;	added to the tail after resetting 'accessed' bit. 
  3739                              <1> ;;
  3740                              <1> ;;
  3741                              <1> ;;	
  3742                              <1> ;; SWAP DISK/FILE (with 4096 bytes swapped page blocks)
  3743                              <1> ;;
  3744                              <1> ;;  00000000  00000004  00000008  0000000C   ...   size-8    size-4
  3745                              <1> ;; +---------+---------+---------+---------+-- --+---------+---------+
  3746                              <1> ;; |descriptr| page(1) | page(2) | page(3) | ... |page(n-1)| page(n) |
  3747                              <1> ;; +---------+---------+---------+---------+-- --+---------+---------+    
  3748                              <1> ;;
  3749                              <1> ;; [swpd_next] = the first free block address in swapped page records
  3750                              <1> ;;    		 for next free block search by 'swap_out' procedure.
  3751                              <1> ;; [swpd_size] = swap disk/file size in sectors (512 bytes)
  3752                              <1> ;;		 NOTE: max. possible swap disk size is 1024 GB
  3753                              <1> ;; 		 (entire swap space must be accessed by using
  3754                              <1> ;;		 31 bit offset address) 
  3755                              <1> ;; [swpd_free] = free block (4096 bytes) count in swap disk/file space
  3756                              <1> ;; [swpd_start] = absolute/start address of the swap disk/file
  3757                              <1> ;;		  0 for file, or beginning sector of the swap partition
  3758                              <1> ;; [swp_drv] = logical drive description table addr. of swap disk/file
  3759                              <1> ;;
  3760                              <1> ;; 					
  3761                              <1> ;; Method:
  3762                              <1> ;;	When the memory (ram) becomes insufficient, page allocation
  3763                              <1> ;;	procedure swaps out a page from memory to the swap disk 
  3764                              <1> ;;	(partition) or swap file to get a new free page at the memory.
  3765                              <1> ;;	Swapping out is performed by using swap page queue.
  3766                              <1> ;;
  3767                              <1> ;; 	Allocation block size of swap disk/file is equal to page size
  3768                              <1> ;;	(4096 bytes). Swapping address (in sectors) is recorded
  3769                              <1> ;;	into relevant page file entry as 31 bit physical (logical)
  3770                              <1> ;;	offset address as 1 bit shifted to left for present flag (0).
  3771                              <1> ;;	Swapped page address is between 1 and swap disk/file size - 4.	  
  3772                              <1> ;;	Absolute physical (logical) address of the swapped page is 
  3773                              <1> ;;	calculated by adding offset value to the swap partition's 
  3774                              <1> ;;	start address. If the swap device (disk) is a virtual disk 
  3775                              <1> ;;	or it is a file, start address of the swap disk/volume is 0, 
  3776                              <1> ;;	and offset value is equal to absolute (physical or logical)
  3777                              <1> ;;	address/position. (It has not to be ZERO if the swap partition 
  3778                              <1> ;;	is in a partitioned virtual hard disk.) 
  3779                              <1> ;;
  3780                              <1> ;;	Note: Swap addresses are always specified/declared in sectors, 
  3781                              <1> ;;	not in bytes or	in blocks/zones/clusters (4096 bytes) as unit.
  3782                              <1> ;;
  3783                              <1> ;;	Swap disk/file allocation is mapped via 'Swap Allocation Table'
  3784                              <1> ;;	at memory as similar to 'Memory Allocation Table'.
  3785                              <1> ;;
  3786                              <1> ;;	Every bit of Swap Allocation Table repsesents one swap block
  3787                              <1> ;;	(equal to page size) respectively. Bit 0 of the S.A.T. byte 0
  3788                              <1> ;;	is reserved for swap disk/file block 0 as descriptor block
  3789                              <1> ;;	(also for compatibility with PTE). If bit value is ZERO,
  3790                              <1> ;;	it means relevant (respective) block is in use, and, 
  3791                              <1> ;;	of course, if bit value is 1, it means relevant (respective)
  3792                              <1> ;;      swap disk/file block is free.
  3793                              <1> ;;	For example: bit 1 of the byte 128 repsesents block 1025 
  3794                              <1> ;;	(128*8+1) or sector (offset) 8200 on the swap disk or
  3795                              <1> ;;	byte (offset/position) 4198400 in the swap file. 
  3796                              <1> ;;	4GB swap space is represented via 128KB Swap Allocation Table.
  3797                              <1> ;;	Initial layout of Swap Allocation Table is as follows:
  3798                              <1> ;;	------------------------------------------------------------
  3799                              <1> ;;	0111111111111111111111111 .... 11111111111111111111111111111
  3800                              <1> ;;	------------------------------------------------------------
  3801                              <1> ;;	(0 is reserved block, 1s represent free blocks respectively.)
  3802                              <1> ;;	(Note: Allocation cell/unit of the table is bit, not byte)
  3803                              <1> ;;
  3804                              <1> ;;	..............................................................
  3805                              <1> ;;
  3806                              <1> ;;	'swap_out' procedure checks 'free_swap_blocks' count at first,
  3807                              <1> ;;	then it searches Swap Allocation Table if free count is not
  3808                              <1> ;;	zero. From begining the [swpd_next] dword value, the first bit 
  3809                              <1> ;;	position with value of 1 on the table is converted to swap
  3810                              <1> ;;	disk/file offset address, in sectors (not 4096 bytes block).
  3811                              <1> ;;	'ldrv_write' procedure is called with ldrv (logical drive
  3812                              <1> ;;	number of physical swap disk or virtual swap disk)
  3813                              <1> ;;	number, sector offset (not absolute sector -LBA- number),
  3814                              <1> ;;	and sector count (8, 512*8 = 4096) and buffer adress
  3815                              <1> ;;	(memory page). That will be a direct disk write procedure.
  3816                              <1> ;;	(for preventing late memory allocation, significant waiting). 
  3817                              <1> ;;	If disk write procedure returns with error or free count of 
  3818                              <1> ;;	swap blocks is ZERO, 'swap_out' procedure will return with
  3819                              <1> ;;	'insufficient memory error' (cf=1). 
  3820                              <1> ;;
  3821                              <1> ;;	(Note: Even if free swap disk/file blocks was not zero,
  3822                              <1> ;;	any disk write error will not be fixed by 'swap_out' procedure,
  3823                              <1> ;;	in other words, 'swap_out' will not check the table for other
  3824                              <1> ;;	free blocks after a disk write error. It will return to 
  3825                              <1> ;;	the caller with error (CF=1) which means swapping is failed. 
  3826                              <1> ;;
  3827                              <1> ;;	After writing the page on to swap disk/file address/sector,
  3828                              <1> ;;	'swap_out' procedure returns with that swap (offset) sector
  3829                              <1> ;;	address (cf=0). 
  3830                              <1> ;;
  3831                              <1> ;;	..............................................................
  3832                              <1> ;;
  3833                              <1> ;;	'swap_in' procedure loads addressed (relevant) swap disk or
  3834                              <1> ;;	file sectors at specified memory page. Then page allocation
  3835                              <1> ;;	procedure updates relevant page table entry with 'present' 
  3836                              <1> ;;	attribute. If swap disk or file reading fails there is nothing
  3837                              <1> ;;	to do, except to terminate the process which is the owner of
  3838                              <1> ;;	the swapped page.
  3839                              <1> ;;
  3840                              <1> ;;	'swap_in' procedure sets the relevant/respective bit value
  3841                              <1> ;;	in the Swap Allocation Table (as free block). 'swap_in' also
  3842                              <1> ;;	updates [swpd_first] pointer if it is required.
  3843                              <1> ;;
  3844                              <1> ;;	..............................................................	 
  3845                              <1> ;;
  3846                              <1> ;;	Note: If [swap_enabled] value is ZERO, that means there is not
  3847                              <1> ;;	a swap disk or swap file in use... 'swap_in' and 'swap_out'
  3848                              <1> ;;	procedures ans 'swap page que' procedures will not be active...
  3849                              <1> ;;	'Insufficient memory' error will be returned by 'swap_out'
  3850                              <1> ;;	and 'general protection fault' will be returned by 'swap_in'
  3851                              <1> ;;	procedure, if it is called mistakenly (a wrong value in a PTE).		
  3852                              <1> ;;
  3853                              <1> 
  3854                              <1> ; 24/12/2021
  3855                              <1> ; ('swap_in' procedure call is disabled)
  3856                              <1> 
  3857                              <1> ;swap_in:
  3858                              <1> 	; 31/08/2015
  3859                              <1> 	; 20/07/2015
  3860                              <1> 	; 28/04/2015
  3861                              <1> 	; 18/04/2015
  3862                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  3863                              <1> 	;
  3864                              <1> 	; INPUT -> 
  3865                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS OF THE MEMORY PAGE
  3866                              <1> 	;	EBP = VIRTUAL (LINEAR) ADDRESS (page fault address)
  3867                              <1> 	;	EAX = Offset Address for the swapped page on the
  3868                              <1> 	;	      swap disk or in the swap file.
  3869                              <1> 	;
  3870                              <1> 	; OUTPUT ->
  3871                              <1> 	;	EAX = 0 if loading at memory has been successful
  3872                              <1> 	;
  3873                              <1> 	;	CF = 1 -> swap disk reading error (disk/file not present
  3874                              <1> 	;		  or sector not present or drive not ready
  3875                              <1> 	;	     EAX = Error code
  3876                              <1> 	;	     [u.error] = EAX 
  3877                              <1> 	;		       = The last error code for the process
  3878                              <1> 	;		         (will be reset after returning to user)	  
  3879                              <1> 	;
  3880                              <1> 	; Modified Registers -> EAX
  3881                              <1> 	;
  3882                              <1> 
  3883                              <1> ;       cmp     dword [swp_drv], 0
  3884                              <1> ;	jna	short swpin_dnp_err
  3885                              <1> ;
  3886                              <1> ;	cmp	eax, [swpd_size]
  3887                              <1> ;	jnb	short swpin_snp_err
  3888                              <1> ;
  3889                              <1> ;	push	esi
  3890                              <1> ;	push	ebx
  3891                              <1> ;	push	ecx
  3892                              <1> ;	mov	esi, [swp_drv]	
  3893                              <1> ;	mov	ecx, PAGE_SIZE / LOGIC_SECT_SIZE  ; 8 !
  3894                              <1> ;		; Note: Even if corresponding physical disk's sector 
  3895                              <1> ;		; size different than 512 bytes, logical disk sector
  3896                              <1> ;		; size is 512 bytes and disk reading procedure
  3897                              <1> ;		; will be performed for reading 4096 bytes
  3898                              <1> ;		; (2*2048, 8*512). 
  3899                              <1> ;	; ESI = Logical disk description table address
  3900                              <1> ;	; EBX = Memory page (buffer) address (physical!)
  3901                              <1> ;	; EAX = Sector adress (offset address, logical sector number)
  3902                              <1> ;	; ECX = Sector count ; 8 sectors
  3903                              <1> ;	push	eax
  3904                              <1> ;	call	logical_disk_read
  3905                              <1> ;	pop	eax
  3906                              <1> ;	jnc	short swpin_read_ok
  3907                              <1> ;	;
  3908                              <1> ;	mov	eax, SWP_DISK_READ_ERR ; drive not ready or read error
  3909                              <1> ;	mov	[u.error], eax
  3910                              <1> ;	jmp	short swpin_retn
  3911                              <1> ;	;
  3912                              <1> ;swpin_read_ok:
  3913                              <1> ;	; EAX = Offset address (logical sector number)
  3914                              <1> ;	call	unlink_swap_block  ; Deallocate swap block	
  3915                              <1> ;	;
  3916                              <1> ;	; EBX = Memory page (buffer) address (physical!)
  3917                              <1> ;	; 20/07/2015
  3918                              <1> ;	mov	ebx, ebp ; virtual address (page fault address)
  3919                              <1> ;       and     bx, ~PAGE_OFF ; ~0FFFh ; reset bits, 0 to 11
  3920                              <1> ;	mov	bl, [u.uno] ; current process number
  3921                              <1> ;	; EBX = Virtual (Linear) address & process number combination
  3922                              <1> ;	call	swap_queue_shift
  3923                              <1> ;	; eax = 0 ; 10/06/2016 (if ebx input > 0, eax output = 0)
  3924                              <1> ;	;sub	eax, eax  ; 0 ; Error Code = 0  (no error)
  3925                              <1> ;	; zf = 1
  3926                              <1> ;swpin_retn:
  3927                              <1> ;	pop	ecx
  3928                              <1> ;	pop	ebx
  3929                              <1> ;	pop	esi
  3930                              <1> ;	retn
  3931                              <1> ;
  3932                              <1> ;swpin_dnp_err:
  3933                              <1> ;	mov	eax, SWP_DISK_NOT_PRESENT_ERR
  3934                              <1> ;swpin_err_retn:
  3935                              <1> ;	mov	[u.error], eax
  3936                              <1> ;	stc
  3937                              <1> ;	retn
  3938                              <1> ;
  3939                              <1> ;swpin_snp_err:
  3940                              <1> ;	mov	eax, SWP_SECTOR_NOT_PRESENT_ERR
  3941                              <1> ;	jmp	short swpin_err_retn
  3942                              <1> 
  3943                              <1> ; 24/12/2021
  3944                              <1> ; ('swap_out' procedure call is disabled)
  3945                              <1> 
  3946                              <1> ;swap_out:
  3947                              <1> 	; 10/06/2016
  3948                              <1> 	; 07/06/2016
  3949                              <1>         ; 23/05/2016
  3950                              <1> 	; 19/05/2016 - TRDOS 386 (TRDOS v2.0)
  3951                              <1> 	; 24/10/2014 - 31/08/2015 (Retro UNIX 386 v1)
  3952                              <1> 	;
  3953                              <1> 	; INPUT -> 
  3954                              <1> 	;	none
  3955                              <1> 	;
  3956                              <1> 	; OUTPUT ->
  3957                              <1> 	;	EAX = Physical page address (which is swapped out
  3958                              <1> 	;	      for allocating a new page)
  3959                              <1> 	;	CF = 1 -> swap disk writing error (disk/file not present
  3960                              <1> 	;		  or sector not present or drive not ready
  3961                              <1> 	;	     EAX = Error code
  3962                              <1> 	;	     [u.error] = EAX 
  3963                              <1> 	;		       = The last error code for the process
  3964                              <1> 	;		         (will be reset after returning to user)	  
  3965                              <1> 	;
  3966                              <1> 	; Modified Registers -> none (except EAX)
  3967                              <1> 	;
  3968                              <1> 
  3969                              <1> ;	cmp 	word [swpq_count], 1
  3970                              <1> ;       jc      swpout_im_err ; 'insufficient memory'
  3971                              <1> ;
  3972                              <1> ;       ;cmp    dword [swp_drv], 1
  3973                              <1> ;	;jc	short swpout_dnp_err ; 'swap disk/file not present'
  3974                              <1> ;
  3975                              <1> ;       cmp     dword [swpd_free], 1
  3976                              <1> ;       jc      swpout_nfspc_err ; 'no free space on swap disk'
  3977                              <1> ;
  3978                              <1> ;	push	ebx ; *
  3979                              <1> ;swpout_1:
  3980                              <1> ;	; 10/06/2016
  3981                              <1> ;	xor	ebx, ebx ; shift the queue and return a PTE value
  3982                              <1> ;	call	swap_queue_shift
  3983                              <1> ;	and	eax, eax	; 0 = empty queue (improper entries)
  3984                              <1> ;       jz      swpout_npts_err        ; There is not any proper PTE
  3985                              <1> ;				       ; pointer in the swap queue
  3986                              <1> ;	; EAX = PTE value of the page
  3987                              <1> ;	; EBX = PTE address of the page
  3988                              <1> ;	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3989                              <1> ;	;
  3990                              <1> ;	; 07/06/2016
  3991                              <1> ;	; 19/05/2016
  3992                              <1> ;	; check this page is in timer events or not
  3993                              <1> ;	
  3994                              <1> ;swpout_timer_page_0:
  3995                              <1> ;	push	edx ; **
  3996                              <1> ;
  3997                              <1> ;	; 07/06/2016
  3998                              <1> ;	cmp	byte [timer_events], 0 
  3999                              <1> ;	jna	short swpout_2
  4000                              <1> ;	;
  4001                              <1> ;	mov	dl, [timer_events]
  4002                              <1> ;
  4003                              <1> ;	push	ecx ; ***
  4004                              <1> ;	push	ebx ; ****
  4005                              <1> ;	mov	ebx, timer_set ; beginning address of timer event
  4006                              <1> ;			       ; structures 
  4007                              <1> ;swpout_timer_page_1:
  4008                              <1> ;	mov	cl, [ebx]
  4009                              <1> ;	or	cl, cl ; 0 = free, >0 = process number
  4010                              <1> ;	jz	short swpout_timer_page_3
  4011                              <1> ;	mov	ecx, [ebx+12] ; response (signal return) address
  4012                              <1> ;	and	cx, PTE_A_CLEAR ; clear offset part (right 12 bits)
  4013                              <1> ;				; of the response byte address, to
  4014                              <1> ;				; get beginning of the page address)
  4015                              <1> ;	cmp	eax, ecx
  4016                              <1> ;	jne	short swpout_timer_page_2 ; not same page
  4017                              <1> ;	
  4018                              <1> ;	; !same page!
  4019                              <1> ;	;
  4020                              <1> ;	; NOTE: // 19/05/2016 // - TRDOS 386 feature only ! -
  4021                              <1> ;	; This page will be used by the kernel to put timer event
  4022                              <1> ;	; response (signal return) byte at the requested address;
  4023                              <1> ;	; in order to prevent a possible wrong write (while
  4024                              <1> ;	; this page is swapped out) on physical memory,
  4025                              <1> ;	; we must protect this page against to be swapped out!
  4026                              <1> ;	;
  4027                              <1> ;	pop	ebx ; ****
  4028                              <1> ;	pop	ecx ; ***
  4029                              <1> ;	pop	edx ; **
  4030                              <1> ;	jmp	short swpout_1	; do not swap out this page !
  4031                              <1> ; 
  4032                              <1> ;swpout_timer_page_2:
  4033                              <1> ;	; 07/06/2016
  4034                              <1> ;	dec	dl
  4035                              <1> ;	jz	short swpout_timer_page_4
  4036                              <1> ;swpout_timer_page_3:
  4037                              <1> ;	;cmp	ebx, timer_set + 240 ; last timer event (15*16) 
  4038                              <1> ;	;jnb	short swpout_timer_page_4
  4039                              <1> ;	add	ebx, 16
  4040                              <1> ;	jmp	short swpout_timer_page_1	
  4041                              <1> ;
  4042                              <1> ;swpout_timer_page_4:
  4043                              <1> ;	pop	ebx ; ****
  4044                              <1> ;	pop	ecx ; ***
  4045                              <1> ;swpout_2:
  4046                              <1> ;	mov	edx, ebx	       ; Page table entry address	
  4047                              <1> ;	mov	ebx, eax	       ; Buffer (Page) Address				
  4048                              <1> ;	;
  4049                              <1> ;	call	link_swap_block
  4050                              <1> ;	jnc	short swpout_3	       ; It may not be needed here	
  4051                              <1> ;				       ; because [swpd_free] value
  4052                              <1> ;				       ; was checked at the beginging. 	
  4053                              <1> ;	pop	edx ; **
  4054                              <1> ;	pop	ebx ; *
  4055                              <1> ;	jmp	short swpout_nfspc_err 
  4056                              <1> ;swpout_3:
  4057                              <1> ;	test	eax, 80000000h ; test bit 31 (this may not be needed!)
  4058                              <1> ;	jnz	short swpout_nfspc_err  ; 10/06/2016 (bit 31 = 1 !)
  4059                              <1> ;	;	
  4060                              <1> ;	push	esi ; **
  4061                              <1> ;	push	ecx ; ***
  4062                              <1> ;	push	eax ; sector address ; (31 bit !, bit 31 = 0)
  4063                              <1> ;	mov	esi, [swp_drv]	
  4064                              <1> ;	mov	ecx, PAGE_SIZE / LOGIC_SECT_SIZE  ; 8 !
  4065                              <1> ;		; Note: Even if corresponding physical disk's sector 
  4066                              <1> ;		; size different than 512 bytes, logical disk sector
  4067                              <1> ;		; size is 512 bytes and disk writing procedure
  4068                              <1> ;		; will be performed for writing 4096 bytes
  4069                              <1> ;		; (2*2048, 8*512). 
  4070                              <1> ;	; ESI = Logical disk description table address
  4071                              <1> ;	; EBX = Buffer (Page) address
  4072                              <1> ;	; EAX = Sector adress (offset address, logical sector number)
  4073                              <1> ;	; ECX = Sector count ; 8 sectors
  4074                              <1> ;	; edx = PTE address
  4075                              <1> ;	call	logical_disk_write
  4076                              <1> ;	; edx = PTE address
  4077                              <1> ;	pop	ecx ; sector address	
  4078                              <1> ;	jnc	short swpout_write_ok
  4079                              <1> ;	;
  4080                              <1> ;	;; call	unlink_swap_block ; this block must be left as 'in use'
  4081                              <1> ;swpout_dw_err:
  4082                              <1> ;	mov	eax, SWP_DISK_WRITE_ERR ; drive not ready or write error
  4083                              <1> ;	mov	[u.error], eax
  4084                              <1> ;	jmp	short swpout_retn
  4085                              <1> ;	;
  4086                              <1> ;swpout_write_ok:
  4087                              <1> ;	; EBX = Buffer (page) address
  4088                              <1> ;	; EDX = Page Table Entry address
  4089                              <1> ;	; ECX = Swap disk sector (file block) address (31 bit)
  4090                              <1> ;	shl 	ecx, 1  ; 31 bit sector address from bit 1 to bit 31 
  4091                              <1> ;	mov 	[edx], ecx 
  4092                              <1> ;		; bit 0 = 0 (swapped page)
  4093                              <1> ;	mov	eax, ebx
  4094                              <1> ;swpout_retn:
  4095                              <1> ;	pop	ecx ; ***
  4096                              <1> ;	pop	esi ; **
  4097                              <1> ;	pop	ebx ; *
  4098                              <1> ;	retn
  4099                              <1> ;
  4100                              <1> ;;swpout_dnp_err:
  4101                              <1> ;;	mov	eax, SWP_DISK_NOT_PRESENT_ERR ; disk not present
  4102                              <1> ;;	jmp	short swpout_err_retn
  4103                              <1> ;swpout_nfspc_err:
  4104                              <1> ;	mov	eax, SWP_NO_FREE_SPACE_ERR ; no free space
  4105                              <1> ;swpout_err_retn:
  4106                              <1> ;	mov	[u.error], eax
  4107                              <1> ;	;stc
  4108                              <1> ;	retn
  4109                              <1> ;swpout_npts_err:
  4110                              <1> ;	mov	eax, SWP_NO_PAGE_TO_SWAP_ERR
  4111                              <1> ;	pop	ebx
  4112                              <1> ;	jmp	short swpout_err_retn
  4113                              <1> ;swpout_im_err:
  4114                              <1> ;	mov	eax, ERR_MINOR_IM ; insufficient (out of) memory
  4115                              <1> ;	jmp	short swpout_err_retn
  4116                              <1> 
  4117                              <1> ; 24/12/2021
  4118                              <1> ; ('swap_queue_shift' procedure call is disabled)
  4119                              <1> 
  4120                              <1> ;swap_queue_shift:
  4121                              <1> 	; 26/03/2017
  4122                              <1> 	; 10/06/2016
  4123                              <1> 	; 09/06/2016 - TRDOS 386 (TRDOS v2.0)
  4124                              <1> 	; 23/10/2014 - 20/07/2015 (Retro UNIX 386 v1)
  4125                              <1> 	;
  4126                              <1> 	; INPUT ->
  4127                              <1> 	;	EBX = Virtual (linear) address (bit 12 to 31) 
  4128                              <1> 	;	      and process number combination (bit 0 to 11)
  4129                              <1> 	;	EBX = 0 -> shift/drop from the head (offset 0)
  4130                              <1> 	;	
  4131                              <1> 	; OUTPUT ->
  4132                              <1> 	;	If EBX input > 0 
  4133                              <1> 	;	   the queue will be shifted 4 bytes (dword),
  4134                              <1> 	; 	   from the tail to the head, up to entry offset
  4135                              <1> 	; 	   which points to EBX input value or nothing
  4136                              <1> 	;	   to do if EBX value is not found on the queue.
  4137                              <1> 	;	   (The entry -with EBX value- will be removed
  4138                              <1> 	;	   from the queue if it is found.)
  4139                              <1> 	;
  4140                              <1> 	;	   EAX = 0		
  4141                              <1> 	;
  4142                              <1> 	;	If EBX input = 0
  4143                              <1> 	;	   the queue will be shifted 4 bytes (dword),
  4144                              <1> 	; 	   from the tail to the head, if the PTE address
  4145                              <1> 	;	   which is pointed in head of the queue is marked
  4146                              <1> 	;	   as "accessed" or it is marked as "non present".
  4147                              <1> 	;	   (If "accessed" flag of the PTE -which is pointed
  4148                              <1> 	;	   in the head- is set -to 1-, it will be reset
  4149                              <1> 	;	   -to 0- and then, the queue will be rotated 
  4150                              <1> 	;	   -without dropping pointer of the PTE from 
  4151                              <1> 	;	   the queue- for 4 bytes on head to tail direction.
  4152                              <1> 	;	   Pointer in the head will be moved into the tail,
  4153                              <1> 	;	   other PTEs will be shifted on head direction.)
  4154                              <1> 	;
  4155                              <1> 	;	   Swap queue will be shifted up to the first
  4156                              <1> 	;	   'present' or 'non accessed' page will be found
  4157                              <1> 	;	   (as pointed) on the queue head (then it will be
  4158                              <1>         ;          removed/dropped from the queue).
  4159                              <1> 	;
  4160                              <1> 	;	   EAX (> 0) = PTE value of the page which is
  4161                              <1> 	;		 (it's pointer -virtual address-) dropped
  4162                              <1> 	;		 (removed) from swap queue.
  4163                              <1> 	;	   EBX = PTE address of the page (if EAX > 0)
  4164                              <1> 	;	         which is (it's pointer -virtual address-)
  4165                              <1> 	;		 dropped (removed) from swap queue.
  4166                              <1> 	;
  4167                              <1> 	;	   EAX = 0 -> empty swap queue ! 
  4168                              <1> 	;
  4169                              <1> 	; Modified Registers -> EAX, EBX
  4170                              <1> 	;
  4171                              <1> ;	movzx   eax, word [swpq_count]  ; Max. 1024
  4172                              <1> ;	and	ax, ax
  4173                              <1> ;	jz	short swpqs_retn
  4174                              <1> ;	push	edi
  4175                              <1> ;	push	esi
  4176                              <1> ;	push	ecx
  4177                              <1> ;	mov	esi, swap_queue
  4178                              <1> ;	mov	ecx, eax
  4179                              <1> ;	or	ebx, ebx
  4180                              <1> ;	jz	short swpqs_7
  4181                              <1> ;swpqs_1:
  4182                              <1> ;	lodsd
  4183                              <1> ;	cmp	eax, ebx
  4184                              <1> ;	je	short swpqs_2
  4185                              <1> ;	loop	swpqs_1
  4186                              <1> ;	; 10/06/2016
  4187                              <1> ;	sub	eax, eax 
  4188                              <1> ;	jmp	short swpqs_6
  4189                              <1> ;swpqs_2:
  4190                              <1> ;	mov	edi, esi
  4191                              <1> ;	sub 	edi, 4
  4192                              <1> ;swpqs_3:
  4193                              <1> ;	dec	word [swpq_count]
  4194                              <1> ;	jz	short swpqs_5
  4195                              <1> ;swpqs_4:
  4196                              <1> ;	dec 	ecx
  4197                              <1> ;	rep	movsd	; shift up (to the head)
  4198                              <1> ;swpqs_5:
  4199                              <1> ;	xor	eax, eax
  4200                              <1> ;	mov	[edi], eax
  4201                              <1> ;swpqs_6:
  4202                              <1> ;	pop	ecx
  4203                              <1> ;	pop	esi
  4204                              <1> ;	pop	edi
  4205                              <1> ;swpqs_retn:
  4206                              <1> ;	retn		
  4207                              <1> ;swpqs_7:
  4208                              <1> ;	mov	edi, esi ; head
  4209                              <1> ;	lodsd
  4210                              <1> ;	; 20/07/2015
  4211                              <1> ;	mov	ebx, eax
  4212                              <1> ;	and	ebx, ~PAGE_OFF ; ~0FFFh 
  4213                              <1> ;		      ; ebx = virtual address (at page boundary)	
  4214                              <1> ;	and	eax, PAGE_OFF ; 0FFFh
  4215                              <1> ;		      ; ax = process number (1 to 4095)
  4216                              <1> ;	cmp	al, [u.uno]
  4217                              <1> ;		; Max. 16 (nproc) processes for Retro UNIX 386 v1
  4218                              <1> ;	jne	short swpqs_8
  4219                              <1> ;	mov	eax, [u.pgdir]
  4220                              <1> ;	jmp	short swpqs_9
  4221                              <1> ;swpqs_8:
  4222                              <1> ;	; 09/06/2016
  4223                              <1> ;	cmp	byte [eax+p.stat-1], 0
  4224                              <1> ;	jna	short swpqs_3     ; free (or terminated) process
  4225                              <1> ;	cmp	byte [eax+p.stat-1], 2 ; waiting
  4226                              <1> ;	ja	short swpqs_3 	  ; zombie (3) or undefined ?	
  4227                              <1> ;
  4228                              <1> ;	;shl	ax, 2
  4229                              <1> ;	shl	al, 2
  4230                              <1> ;	mov 	eax, [eax+p.upage-4]
  4231                              <1> ;	or	eax, eax
  4232                              <1> ;	jz	short swpqs_3 ; invalid upage
  4233                              <1> ;	add	eax, u.pgdir - user
  4234                              <1> ;			 ; u.pgdir value for the process
  4235                              <1> ;			 ; is in [eax]
  4236                              <1> ;	mov	eax, [eax]
  4237                              <1> ;	and	eax, eax
  4238                              <1> ;	jz	short swpqs_3 ; invalid page directory
  4239                              <1> ;swpqs_9:
  4240                              <1> ;	push	edx
  4241                              <1> ;	; eax = page directory
  4242                              <1> ;	; ebx = virtual address
  4243                              <1> ;	call	get_pte
  4244                              <1> ;	mov	ebx, edx	; PTE address
  4245                              <1> ;	pop	edx
  4246                              <1> ;	; 10/06/2016
  4247                              <1> ;	jc	short swpqs_13 ; empty PDE
  4248                              <1> ;	; EAX = PTE value
  4249                              <1> ;	test	al, PTE_A_PRESENT ; bit 0 = 1
  4250                              <1> ;	jz	short swpqs_13  ; Drop non-present page
  4251                              <1> ;			        ; from the queue (head)
  4252                              <1> ;	test	al, PTE_A_WRITE	; bit 1 = 0 (read only)
  4253                              <1> ;	jz	short swpqs_13  ; Drop read only page
  4254                              <1> ;			        ; from the queue (head) 	
  4255                              <1> ;	;test	al, PTE_A_ACCESS ; bit 5 = 1 (Accessed)
  4256                              <1> ;	;jnz	short swpqs_11  ; present
  4257                              <1> ;			        ; accessed page
  4258                              <1> ;       btr     eax, PTE_A_ACCESS_BIT ; reset 'accessed' bit
  4259                              <1> ;	jc	short swpqs_11  ; accessed page
  4260                              <1> ;
  4261                              <1> ;	dec	ecx
  4262                              <1> ;	mov	[swpq_count], cx
  4263                              <1> ;       jz      short swpqs_10
  4264                              <1> ;		; esi = head + 4
  4265                              <1> ;		; edi = head
  4266                              <1> ;	rep	movsd	 ; n = 1 to k-1, [n - 1] = [n]
  4267                              <1> ;swpqs_10:
  4268                              <1> ;	mov	[edi], ecx ; 0
  4269                              <1> ;	jmp	short swpqs_6 ; 26/03/2017
  4270                              <1> ;
  4271                              <1> ;swpqs_11:
  4272                              <1> ;	mov	[ebx], eax     ; save changed attribute
  4273                              <1> ;	; Rotation (head -> tail)
  4274                              <1> ;	dec	ecx     ; entry count -> last entry number		
  4275                              <1> ;	jz	short swpqs_10
  4276                              <1> ;		; esi = head + 4
  4277                              <1> ;		; edi = head
  4278                              <1> ;	mov	eax, [edi] ; 20/07/2015
  4279                              <1> ;	rep	movsd	 ; n = 1 to k-1, [n - 1] = [n]
  4280                              <1> ;	mov	[edi], eax ; head -> tail ; [k] = [1]
  4281                              <1> ;
  4282                              <1> ;	mov	cx, [swpq_count]
  4283                              <1> ;
  4284                              <1> ;swpqs_12:
  4285                              <1> ;	mov	esi, swap_queue ; head
  4286                              <1> ;       jmp     swpqs_7
  4287                              <1> ;
  4288                              <1> ;swpqs_13:
  4289                              <1> ;	dec	ecx
  4290                              <1> ;	mov	[swpq_count], cx
  4291                              <1> ;       jz      swpqs_5
  4292                              <1> ;	jmp	short swpqs_12
  4293                              <1> 
  4294                              <1> ; 24/12/2021
  4295                              <1> ; ('add_to_swp_queue' procedure call is disabled)
  4296                              <1> 
  4297                              <1> ;add_to_swap_queue:
  4298                              <1> 	; 20/02/2017
  4299                              <1> 	; 20/07/2015
  4300                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4301                              <1> 	;
  4302                              <1> 	; Adds new page to swap queue
  4303                              <1> 	; (page directories and page tables must not be added
  4304                              <1> 	; to swap queue)	
  4305                              <1> 	;
  4306                              <1> 	; INPUT ->
  4307                              <1> 	;	EBX = Linear (Virtual) addr for current process
  4308                              <1> 	;	[u.uno]
  4309                              <1> 	;	20/02/2017
  4310                              <1> 	;	(Linear address = CORE + user's virtual address)
  4311                              <1> 	;
  4312                              <1> 	; OUTPUT ->
  4313                              <1> 	;	EAX = [swpq_count]
  4314                              <1> 	;	      (after the PTE has been added)
  4315                              <1> 	;	EAX = 0 -> Swap queue is full, (1024 entries)
  4316                              <1> 	;	      the PTE could not be added.
  4317                              <1> 	;
  4318                              <1> 	; Modified Registers -> EAX
  4319                              <1> 	;
  4320                              <1> ;	push	ebx
  4321                              <1> ;       and     bx, ~PAGE_OFF ; ~0FFFh ; reset bits, 0 to 11
  4322                              <1> ;	mov	bl, [u.uno] ; current process number
  4323                              <1> ;	call	swap_queue_shift ; drop from the queue if
  4324                              <1> ;				 ; it is already on the queue
  4325                              <1> ;		; then add it to the tail of the queue
  4326                              <1> ;	movzx	eax, word [swpq_count]
  4327                              <1> ;	cmp	ax, 1024
  4328                              <1> ;	jb	short atsq_1
  4329                              <1> ;	sub	ax, ax
  4330                              <1> ;	pop	ebx
  4331                              <1> ;	retn
  4332                              <1> ;atsq_1:
  4333                              <1> ;	push	esi
  4334                              <1> ;	mov	esi, swap_queue
  4335                              <1> ;	and	ax, ax
  4336                              <1> ;	jz	short atsq_2
  4337                              <1> ;	shl	ax, 2	; convert to offset
  4338                              <1> ;	add	esi, eax
  4339                              <1> ;	shr	ax, 2
  4340                              <1> ;atsq_2:
  4341                              <1> ;	inc	ax
  4342                              <1> ;	mov	[esi], ebx ; Virtual address + [u.uno] combination
  4343                              <1> ;	mov	[swpq_count], ax
  4344                              <1> ;	pop	esi
  4345                              <1> ;	pop	ebx
  4346                              <1> ;	retn
  4347                              <1> 
  4348                              <1> ; 24/12/2021
  4349                              <1> ; ('unlink_swap_block' procedure call is disabled)
  4350                              <1> 
  4351                              <1> ;unlink_swap_block:
  4352                              <1> 	; 15/09/2015
  4353                              <1> 	; 30/04/2015
  4354                              <1> 	; 18/04/2015
  4355                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4356                              <1> 	;
  4357                              <1> 	; INPUT -> 
  4358                              <1> 	;	EAX = swap disk/file offset address
  4359                              <1> 	;	      (bit 1 to bit 31)
  4360                              <1> 	; OUTPUT ->
  4361                              <1> 	;	[swpd_free] is increased
  4362                              <1> 	;	(corresponding SWAP DISK ALLOC. TABLE bit is SET)
  4363                              <1> 	;
  4364                              <1> 	; Modified Registers -> EAX
  4365                              <1> 	;
  4366                              <1> ;	push	ebx
  4367                              <1> ;	push	edx
  4368                              <1> ;	;
  4369                              <1> ;	shr	eax, SECTOR_SHIFT+1  ;3+1 ; shift sector address to 
  4370                              <1> ;				     ; 3 bits right
  4371                              <1> ;				     ; to get swap block/page number
  4372                              <1> ;	mov	edx, eax
  4373                              <1> ;	; 15/09/2015
  4374                              <1> ;	shr	edx, 3		     ; to get offset to S.A.T.
  4375                              <1> ;				     ; (1 allocation bit = 1 page)
  4376                              <1> ;				     ; (1 allocation bytes = 8 pages)
  4377                              <1> ;	and	dl, 0FCh 	     ; clear lower 2 bits
  4378                              <1> ;				     ; (to get 32 bit position)			
  4379                              <1> ;	;
  4380                              <1> ;	mov	ebx, swap_alloc_table ; Swap Allocation Table address
  4381                              <1> ;	add	ebx, edx
  4382                              <1> ;	and	eax, 1Fh	     ; lower 5 bits only
  4383                              <1> ;				     ; (allocation bit position)	 
  4384                              <1> ;	cmp 	eax, [swpd_next]     ; is the new free block addr. lower
  4385                              <1> ;				     ; than the address in 'swpd_next' ?
  4386                              <1> ;				     ; (next/first free block value)		
  4387                              <1> ;	jnb	short uswpbl_1	     ; no	
  4388                              <1> ;	mov	[swpd_next], eax     ; yes	
  4389                              <1> ;uswpbl_1:
  4390                              <1> ;	bts	[ebx], eax	     ; unlink/release/deallocate block
  4391                              <1> ;				     ; set relevant bit to 1.
  4392                              <1> ;				     ; set CF to the previous bit value	
  4393                              <1> ;	cmc			     ; complement carry flag	
  4394                              <1> ;	jc	short uswpbl_2	     ; do not increase swfd_free count
  4395                              <1> ;				     ; if the block is already deallocated
  4396                              <1> ;				     ; before.	
  4397                              <1> ;       inc     dword [swpd_free]
  4398                              <1> ;uswpbl_2:
  4399                              <1> ;	pop	edx
  4400                              <1> ;	pop	ebx
  4401                              <1> ;	retn
  4402                              <1> 
  4403                              <1> ; 24/12/2021
  4404                              <1> ; ('link_swap_block' procedure call is disabled)
  4405                              <1> 
  4406                              <1> ;link_swap_block:
  4407                              <1> 	; 01/07/2015
  4408                              <1> 	; 18/04/2015
  4409                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4410                              <1> 	;
  4411                              <1> 	; INPUT -> none
  4412                              <1> 	;
  4413                              <1> 	; OUTPUT ->
  4414                              <1> 	;	EAX = OFFSET ADDRESS OF THE ALLOCATED BLOCK (4096 bytes)
  4415                              <1> 	;	      in sectors (corresponding 
  4416                              <1> 	;	      SWAP DISK ALLOCATION TABLE bit is RESET)
  4417                              <1> 	;
  4418                              <1> 	;	CF = 1 and EAX = 0 
  4419                              <1> 	; 		   if there is not a free block to be allocated	
  4420                              <1> 	;
  4421                              <1> 	; Modified Registers -> none (except EAX)
  4422                              <1> 	;
  4423                              <1> 
  4424                              <1> ;	;mov	eax, [swpd_free]
  4425                              <1> ;	;and	eax, eax
  4426                              <1> ;	;jz	short out_of_swpspc
  4427                              <1> ;	;
  4428                              <1> ;	push	ebx
  4429                              <1> ;	push	ecx
  4430                              <1> ;	;
  4431                              <1> ;	mov	ebx, swap_alloc_table ; Swap Allocation Table offset
  4432                              <1> ;	mov	ecx, ebx
  4433                              <1> ;	add	ebx, [swpd_next] ; Free block searching starts from here
  4434                              <1> ;				 ; next_free_swap_block >> 5
  4435                              <1> ;	add	ecx, [swpd_last] ; Free block searching ends here
  4436                              <1> ;				 ; (total_swap_blocks - 1) >> 5
  4437                              <1> ;lswbl_scan:
  4438                              <1> ;	cmp	ebx, ecx
  4439                              <1> ;	ja	short lswbl_notfound
  4440                              <1> ;	;
  4441                              <1> ;	bsf	eax, [ebx] ; Scans source operand for first bit set (1).
  4442                              <1> ;			   ; Clears ZF if a bit is found set (1) and 
  4443                              <1> ;			   ; loads the destination with an index to
  4444                              <1> ;			   ; first set bit. (0 -> 31) 
  4445                              <1> ;			   ; Sets ZF to 1 if no bits are found set.
  4446                              <1> ;	; 01/07/2015
  4447                              <1> ;	jnz	short lswbl_found ; ZF = 0 -> a free block has been found
  4448                              <1> ;			 ;
  4449                              <1> ;			 ; NOTE:  a Swap Disk Allocation Table bit 
  4450                              <1> ;			 ;	  with value of 1 means 
  4451                              <1> ;			 ;	  the corresponding page is free 
  4452                              <1> ;			 ;	  (Retro UNIX 386 v1 feaure only!)
  4453                              <1> ;	add	ebx, 4
  4454                              <1> ;			 ; We return back for searching next page block
  4455                              <1> ;			 ; NOTE: [swpd_free] is not ZERO; so, 
  4456                              <1> ;			 ;	 we always will find at least 1 free block here.
  4457                              <1> ;	jmp    	short lswbl_scan
  4458                              <1> ;	;
  4459                              <1> ;lswbl_notfound:	
  4460                              <1> ;	sub	ecx, swap_alloc_table
  4461                              <1> ;	mov	[swpd_next], ecx ; next/first free page = last page 
  4462                              <1> ;				 ; (unlink_swap_block procedure will change it)
  4463                              <1> ;	xor	eax, eax
  4464                              <1> ;	mov	[swpd_free], eax
  4465                              <1> ;	stc
  4466                              <1> ;lswbl_ok:
  4467                              <1> ;	pop	ecx
  4468                              <1> ;	pop	ebx
  4469                              <1> ;	retn
  4470                              <1> ;	;
  4471                              <1> ;;out_of_swpspc:
  4472                              <1> ;;	stc
  4473                              <1> ;;	retn
  4474                              <1> ;
  4475                              <1> ;lswbl_found:
  4476                              <1> ;	mov	ecx, ebx
  4477                              <1> ;	sub	ecx, swap_alloc_table
  4478                              <1> ;	mov	[swpd_next], ecx ; Set first free block searching start
  4479                              <1> ;				 ; address/offset (to the next)
  4480                              <1> ;       dec     dword [swpd_free] ; 1 block has been allocated (X = X-1) 
  4481                              <1> ;	;
  4482                              <1> ;	btr	[ebx], eax	 ; The destination bit indexed by the source value
  4483                              <1> ;				 ; is copied into the Carry Flag and then cleared
  4484                              <1> ;				 ; in the destination.
  4485                              <1> ;				 ;
  4486                              <1> ;				 ; Reset the bit which is corresponding to the 
  4487                              <1> ;				 ; (just) allocated block.
  4488                              <1> ;	shl	ecx, 5		 ; (block offset * 32) + block index
  4489                              <1> ;	add	eax, ecx	 ; = block number
  4490                              <1> ;	shl	eax, SECTOR_SHIFT ; 3, sector (offset) address of the block
  4491                              <1> ;				 ; 1 block =  8 sectors
  4492                              <1> ;	;
  4493                              <1> ;	; EAX = offset address of swap disk/file sector (beginning of the block)
  4494                              <1> ;	;
  4495                              <1> ;	; NOTE: The relevant page table entry will be updated
  4496                              <1> ;	;       according to this EAX value...
  4497                              <1> ;	;
  4498                              <1> ;	jmp	short lswbl_ok
  4499                              <1> 
  4500                              <1> ; 24/12/2021
  4501                              <1> ; ('logical_disk_read' procedure call is disabled)
  4502                              <1> 
  4503                              <1> ;logical_disk_read:
  4504                              <1> 	; 20/07/2015
  4505                              <1> 	; 09/03/2015 (temporary code here)
  4506                              <1> 	;
  4507                              <1> 	; INPUT ->
  4508                              <1> 	; 	ESI = Logical disk description table address
  4509                              <1> 	; 	EBX = Memory page (buffer) address (physical!)
  4510                              <1> 	; 	EAX = Sector adress (offset address, logical sector number)
  4511                              <1> 	; 	ECX = Sector count
  4512                              <1> 	;
  4513                              <1> 	;
  4514                              <1> ;	retn
  4515                              <1> 
  4516                              <1> ; 24/12/2021
  4517                              <1> ; ('logical_disk_write' procedure call is disabled)
  4518                              <1> 
  4519                              <1> ;logical_disk_write:
  4520                              <1> 	; 20/07/2015
  4521                              <1> 	; 09/03/2015 (temporary code here)
  4522                              <1> 	;
  4523                              <1> 	; INPUT ->
  4524                              <1> 	; 	ESI = Logical disk description table address
  4525                              <1> 	; 	EBX = Memory page (buffer) address (physical!)
  4526                              <1> 	; 	EAX = Sector adress (offset address, logical sector number)
  4527                              <1> 	; 	ECX = Sector count
  4528                              <1> 	;
  4529                              <1> ;	retn
  4530                              <1> 
  4531                              <1> get_physical_addr:
  4532                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4533                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  4534                              <1> 	; 18/10/2015
  4535                              <1> 	; 29/07/2015
  4536                              <1> 	; 20/07/2015
  4537                              <1> 	; 04/06/2015
  4538                              <1> 	; 20/05/2015
  4539                              <1> 	; 28/04/2015
  4540                              <1> 	; 18/04/2015
  4541                              <1> 	; Get physical address
  4542                              <1> 	;     (allocates a new page for user if it is not present)
  4543                              <1> 	;	
  4544                              <1> 	; (This subroutine is needed for mapping user's virtual 
  4545                              <1> 	; (buffer) address to physical address (of the buffer).)
  4546                              <1> 	; ('sys write', 'sys read' system calls...)
  4547                              <1> 	;
  4548                              <1> 	; INPUT ->
  4549                              <1> 	;	EBX = virtual address
  4550                              <1> 	;	u.pgdir = page directory (physical) address
  4551                              <1> 	;
  4552                              <1> 	; OUTPUT ->
  4553                              <1> 	;	EAX = physical address 
  4554                              <1> 	;	EBX = linear address	
  4555                              <1> 	;	EDX = physical address of the page frame
  4556                              <1> 	;	      (with attribute bits)
  4557                              <1> 	;	ECX = byte count within the page frame
  4558                              <1> 	;
  4559                              <1> 	; Modified Registers -> EAX, EBX, ECX, EDX
  4560                              <1> 	;
  4561                              <1> 
  4562                              <1> 	; 19/04/2020 - Retro UNIX386 v2
  4563 000031A2 A1[F16E0000]        <1> 	mov	eax, [u.pgdir]
  4564                              <1> 
  4565                              <1> ifs_get_physical_addr: ; 19/04/2020 - Retro UNIX 386 v2
  4566                              <1> 	
  4567 000031A7 81C300004000        <1> 	add	ebx, CORE ; 18/10/2015
  4568                              <1> 	;
  4569                              <1> 	;mov	eax, [u.pgdir]
  4570 000031AD E816FDFFFF          <1> 	call	get_pte
  4571                              <1> 		; EDX = Page table entry address (if CF=0)
  4572                              <1> 	        ;       Page directory entry address (if CF=1)
  4573                              <1> 		;       (Bit 0 value is 0 if PT is not present)
  4574                              <1> 		; EAX = Page table entry value (page address)
  4575                              <1> 		;	CF = 1 -> PDE not present or invalid ? 
  4576 000031B2 731C                <1> 	jnc	short gpa_1
  4577                              <1> 	;
  4578 000031B4 E8FDFBFFFF          <1> 	call	allocate_page
  4579 000031B9 724B                <1> 	jc	short gpa_im_err  ; 'insufficient memory' error
  4580                              <1> gpa_0:
  4581 000031BB E867FCFFFF          <1> 	call 	clear_page
  4582                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  4583 000031C0 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER ; 4+2+1 = 7
  4584                              <1> 			   ; lower 3 bits are used as U/S, R/W, P flags
  4585                              <1> 			   ; (user, writable, present page)	
  4586 000031C2 8902                <1> 	mov	[edx], eax ; Let's put the new page directory entry here !
  4587 000031C4 A1[F16E0000]        <1> 	mov	eax, [u.pgdir]	
  4588 000031C9 E8FAFCFFFF          <1> 	call	get_pte
  4589 000031CE 7236                <1> 	jc	short gpa_im_err ; 'insufficient memory' error
  4590                              <1> gpa_1:
  4591                              <1> 	; EAX = PTE value, EDX = PTE address
  4592 000031D0 A801                <1> 	test 	al, PTE_A_PRESENT
  4593 000031D2 750A                <1> 	jnz	short gpa_3
  4594 000031D4 09C0                <1> 	or	eax, eax
  4595 000031D6 7420                <1> 	jz	short gpa_4  ; Allocate a new page
  4596                              <1> 
  4597                              <1> ; 24/12/2021
  4598                              <1> ; ('reload_page' procedure call is disabled)
  4599 000031D8 EB2C                <1> 	jmp	short gpa_im_err
  4600                              <1> 
  4601                              <1> 	; 20/07/2015
  4602                              <1> ;	push	ebp
  4603                              <1> ;	mov	ebp, ebx ; virtual (linear) address
  4604                              <1> ;	; reload swapped page
  4605                              <1> ;	call	reload_page ; 28/04/2015
  4606                              <1> ;	pop	ebp
  4607                              <1> ;	jc	short gpa_retn
  4608                              <1> gpa_2:
  4609                              <1> ; 24/12/2021
  4610                              <1> ; ('add_to_swap_queue' procedure call is disabled)
  4611                              <1> 
  4612                              <1> 	; 20/07/2015
  4613                              <1> 	; 20/05/2015
  4614                              <1> 	; add this page to swap queue
  4615                              <1> ;	push	eax 
  4616                              <1> ;	; EBX = Linear (CORE+virtual) address ; 20/02/2017 
  4617                              <1> ;	call 	add_to_swap_queue
  4618                              <1> ;	pop	eax
  4619                              <1> 		; PTE address in EDX
  4620                              <1> 		; virtual address in EBX
  4621                              <1> 	; EAX = memory page address
  4622 000031DA 0C07                <1> 	or	al, PTE_A_PRESENT + PTE_A_USER + PTE_A_WRITE
  4623                              <1> 				  ; present flag, bit 0 = 1
  4624                              <1> 				  ; user flag, bit 2 = 1	
  4625                              <1> 				  ; writable flag, bit 1 = 1
  4626 000031DC 8902                <1> 	mov	[edx], eax  ; Update PTE value
  4627                              <1> gpa_3:
  4628                              <1> 	; 18/10/2015
  4629 000031DE 89D9                <1> 	mov	ecx, ebx
  4630 000031E0 81E1FF0F0000        <1> 	and	ecx, PAGE_OFF
  4631 000031E6 89C2                <1> 	mov 	edx, eax
  4632 000031E8 662500F0            <1> 	and	ax, PTE_A_CLEAR
  4633 000031EC 01C8                <1> 	add	eax, ecx
  4634 000031EE F7D9                <1> 	neg	ecx ; 1 -> -1 (0FFFFFFFFh), 4095 (0FFFh) -> -4095
  4635 000031F0 81C100100000        <1> 	add	ecx, PAGE_SIZE
  4636 000031F6 F8                  <1> 	clc
  4637                              <1> gpa_retn:
  4638 000031F7 C3                  <1> 	retn	
  4639                              <1> gpa_4:	
  4640 000031F8 E8B9FBFFFF          <1> 	call	allocate_page
  4641 000031FD 7207                <1> 	jc	short gpa_im_err ; 'insufficient memory' error
  4642 000031FF E823FCFFFF          <1> 	call	clear_page
  4643 00003204 EBD4                <1> 	jmp	short gpa_2
  4644                              <1> 
  4645                              <1> gpa_im_err:	
  4646 00003206 B804000000          <1> 	mov	eax, ERR_MINOR_IM ; Insufficient memory (minor) error!
  4647                              <1> 				  ; Major error = 0 (No protection fault)	
  4648 0000320B C3                  <1> 	retn
  4649                              <1> 
  4650                              <1> ; 24/12/2021
  4651                              <1> ; ('reload_page' procedure call is disabled)
  4652                              <1> 
  4653                              <1> ;reload_page:
  4654                              <1> 	; 20/07/2015
  4655                              <1> 	; 28/04/2015 (Retro UNIX 386 v1 - beginning)
  4656                              <1> 	;
  4657                              <1> 	; Reload (Restore) swapped page at memory
  4658                              <1> 	;
  4659                              <1> 	; INPUT -> 
  4660                              <1> 	;	EBP = Virtual (linear) memory address
  4661                              <1> 	;	EAX = PTE value (swap disk sector address)
  4662                              <1> 	;	(Swap disk sector address = bit 1 to bit 31 of EAX)	
  4663                              <1> 	; OUTPUT ->
  4664                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF RELOADED PAGE
  4665                              <1> 	;
  4666                              <1> 	;	CF = 1 and EAX = error code
  4667                              <1> 	;
  4668                              <1> 	; Modified Registers -> none (except EAX)
  4669                              <1> 	;
  4670                              <1> ;	shr	eax, 1   ; Convert PTE value to swap disk address 
  4671                              <1> ;	push	ebx      ;
  4672                              <1> ;	mov	ebx, eax ; Swap disk (offset) address	
  4673                              <1> ;	call	allocate_page
  4674                              <1> ;	jc	short rlp_im_err
  4675                              <1> ;	xchg 	eax, ebx	
  4676                              <1> ;	; EBX = Physical memory (page) address
  4677                              <1> ;	; EAX = Swap disk (offset) address
  4678                              <1> ;	; EBP = Virtual (linear) memory address
  4679                              <1> ;	call	swap_in
  4680                              <1> ;	jc	short rlp_swp_err  ; (swap disk/file read error)
  4681                              <1> ;	mov	eax, ebx	
  4682                              <1> ;rlp_retn:
  4683                              <1> ;	pop	ebx
  4684                              <1> ;	retn
  4685                              <1> ;	
  4686                              <1> ;rlp_im_err:	
  4687                              <1> ;	mov	eax, ERR_MINOR_IM ; Insufficient memory (minor) error!
  4688                              <1> ;				  ; Major error = 0 (No protection fault)	
  4689                              <1> ;	jmp	short rlp_retn
  4690                              <1> ;
  4691                              <1> ;rlp_swp_err:
  4692                              <1> ;	mov 	eax, SWP_DISK_READ_ERR ; Swap disk read error !
  4693                              <1> ;	jmp	short rlp_retn
  4694                              <1> 
  4695                              <1> copy_page_dir:
  4696                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4697                              <1> 	; 19/09/2015
  4698                              <1> 	; temporary - 07/09/2015
  4699                              <1> 	; 07/09/2015 (Retro UNIX 386 v1 - beginning)
  4700                              <1> 	;
  4701                              <1> 	; INPUT -> 
  4702                              <1> 	;	[u.pgdir] = PHYSICAL (real/flat) ADDRESS of the parent's
  4703                              <1> 	;		    page directory.
  4704                              <1> 	; OUTPUT ->
  4705                              <1> 	;	EAX =  PHYSICAL (real/flat) ADDRESS of the child's
  4706                              <1> 	;	       page directory.
  4707                              <1> 	;	(New page directory with new page table entries.)
  4708                              <1> 	;	(New page tables with read only copies of the parent's
  4709                              <1> 	;	pages.)
  4710                              <1> 	;	EAX = 0 -> Error (CF = 1)
  4711                              <1> 	;
  4712                              <1> 	; Modified Registers -> none (except EAX)
  4713                              <1> 	;
  4714 0000320C E8A5FBFFFF          <1> 	call	allocate_page
  4715 00003211 723E                <1> 	jc	short cpd_err
  4716                              <1> 	;
  4717 00003213 55                  <1> 	push	ebp ; 20/07/2015
  4718 00003214 56                  <1> 	push	esi
  4719 00003215 57                  <1> 	push	edi
  4720 00003216 53                  <1> 	push	ebx
  4721 00003217 51                  <1> 	push	ecx
  4722 00003218 8B35[F16E0000]      <1> 	mov	esi, [u.pgdir]
  4723 0000321E 89C7                <1> 	mov	edi, eax
  4724 00003220 50                  <1> 	push	eax ; save child's page directory address
  4725                              <1> 	; copy PDE 0 from the parent's page dir to the child's page dir
  4726                              <1> 	; (use same system space for all user page tables) 
  4727 00003221 A5                  <1> 	movsd
  4728 00003222 BD00004000          <1> 	mov	ebp, 1024*4096 ; pass the 1st 4MB (system space)
  4729 00003227 B9FF030000          <1> 	mov	ecx, (PAGE_SIZE / 4) - 1 ; 1023
  4730                              <1> cpd_0:	
  4731 0000322C AD                  <1> 	lodsd
  4732                              <1> 	;or	eax, eax
  4733                              <1>         ;jnz	short cpd_1
  4734 0000322D A801                <1> 	test	al, PDE_A_PRESENT ;  bit 0 =  1
  4735 0000322F 7508                <1> 	jnz	short cpd_1
  4736                              <1>  	; (virtual address at the end of the page table)	
  4737 00003231 81C500004000        <1> 	add	ebp, 1024*4096 ; page size * PTE count
  4738 00003237 EB0F                <1> 	jmp	short cpd_2
  4739                              <1> cpd_1:	
  4740 00003239 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear attribute bits
  4741 0000323D 89C3                <1> 	mov	ebx, eax
  4742                              <1> 	; EBX = Parent's page table address
  4743 0000323F E81F000000          <1> 	call	copy_page_table
  4744 00003244 720C                <1> 	jc	short cpd_p_err
  4745                              <1> 	; EAX = Child's page table address
  4746 00003246 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER
  4747                              <1> 			 ; set bit 0, bit 1 and bit 2 to 1
  4748                              <1> 			 ; (present, writable, user)
  4749                              <1> cpd_2:
  4750 00003248 AB                  <1> 	stosd
  4751 00003249 E2E1                <1> 	loop	cpd_0
  4752                              <1> 	;
  4753 0000324B 58                  <1> 	pop	eax  ; restore child's page directory address
  4754                              <1> cpd_3:
  4755 0000324C 59                  <1> 	pop	ecx
  4756 0000324D 5B                  <1> 	pop	ebx
  4757 0000324E 5F                  <1> 	pop	edi
  4758 0000324F 5E                  <1> 	pop	esi
  4759 00003250 5D                  <1> 	pop	ebp
  4760                              <1> cpd_err:
  4761 00003251 C3                  <1> 	retn
  4762                              <1> cpd_p_err:
  4763                              <1> 	; release the allocated pages missing (recover free space)
  4764 00003252 58                  <1> 	pop	eax  ; the new page directory address (physical)
  4765 00003253 8B1D[F16E0000]      <1> 	mov	ebx, [u.pgdir] ; parent's page directory address 
  4766 00003259 E888FCFFFF          <1> 	call 	deallocate_page_dir
  4767 0000325E 29C0                <1> 	sub	eax, eax ; 0
  4768 00003260 F9                  <1> 	stc
  4769 00003261 EBE9                <1> 	jmp	short cpd_3	
  4770                              <1> 
  4771                              <1> copy_page_table:
  4772                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4773                              <1> 	; 19/09/2015
  4774                              <1> 	; temporary - 07/09/2015
  4775                              <1> 	; 07/09/2015 (Retro UNIX 386 v1 - beginning)
  4776                              <1> 	;
  4777                              <1> 	; INPUT -> 
  4778                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS of the parent's page table.
  4779                              <1> 	;	EBP = page table entry index (from 'copy_page_dir')
  4780                              <1> 	; OUTPUT ->
  4781                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS of the child's page table.
  4782                              <1> 	;	EBP = (recent) page table index (for 'add_to_swap_queue')	
  4783                              <1> 	;	CF = 1 -> error 
  4784                              <1> 	;
  4785                              <1> 	; Modified Registers -> EBP (except EAX)
  4786                              <1> 	;
  4787 00003263 E84EFBFFFF          <1> 	call	allocate_page
  4788 00003268 7244                <1> 	jc	short cpt_err
  4789                              <1> 	;
  4790 0000326A 50                  <1> 	push	eax ; *
  4791                              <1> 	;push 	ebx
  4792 0000326B 56                  <1> 	push	esi
  4793 0000326C 57                  <1> 	push	edi
  4794 0000326D 52                  <1> 	push	edx
  4795 0000326E 51                  <1> 	push	ecx
  4796                              <1> 	;
  4797 0000326F 89DE                <1> 	mov	esi, ebx
  4798 00003271 89C7                <1> 	mov	edi, eax
  4799 00003273 89C2                <1> 	mov	edx, eax
  4800 00003275 81C200100000        <1> 	add	edx, PAGE_SIZE 	
  4801                              <1> cpt_0:
  4802 0000327B AD                  <1> 	lodsd
  4803 0000327C A801                <1> 	test	al, PTE_A_PRESENT ;  bit 0 = 1
  4804                              <1> 	;jnz	short cpt_1 (*)
  4805                              <1> 	; 24/12/2021
  4806                              <1> 	;and	eax, eax (*)
  4807 0000327E 741E                <1> 	jz	short cpt_2  ; 24/12/2021
  4808                              <1> 	
  4809                              <1> ; 24/12/2021
  4810                              <1> ; ('reload_page' procedure call is disabled)
  4811                              <1> ;
  4812                              <1> ;	; ebp = virtual (linear) address of the memory page
  4813                              <1> ;	call	reload_page ; 28/04/2015
  4814                              <1> ;	jc	short cpt_p_err
  4815                              <1> cpt_1:
  4816 00003280 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  4817 00003284 89C1                <1> 	mov	ecx, eax
  4818                              <1> 	; Allocate a new page for the child process
  4819 00003286 E82BFBFFFF          <1> 	call	allocate_page
  4820 0000328B 721C                <1> 	jc	short cpt_p_err
  4821 0000328D 57                  <1> 	push	edi
  4822 0000328E 56                  <1> 	push	esi
  4823 0000328F 89CE                <1> 	mov	esi, ecx
  4824 00003291 89C7                <1> 	mov	edi, eax
  4825 00003293 B900040000          <1> 	mov	ecx, PAGE_SIZE/4
  4826 00003298 F3A5                <1> 	rep	movsd	; copy page (4096 bytes)
  4827 0000329A 5E                  <1> 	pop	esi
  4828 0000329B 5F                  <1> 	pop	edi
  4829                              <1> 	; 
  4830                              <1> ; 24/12/2021
  4831                              <1> ; ('add_to_swap_queue' procedure call is disabled)	
  4832                              <1> ;
  4833                              <1> ;	push	ebx
  4834                              <1> ;	push	eax
  4835                              <1> ;	mov	ebx, ebp
  4836                              <1> ;	; ebx = virtual address of the memory page
  4837                              <1> ;	call	add_to_swap_queue
  4838                              <1> ;	pop	eax
  4839                              <1> ;	pop	ebx
  4840                              <1> 	;
  4841                              <1> 	;or	ax, PTE_A_USER+PTE_A_PRESENT 
  4842 0000329C 0C07                <1> 	or	al, PTE_A_USER+PTE_A_WRITE+PTE_A_PRESENT 
  4843                              <1> cpt_2:
  4844 0000329E AB                  <1> 	stosd  ; EDI points to child's PTE  	 
  4845                              <1> 	;
  4846 0000329F 81C500100000        <1> 	add	ebp, 4096 ; 20/07/2015 (next page)
  4847                              <1> 	;
  4848 000032A5 39D7                <1> 	cmp	edi, edx
  4849 000032A7 72D2                <1> 	jb	short cpt_0
  4850                              <1> cpt_p_err:
  4851 000032A9 59                  <1> 	pop	ecx
  4852 000032AA 5A                  <1> 	pop	edx
  4853 000032AB 5F                  <1> 	pop	edi
  4854 000032AC 5E                  <1> 	pop	esi
  4855                              <1> 	;pop	ebx
  4856 000032AD 58                  <1> 	pop	eax ; *
  4857                              <1> cpt_err:
  4858 000032AE C3                  <1> 	retn
  4859                              <1> 
  4860                              <1> ; /// End Of MEMORY MANAGEMENT FUNCTIONS ///
  4861                              <1> 
  4862                              <1> ;; Data:
  4863                              <1> 
  4864                              <1> ; 09/03/2015
  4865                              <1> ;swpq_count: dw 0 ; count of pages on the swap que
  4866                              <1> ;swp_drv:    dd 0 ; logical drive description table address of the swap drive/disk
  4867                              <1> ;swpd_size:  dd 0 ; size of swap drive/disk (volume) in sectors (512 bytes).
  4868                              <1> ;swpd_free:  dd 0 ; free page blocks (4096 bytes) on swap disk/drive (logical)
  4869                              <1> ;swpd_next:  dd 0 ; next free page block
  4870                              <1> ;swpd_last:  dd 0 ; last swap page block		 		
  2090                                  %include 'sysdefs.inc' ; 09/03/2015
  2091                              <1> ; Retro UNIX 386 v1.1 Kernel - SYSDEFS.INC
  2092                              <1> ; Last Modification: 08/02//2022
  2093                              <1> ;
  2094                              <1> ; ///////// RETRO UNIX 386 V1 SYSTEM DEFINITIONS ///////////////
  2095                              <1> ; (Modified from 
  2096                              <1> ;	Retro UNIX 8086 v1 system definitions in 'UNIX.ASM', 01/09/2014)
  2097                              <1> ; ((UNIX.ASM (RETRO UNIX 8086 V1 Kernel), 11/03/2013 - 01/09/2014))
  2098                              <1> ; 	UNIX.ASM (MASM 6.11) --> SYSDEFS.INC (NASM 2.11)
  2099                              <1> ; ----------------------------------------------------------------------------
  2100                              <1> ;
  2101                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2102                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2103                              <1> ; <Bell Laboratories (17/3/1972)>
  2104                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2105                              <1> ;
  2106                              <1> ; ****************************************************************************
  2107                              <1> 
  2108                              <1> nproc 	equ	16  ; number of processes
  2109                              <1> nfiles 	equ	50
  2110                              <1> ntty	equ     8   ; 8+1 -> 8 (10/05/2013)
  2111                              <1> nbuf	equ	6   ; number of buffers (04/02/2016)
  2112                              <1> 
  2113                              <1> ;csgmnt	equ	2000h	; 26/05/2013 (segment of process 1)
  2114                              <1> ;core	equ 	0  	    ; 19/04/2013	
  2115                              <1> ;ecore	equ	32768 - 64  ; 04/06/2013 (24/05/2013)
  2116                              <1> 	; (if total size of argument list and arguments is 128 bytes)
  2117                              <1> 	; maximum executable file size = 32768-(64+40+128-6) = 32530 bytes
  2118                              <1> 	; maximum stack size = 40 bytes (+6 bytes for 'IRET' at 32570)	
  2119                              <1> 	; initial value of user's stack pointer = 32768-64-128-2 = 32574
  2120                              <1> 	; 	(sp=32768-args_space-2 at the beginning of execution)
  2121                              <1> 	; argument list offset = 32768-64-128 = 32576 (if it is 128 bytes)
  2122                              <1> 	; 'u' structure offset (for the '/core' dump file) = 32704
  2123                              <1> 	; '/core' dump file size = 32768 bytes
  2124                              <1>  
  2125                              <1> ; 08/03/2014 
  2126                              <1> ;sdsegmnt equ	6C0h  ; 256*16 bytes (swap data segment size for 16 processes)		 	 
  2127                              <1> ; 19/04/2013 Retro UNIX 8086 v1 feaure only !
  2128                              <1> ;;sdsegmnt equ 	740h  ; swap data segment (for user structures and registers)
  2129                              <1> 
  2130                              <1> ; 30/08/2013
  2131                              <1> time_count equ 4 ; 10 --> 4 01/02/2014
  2132                              <1> 
  2133                              <1> ; 05/02/2014
  2134                              <1> ; process status
  2135                              <1> ;SFREE 	equ 0
  2136                              <1> ;SRUN	equ 1
  2137                              <1> ;SWAIT	equ 2
  2138                              <1> ;SZOMB	equ 3
  2139                              <1> ;SSLEEP	equ 4 ; Retro UNIX 8086 V1 extension (for sleep and wakeup)
  2140                              <1> 
  2141                              <1> ; 09/03/2015
  2142                              <1> userdata equ 80000h ; user structure data address for current user ; temporary
  2143                              <1> swap_queue equ 90000h - 2000h ; swap queue address ; temporary
  2144                              <1> swap_alloc_table equ 0D0000h  ;  swap allocation table address ; temporary
  2145                              <1> 
  2146                              <1> ; 17/09/2015
  2147                              <1> ESPACE equ 48 ; [u.usp] (at 'sysent') - [u.sp] value for error return
  2148                              <1> 
  2149                              <1> ; 21/09/2015 (36) 
  2150                              <1> ; 01/07/2015 (35)
  2151                              <1> ; 14/07/2013 (0-34)
  2152                              <1> ; UNIX v1 system calls
  2153                              <1> _rele 	equ 0
  2154                              <1> _exit 	equ 1
  2155                              <1> _fork 	equ 2
  2156                              <1> _read 	equ 3
  2157                              <1> _write	equ 4
  2158                              <1> _open	equ 5
  2159                              <1> _close 	equ 6
  2160                              <1> _wait 	equ 7
  2161                              <1> _creat 	equ 8
  2162                              <1> _link 	equ 9
  2163                              <1> _unlink	equ 10
  2164                              <1> _exec	equ 11
  2165                              <1> _chdir	equ 12
  2166                              <1> _time 	equ 13
  2167                              <1> _mkdir 	equ 14
  2168                              <1> _chmod	equ 15
  2169                              <1> _chown	equ 16
  2170                              <1> _break	equ 17
  2171                              <1> _stat	equ 18
  2172                              <1> _seek	equ 19
  2173                              <1> _tell 	equ 20
  2174                              <1> _mount	equ 21
  2175                              <1> _umount	equ 22
  2176                              <1> _setuid	equ 23
  2177                              <1> _getuid	equ 24
  2178                              <1> _stime	equ 25
  2179                              <1> _quit	equ 26	
  2180                              <1> _intr	equ 27
  2181                              <1> _fstat	equ 28
  2182                              <1> _emt 	equ 29
  2183                              <1> _mdate 	equ 30
  2184                              <1> _stty 	equ 31
  2185                              <1> _gtty	equ 32
  2186                              <1> _ilgins	equ 33
  2187                              <1> _sleep	equ 34 ; Retro UNIX 8086 v1 feature only !
  2188                              <1> _msg	equ 35 ; Retro UNIX 386 v1 feature only !
  2189                              <1> _geterr	equ 36 ; Retro UNIX 386 v1 feature only !
  2190                              <1> 
  2191                              <1> %macro sys 1-4
  2192                              <1>     ; 13/04/2015
  2193                              <1>     ; Retro UNIX 386 v1 system call.		
  2194                              <1>     mov eax, %1
  2195                              <1>     %if %0 >= 2   
  2196                              <1>         mov ebx, %2
  2197                              <1>         %if %0 >= 3    
  2198                              <1>             mov ecx, %3
  2199                              <1>             %if %0 = 4
  2200                              <1>                mov edx, %4   
  2201                              <1>             %endif
  2202                              <1>         %endif
  2203                              <1>     %endif
  2204                              <1>     int 30h	   
  2205                              <1> %endmacro
  2206                              <1> 
  2207                              <1> ; 13/05/2015 - ERROR CODES
  2208                              <1> ERR_FILE_NOT_OPEN  equ 10 ; 'file not open !' error
  2209                              <1> ERR_FILE_ACCESS    equ 11 ; 'permission denied !' error
  2210                              <1> ; 14/05/2015
  2211                              <1> ERR_DIR_ACCESS     equ 11 ; 'permission denied !' error
  2212                              <1> ERR_FILE_NOT_FOUND equ 12 ; 'file not found !' error
  2213                              <1> ERR_TOO_MANY_FILES equ 13 ; 'too many open files !' error
  2214                              <1> ERR_DIR_EXISTS     equ 14 ; 'directory already exists !' error 	
  2215                              <1> ; 16/05/2015		
  2216                              <1> ERR_DRV_NOT_RDY    equ 15 ; 'drive not ready !' error
  2217                              <1> ; 18/05/2015
  2218                              <1> ERR_DEV_NOT_RDY    equ 15 ; 'device not ready !' error
  2219                              <1> ERR_DEV_ACCESS     equ 11 ; 'permission denied !' error 
  2220                              <1> ERR_DEV_NOT_OPEN   equ 10 ; 'device not open !' error	
  2221                              <1> ; 07/06/2015
  2222                              <1> ERR_FILE_EOF	   equ 16 ; 'end of file !' error
  2223                              <1> ERR_DEV_VOL_SIZE   equ 16 ; 'out of volume' error
  2224                              <1> ; 09/06/2015
  2225                              <1> ERR_DRV_READ	   equ 17 ; 'disk read error !'
  2226                              <1> ERR_DRV_WRITE	   equ 18 ; 'disk write error !'
  2227                              <1> ; 16/06/2015
  2228                              <1> ERR_NOT_DIR	   equ 19 ; 'not a (valid) directory !' error
  2229                              <1> ERR_FILE_SIZE	   equ 20 ; 'file size error !'	
  2230                              <1> ; 22/06/2015
  2231                              <1> ERR_NOT_SUPERUSER  equ 11 ; 'permission denied !' error
  2232                              <1> ERR_NOT_OWNER      equ 11 ; 'permission denied !' error
  2233                              <1> ERR_NOT_FILE       equ 11 ; 'permission denied !' error	
  2234                              <1> ; 23/06/2015
  2235                              <1> ERR_FILE_EXISTS    equ 14 ; 'file already exists !' error
  2236                              <1> ERR_DRV_NOT_SAME   equ 21 ; 'not same drive !' error
  2237                              <1> ERR_DIR_NOT_FOUND  equ 12 ; 'directory not found !' error
  2238                              <1> ERR_NOT_EXECUTABLE equ 22 ; 'not executable file !' error
  2239                              <1> ; 27/06/2015
  2240                              <1> ERR_INV_PARAMETER  equ 23 ; 'invalid parameter !' error
  2241                              <1> ERR_INV_DEV_NAME   equ 24 ; 'invalid device name !' error
  2242                              <1> ; 29/06/2015
  2243                              <1> ERR_TIME_OUT	   equ 25 ; 'time out !' error			
  2244                              <1> ERR_DEV_NOT_RESP   equ 25 ; 'device not responding !' error
  2245                              <1> ; 08/02/2022 
  2246                              <1> ; (error numbers from TRDOS 386 v2.0 'sysdefs.s')
  2247                              <1> ; 10/10/2016
  2248                              <1> ERR_INV_FILE_NAME  equ 26 ; 'invalid file name !' error
  2249                              <1> ; 18/05/2016
  2250                              <1> ERR_MISC	   equ 27 ; miscellaneous/other errors
  2251                              <1> ; 15/10/2016
  2252                              <1> ERR_INV_FORMAT	   equ 28 ; 'invalid format !' error
  2253                              <1> ERR_INV_DATA	   equ 29 ; 'invalid data !' error
  2254                              <1> ; 16/10/2016
  2255                              <1> ERR_DISK_WRITE	   equ 30 ; 'disk write protected !'
  2256                              <1> ; 08/02/2022
  2257                              <1> ERR_INV_FS	   equ 28  ;'invalid fs/superblock !' error
  2258                              <1> 
  2259                              <1> ; 26/08/2015
  2260                              <1> ; 24/07/2015
  2261                              <1> ; 24/06/2015
  2262                              <1> MAX_ARG_LEN	   equ 256 ; max. length of sys exec arguments
  2263                              <1> ; 01/07/2015
  2264                              <1> MAX_MSG_LEN	   equ 255 ; max. msg length for 'sysmsg'
  2265                              <1> ; 24/12/2021
  2266                              <1> ERR_INV_FUNC	   equ 1  ; 'invalid system call !' error	 					 		
  2091                                  %include 'u0.s'        ; 15/03/2015
  2092                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS0.INC
  2093                              <1> ; Last Modification: 26/02/2022
  2094                              <1> ; ----------------------------------------------------------------------------
  2095                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2096                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2097                              <1> ;
  2098                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2099                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2100                              <1> ; <Bell Laboratories (17/3/1972)>
  2101                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2102                              <1> ;
  2103                              <1> ; Retro UNIX 8086 v1 - U0.ASM (28/07/2014) //// UNIX v1 -> u0.s
  2104                              <1> ;
  2105                              <1> ; ****************************************************************************
  2106                              <1> 
  2107                              <1> sys_init:
  2108                              <1> 	; 26/02/2022
  2109                              <1> 	; 08/01/2022
  2110                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2111                              <1> 	; 18/10/2015
  2112                              <1> 	; 28/08/2015
  2113                              <1> 	; 24/08/2015
  2114                              <1> 	; 14/08/2015
  2115                              <1> 	; 24/07/2015 
  2116                              <1> 	; 02/07/2015
  2117                              <1> 	; 01/07/2015
  2118                              <1> 	; 23/06/2015
  2119                              <1> 	; 15/04/2015
  2120                              <1> 	; 13/03/2015
  2121                              <1> 	; 11/03/2015 (Retro UNIX 386 v1 - Beginning)
  2122                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2123                              <1> 	;
  2124                              <1> 	;call	ldrv_init ; Logical drive description tables initialization
  2125                              <1> 	;
  2126                              <1> 	; 14/02/2014
  2127                              <1> 	; 14/07/2013
  2128                              <1> 	;;mov	ax, 41
  2129                              <1> 	; 24/12/2021
  2130                              <1> 	;xor	eax, eax
  2131                              <1> 	;mov	al, 41
  2132                              <1> 	;mov	[rootdir], ax
  2133                              <1> 	;mov	[u.cdir], ax
  2134                              <1> 	;;and	al, 1 ; 15/04/2015
  2135                              <1> 	;inc	al  ; ax = 1
  2136 000032AF B001                <1> 	mov	al, 1
  2137 000032B1 A2[E76E0000]        <1> 	mov	[u.uno], al
  2138                              <1> 	;mov	[mpid], ax
  2139                              <1> 	;mov	[p.pid], ax
  2140 000032B6 A2[866E0000]        <1> 	mov	[mpid], al
  2141 000032BB A2[B86B0000]        <1> 	mov	[p.pid], al	
  2142 000032C0 A2[186C0000]        <1> 	mov	[p.stat], al ; SRUN, 05/02/2014
  2143                              <1> 	; 24/12/2021
  2144 000032C5 B029                <1> 	mov	al, 41
  2145                              <1> 	;mov	[rootdir], ax
  2146                              <1> 	;mov	[u.cdir], ax
  2147 000032C7 A2[886E0000]        <1> 	mov	[rootdir], al
  2148 000032CC A2[9C6E0000]        <1> 	mov	[u.cdir], al
  2149                              <1> 	;
  2150 000032D1 B004                <1> 	mov	al, time_count ; 30/08/2013
  2151 000032D3 A2[DA6E0000]        <1> 	mov	[u.quant], al ; 14/07/2013
  2152                              <1> 	; 02/07/2015
  2153 000032D8 A1[D86A0000]        <1> 	mov	eax, [k_page_dir]
  2154                              <1> 	;sub	eax, eax
  2155 000032DD A3[F16E0000]        <1> 	mov	[u.pgdir], eax ; reset
  2156                              <1> 	; 18/10/2015
  2157                              <1> 	;mov	[u.ppgdir], eax ; 0
  2158                              <1> 	; 26/02/2022
  2159                              <1>  	;call	epoch
  2160                              <1> 	;mov	[s.time], eax ; 13/03/2015
  2161                              <1> 	; 17/07/2013
  2162 000032E2 E88F060000          <1> 	call 	bf_init ; buffer initialization
  2163                              <1> 	; 26/02/2022
  2164                              <1> 	; (save sysinit time on sb0)
  2165 000032E7 E829030000          <1> 	call	epoch
  2166 000032EC A3[E47C0000]        <1> 	mov	[s.time], eax ; 13/03/2015
  2167                              <1> 	; 23/06/2015
  2168 000032F1 E8C0FAFFFF          <1> 	call	allocate_page
  2169                              <1> 	;;jc	error
  2170                              <1> 	;jc	panic   ; jc short panic (01/07/2015)
  2171                              <1> 	; 24/12/2021
  2172 000032F6 7305                <1> 	jnc	short sysinit_1
  2173 000032F8 E989000000          <1> 	jmp	panic
  2174                              <1> sysinit_1:
  2175 000032FD A3[E86E0000]        <1> 	mov	[u.upage], eax ; user structure page	
  2176 00003302 A3[286C0000]        <1> 	mov	[p.upage], eax
  2177                              <1> 	;
  2178 00003307 E81BFBFFFF          <1> 	call	clear_page
  2179                              <1> 	;
  2180                              <1> 	; 14/08/2015
  2181 0000330C FA                  <1> 	cli
  2182                              <1> 	; 14/03/2015
  2183                              <1> 	; 17/01/2014
  2184 0000330D E8D0010000          <1> 	call	sp_init ; serial port initialization
  2185                              <1> 	; 14/08/2015
  2186 00003312 FB                  <1> 	sti
  2187                              <1> 	;
  2188                              <1> 	; 30/06/2015
  2189                              <1> 	;mov	esi, kernel_init_ok_msg
  2190                              <1> 	;call 	print_msg
  2191                              <1> 	;
  2192 00003313 30DB                <1> 	xor	bl, bl ; video page 0
  2193                              <1> vp_clr_nxt:  ; clear video pages (reset cursor positions)
  2194 00003315 E8500F0000          <1> 	call 	vp_clr  ; 17/07/2013
  2195 0000331A FEC3                <1> 	inc	bl
  2196 0000331C 80FB08              <1> 	cmp	bl, 8
  2197 0000331F 72F4                <1> 	jb	short vp_clr_nxt
  2198                              <1> 	;
  2199                              <1> 	; 24/07/2015
  2200                              <1> 	;push    KDATA
  2201                              <1>         ;push    esp
  2202                              <1> 	;mov	[tss.esp0], esp
  2203                              <1>         ;mov     word [tss.ss0], KDATA
  2204                              <1> 	;
  2205                              <1> 	; 08/01/2022
  2206                              <1> 	; 24/08/2015
  2207                              <1> 	;; temporary (01/07/2015)
  2208                              <1> 	;mov	byte [u.quant], time_count ; 4 
  2209                              <1> 			       ; it is not needed here !
  2210                              <1> 	;;inc	byte [u.kcall] ; 'the caller is kernel' sign
  2211 00003321 FE0D[8F6E0000]      <1> 	dec 	byte [sysflg] ; FFh = ready for system call
  2212                              <1> 			      ; 0 = executing a system call
  2213                              <1> 	;;sys 	_msg, kernel_init_ok_msg, 255, 0
  2214                              <1> 	;
  2215                              <1> 	;;; 06/08/2015
  2216                              <1> 	;;;call	getch ; wait for a key stroke
  2217                              <1> 	;;mov 	ecx, 0FFFFFFFh	
  2218                              <1> ;;sys_init_msg_wait:
  2219                              <1> ;;	push 	ecx
  2220                              <1> ;;	mov	al, 1
  2221                              <1> ;;	mov 	ah, [ptty] ; active (current) video page
  2222                              <1> ;;	call	getc_n
  2223                              <1> ;;	pop	ecx
  2224                              <1> ;;	jnz	short sys_init_msg_ok
  2225                              <1> ;;	loop	sys_init_msg_wait
  2226                              <1> 	;
  2227                              <1> ;;sys_init_msg_ok:
  2228                              <1> 	; 28/08/2015 (initial settings for the 1st 'rswap')
  2229 00003327 6A10                <1> 	push	KDATA ; ss
  2230 00003329 54                  <1> 	push	esp
  2231 0000332A 9C                  <1> 	pushfd
  2232 0000332B 6A08                <1> 	push	KCODE ; cs
  2233 0000332D 68[5A330000]        <1> 	push	init_exec ; eip
  2234 00003332 8925[906E0000]      <1> 	mov	[u.sp], esp
  2235 00003338 1E                  <1> 	push	ds
  2236 00003339 06                  <1> 	push	es
  2237 0000333A 0FA0                <1> 	push	fs
  2238 0000333C 0FA8                <1> 	push	gs	
  2239 0000333E 60                  <1> 	pushad
  2240 0000333F 8925[946E0000]      <1> 	mov	[u.usp], esp
  2241 00003345 E8641B0000          <1> 	call	wswap ; save current user (u) structure, user registers
  2242                              <1> 		      ; and interrupt return components (for IRET)
  2243 0000334A 61                  <1> 	popad
  2244 0000334B 6658                <1> 	pop	ax ; gs
  2245 0000334D 6658                <1> 	pop	ax ; fs
  2246 0000334F 6658                <1> 	pop	ax ; es
  2247 00003351 6658                <1> 	pop	ax ; ds	
  2248 00003353 58                  <1> 	pop	eax ; eip (init_exec)
  2249 00003354 6658                <1> 	pop	ax ; cs (KCODE)
  2250 00003356 58                  <1> 	pop	eax ; E-FLAGS
  2251 00003357 58                  <1> 	pop	eax ; esp
  2252 00003358 6658                <1> 	pop	ax ; ss (KDATA)
  2253                              <1> 	;
  2254                              <1> 	; 08/01/2022 ([u.ppgdir] is zero already)
  2255                              <1> 	;xor	eax, eax ; 0
  2256                              <1> 	;mov	[u.ppgdir], eax ; reset (to zero) for '/etc/init'
  2257                              <1> 	;
  2258                              <1> 	; 02/07/2015
  2259                              <1> 	; [u.pgdir ] = [k_page_dir]
  2260                              <1> 	; [u.ppgdir] = 0 (page dir of the parent process)
  2261                              <1> 	;     (The caller is os kernel sign for 'sysexec')
  2262                              <1> init_exec:
  2263                              <1> 	; 13/03/2013
  2264                              <1> 	; 24/07/2013
  2265 0000335A BB[7C330000]        <1> 	mov	ebx, init_file
  2266 0000335F B9[74330000]        <1> 	mov	ecx, init_argp
  2267                              <1> 	; EBX contains 'etc/init' asciiz file name address  
  2268                              <1> 	; ECX contains address of argument list pointer
  2269                              <1> 	;
  2270                              <1> 	;dec 	byte [sysflg] ; FFh = ready for system call
  2271                              <1> 			      ; 0 = executing a system call
  2272                              <1> 	sys	_exec  ; execute file
  2192                              <2> 
  2193                              <2> 
  2194 00003364 B80B000000          <2>  mov eax, %1
  2195                              <2>  %if %0 >= 2
  2196                              <2>  mov ebx, %2
  2197                              <2>  %if %0 >= 3
  2198                              <2>  mov ecx, %3
  2199                              <2>  %if %0 = 4
  2200                              <2>  mov edx, %4
  2201                              <2>  %endif
  2202                              <2>  %endif
  2203                              <2>  %endif
  2204 00003369 CD30                <2>  int 30h
  2273 0000336B 7319                <1> 	jnc	short panic
  2274                              <1> 	;
  2275 0000336D BE[EC670000]        <1> 	mov	esi, etc_init_err_msg
  2276                              <1> 	; 08/01/2022
  2277                              <1> 	;call 	print_msg
  2278 00003372 EB17                <1> 	jmp	short key_to_reboot
  2279                              <1> 
  2280                              <1> ;align 4
  2281                              <1> init_argp:
  2282 00003374 [7C330000]00000000  <1> 	dd 	init_file, 0  ; 23/06/2015 (dw -> dd)
  2283                              <1> init_file:
  2284                              <1> 	; 24/08/2015
  2285 0000337C 2F6574632F696E6974- <1> 	db 	'/etc/init', 0
  2285 00003385 00                  <1>
  2286                              <1> panic:
  2287                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2288                              <1> 	; 07/03/2014 (Retro UNIX 8086 v1)
  2289 00003386 BE[D1670000]        <1> 	mov 	esi, panic_msg
  2290                              <1> key_to_reboot: ; 08/01/2022 (Retro UNIX 386 v1.1)
  2291 0000338B E819000000          <1> 	call 	print_msg
  2292                              <1> ;key_to_reboot:
  2293                              <1> 	; 15/11/2015
  2294 00003390 E8D32B0000          <1> 	call 	getch 
  2295                              <1> 		; wait for a character from the current tty
  2296                              <1> 	;
  2297 00003395 B00A                <1> 	mov	al, 0Ah
  2298 00003397 8A1D[066B0000]      <1> 	mov	bl, [ptty] ; [active_page]
  2299 0000339D B407                <1> 	mov	ah, 07h ; Black background, 
  2300                              <1> 			; light gray forecolor
  2301 0000339F E822E0FFFF          <1> 	call 	write_tty
  2302 000033A4 E9BDDCFFFF          <1> 	jmp	cpu_reset 
  2303                              <1> 
  2304                              <1> print_msg:
  2305                              <1> 	; 01/07/2015
  2306                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2307                              <1> 	; 07/03/2014 (Retro UNIX 8086 v1)
  2308                              <1> 	; (Modified registers: EAX, EBX, ECX, EDX, ESI, EDI)
  2309                              <1> 	;
  2310                              <1> 	;
  2311 000033A9 AC                  <1> 	lodsb
  2312                              <1> pmsg1:
  2313 000033AA 56                  <1> 	push 	esi
  2314 000033AB 0FB61D[066B0000]    <1> 	movzx	ebx, byte [ptty]
  2315 000033B2 B407                <1> 	mov	ah, 07h ; Black background, light gray forecolor
  2316 000033B4 E80DE0FFFF          <1> 	call 	write_tty
  2317 000033B9 5E                  <1> 	pop	esi
  2318 000033BA AC                  <1> 	lodsb
  2319 000033BB 20C0                <1> 	and 	al, al
  2320 000033BD 75EB                <1> 	jnz 	short pmsg1
  2321 000033BF C3                  <1> 	retn
  2322                              <1> 	
  2323                              <1> ctrlbrk:
  2324                              <1> 	; 04/02/2022
  2325                              <1> 	; 01/02/2022
  2326                              <1> 	; 12/11/2015
  2327                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2328                              <1> 	; 06/12/2013 (Retro UNIX 8086 v1)
  2329                              <1> 	;
  2330                              <1> 	; INT 1Bh (control+break) handler
  2331                              <1> 	;
  2332                              <1>       	; Retro Unix 8086 v1 feature only!
  2333                              <1>       	;
  2334 000033C0 66833D[DC6E0000]00  <1> 	cmp 	word [u.intr], 0
  2335 000033C8 764B                <1> 	jna 	short cbrk4
  2336                              <1> cbrk0:
  2337                              <1> 	; 12/11/2015
  2338                              <1> 	; 06/12/2013
  2339 000033CA 66833D[DE6E0000]00  <1> 	cmp 	word [u.quit], 0
  2340 000033D2 7441                <1> 	jz	short cbrk4
  2341                              <1> 	;
  2342                              <1> 	; 20/09/2013	
  2343                              <1> 	;push 	ax
  2344                              <1> 	; 01/02/2022
  2345 000033D4 50                  <1> 	push	eax
  2346                              <1> 
  2347                              <1> 	; 04/02/2022
  2348                              <1> 	; (repetitive ctrl+brk check) 
  2349 000033D5 66A1[DE6E0000]      <1> 	mov	ax, [u.quit]
  2350 000033DB 6640                <1> 	inc	ax ; 0FFFFh -> 0
  2351 000033DD 7435                <1> 	jz	short cbrk3
  2352                              <1> 
  2353                              <1> 	; 20/09/2013
  2354 000033DF A0[066B0000]        <1> 	mov	al, [ptty]
  2355                              <1> 	;
  2356                              <1> 	; 12/11/2015
  2357                              <1> 	;
  2358                              <1> 	; ctrl+break (EOT, CTRL+D) from serial port
  2359                              <1> 	; or ctrl+break from console (pseudo) tty
  2360                              <1> 	; (!redirection!)
  2361                              <1> 	;
  2362 000033E4 3C08                <1> 	cmp	al, 8 ; serial port tty nums > 7
  2363 000033E6 7211                <1>         jb      short cbrk1 ; console (pseudo) tty
  2364                              <1> 	;	
  2365                              <1> 	; Serial port interrupt handler sets [ptty]
  2366                              <1> 	; to the port's tty number (as temporary).
  2367                              <1> 	;
  2368                              <1> 	; If active process is using a stdin or 
  2369                              <1> 	; stdout redirection (by the shell),
  2370                              <1>         ; console tty keyboard must be available
  2371                              <1> 	; to terminate running process,
  2372                              <1> 	; in order to prevent a deadlock. 
  2373                              <1> 	;
  2374 000033E8 52                  <1> 	push	edx
  2375 000033E9 0FB615[E76E0000]    <1> 	movzx	edx, byte [u.uno]
  2376 000033F0 3A82[F76B0000]      <1> 	cmp     al, [edx+p.ttyc-1] ; console tty (rw)
  2377 000033F6 5A                  <1> 	pop	edx
  2378 000033F7 7412                <1> 	je	short cbrk2
  2379                              <1> cbrk1:
  2380 000033F9 FEC0                <1> 	inc 	al  ; [u.ttyp] : 1 based tty number
  2381                              <1> 	; 06/12/2013
  2382 000033FB 3A05[C86E0000]      <1> 	cmp	al, [u.ttyp] ; recent open tty (r)
  2383 00003401 7408                <1> 	je	short cbrk2	
  2384 00003403 3A05[C96E0000]      <1>         cmp     al, [u.ttyp+1] ; recent open tty (w)
  2385 00003409 7509                <1> 	jne	short cbrk3	
  2386                              <1> cbrk2:
  2387                              <1> 	;; 06/12/2013
  2388                              <1> 	;mov	ax, [u.quit]
  2389                              <1> 	;and	ax, ax
  2390                              <1> 	;jz	short cbrk3
  2391                              <1> 	;
  2392                              <1> 	;xor	ax, ax ; 0
  2393                              <1> 	;dec	ax
  2394                              <1> 	; 01/02/2022
  2395 0000340B 31C0                <1> 	xor	eax, eax ; 0
  2396 0000340D 48                  <1> 	dec	eax ; 0FFFFFFFFh
  2397                              <1> 	; 0FFFFh = 'ctrl+brk' keystroke
  2398 0000340E 66A3[DE6E0000]      <1> 	mov	[u.quit], ax
  2399                              <1> cbrk3:
  2400                              <1> 	;pop	ax
  2401                              <1> 	; 01/02/2022
  2402 00003414 58                  <1> 	pop	eax
  2403                              <1> cbrk4:
  2404 00003415 C3                  <1> 	retn
  2405                              <1> 
  2406                              <1> com2_int:
  2407                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2408                              <1> 	; 07/11/2015 
  2409                              <1> 	; 24/10/2015
  2410                              <1> 	; 23/10/2015
  2411                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - Beginning)
  2412                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2413                              <1> 	; < serial port 2 interrupt handler >
  2414                              <1> 	;
  2415 00003416 890424              <1> 	mov 	[esp], eax ; overwrite call return address
  2416                              <1> 	;;push	eax
  2417                              <1> 	; 08/01/2022
  2418 00003419 29C0                <1> 	sub	eax, eax
  2419 0000341B B009                <1> 	mov	al, 9
  2420                              <1> 	;mov	ax, 9
  2421 0000341D EB07                <1> 	jmp	short comm_int
  2422                              <1> com1_int:
  2423                              <1> 	; 07/11/2015
  2424                              <1> 	; 24/10/2015
  2425 0000341F 890424              <1> 	mov 	[esp], eax ; overwrite call return address
  2426                              <1> 	; 23/10/2015
  2427                              <1> 	;push	eax
  2428                              <1> 	; 08/01/2022
  2429 00003422 29C0                <1> 	sub	eax, eax
  2430 00003424 B008                <1> 	mov	al, 8
  2431                              <1> 	;mov	ax, 8
  2432                              <1> comm_int:
  2433                              <1> 	; 08/01/2022
  2434                              <1> 	; 20/11/2015
  2435                              <1> 	; 18/11/2015
  2436                              <1> 	; 17/11/2015
  2437                              <1> 	; 16/11/2015
  2438                              <1> 	; 09/11/2015
  2439                              <1> 	; 08/11/2015
  2440                              <1> 	; 07/11/2015
  2441                              <1> 	; 06/11/2015 (serial4.asm, 'serial')
  2442                              <1> 	; 01/11/2015
  2443                              <1> 	; 26/10/2015
  2444                              <1> 	; 23/10/2015
  2445 00003426 53                  <1> 	push	ebx
  2446 00003427 56                  <1> 	push	esi
  2447 00003428 57                  <1> 	push	edi
  2448 00003429 1E                  <1> 	push 	ds
  2449 0000342A 06                  <1> 	push 	es
  2450                              <1> 	; 18/11/2015
  2451 0000342B 0F20DB              <1> 	mov	ebx, cr3
  2452 0000342E 53                  <1> 	push	ebx ; ****
  2453                              <1> 	;
  2454 0000342F 51                  <1> 	push	ecx ; ***
  2455 00003430 52                  <1> 	push	edx ; **
  2456                              <1> 	;
  2457 00003431 BB10000000          <1> 	mov	ebx, KDATA
  2458 00003436 8EDB                <1> 	mov	ds, bx
  2459 00003438 8EC3                <1> 	mov	es, bx
  2460                              <1> 	;
  2461 0000343A 8B0D[D86A0000]      <1> 	mov	ecx, [k_page_dir]
  2462 00003440 0F22D9              <1> 	mov	cr3, ecx
  2463                              <1> 	; 20/11/2015
  2464                              <1> 	; Interrupt identification register
  2465 00003443 66BAFA02            <1> 	mov	dx, 2FAh ; COM2
  2466                              <1> 	;
  2467 00003447 3C08                <1> 	cmp 	al, 8 
  2468 00003449 7702                <1> 	ja 	short com_i0
  2469                              <1> 	;
  2470                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1)
  2471                              <1> 	; 20/11/2015
  2472                              <1> 	; 17/11/2015
  2473                              <1> 	; 16/11/2015
  2474                              <1> 	; 15/11/2015
  2475                              <1> 	; 24/10/2015
  2476                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - Beginning)
  2477                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2478                              <1> 	; < serial port 1 interrupt handler >
  2479                              <1> 	;
  2480 0000344B FEC6                <1> 	inc	dh ; 3FAh ; COM1 Interrupt id. register
  2481                              <1> com_i0:
  2482                              <1> 	;push	eax ; *
  2483                              <1> 	; 07/11/2015
  2484 0000344D A2[466B0000]        <1> 	mov 	byte [ccomport], al
  2485                              <1> 	; 09/11/2015
  2486                              <1> 	;movzx	ebx, ax ; 8 or 9
  2487                              <1> 	; 08/01/2022
  2488 00003452 89C3                <1> 	mov	ebx, eax ; 8 or 9
  2489                              <1> 	; 17/11/2015
  2490                              <1>  	; reset request for response status
  2491 00003454 88A3[3C6B0000]      <1> 	mov	[ebx+req_resp-8], ah ; 0
  2492                              <1> 	;
  2493                              <1> 	; 20/11/2015
  2494 0000345A EC                  <1> 	in	al, dx		; read interrupt id. register
  2495 0000345B EB00                <1> 	JMP	$+2	   	; I/O DELAY
  2496 0000345D 2404                <1> 	and	al, 4		; received data available?	
  2497 0000345F 7470                <1> 	jz	short com_eoi	; (transmit. holding reg. empty)
  2498                              <1> 	;
  2499                              <1> 	; 20/11/2015
  2500 00003461 80EA02              <1> 	sub	dl, 3FAh-3F8h	; data register (3F8h, 2F8h)
  2501 00003464 EC                  <1> 	in	al, dx     	; read character
  2502                              <1> 	;JMP	$+2	   	; I/O DELAY
  2503                              <1> 	; 08/11/2015
  2504                              <1> 	; 07/11/2015
  2505 00003465 89DE                <1> 	mov	esi, ebx 
  2506 00003467 89DF                <1> 	mov	edi, ebx
  2507 00003469 81C6[406B0000]      <1> 	add 	esi, rchar - 8 ; points to last received char
  2508 0000346F 81C7[426B0000]      <1> 	add	edi, schar - 8 ; points to last sent char
  2509 00003475 8806                <1> 	mov	[esi], al ; received char (current char)
  2510                              <1> 	; query
  2511 00003477 20C0                <1> 	and	al, al
  2512 00003479 7527                <1> 	jnz	short com_i2
  2513                              <1>    	; response
  2514                              <1> 	; 17/11/2015
  2515                              <1> 	; set request for response status
  2516 0000347B FE83[3C6B0000]      <1>         inc     byte [ebx+req_resp-8] ; 1 
  2517                              <1> 	;
  2518 00003481 6683C205            <1> 	add	dx, 3FDh-3F8h	; (3FDh, 2FDh)
  2519 00003485 EC                  <1> 	in	al, dx	   	; read line status register 
  2520 00003486 EB00                <1> 	JMP	$+2	   	; I/O DELAY
  2521 00003488 2420                <1> 	and	al, 20h	   	; transmitter holding reg. empty?
  2522 0000348A 7445                <1> 	jz	short com_eoi 	; no
  2523 0000348C B0FF                <1> 	mov 	al, 0FFh   	; response			
  2524 0000348E 6683EA05            <1> 	sub	dx, 3FDh-3F8h 	; data port (3F8h, 2F8h)
  2525 00003492 EE                  <1> 	out	dx, al	   	; send on serial port
  2526                              <1> 	; 17/11/2015
  2527 00003493 803F00              <1> 	cmp 	byte [edi], 0   ; query ? (schar)
  2528 00003496 7502                <1> 	jne 	short com_i1    ; no
  2529 00003498 8807                <1> 	mov	[edi], al 	; 0FFh (responded)
  2530                              <1> com_i1:
  2531                              <1> 	; 17/11/2015
  2532                              <1> 	; reset request for response status (again)
  2533 0000349A FE8B[3C6B0000]      <1>         dec     byte [ebx+req_resp-8] ; 0 
  2534 000034A0 EB2F                <1> 	jmp	short com_eoi
  2535                              <1> com_i2:	
  2536                              <1> 	; 08/11/2015
  2537 000034A2 3CFF                <1> 	cmp 	al, 0FFh	; (response ?)
  2538 000034A4 7417                <1> 	je	short com_i3	; (check for response signal)
  2539                              <1> 	; 07/11/2015
  2540 000034A6 3C04                <1> 	cmp	al, 04h	; EOT
  2541 000034A8 751C                <1> 	jne	short com_i4	
  2542                              <1> 	; EOT = 04h (End of Transmit) - 'CTRL + D'
  2543                              <1> 	;(an EOT char is supposed as a ctrl+brk from the terminal)
  2544                              <1> 	; 08/11/2015
  2545                              <1> 		; ptty -> tty 0 to 7 (pseudo screens)
  2546 000034AA 861D[066B0000]      <1> 	xchg	bl, [ptty]  ; tty number (8 or 9)
  2547 000034B0 E80BFFFFFF          <1> 	call 	ctrlbrk
  2548 000034B5 861D[066B0000]      <1> 	xchg	[ptty], bl ; (restore ptty value and BL value)
  2549                              <1> 	;mov	al, 04h ; EOT
  2550                              <1> 	; 08/11/2015
  2551 000034BB EB09                <1> 	jmp	short com_i4	
  2552                              <1> com_i3:
  2553                              <1> 	; 08/11/2015
  2554                              <1> 	; If 0FFh has been received just after a query
  2555                              <1> 	; (schar, ZERO), it is a response signal.
  2556                              <1> 	; 17/11/2015
  2557 000034BD 803F00              <1>         cmp     byte [edi], 0 ; query ? (schar)
  2558 000034C0 7704                <1> 	ja	short com_i4 ; no
  2559                              <1> 	; reset query status (schar)
  2560 000034C2 8807                <1> 	mov	[edi], al ; 0FFh
  2561 000034C4 FEC0                <1> 	inc	al ; 0
  2562                              <1> com_i4:
  2563                              <1> 	; 27/07/2014
  2564                              <1> 	; 09/07/2014
  2565 000034C6 D0E3                <1> 	shl	bl, 1	
  2566 000034C8 81C3[086B0000]      <1> 	add	ebx, ttychr
  2567                              <1> 	; 23/07/2014 (always overwrite)
  2568                              <1> 	;;cmp	word [ebx], 0
  2569                              <1> 	;;ja	short com_eoi
  2570                              <1> 	;
  2571 000034CE 668903              <1> 	mov	[ebx], ax   ; Save ascii code
  2572                              <1> 			    ; scan code = 0
  2573                              <1> com_eoi:
  2574                              <1> 	;mov	al, 20h
  2575                              <1> 	;out	20h, al	   ; end of interrupt
  2576                              <1> 	;
  2577                              <1> 	; 07/11/2015
  2578                              <1>       	;pop	eax ; *
  2579 000034D1 A0[466B0000]        <1> 	mov	al, byte [ccomport] ; current COM port
  2580                              <1> 	; al = tty number (8 or 9)
  2581 000034D6 E8AD1A0000          <1>         call	wakeup
  2582                              <1> com_iret:
  2583                              <1> 	; 23/10/2015
  2584 000034DB 5A                  <1> 	pop	edx ; **
  2585 000034DC 59                  <1> 	pop	ecx ; ***
  2586                              <1> 	; 18/11/2015
  2587                              <1> 	;pop	eax ; ****
  2588                              <1> 	;mov	cr3, eax
  2589                              <1> 	;jmp	iiret
  2590 000034DD E9C2D4FFFF          <1> 	jmp	iiretp
  2591                              <1> 
  2592                              <1> ;iiretp: ; 01/09/2015
  2593                              <1> ;	; 28/08/2015
  2594                              <1> ;	pop	eax ; (*) page directory
  2595                              <1> ;	mov	cr3, eax
  2596                              <1> ;iiret:
  2597                              <1> ;	; 22/08/2014
  2598                              <1> ;	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  2599                              <1> ;	out	20h, al	; 8259 PORT
  2600                              <1> ;	;
  2601                              <1> ;	pop	es
  2602                              <1> ;	pop	ds
  2603                              <1> ;	pop	edi
  2604                              <1> ;	pop	esi
  2605                              <1> ;	pop	ebx ; 29/08/2014
  2606                              <1> ;	pop 	eax
  2607                              <1> ;	iretd
  2608                              <1> 
  2609                              <1> sp_init:
  2610                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2611                              <1> 	; 07/11/2015
  2612                              <1> 	; 29/10/2015
  2613                              <1> 	; 26/10/2015
  2614                              <1> 	; 23/10/2015
  2615                              <1> 	; 29/06/2015
  2616                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - 115200 baud)
  2617                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1 - 9600 baud)
  2618                              <1> 	; Initialization of Serial Port Communication Parameters
  2619                              <1> 	; (COM1 base port address = 3F8h, COM1 Interrupt = IRQ 4)
  2620                              <1> 	; (COM2 base port address = 2F8h, COM1 Interrupt = IRQ 3)
  2621                              <1> 	;
  2622                              <1> 	; ((Modified registers: EAX, ECX, EDX, EBX))
  2623                              <1> 	;
  2624                              <1> 	; INPUT:  (29/06/2015)
  2625                              <1> 	;	AL = 0 for COM1
  2626                              <1> 	;	     1 for COM2
  2627                              <1> 	;	AH = Communication parameters	
  2628                              <1> 	;
  2629                              <1> 	;  (*) Communication parameters (except BAUD RATE):
  2630                              <1> 	;	Bit	4	3	2	1	0
  2631                              <1> 	;		-PARITY--   STOP BIT  -WORD LENGTH-	 		 
  2632                              <1> 	;  this one -->	00 = none    0 = 1 bit  11 = 8 bits
  2633                              <1> 	;		01 = odd     1 = 2 bits	10 = 7 bits
  2634                              <1> 	;		11 = even
  2635                              <1> 	;  Baud rate setting bits: (29/06/2015)
  2636                              <1> 	;		Retro UNIX 386 v1 feature only !
  2637                              <1> 	;	Bit	7    6    5  | Baud rate
  2638                              <1> 	;		------------------------
  2639                              <1> 	;	value	0    0    0  | Default (Divisor = 1)
  2640                              <1> 	;		0    0    1  | 9600 (12)
  2641                              <1> 	;		0    1    0  | 19200 (6) 
  2642                              <1> 	;		0    1	  1  | 38400 (3) 
  2643                              <1> 	;		1    0	  0  | 14400 (8)
  2644                              <1> 	;		1    0	  1  | 28800 (4)
  2645                              <1> 	;		1    1    0  | 57600 (2)
  2646                              <1> 	;		1    1    1  | 115200 (1) 	
  2647                              <1> 	
  2648                              <1> 	; References:	
  2649                              <1> 	; (1) IBM PC-XT Model 286 BIOS Source Code
  2650                              <1> 	;     RS232.ASM --- 10/06/1985 COMMUNICATIONS BIOS (RS232)
  2651                              <1> 	; (2) Award BIOS 1999 - ATORGS.ASM
  2652                              <1> 	; (3) http://wiki.osdev.org/Serial_Ports
  2653                              <1> 	;
  2654                              <1> 	; Set communication parameters for COM1 (= 03h)	
  2655                              <1> 	;
  2656 000034E2 BB[426B0000]        <1> 	mov	ebx, com1p		; COM1 parameters  
  2657 000034E7 66BAF803            <1> 	mov	dx, 3F8h		; COM1
  2658                              <1> 	; 29/10/2015
  2659 000034EB 66B90103            <1> 	mov	cx, 301h  ; divisor = 1 (115200 baud)
  2660 000034EF E84F000000          <1> 	call	sp_i3	; call A4	
  2661 000034F4 A880                <1> 	test	al, 80h
  2662 000034F6 740E                <1> 	jz	short sp_i0 ; OK..
  2663                              <1> 		; Error !
  2664                              <1> 	;mov	dx, 3F8h
  2665 000034F8 80EA05              <1> 	sub	dl, 5 ; 3FDh -> 3F8h
  2666                              <1> 	;mov	cx, 30Eh  ; divisor = 12 (9600 baud)
  2667                              <1> 	; 08/01/2022
  2668 000034FB B10E                <1> 	mov	cl, 0Eh ; cx = 30Eh, divisor = 12 (9600 baud)
  2669 000034FD E841000000          <1> 	call	sp_i3	; call A4	
  2670 00003502 A880                <1> 	test	al, 80h
  2671 00003504 7508                <1> 	jnz	short sp_i1
  2672                              <1> sp_i0:
  2673                              <1>         ; (Note: Serial port interrupts will be disabled here...)	
  2674                              <1>         ; (INT 14h initialization code disables interrupts.)
  2675                              <1> 	;
  2676 00003506 C603E3              <1> 	mov	byte [ebx], 0E3h ; 11100011b
  2677 00003509 E8BF000000          <1> 	call	sp_i5 ; 29/06/2015
  2678                              <1> sp_i1:
  2679 0000350E 43                  <1> 	inc	ebx
  2680 0000350F 66BAF802            <1> 	mov	dx, 2F8h		; COM2
  2681                              <1> 	; 29/10/2015
  2682                              <1> 	;mov	cx, 301h  ; divisor = 1 (115200 baud)
  2683                              <1> 	; 08/01/2022
  2684 00003513 B101                <1> 	mov	cl, 01h ; cx = 301h, divisor = 1 (115200 baud)
  2685 00003515 E829000000          <1> 	call	sp_i3	; call A4	
  2686 0000351A A880                <1> 	test	al, 80h
  2687 0000351C 740E                <1> 	jz	short sp_i2 ; OK..
  2688                              <1> 		; Error !
  2689                              <1> 	;mov	dx, 2F8h
  2690 0000351E 80EA05              <1> 	sub	dl, 5 ; 2FDh -> 2F8h
  2691                              <1> 	;mov	cx, 30Eh  ; divisor = 12 (9600 baud)
  2692                              <1> 	; 08/01/2022
  2693 00003521 B10E                <1> 	mov	cl, 0Eh ; cx = 30Eh, divisor = 12 (9600 baud)
  2694 00003523 E81B000000          <1> 	call	sp_i3	; call A4	
  2695 00003528 A880                <1> 	test	al, 80h
  2696 0000352A 7516                <1> 	jnz	short sp_i7
  2697                              <1> sp_i2:
  2698 0000352C C603E3              <1> 	mov	byte [ebx], 0E3h ; 11100011b
  2699                              <1> sp_i6:
  2700                              <1> 	;; COM2 - enabling IRQ 3
  2701                              <1> 	; 08/01/2022
  2702 0000352F B4F7                <1> 	mov	ah, 0F7h ; enable IRQ 3 (COM2)
  2703                              <1> 	; 07/11/2015
  2704                              <1> 	; 26/10/2015
  2705                              <1> 	;pushf
  2706                              <1> 	;cli
  2707                              <1> 	;;
  2708                              <1> 	;;mov	dx, 2FCh   		; modem control register
  2709                              <1> 	;mov	dl, 0FCh ; 08/01/2022
  2710                              <1> 	;in	al, dx 	   		; read register
  2711                              <1> 	;JMP	$+2	   		; I/O DELAY
  2712                              <1> 	;or	al, 8      		; enable bit 3 (OUT2)
  2713                              <1> 	;out	dx, al     		; write back to register
  2714                              <1> 	;JMP	$+2	   		; I/O DELAY
  2715                              <1> 	;;mov	dx, 2F9h   		; interrupt enable register
  2716                              <1> 	;mov	dl, 0F9h ; 08/01/2022
  2717                              <1> 	;in	al, dx     		; read register
  2718                              <1> 	;JMP	$+2	   		; I/O DELAY
  2719                              <1> 	;;or	al, 1      		; receiver data interrupt enable and
  2720                              <1> 	;or	al, 3	   		; transmitter empty interrupt enable
  2721                              <1> 	;out	dx, al 	   		; write back to register
  2722                              <1> 	;JMP	$+2        		; I/O DELAY
  2723                              <1> 	;in	al, 21h    		; read interrupt mask register
  2724                              <1> 	;JMP	$+2	   		; I/O DELAY
  2725                              <1> 	;and	al, 0F7h   		; enable IRQ 3 (COM2)
  2726                              <1> 	;out	21h, al    		; write back to register
  2727                              <1> 	;
  2728                              <1> 	; 08/01/2022
  2729 00003531 9C                  <1> 	pushf
  2730 00003532 E8AA000000          <1> 	call	sp_i8
  2731                              <1> 	; 23/10/2015
  2732 00003537 B8[16340000]        <1> 	mov 	eax, com2_int
  2733 0000353C A3[D5390000]        <1> 	mov	[com2_irq3], eax
  2734                              <1> 	; 26/10/2015
  2735 00003541 9D                  <1> 	popf	
  2736                              <1> sp_i7:
  2737 00003542 C3                  <1> 	retn
  2738                              <1> 
  2739                              <1> sp_i3:
  2740                              <1> ;A4:  	;-----	INITIALIZE THE COMMUNICATIONS PORT
  2741                              <1> 	; 28/10/2015
  2742 00003543 FEC2                <1> 	inc	dl	; 3F9h (2F9h)	; 3F9h, COM1 Interrupt enable register 
  2743 00003545 B000                <1> 	mov	al, 0
  2744 00003547 EE                  <1> 	out	dx, al			; disable serial port interrupt
  2745 00003548 EB00                <1> 	JMP	$+2			; I/O DELAY
  2746 0000354A 80C202              <1> 	add	dl, 2 	; 3FBh (2FBh)	; COM1 Line control register (3FBh)
  2747 0000354D B080                <1> 	mov	al, 80h			
  2748 0000354F EE                  <1> 	out	dx, al			; SET DLAB=1 ; divisor latch access bit
  2749                              <1> 	;-----	SET BAUD RATE DIVISOR
  2750                              <1> 	; 26/10/2015
  2751 00003550 80EA03              <1> 	sub 	dl, 3   ; 3F8h (2F8h)	; register for least significant byte
  2752                              <1> 					; of the divisor value
  2753 00003553 88C8                <1> 	mov	al, cl	; 1
  2754 00003555 EE                  <1> 	out	dx, al			; 1 = 115200 baud (Retro UNIX 386 v1)
  2755                              <1> 					; 2 = 57600 baud
  2756                              <1> 					; 3 = 38400 baud
  2757                              <1> 					; 6 = 19200 baud
  2758                              <1> 					; 12 = 9600 baud (Retro UNIX 8086 v1)
  2759 00003556 EB00                <1> 	JMP	$+2			; I/O DELAY
  2760 00003558 28C0                <1> 	sub	al, al
  2761 0000355A FEC2                <1> 	inc	dl      ; 3F9h (2F9h)	; register for most significant byte
  2762                              <1> 					; of the divisor value
  2763 0000355C EE                  <1> 	out	dx, al ; 0
  2764 0000355D EB00                <1> 	JMP	$+2			; I/O DELAY
  2765                              <1> 	;	
  2766 0000355F 88E8                <1> 	mov	al, ch ; 3		; 8 data bits, 1 stop bit, no parity
  2767                              <1> 	;and	al, 1Fh ; Bits 0,1,2,3,4	
  2768 00003561 80C202              <1> 	add	dl, 2	; 3FBh (2FBh)	; Line control register
  2769 00003564 EE                  <1> 	out	dx, al			
  2770 00003565 EB00                <1> 	JMP	$+2			; I/O DELAY
  2771                              <1> 	; 29/10/2015
  2772 00003567 FECA                <1> 	dec 	dl 	; 3FAh (2FAh)	; FIFO Control register (16550/16750)
  2773 00003569 30C0                <1> 	xor	al, al			; 0
  2774 0000356B EE                  <1> 	out	dx, al			; Disable FIFOs (reset to 8250 mode)
  2775 0000356C EB00                <1> 	JMP	$+2	
  2776                              <1> sp_i4:
  2777                              <1> ;A18:	;-----	COMM PORT STATUS ROUTINE
  2778                              <1> 	; 29/06/2015 (line status after modem status)
  2779 0000356E 80C204              <1> 	add	dl, 4	; 3FEh (2FEh)	; Modem status register
  2780                              <1> sp_i4s:
  2781 00003571 EC                  <1> 	in	al, dx			; GET MODEM CONTROL STATUS
  2782 00003572 EB00                <1> 	JMP	$+2			; I/O DELAY
  2783 00003574 88C4                <1> 	mov	ah, al			; PUT IN (AH) FOR RETURN
  2784 00003576 FECA                <1> 	dec	dl	; 3FDh (2FDh)	; POINT TO LINE STATUS REGISTER
  2785                              <1> 					; dx = 3FDh for COM1, 2FDh for COM2
  2786 00003578 EC                  <1> 	in	al, dx			; GET LINE CONTROL STATUS
  2787                              <1> 	; AL = Line status, AH = Modem status
  2788 00003579 C3                  <1> 	retn
  2789                              <1> 
  2790                              <1> sp_status:
  2791                              <1> 	; 29/06/2015
  2792                              <1> 	; 27/06/2015 (Retro UNIX 386 v1)
  2793                              <1> 	; Get serial port status
  2794 0000357A 66BAFE03            <1> 	mov	dx, 3FEh		; Modem status register (COM1)
  2795 0000357E 28C6                <1> 	sub	dh, al			; dh = 2 for COM2 (al = 1)
  2796                              <1> 					; dx = 2FEh for COM2
  2797 00003580 EBEF                <1> 	jmp	short sp_i4s
  2798                              <1> 
  2799                              <1> sp_setp: ; Set serial port communication parameters
  2800                              <1> 	; 08/01/2022
  2801                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2802                              <1> 	; 07/11/2015
  2803                              <1> 	; 29/10/2015
  2804                              <1> 	; 29/06/2015
  2805                              <1> 	; Retro UNIX 386 v1 feature only !	
  2806                              <1> 	;
  2807                              <1> 	; INPUT:
  2808                              <1> 	;	AL = 0 for COM1
  2809                              <1> 	;	     1 for COM2
  2810                              <1> 	;	AH = Communication parameters (*)
  2811                              <1> 	; OUTPUT:
  2812                              <1> 	;	CL = Line status
  2813                              <1> 	;	CH = Modem status
  2814                              <1> 	;   If cf = 1 -> Error code in [u.error]
  2815                              <1> 	;		 'invalid parameter !' 
  2816                              <1> 	;		 	 or
  2817                              <1> 	;		 'device not ready !' error
  2818                              <1> 	;	
  2819                              <1> 	;  (*) Communication parameters (except BAUD RATE):
  2820                              <1> 	;	Bit	4	3	2	1	0
  2821                              <1> 	;		-PARITY--   STOP BIT  -WORD LENGTH-	 		 
  2822                              <1> 	;  this one -->	00 = none    0 = 1 bit  11 = 8 bits
  2823                              <1> 	;		01 = odd     1 = 2 bits	10 = 7 bits
  2824                              <1> 	;		11 = even
  2825                              <1> 	;  Baud rate setting bits: (29/06/2015)
  2826                              <1> 	;		Retro UNIX 386 v1 feature only !
  2827                              <1> 	;	Bit	7    6    5  | Baud rate
  2828                              <1> 	;		------------------------
  2829                              <1> 	;	value	0    0    0  | Default (Divisor = 1)
  2830                              <1> 	;		0    0    1  | 9600 (12)
  2831                              <1> 	;		0    1    0  | 19200 (6) 
  2832                              <1> 	;		0    1	  1  | 38400 (3) 
  2833                              <1> 	;		1    0	  0  | 14400 (8)
  2834                              <1> 	;		1    0	  1  | 28800 (4)
  2835                              <1> 	;		1    1    0  | 57600 (2)
  2836                              <1> 	;		1    1    1  | 115200 (1) 
  2837                              <1> 	;
  2838                              <1> 	; (COM1 base port address = 3F8h, COM1 Interrupt = IRQ 4)
  2839                              <1> 	; (COM2 base port address = 2F8h, COM1 Interrupt = IRQ 3)
  2840                              <1> 	;
  2841                              <1> 	; ((Modified registers: EAX, ECX, EDX, EBX))
  2842                              <1> 	;
  2843 00003582 66BAF803            <1> 	mov	dx, 3F8h
  2844 00003586 BB[426B0000]        <1> 	mov	ebx, com1p ; COM1 control byte offset
  2845 0000358B 3C01                <1> 	cmp	al, 1
  2846 0000358D 7770                <1> 	ja 	short sp_invp_err
  2847 0000358F 7203                <1> 	jb	short sp_setp1 ;  COM1 (AL = 0)
  2848 00003591 FECE                <1> 	dec	dh ; 2F8h
  2849 00003593 43                  <1> 	inc	ebx ; COM2 control byte offset
  2850                              <1> sp_setp1:
  2851                              <1> 	; 29/10/2015
  2852 00003594 8823                <1> 	mov	[ebx], ah
  2853 00003596 0FB6CC              <1> 	movzx 	ecx, ah
  2854 00003599 C0E905              <1> 	shr	cl, 5 ; -> baud rate index
  2855 0000359C 80E41F              <1> 	and	ah, 1Fh ; communication parameters except baud rate
  2856 0000359F 8A81[0E360000]      <1> 	mov	al, [ecx+b_div_tbl]
  2857 000035A5 6689C1              <1> 	mov	cx, ax
  2858 000035A8 E896FFFFFF          <1> 	call	sp_i3
  2859 000035AD 6689C1              <1> 	mov	cx, ax ; CL = Line status, CH = Modem status
  2860 000035B0 A880                <1> 	test	al, 80h
  2861 000035B2 740F                <1> 	jz	short sp_setp2
  2862 000035B4 C603E3              <1>         mov     byte [ebx], 0E3h ; Reset to initial value (11100011b)
  2863                              <1> stp_dnr_err:
  2864 000035B7 C705[ED6E0000]0F00- <1> 	mov	dword [u.error], ERR_DEV_NOT_RDY ; 'device not ready !'
  2864 000035BF 0000                <1>
  2865                              <1> 	; CL = Line status, CH = Modem status
  2866 000035C1 F9                  <1> 	stc
  2867 000035C2 C3                  <1> 	retn
  2868                              <1> sp_setp2:
  2869 000035C3 80FE02              <1> 	cmp	dh, 2 ; COM2 (2F?h)
  2870                              <1>         ;jna	sp_i6
  2871                              <1> 		      ; COM1 (3F?h)
  2872                              <1> 	; 24/12/2021
  2873 000035C6 7705                <1> 	ja	short sp_i5
  2874 000035C8 E962FFFFFF          <1> 	jmp	sp_i6
  2875                              <1> sp_i5: 
  2876                              <1> 	; 08/01/2022
  2877 000035CD B4EF                <1> 	mov	ah, 0EFh ; enable IRQ 4 (COM1)
  2878                              <1> 	; 07/11/2015
  2879                              <1> 	; 26/10/2015
  2880                              <1> 	; 29/06/2015
  2881                              <1> 	;
  2882                              <1> 	;; COM1 - enabling IRQ 4
  2883                              <1> 	;pushf
  2884                              <1> 	;cli
  2885                              <1> 	;;mov	dx, 3FCh   		; modem control register
  2886                              <1> 	;mov	dl, 0FCh ; 08/01/2022
  2887                              <1> 	;in	al, dx 	   		; read register
  2888                              <1> 	;JMP	$+2			; I/O DELAY
  2889                              <1> 	;or	al, 8      		; enable bit 3 (OUT2)
  2890                              <1> 	;out	dx, al     		; write back to register
  2891                              <1> 	;JMP	$+2			; I/O DELAY
  2892                              <1> 	;;mov	dx, 3F9h   		; interrupt enable register
  2893                              <1> 	;mov	dl, 0F9h ; 08/01/2022
  2894                              <1> 	;in	al, dx     		; read register
  2895                              <1> 	;JMP	$+2			; I/O DELAY
  2896                              <1> 	;;or	al, 1      		; receiver data interrupt enable and
  2897                              <1> 	;or	al, 3	   		; transmitter empty interrupt enable
  2898                              <1> 	;out	dx, al 	   		; write back to register
  2899                              <1> 	;JMP	$+2        		; I/O DELAY
  2900                              <1> 	;in	al, 21h    		; read interrupt mask register
  2901                              <1> 	;JMP	$+2			; I/O DELAY
  2902                              <1> 	;and	al, 0EFh   		; enable IRQ 4 (COM1)
  2903                              <1> 	;out	21h, al    		; write back to register
  2904                              <1> 	;
  2905                              <1> 	; 08/01/2022
  2906 000035CF 9C                  <1> 	pushf
  2907 000035D0 E80C000000          <1> 	call	sp_i8
  2908                              <1> 	; 23/10/2015
  2909 000035D5 B8[1F340000]        <1> 	mov 	eax, com1_int
  2910 000035DA A3[D1390000]        <1> 	mov	[com1_irq4], eax
  2911                              <1> 	; 26/10/2015
  2912 000035DF 9D                  <1> 	popf
  2913 000035E0 C3                  <1> 	retn
  2914                              <1> 
  2915                              <1> sp_i8:
  2916                              <1> 	; 08/01/2022
  2917                              <1> 	;pushf
  2918 000035E1 FA                  <1> 	cli
  2919                              <1> 	;
  2920                              <1> 	;mov	dx, 2FCh  ; 3FCh	; modem control register
  2921 000035E2 B2FC                <1> 	mov	dl, 0FCh
  2922 000035E4 EC                  <1> 	in	al, dx 	   		; read register
  2923 000035E5 EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2924 000035E7 0C08                <1> 	or	al, 8      		; enable bit 3 (OUT2)
  2925 000035E9 EE                  <1> 	out	dx, al     		; write back to register
  2926 000035EA EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2927                              <1> 	;mov	dx, 2F9h  ; 3F9h 	; interrupt enable register
  2928 000035EC B2F9                <1> 	mov	dl, 0F9h
  2929 000035EE EC                  <1> 	in	al, dx     		; read register
  2930 000035EF EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2931                              <1> 	;or	al, 1      		; receiver data interrupt enable and
  2932 000035F1 0C03                <1> 	or	al, 3	   		; transmitter empty interrupt enable
  2933 000035F3 EE                  <1> 	out	dx, al 	   		; write back to register
  2934 000035F4 EB00                <1> 	JMP	$+2        		; I/O DELAY
  2935 000035F6 E421                <1> 	in	al, 21h    		; read interrupt mask register
  2936 000035F8 EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2937                              <1> 	;and	al, 0F7h  ; 0EFh	; enable IRQ 3 (COM2)
  2938 000035FA 20E0                <1> 	and	al, ah	; 0F7h or 0EFh 
  2939 000035FC E621                <1> 	out	21h, al    		; write back to register
  2940                              <1> 	;
  2941                              <1> 	;popf	
  2942 000035FE C3                  <1> 	retn
  2943                              <1> 
  2944                              <1> sp_invp_err:
  2945 000035FF C705[ED6E0000]1700- <1> 	mov	dword [u.error], ERR_INV_PARAMETER ; 'invalid parameter !' 
  2945 00003607 0000                <1>
  2946 00003609 31C9                <1> 	xor	ecx, ecx
  2947 0000360B 49                  <1> 	dec	ecx ; 0FFFFh
  2948 0000360C F9                  <1> 	stc
  2949 0000360D C3                  <1> 	retn
  2950                              <1> 
  2951                              <1> ; 29/10/2015
  2952                              <1> b_div_tbl: ; Baud rate divisor table (115200/divisor)
  2953 0000360E 010C0603080401      <1> 	db	1, 12, 6, 3, 8, 4, 1
  2954                              <1> 
  2955                              <1> ; Retro UNIX 8086 v1 - UNIX.ASM (01/09/2014) 
  2956                              <1> epoch:
  2957                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2958                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  2959                              <1> 	; 09/04/2013 (Retro UNIX 8086 v1 - UNIX.ASM)
  2960                              <1> 	; 'epoch' procedure prototype: 
  2961                              <1> 	; 	            UNIXCOPY.ASM, 10/03/2013
  2962                              <1> 	; 14/11/2012
  2963                              <1> 	; unixboot.asm (boot file configuration)
  2964                              <1> 	; version of "epoch" procedure in "unixproc.asm"
  2965                              <1> 	; 21/7/2012
  2966                              <1> 	; 15/7/2012
  2967                              <1> 	; 14/7/2012		
  2968                              <1> 	; Erdogan Tan - RETRO UNIX v0.1
  2969                              <1> 	; compute current date and time as UNIX Epoch/Time
  2970                              <1> 	; UNIX Epoch: seconds since 1/1/1970 00:00:00
  2971                              <1> 	;
  2972                              <1>         ;  ((Modified registers: EAX, EDX, ECX, EBX))  
  2973                              <1> 	;
  2974 00003615 E81B010000          <1> 	call 	get_rtc_time		; Return Current Time
  2975 0000361A 86E9                <1>         xchg 	ch,cl
  2976 0000361C 66890D[46680000]    <1>         mov 	[hour], cx
  2977 00003623 86F2                <1>         xchg 	dh,dl
  2978 00003625 668915[4A680000]    <1>         mov 	[second], dx
  2979                              <1> 	;
  2980 0000362C E835010000          <1>         call 	get_rtc_date		; Return Current Date
  2981 00003631 86E9                <1>         xchg 	ch,cl
  2982 00003633 66890D[40680000]    <1>         mov 	[year], cx
  2983 0000363A 86F2                <1>         xchg 	dh,dl
  2984 0000363C 668915[42680000]    <1>         mov 	[month], dx
  2985                              <1> 	;
  2986 00003643 66B93030            <1> 	mov 	cx, 3030h
  2987                              <1> 	;
  2988 00003647 A0[46680000]        <1> 	mov 	al, [hour] ; Hour
  2989                              <1>         	; AL <= BCD number)
  2990 0000364C D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2991                              <1> 					; AH = AL / 10h
  2992                              <1> 					; AL = AL MOD 10h
  2993 0000364E D50A                <1>         aad 	; AX= AH*10+AL
  2994 00003650 A2[46680000]        <1> 	mov 	[hour], al
  2995 00003655 A0[47680000]        <1> 	mov 	al, [hour+1] ; Minute
  2996                              <1>         	; AL <= BCD number)
  2997 0000365A D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2998                              <1> 					; AH = AL / 10h
  2999                              <1> 					; AL = AL MOD 10h
  3000 0000365C D50A                <1>         aad 	; AX= AH*10+AL
  3001 0000365E A2[48680000]        <1> 	mov 	[minute], al
  3002 00003663 A0[4A680000]        <1> 	mov 	al, [second] ; Second
  3003                              <1>         	; AL <= BCD number)
  3004 00003668 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  3005                              <1> 					; AH = AL / 10h
  3006                              <1> 					; AL = AL MOD 10h
  3007 0000366A D50A                <1>         aad 	; AX= AH*10+AL
  3008 0000366C A2[4A680000]        <1> 	mov 	[second], al
  3009 00003671 66A1[40680000]      <1> 	mov 	ax, [year] ; Year (century)
  3010                              <1>  	;push 	ax
  3011                              <1> 	; 08/01/2022
  3012 00003677 50                  <1> 	push	eax
  3013                              <1> 	   	; AL <= BCD number)
  3014 00003678 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  3015                              <1> 					; AH = AL / 10h
  3016                              <1> 					; AL = AL MOD 10h
  3017 0000367A D50A                <1>         aad 	; AX= AH*10+AL
  3018 0000367C B464                <1> 	mov 	ah, 100
  3019 0000367E F6E4                <1> 	mul 	ah
  3020 00003680 66A3[40680000]      <1> 	mov 	[year], ax
  3021                              <1> 	;pop	ax
  3022                              <1> 	; 08/01/2022
  3023 00003686 58                  <1> 	pop	eax
  3024 00003687 88E0                <1> 	mov	al, ah
  3025                              <1>         	; AL <= BCD number)
  3026 00003689 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  3027                              <1> 					; AH = AL / 10h
  3028                              <1> 					; AL = AL MOD 10h
  3029 0000368B D50A                <1>         aad 	; AX= AH*10+AL
  3030 0000368D 660105[40680000]    <1> 	add 	[year], ax
  3031 00003694 A0[42680000]        <1> 	mov 	al, [month] ; Month
  3032                              <1>            	; AL <= BCD number)
  3033 00003699 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  3034                              <1> 					; AH = AL / 10h
  3035                              <1> 					; AL = AL MOD 10h
  3036 0000369B D50A                <1>         aad 	; AX= AH*10+AL
  3037 0000369D A2[42680000]        <1> 	mov 	[month], al	
  3038 000036A2 A0[43680000]        <1>         mov     al, [month+1]      	; Day
  3039                              <1>            	; AL <= BCD number)
  3040 000036A7 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  3041                              <1> 					; AH = AL / 10h
  3042                              <1> 					; AL = AL MOD 10h
  3043 000036A9 D50A                <1>         aad 	; AX= AH*10+AL
  3044 000036AB A2[44680000]        <1>         mov     [day], al
  3045                              <1> 	
  3046                              <1> convert_to_epoch:
  3047                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit modification)
  3048                              <1> 	; 09/04/2013 (Retro UNIX 8086 v1)
  3049                              <1> 	;
  3050                              <1> 	; ((Modified registers: EAX, EDX, EBX)) 
  3051                              <1> 	;
  3052                              <1> 	; Derived from DALLAS Semiconductor
  3053                              <1> 	; Application Note 31 (DS1602/DS1603)
  3054                              <1> 	; 6 May 1998
  3055 000036B0 29C0                <1> 	sub 	eax, eax
  3056 000036B2 66A1[40680000]      <1> 	mov 	ax, [year]
  3057 000036B8 662DB207            <1> 	sub 	ax, 1970
  3058 000036BC BA6D010000          <1> 	mov 	edx, 365
  3059 000036C1 F7E2                <1> 	mul 	edx
  3060 000036C3 31DB                <1> 	xor 	ebx, ebx
  3061 000036C5 8A1D[42680000]      <1> 	mov 	bl, [month]
  3062 000036CB FECB                <1> 	dec 	bl
  3063 000036CD D0E3                <1> 	shl 	bl, 1
  3064                              <1> 	;sub	edx, edx
  3065 000036CF 668B93[4C680000]    <1> 	mov 	dx, [EBX+DMonth]
  3066 000036D6 8A1D[44680000]      <1>         mov     bl, [day]
  3067 000036DC FECB                <1> 	dec 	bl
  3068 000036DE 01D0                <1> 	add 	eax, edx
  3069 000036E0 01D8                <1> 	add 	eax, ebx
  3070                              <1> 			; EAX = days since 1/1/1970
  3071 000036E2 668B15[40680000]    <1> 	mov 	dx, [year]
  3072 000036E9 6681EAB107          <1> 	sub 	dx, 1969
  3073 000036EE 66D1EA              <1> 	shr 	dx, 1
  3074 000036F1 66D1EA              <1> 	shr 	dx, 1		
  3075                              <1> 		; (year-1969)/4
  3076 000036F4 01D0                <1> 	add 	eax, edx
  3077                              <1> 			; + leap days since 1/1/1970
  3078 000036F6 803D[42680000]02    <1> 	cmp 	byte [month], 2	; if past february
  3079 000036FD 7610                <1> 	jna 	short cte1
  3080 000036FF 668B15[40680000]    <1> 	mov 	dx, [year]
  3081 00003706 6683E203            <1> 	and 	dx, 3 ; year mod 4
  3082 0000370A 7503                <1> 	jnz 	short cte1		
  3083                              <1> 			; and if leap year
  3084 0000370C 83C001              <1> 	add 	eax, 1 	; add this year's leap day (february 29)
  3085                              <1> cte1: 			; compute seconds since 1/1/1970
  3086 0000370F BA18000000          <1> 	mov 	edx, 24
  3087 00003714 F7E2                <1> 	mul	edx
  3088 00003716 8A15[46680000]      <1> 	mov 	dl, [hour]
  3089 0000371C 01D0                <1> 	add 	eax, edx
  3090                              <1> 		; EAX = hours since 1/1/1970 00:00:00
  3091                              <1> 	;mov	ebx, 60
  3092 0000371E B33C                <1> 	mov	bl, 60
  3093 00003720 F7E3                <1> 	mul	ebx
  3094 00003722 8A15[48680000]      <1> 	mov 	dl, [minute]
  3095 00003728 01D0                <1> 	add 	eax, edx
  3096                              <1> 		; EAX = minutes since 1/1/1970 00:00:00
  3097                              <1> 	;mov 	ebx, 60
  3098 0000372A F7E3                <1> 	mul	ebx
  3099 0000372C 8A15[4A680000]      <1> 	mov 	dl, [second]
  3100 00003732 01D0                <1> 	add 	eax, edx
  3101                              <1>  		; EAX -> seconds since 1/1/1970 00:00:00
  3102 00003734 C3                  <1> 	retn
  3103                              <1> 
  3104                              <1> get_rtc_time:
  3105                              <1> 	; 15/03/2015
  3106                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3107                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3108                              <1> 	; INT 1Ah
  3109                              <1> 	; (AH) = 02H  READ THE REAL TIME CLOCK AND RETURN WITH,	:
  3110                              <1> 	;       (CH) = HOURS IN BCD (00-23)			:
  3111                              <1> 	;       (CL) = MINUTES IN BCD (00-59)			:
  3112                              <1> 	;       (DH) = SECONDS IN BCD (00-59)			:
  3113                              <1> 	;       (DL) = DAYLIGHT SAVINGS ENABLE (00-01).		:
  3114                              <1> 	;								
  3115                              <1> RTC_20: 				; GET RTC TIME
  3116 00003735 FA                  <1> 	cli
  3117 00003736 E805D4FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3118 0000373B 7227                <1> 	JC	short RTC_29		; EXIT IF ERROR (CY= 1)
  3119                              <1> 
  3120 0000373D B000                <1> 	MOV	AL, CMOS_SECONDS 	; SET ADDRESS OF SECONDS
  3121 0000373F E8E6D3FFFF          <1> 	CALL	CMOS_READ		; GET SECONDS
  3122 00003744 88C6                <1> 	MOV	DH, AL			; SAVE
  3123 00003746 B00B                <1> 	MOV	AL, CMOS_REG_B		; ADDRESS ALARM REGISTER
  3124 00003748 E8DDD3FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT VALUE OF DSE BIT
  3125 0000374D 2401                <1> 	AND	AL, 00000001B		; MASK FOR VALID DSE BIT
  3126 0000374F 88C2                <1> 	MOV	DL, AL			; SET [DL] TO ZERO FOR NO DSE BIT
  3127 00003751 B002                <1> 	MOV	AL, CMOS_MINUTES 	; SET ADDRESS OF MINUTES
  3128 00003753 E8D2D3FFFF          <1> 	CALL	CMOS_READ		; GET MINUTES
  3129 00003758 88C1                <1> 	MOV	CL, AL			; SAVE
  3130 0000375A B004                <1> 	MOV	AL, CMOS_HOURS		; SET ADDRESS OF HOURS
  3131 0000375C E8C9D3FFFF          <1> 	CALL	CMOS_READ		; GET HOURS
  3132 00003761 88C5                <1> 	MOV	CH, AL			; SAVE
  3133 00003763 F8                  <1> 	CLC				; SET CY= 0
  3134                              <1> RTC_29:
  3135 00003764 FB                  <1> 	sti
  3136 00003765 C3                  <1> 	RETn				; RETURN WITH RESULT IN CARRY FLAG
  3137                              <1> 
  3138                              <1> get_rtc_date:
  3139                              <1> 	; 15/03/2015
  3140                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3141                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3142                              <1> 	; INT 1Ah
  3143                              <1> 	; (AH) = 04H  READ THE DATE FROM THE REAL TIME CLOCK AND RETURN WITH,:
  3144                              <1> 	;      (CH) = CENTURY IN BCD (19 OR 20) 		       :
  3145                              <1> 	;      (CL) = YEAR IN BCD (00-99)			       :
  3146                              <1> 	;      (DH) = MONTH IN BCD (01-12)			       :
  3147                              <1> 	;      (DL) = DAY IN BCD (01-31).		
  3148                              <1> 	;
  3149                              <1> RTC_40: 				; GET RTC DATE
  3150 00003766 FA                  <1> 	cli
  3151 00003767 E8D4D3FFFF          <1> 	CALL	UPD_IPR			; CHECK FOR UPDATE IN PROCESS
  3152 0000376C 7225                <1> 	JC	short RTC_49		; EXIT IF ERROR (CY= 1)
  3153                              <1> 
  3154 0000376E B007                <1> 	MOV	AL, CMOS_DAY_MONTH	; ADDRESS DAY OF MONTH
  3155 00003770 E8B5D3FFFF          <1> 	CALL	CMOS_READ		; READ DAY OF MONTH
  3156 00003775 88C2                <1> 	MOV	DL, AL			; SAVE
  3157 00003777 B008                <1> 	MOV	AL, CMOS_MONTH		; ADDRESS MONTH
  3158 00003779 E8ACD3FFFF          <1> 	CALL	CMOS_READ		; READ MONTH
  3159 0000377E 88C6                <1> 	MOV	DH, AL			; SAVE
  3160 00003780 B009                <1> 	MOV	AL, CMOS_YEAR		; ADDRESS YEAR
  3161 00003782 E8A3D3FFFF          <1> 	CALL	CMOS_READ		; READ YEAR
  3162 00003787 88C1                <1> 	MOV	CL, AL			; SAVE
  3163 00003789 B032                <1> 	MOV	AL, CMOS_CENTURY 	; ADDRESS CENTURY LOCATION
  3164 0000378B E89AD3FFFF          <1> 	CALL	CMOS_READ		; GET CENTURY BYTE
  3165 00003790 88C5                <1> 	MOV	CH, AL			; SAVE
  3166 00003792 F8                  <1> 	CLC				; SET CY=0
  3167                              <1> RTC_49:
  3168 00003793 FB                  <1> 	sti
  3169 00003794 C3                  <1> 	RETn				; RETURN WITH RESULTS IN CARRY FLAG
  3170                              <1> 
  3171                              <1> set_date_time:
  3172                              <1> convert_from_epoch:
  3173                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  3174                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  3175                              <1> 	; 'convert_from_epoch' procedure prototype: 
  3176                              <1> 	; 	            UNIXCOPY.ASM, 10/03/2013
  3177                              <1> 	;
  3178                              <1> 	; ((Modified registers: EAX, EDX, ECX, EBX))	
  3179                              <1> 	;
  3180                              <1> 	; Derived from DALLAS Semiconductor
  3181                              <1> 	; Application Note 31 (DS1602/DS1603)
  3182                              <1> 	; 6 May 1998
  3183                              <1> 	;
  3184                              <1> 	; INPUT:
  3185                              <1> 	; EAX = Unix (Epoch) Time
  3186                              <1> 	;
  3187 00003795 31D2                <1> 	xor 	edx, edx
  3188 00003797 B93C000000          <1> 	mov 	ecx, 60
  3189 0000379C F7F1                <1> 	div	ecx
  3190                              <1> 	;mov 	[imin], eax  ; whole minutes
  3191                              <1> 			     ; since 1/1/1970
  3192 0000379E 668915[4A680000]    <1> 	mov 	[second], dx ; leftover seconds
  3193 000037A5 29D2                <1> 	sub 	edx, edx
  3194 000037A7 F7F1                <1> 	div	ecx
  3195                              <1> 	;mov 	[ihrs], eax  ; whole hours
  3196                              <1> 	;		     ; since 1/1/1970
  3197 000037A9 668915[48680000]    <1> 	mov 	[minute], dx ; leftover minutes
  3198 000037B0 31D2                <1> 	xor	edx, edx
  3199                              <1> 	;mov 	cx, 24
  3200 000037B2 B118                <1> 	mov 	cl, 24
  3201 000037B4 F7F1                <1> 	div	ecx
  3202                              <1> 	;mov 	[iday], ax   ; whole days
  3203                              <1> 			     ; since 1/1/1970
  3204 000037B6 668915[46680000]    <1> 	mov 	[hour], dx   ; leftover hours
  3205 000037BD 05DB020000          <1> 	add 	eax, 365+366 ; whole day since
  3206                              <1> 			     ; 1/1/1968 	
  3207                              <1> 	;mov 	[iday], ax
  3208 000037C2 50                  <1> 	push 	eax
  3209 000037C3 29D2                <1> 	sub	edx, edx
  3210 000037C5 B9B5050000          <1> 	mov 	ecx, (4*365)+1 ; 4 years = 1461 days
  3211 000037CA F7F1                <1> 	div	ecx
  3212 000037CC 59                  <1> 	pop 	ecx
  3213                              <1> 	;mov 	[lday], ax   ; count of quadyrs (4 years)
  3214 000037CD 6652                <1> 	push 	dx
  3215                              <1> 	;mov 	[qday], dx   ; days since quadyr began
  3216 000037CF 6683FA3C            <1> 	cmp 	dx, 31+29    ; if past feb 29 then
  3217 000037D3 F5                  <1> 	cmc		     ; add this quadyr's leap day
  3218 000037D4 83D000              <1> 	adc 	eax, 0	     ; to # of qadyrs (leap days)
  3219                              <1> 	;mov 	[lday], ax   ; since 1968			  
  3220                              <1> 	;mov 	cx, [iday]
  3221 000037D7 91                  <1> 	xchg 	ecx, eax     ; ECX = lday, EAX = iday		  
  3222 000037D8 29C8                <1> 	sub 	eax, ecx     ; iday - lday
  3223 000037DA B96D010000          <1> 	mov 	ecx, 365
  3224 000037DF 31D2                <1> 	xor	edx, edx
  3225                              <1> 	; EAX = iday-lday, EDX = 0
  3226 000037E1 F7F1                <1> 	div	ecx
  3227                              <1> 	;mov 	[iyrs], ax   ; whole years since 1968
  3228                              <1> 	;jday = iday - (iyrs*365) - lday
  3229                              <1> 	;mov [jday], dx      ; days since 1/1 of current year
  3230                              <1> 	;add	eax, 1968
  3231 000037E3 6605B007            <1> 	add 	ax, 1968     ; compute year
  3232 000037E7 66A3[40680000]      <1> 	mov 	[year], ax
  3233 000037ED 6689D1              <1> 	mov 	cx, dx
  3234                              <1> 	;mov 	dx, [qday]
  3235 000037F0 665A                <1> 	pop 	dx
  3236 000037F2 6681FA6D01          <1> 	cmp 	dx, 365	     ; if qday <= 365 and qday >= 60	
  3237 000037F7 7709                <1> 	ja 	short cfe1   ; jday = jday +1
  3238 000037F9 6683FA3C            <1> 	cmp 	dx, 60       ; if past 2/29 and leap year then
  3239 000037FD F5                  <1>         cmc		     ; add a leap day to the # of whole
  3240 000037FE 6683D100            <1> 	adc 	cx, 0        ; days since 1/1 of current year
  3241                              <1> cfe1:			
  3242                              <1> 	;mov 	[jday], cx
  3243 00003802 66BB0C00            <1> 	mov 	bx, 12       ; estimate month
  3244 00003806 66BA6E01            <1> 	mov 	dx, 366      ; mday, max. days since 1/1 is 365
  3245 0000380A 6683E003            <1> 	and 	ax, 11b      ; year mod 4 (and dx, 3) 
  3246                              <1> cfe2:	; Month calculation  ; 0 to 11  (11 to 0)	
  3247 0000380E 6639D1              <1> 	cmp 	cx, dx       ; mday = # of days passed from 1/1
  3248 00003811 731D                <1> 	jnb 	short cfe3
  3249 00003813 664B                <1> 	dec 	bx           ; month = month - 1
  3250 00003815 66D1E3              <1> 	shl 	bx, 1 
  3251 00003818 668B93[4C680000]    <1> 	mov 	dx, [EBX+DMonth] ; # elapsed days at 1st of month
  3252 0000381F 66D1EB              <1> 	shr 	bx, 1        ; bx = month - 1 (0 to 11)
  3253 00003822 6683FB01            <1> 	cmp	bx, 1        ; if month > 2 and year mod 4  = 0	
  3254 00003826 76E6                <1> 	jna 	short cfe2   ; then mday = mday + 1
  3255 00003828 08C0                <1> 	or 	al, al       ; if past 2/29 and leap year then
  3256 0000382A 75E2                <1> 	jnz 	short cfe2   ; add leap day (to mday)
  3257 0000382C 6642                <1> 	inc 	dx           ; mday = mday + 1
  3258 0000382E EBDE                <1> 	jmp 	short cfe2
  3259                              <1> cfe3:
  3260 00003830 6643                <1> 	inc 	bx	     ; -> bx = month, 1 to 12
  3261 00003832 66891D[42680000]    <1> 	mov 	[month], bx
  3262 00003839 6629D1              <1> 	sub 	cx, dx	     ; day = jday - mday + 1	
  3263 0000383C 6641                <1> 	inc 	cx 			  
  3264 0000383E 66890D[44680000]    <1> 	mov 	[day], cx
  3265                              <1> 	
  3266                              <1> 	; eax, ebx, ecx, edx is changed at return
  3267                              <1> 	; output ->
  3268                              <1> 	; [year], [month], [day], [hour], [minute], [second]
  3269                              <1> 	
  3270                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  3271                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  3272                              <1> set_date:
  3273 00003845 A0[41680000]        <1>         mov     al, [year+1]
  3274 0000384A D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3275 0000384C D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3276                              <1> 			     ; AL = AH * 10h + AL
  3277 0000384E 88C5                <1> 	mov 	ch, al ; century (BCD)
  3278 00003850 A0[40680000]        <1> 	mov 	al, [year]
  3279 00003855 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3280 00003857 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3281                              <1> 			     ; AL = AH * 10h + AL
  3282 00003859 88C1                <1> 	mov 	cl, al ; year (BCD)
  3283 0000385B A0[42680000]        <1>         mov 	al, [month]
  3284 00003860 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3285 00003862 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3286                              <1> 			     ; AL = AH * 10h + AL
  3287 00003864 88C6                <1> 	mov 	dh, al ; month (BCD)
  3288 00003866 A0[44680000]        <1> 	mov 	al, [day]
  3289 0000386B D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3290 0000386D D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3291                              <1> 			     ; AL = AH * 10h + AL
  3292 0000386F 88C6                <1> 	mov 	dh, al ; day (BCD)
  3293                              <1> 	; Set real-time clock date
  3294 00003871 E879000000          <1> 	call	set_rtc_date
  3295                              <1> set_time:
  3296                              <1>         ; Read real-time clock time 
  3297                              <1> 	; (get day light saving time bit status)
  3298 00003876 FA                  <1>  	cli
  3299 00003877 E8C4D2FFFF          <1> 	CALL	UPD_IPR 	; CHECK FOR UPDATE IN PROCESS
  3300                              <1> 	; cf = 1 -> al = 0
  3301 0000387C 7207                <1>         jc      short stime1
  3302 0000387E B00B                <1> 	MOV	AL, CMOS_REG_B	; ADDRESS ALARM REGISTER
  3303 00003880 E8A5D2FFFF          <1> 	CALL	CMOS_READ	; READ CURRENT VALUE OF DSE BIT
  3304                              <1> stime1:
  3305 00003885 FB                  <1> 	sti
  3306 00003886 2401                <1> 	AND	AL, 00000001B	; MASK FOR VALID DSE BIT
  3307 00003888 88C2                <1> 	MOV	DL, AL		; SET [DL] TO ZERO FOR NO DSE BIT
  3308                              <1> 	; DL = 1 or 0 (day light saving time)
  3309                              <1> 	;	
  3310 0000388A A0[46680000]        <1> 	mov 	al, [hour]
  3311 0000388F D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3312 00003891 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3313                              <1> 			     ; AL = AH * 10h + AL
  3314 00003893 88C5                <1> 	mov 	ch, al ; hour (BCD)
  3315 00003895 A0[48680000]        <1>         mov     al, [minute]
  3316 0000389A D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3317 0000389C D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3318                              <1> 			     ; AL = AH * 10h + AL
  3319 0000389E 88C1                <1> 	mov 	cl, al       ; minute (BCD)
  3320 000038A0 A0[4A680000]        <1>         mov     al, [second]
  3321 000038A5 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3322 000038A7 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3323                              <1> 			     ; AL = AH * 10h + AL
  3324 000038A9 88C6                <1> 	mov 	dh, al	     ; second (BCD)
  3325                              <1> 	; Set real-time clock time
  3326                              <1>  	; call	set_rtc_time
  3327                              <1> set_rtc_time:
  3328                              <1> 	; 15/04/2015 (257, POSTEQU.INC -> H EQU 256, X EQU H+1)
  3329                              <1> 	; 15/03/2015
  3330                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3331                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3332                              <1> 	; INT 1Ah
  3333                              <1> 	; (AH) = 03H  SET THE REAL TIME CLOCK USING,			:
  3334                              <1> 	;      (CH) = HOURS IN BCD (00-23)			       	:
  3335                              <1> 	;      (CL) = MINUTES IN BCD (00-59)			       	:
  3336                              <1> 	;      (DH) = SECONDS IN BCD (00-59)			       	:
  3337                              <1> 	;      (DL) = 01 IF DAYLIGHT SAVINGS ENABLE OPTION, ELSE 00.    :
  3338                              <1> 	;								:
  3339                              <1> 	;  NOTE: (DL)= 00 IF DAYLIGHT SAVINGS TIME ENABLE IS NOT ENABLED. :
  3340                              <1> 	;        (DL)= 01 ENABLES TWO SPECIAL UPDATES THE LAST SUNDAY IN  :
  3341                              <1> 	;         APRIL   (1:59:59 --> 3:00:00 AM) AND THE LAST SUNDAY IN :
  3342                              <1> 	;         OCTOBER (1:59:59 --> 1:00:00 AM) THE FIRST TIME.	  :
  3343                              <1> 	;
  3344                              <1> RTC_30: 				; SET RTC TIME
  3345 000038AB FA                  <1> 	cli
  3346 000038AC E88FD2FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3347 000038B1 7305                <1> 	JNC	short RTC_35		; GO AROUND IF CLOCK OPERATING
  3348 000038B3 E886000000          <1> 	CALL	RTC_STA 		; ELSE TRY INITIALIZING CLOCK
  3349                              <1> RTC_35:
  3350 000038B8 88F4                <1> 	MOV	AH, DH			; GET TIME BYTE - SECONDS
  3351 000038BA B000                <1> 	MOV	AL, CMOS_SECONDS 	; ADDRESS SECONDS
  3352 000038BC E89D000000          <1> 	CALL	CMOS_WRITE		; UPDATE SECONDS
  3353 000038C1 88CC                <1> 	MOV	AH, CL			; GET TIME BYTE - MINUTES
  3354 000038C3 B002                <1> 	MOV	AL, CMOS_MINUTES 	; ADDRESS MINUTES
  3355 000038C5 E894000000          <1> 	CALL	CMOS_WRITE		; UPDATE MINUTES
  3356 000038CA 88EC                <1> 	MOV	AH, CH			; GET TIME BYTE - HOURS
  3357 000038CC B004                <1> 	MOV	AL, CMOS_HOURS		; ADDRESS HOURS
  3358 000038CE E88B000000          <1> 	CALL	CMOS_WRITE		; UPDATE ADDRESS
  3359                              <1> 	;MOV	AX, X*CMOS_REG_B 	; ADDRESS ALARM REGISTER
  3360 000038D3 66B80B0B            <1> 	MOV	AX, 257*CMOS_REG_B 	; 
  3361 000038D7 E84ED2FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT TIME
  3362 000038DC 2462                <1> 	AND	AL, 01100010B		; MASK FOR VALID BIT POSITIONS
  3363 000038DE 0C02                <1> 	OR	AL, 00000010B		; TURN ON 24 HOUR MODE
  3364 000038E0 80E201              <1> 	AND	DL, 00000001B		; USE ONLY THE DSE BIT
  3365 000038E3 08D0                <1> 	OR	AL, DL			; GET DAY LIGHT SAVINGS TIME BIT (OSE)
  3366 000038E5 86E0                <1> 	XCHG	AH, AL			; PLACE IN WORK REGISTER AND GET ADDRESS
  3367 000038E7 E872000000          <1> 	CALL	CMOS_WRITE		; SET NEW ALARM BITS
  3368 000038EC F8                  <1> 	CLC				; SET CY= 0
  3369 000038ED FB                  <1> 	sti
  3370 000038EE C3                  <1> 	RETn				; RETURN WITH CY= 0
  3371                              <1> 
  3372                              <1> set_rtc_date:
  3373                              <1> 	; 15/04/2015 (257, POSTEQU.INC -> H EQU 256, X EQU H+1)
  3374                              <1> 	; 15/03/2015
  3375                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3376                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3377                              <1> 	; INT 1Ah
  3378                              <1> 	; (AH) = 05H  SET THE DATE INTO THE REAL TIME CLOCK USING, :
  3379                              <1> 	;     (CH) = CENTURY IN BCD (19 OR 20)			   :
  3380                              <1> 	;     (CL) = YEAR IN BCD (00-99)			   :
  3381                              <1> 	;     (DH) = MONTH IN BCD (01-12)			   :
  3382                              <1> 	;     (DL) = DAY IN BCD (01-31).
  3383                              <1> 	;
  3384                              <1> RTC_50: 				; SET RTC DATE
  3385 000038EF FA                  <1> 	cli
  3386 000038F0 E84BD2FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3387 000038F5 7305                <1> 	JNC	short RTC_55		; GO AROUND IF NO ERROR
  3388 000038F7 E842000000          <1> 	CALL	RTC_STA 		; ELSE INITIALIZE CLOCK
  3389                              <1> RTC_55:
  3390 000038FC 66B80600            <1> 	MOV	AX, CMOS_DAY_WEEK	; ADDRESS OF DAY OF WEEK BYTE
  3391 00003900 E859000000          <1> 	CALL	CMOS_WRITE		; LOAD ZEROS TO DAY OF WEEK
  3392 00003905 88D4                <1> 	MOV	AH, DL			; GET DAY OF MONTH BYTE
  3393 00003907 B007                <1> 	MOV	AL, CMOS_DAY_MONTH	; ADDRESS DAY OF MONTH BYTE
  3394 00003909 E850000000          <1> 	CALL	CMOS_WRITE		; WRITE OF DAY OF MONTH REGISTER
  3395 0000390E 88F4                <1> 	MOV	AH, DH			; GET MONTH
  3396 00003910 B008                <1> 	MOV	AL, CMOS_MONTH		; ADDRESS MONTH BYTE
  3397 00003912 E847000000          <1> 	CALL	CMOS_WRITE		; WRITE MONTH REGISTER
  3398 00003917 88CC                <1> 	MOV	AH, CL			; GET YEAR BYTE
  3399 00003919 B009                <1> 	MOV	AL, CMOS_YEAR		; ADDRESS YEAR REGISTER
  3400 0000391B E83E000000          <1> 	CALL	CMOS_WRITE		; WRITE YEAR REGISTER
  3401 00003920 88EC                <1> 	MOV	AH, CH			; GET CENTURY BYTE
  3402 00003922 B032                <1> 	MOV	AL, CMOS_CENTURY 	; ADDRESS CENTURY BYTE
  3403 00003924 E835000000          <1> 	CALL	CMOS_WRITE		; WRITE CENTURY LOCATION
  3404                              <1> 	;MOV	AX, X*CMOS_REG_B 	; ADDRESS ALARM REGISTER
  3405 00003929 66B80B0B            <1> 	MOV	AX, 257*CMOS_REG_B 	; 
  3406 0000392D E8F8D1FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT SETTINGS
  3407 00003932 247F                <1> 	AND	AL, 07FH 		; CLEAR 'SET BIT'
  3408 00003934 86E0                <1> 	XCHG	AH, AL			; MOVE TO WORK REGISTER
  3409 00003936 E823000000          <1> 	CALL	CMOS_WRITE		; AND START CLOCK UPDATING
  3410 0000393B F8                  <1> 	CLC				; SET CY= 0
  3411 0000393C FB                  <1> 	sti
  3412 0000393D C3                  <1> 	RETn				; RETURN CY=0
  3413                              <1> 
  3414                              <1> 	; 15/03/2015
  3415                              <1> RTC_STA:				; INITIALIZE REAL TIME CLOCK
  3416 0000393E B426                <1> 	mov	ah, 26h
  3417 00003940 B00A                <1> 	mov	al, CMOS_REG_A		; ADDRESS REGISTER A AND LOAD DATA MASK
  3418 00003942 E817000000          <1> 	CALL	CMOS_WRITE		; INITIALIZE STATUS REGISTER A
  3419 00003947 B482                <1> 	mov	ah, 82h
  3420 00003949 B00B                <1> 	mov 	al, CMOS_REG_B		; SET "SET BIT" FOR CLOCK INITIALIZATION
  3421 0000394B E80E000000          <1> 	CALL	CMOS_WRITE		; AND 24 HOUR MODE TO REGISTER B
  3422 00003950 B00C                <1> 	MOV	AL, CMOS_REG_C		; ADDRESS REGISTER C
  3423 00003952 E8D3D1FFFF          <1> 	CALL	CMOS_READ		; READ REGISTER C TO INITIALIZE
  3424 00003957 B00D                <1> 	MOV	AL, CMOS_REG_D		; ADDRESS REGISTER D
  3425                              <1> 	;CALL	CMOS_READ		; READ REGISTER D TO INITIALIZE
  3426                              <1> 	;RETn
  3427                              <1> 	; 12/01/2022
  3428 00003959 E9CCD1FFFF          <1> 	jmp	CMOS_READ
  3429                              <1> 
  3430                              <1> 	; 15/03/2015
  3431                              <1> 	; IBM PC/XT Model 286 BIOS source code ----- 10/06/85 (test4.asm)
  3432                              <1> CMOS_WRITE:			; WRITE (AH) TO LOCATION (AL)
  3433 0000395E 9C                  <1> 	pushf			; SAVE INTERRUPT ENABLE STATUS AND FLAGS
  3434                              <1> 	;push	ax		; SAVE WORK REGISTER VALUES
  3435 0000395F D0C0                <1> 	rol	al, 1		; MOVE NMI BIT TO LOW POSITION
  3436 00003961 F9                  <1> 	stc			; FORCE NMI BIT ON IN CARRY FLAG
  3437 00003962 D0D8                <1> 	rcr	al, 1		; HIGH BIT ON TO DISABLE NMI - OLD IN CY
  3438 00003964 FA                  <1> 	cli			; DISABLE INTERRUPTS
  3439 00003965 E670                <1> 	out	CMOS_PORT, al	; ADDRESS LOCATION AND DISABLE NMI
  3440 00003967 88E0                <1> 	mov	al, ah		; GET THE DATA BYTE TO WRITE
  3441 00003969 E671                <1> 	out	CMOS_DATA, al	; PLACE IN REQUESTED CMOS LOCATION
  3442 0000396B B01E                <1> 	mov	al, CMOS_SHUT_DOWN*2 ; GET ADDRESS OF DEFAULT LOCATION
  3443 0000396D D0D8                <1> 	rcr	al, 1		; PUT ORIGINAL NMI MASK BIT INTO ADDRESS
  3444 0000396F E670                <1> 	out	CMOS_PORT, al	; SET DEFAULT TO READ ONLY REGISTER
  3445 00003971 90                  <1> 	nop			; I/O DELAY
  3446 00003972 E471                <1> 	in	al, CMOS_DATA	; OPEN STANDBY LATCH
  3447                              <1> 	;pop	ax		; RESTORE WORK REGISTERS
  3448 00003974 9D                  <1> 	popf	
  3449 00003975 C3                  <1> 	RETn
  3450                              <1> 
  3451                              <1> bf_init:
  3452                              <1> 	; 14/08/2015
  3453                              <1> 	; 02/07/2015
  3454                              <1> 	; 01/07/2015
  3455                              <1> 	; 15/04/2015 (Retro UNIX 386 v1 - Beginning)
  3456                              <1> 	; Buffer (pointer) initialization !
  3457                              <1> 	; 
  3458                              <1> 	; 17/07/2013 - 24/07/2013
  3459                              <1> 	; Retro UNIX 8086 v1 (U9.ASM)
  3460                              <1> 	; (Retro UNIX 8086 v1 feature only !)
  3461                              <1> 	;
  3462 00003976 BF[5C6E0000]        <1> 	mov	edi, bufp 
  3463 0000397B B8[507B0000]        <1> 	mov	eax, buffer + (nbuf*520) 
  3464 00003980 29D2                <1> 	sub	edx, edx
  3465 00003982 FECA                <1> 	dec	dl
  3466 00003984 31C9                <1> 	xor	ecx, ecx
  3467 00003986 49                  <1> 	dec	ecx
  3468                              <1> bi0:
  3469 00003987 2D08020000          <1> 	sub	eax, 520 ; 8 header + 512 data
  3470 0000398C AB                  <1> 	stosd
  3471 0000398D 89C6                <1> 	mov	esi, eax
  3472 0000398F 8916                <1> 	mov	[esi], edx ; 000000FFh
  3473                              <1> 			   ; Not a valid device sign
  3474 00003991 894E04              <1> 	mov	[esi+4], ecx ; 0FFFFFFFFh
  3475                              <1> 		      ; Not a valid block number sign 	 	
  3476 00003994 3D[206F0000]        <1> 	cmp	eax, buffer
  3477 00003999 77EC                <1> 	ja	short bi0
  3478 0000399B B8[507B0000]        <1> 	mov	eax, sb0
  3479 000039A0 AB                  <1> 	stosd
  3480 000039A1 B8[587D0000]        <1> 	mov	eax, sb1
  3481 000039A6 AB                  <1> 	stosd
  3482 000039A7 89C6                <1> 	mov	esi, eax ; offset sb1
  3483 000039A9 8916                <1> 	mov	[esi], edx ; 000000FFh
  3484                              <1> 			   ; Not a valid device sign
  3485 000039AB 894E04              <1> 	mov	[esi+4], ecx ; 0FFFFFFFFh
  3486                              <1> 		      ; Not a valid block number sign 	 
  3487                              <1> 	; 14/08/2015
  3488                              <1> 	;call 	rdev_init
  3489                              <1> 	;retn
  3490                              <1> 
  3491                              <1> rdev_init: ; root device, super block buffer initialization
  3492                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3493                              <1> 	; 14/08/2015
  3494                              <1> 	; Retro UNIX 386 v1 feature only !
  3495                              <1> 	;
  3496                              <1> 	; NOTE: Disk partitions (file systems), logical
  3497                              <1> 	; drive initialization, partition's start sector etc.
  3498                              <1> 	; will be coded here, later in 'ldrv_init'	
  3499                              <1> 
  3500 000039AE 0FB605[CA650000]    <1> 	movzx	eax, byte [boot_drv]
  3501                              <1> rdi_0:
  3502 000039B5 3C80                <1> 	cmp	al, 80h
  3503 000039B7 7202                <1> 	jb	short rdi_1
  3504 000039B9 2C7E                <1> 	sub	al, 7Eh ; 80h = 2 (hd0), 81h = 3 (hd1)
  3505                              <1> rdi_1:
  3506 000039BB A2[806E0000]        <1> 	mov	[rdev], al
  3507 000039C0 BB[507B0000]        <1>         mov	ebx, sb0 ; super block buffer
  3508 000039C5 8903                <1> 	mov 	[ebx], eax
  3509 000039C7 B001                <1> 	mov	al, 1 ; eax = 1
  3510 000039C9 894304              <1> 	mov	[ebx+4], eax ; super block address on disk
  3511                              <1> 	;call 	diskio
  3512                              <1> 	;retn
  3513                              <1> 	; 24/12/2021
  3514 000039CC E979240000          <1> 	jmp	diskio
  3515                              <1> 
  3516                              <1> ; 23/10/2015
  3517                              <1> com1_irq4:
  3518 000039D1 [D9390000]          <1> 	dd	dummy_retn
  3519                              <1> com2_irq3:
  3520 000039D5 [D9390000]          <1> 	dd	dummy_retn
  3521                              <1> 
  3522                              <1> dummy_retn:
  3523 000039D9 C3                  <1> 	retn
  2092                                  %include 'u1.s'        ; 10/05/2015
  2093                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS1.INC
  2094                              <1> ; Last Modification: 27/02/2022
  2095                              <1> ; ----------------------------------------------------------------------------
  2096                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2097                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2098                              <1> ;
  2099                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2100                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2101                              <1> ; <Bell Laboratories (17/3/1972)>
  2102                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2103                              <1> ;
  2104                              <1> ; Retro UNIX 8086 v1 - U1.ASM (12/07/2014) //// UNIX v1 -> u1.s
  2105                              <1> ;
  2106                              <1> ; ****************************************************************************
  2107                              <1> 
  2108                              <1> unkni: ; / used for all system calls
  2109                              <1> sysent: ; < enter to system call >
  2110                              <1> 	; 08/01/2022
  2111                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2112                              <1> 	; 19/10/2015
  2113                              <1> 	; 21/09/2015
  2114                              <1> 	; 01/07/2015
  2115                              <1> 	; 19/05/2015
  2116                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2117                              <1> 	; 10/04/2013 - 18/01/2014 (Retro UNIX 8086 v1)
  2118                              <1> 	;
  2119                              <1> 	; 'unkni' or 'sysent' is sytem entry from various traps. 
  2120                              <1> 	; The trap type is determined and an indirect jump is made to 
  2121                              <1> 	; the appropriate system call handler. If there is a trap inside
  2122                              <1> 	; the system a jump to panic is made. All user registers are saved 
  2123                              <1> 	; and u.sp points to the end of the users stack. The sys (trap)
  2124                              <1> 	; instructor is decoded to get the the system code part (see
  2125                              <1> 	; trap instruction in the PDP-11 handbook) and from this 
  2126                              <1> 	; the indirect jump address is calculated. If a bad system call is
  2127                              <1> 	; made, i.e., the limits of the jump table are exceeded, 'badsys'
  2128                              <1> 	; is called. If the call is legitimate control passes to the
  2129                              <1> 	; appropriate system routine.
  2130                              <1> 	;
  2131                              <1> 	; Calling sequence:
  2132                              <1> 	;	Through a trap caused by any sys call outside the system.
  2133                              <1> 	; Arguments:
  2134                              <1> 	;	Arguments of particular system call.	
  2135                              <1> 	; ...............................................................
  2136                              <1> 	;	
  2137                              <1> 	; Retro UNIX 8086 v1 modification: 
  2138                              <1> 	;       System call number is in EAX register.
  2139                              <1> 	;
  2140                              <1> 	;       Other parameters are in EDX, EBX, ECX, ESI, EDI, EBP
  2141                              <1> 	;	registers depending of function details.
  2142                              <1>   	;
  2143                              <1> 	; 16/04/2015
  2144 000039DA 368925[906E0000]    <1>         mov     [ss:u.sp], esp ; Kernel stack points to return address
  2145                              <1> 	; save user registers
  2146 000039E1 1E                  <1> 	push	ds
  2147 000039E2 06                  <1> 	push	es
  2148 000039E3 0FA0                <1> 	push	fs
  2149 000039E5 0FA8                <1> 	push	gs
  2150 000039E7 60                  <1> 	pushad  ; eax, ecx, edx, ebx, esp -before pushad-, ebp, esi, edi
  2151                              <1> 	;
  2152                              <1> 	; ESPACE = esp - [ss:u.sp] ; 4*12 = 48 ; 17/09/2015
  2153                              <1> 	; 	(ESPACE is size of space in kernel stack 
  2154                              <1> 	;	for saving/restoring user registers.)
  2155                              <1> 	;
  2156 000039E8 50                  <1> 	push	eax ; 01/07/2015
  2157 000039E9 66B81000            <1> 	mov     ax, KDATA
  2158 000039ED 8ED8                <1>         mov     ds, ax
  2159 000039EF 8EC0                <1>         mov     es, ax
  2160 000039F1 8EE0                <1>         mov     fs, ax
  2161 000039F3 8EE8                <1>         mov     gs, ax
  2162 000039F5 A1[D86A0000]        <1> 	mov	eax, [k_page_dir]
  2163 000039FA 0F22D8              <1> 	mov	cr3, eax
  2164 000039FD 58                  <1> 	pop	eax ; 01/07/2015
  2165                              <1> 	; 19/10/2015
  2166 000039FE FC                  <1> 	cld
  2167                              <1> 	;
  2168 000039FF FE05[8F6E0000]      <1> 	inc	byte [sysflg]
  2169                              <1> 		; incb sysflg / indicate a system routine is in progress
  2170 00003A05 FB                  <1>         sti 	; 18/01/2014
  2171                              <1> 	;jnz	panic ; 24/05/2013
  2172                              <1> 	; 24/12/2021
  2173 00003A06 7405                <1> 	jz	short _1
  2174 00003A08 E979F9FFFF          <1> 	jmp	panic
  2175                              <1> 		; beq 1f
  2176                              <1> 		; jmp panic ; / called if trap inside system
  2177                              <1> ;1:
  2178                              <1> _1:	; 24/12/2021
  2179                              <1> 	; 16/04/2015
  2180 00003A0D A3[986E0000]        <1> 	mov	[u.r0], eax
  2181 00003A12 8925[946E0000]      <1> 	mov	[u.usp], esp ; kernel stack points to user's registers
  2182                              <1> 	;
  2183                              <1> 		; mov $s.syst+2,clockp
  2184                              <1> 		; mov r0,-(sp) / save user registers 
  2185                              <1> 		; mov sp,u.r0 / pointer to bottom of users stack 
  2186                              <1> 			   ; / in u.r0
  2187                              <1> 		; mov r1,-(sp)
  2188                              <1> 		; mov r2,-(sp)
  2189                              <1> 		; mov r3,-(sp)
  2190                              <1> 		; mov r4,-(sp)
  2191                              <1> 		; mov r5,-(sp)
  2192                              <1> 		; mov ac,-(sp) / "accumulator" register for extended
  2193                              <1> 		             ; / arithmetic unit
  2194                              <1> 		; mov mq,-(sp) / "multiplier quotient" register for the
  2195                              <1> 		             ; / extended arithmetic unit
  2196                              <1> 		; mov sc,-(sp) / "step count" register for the extended
  2197                              <1> 		             ; / arithmetic unit
  2198                              <1> 		; mov sp,u.sp / u.sp points to top of users stack
  2199                              <1> 		; mov 18.(sp),r0 / store pc in r0
  2200                              <1> 		; mov -(r0),r0 / sys inst in r0      10400xxx
  2201                              <1> 		; sub $sys,r0 / get xxx code
  2202 00003A18 C1E002              <1> 	shl	eax, 2
  2203                              <1> 		; asl r0 / multiply by 2 to jump indirect in bytes
  2204 00003A1B 3D94000000          <1> 	cmp	eax, end_of_syscalls - syscalls
  2205                              <1> 		; cmp r0,$2f-1f / limit of table (35) exceeded
  2206                              <1> 	;jnb	short badsys
  2207                              <1> 		; bhis badsys / yes, bad system call
  2208                              <1> 	; 08/01/2022
  2209 00003A20 7205                <1> 	jb	short _2
  2210 00003A22 E95D010000          <1> 	jmp	badsys
  2211                              <1> _2:
  2212                              <1> 	; 08/01/2022
  2213                              <1> 	;cmc
  2214                              <1> 	;pushf	
  2215                              <1> 	;push	eax
  2216 00003A27 8B2D[906E0000]      <1>  	mov 	ebp, [u.sp] ; Kernel stack at the beginning of sys call
  2217                              <1> 	;mov	al, 0FEh ; 11111110b
  2218                              <1> 	;;adc	al, 0 ; al = al + cf
  2219                              <1> 	;and	[ebp+8], al ; flags (reset carry flag)
  2220 00003A2D 806508FE            <1> 	and	byte [ebp+8], 0FEh ; 11111110b ; 25/12/2021
  2221                              <1> 		; bic $341,20.(sp) / set users processor priority to 0 
  2222                              <1> 				 ; / and clear carry bit
  2223                              <1> 	;pop	ebp ; eax
  2224 00003A31 89C5                <1> 	mov	ebp, eax ; 25/12/2021
  2225                              <1> 	;popf
  2226                              <1>         ;;jc	badsys
  2227                              <1> 	; 24/12/2021
  2228                              <1> 	;jnc	short _3  ; 08/01/2022
  2229                              <1> 	;jmp	badsys
  2230                              <1> ;_3:
  2231 00003A33 A1[986E0000]        <1> 	mov	eax, [u.r0]
  2232                              <1> 	; system call registers: EAX, EDX, ECX, EBX, ESI, EDI
  2233 00003A38 FFA5[3E3A0000]      <1> 	jmp	dword [ebp+syscalls]
  2234                              <1> 		; jmp *1f(r0) / jump indirect thru table of addresses
  2235                              <1> 		            ; / to proper system routine.
  2236                              <1> syscalls: ; 1:
  2237                              <1> 	; 21/09/2015
  2238                              <1> 	; 01/07/2015
  2239                              <1> 	; 16/04/2015 (32 bit address modification) 
  2240 00003A3E [4E3B0000]          <1> 	dd sysrele	; / 0
  2241 00003A42 [F63B0000]          <1> 	dd sysexit 	; / 1
  2242 00003A46 [213D0000]          <1> 	dd sysfork 	; / 2
  2243 00003A4A [273E0000]          <1> 	dd sysread 	; / 3
  2244 00003A4E [3A3E0000]          <1> 	dd syswrite 	; / 4
  2245 00003A52 [A33E0000]          <1> 	dd sysopen 	; / 5
  2246 00003A56 [CE3F0000]          <1> 	dd sysclose 	; / 6
  2247 00003A5A [9C3C0000]          <1> 	dd syswait 	; / 7
  2248 00003A5E [4B3F0000]          <1> 	dd syscreat 	; / 8
  2249 00003A62 [87430000]          <1> 	dd syslink 	; / 9
  2250 00003A66 [43440000]          <1> 	dd sysunlink 	; / 10
  2251 00003A6A [0D450000]          <1> 	dd sysexec 	; / 11
  2252 00003A6E [3B4B0000]          <1> 	dd syschdir 	; / 12
  2253 00003A72 [1B4C0000]          <1> 	dd systime 	; / 13
  2254 00003A76 [873F0000]          <1> 	dd sysmkdir 	; / 14
  2255 00003A7A [8B4B0000]          <1> 	dd syschmod 	; / 15
  2256 00003A7E [EB4B0000]          <1> 	dd syschown 	; / 16
  2257 00003A82 [4E4C0000]          <1> 	dd sysbreak 	; / 17
  2258 00003A86 [CA480000]          <1> 	dd sysstat 	; / 18
  2259 00003A8A [1E4D0000]          <1> 	dd sysseek 	; / 19
  2260 00003A8E [304D0000]          <1> 	dd systell 	; / 20
  2261 00003A92 [ED570000]          <1> 	dd sysmount 	; / 21
  2262 00003A96 [CC580000]          <1> 	dd sysumount 	; / 22
  2263 00003A9A [AC4D0000]          <1> 	dd syssetuid 	; / 23
  2264 00003A9E [DD4D0000]          <1> 	dd sysgetuid 	; / 24
  2265 00003AA2 [2A4C0000]          <1> 	dd sysstime 	; / 25
  2266 00003AA6 [A04D0000]          <1> 	dd sysquit 	; / 26
  2267 00003AAA [944D0000]          <1> 	dd sysintr 	; / 27
  2268 00003AAE [A7480000]          <1> 	dd sysfstat 	; / 28
  2269 00003AB2 [EB3F0000]          <1> 	dd sysemt 	; / 29
  2270 00003AB6 [37400000]          <1> 	dd sysmdate 	; / 30
  2271 00003ABA [91400000]          <1> 	dd sysstty 	; / 31
  2272 00003ABE [7A420000]          <1> 	dd sysgtty 	; / 32
  2273 00003AC2 [32400000]          <1> 	dd sysilgins 	; / 33
  2274 00003AC6 [03610000]          <1> 	dd syssleep 	; 34 ; Retro UNIX 8086 v1 feature only !
  2275                              <1> 			     ; 11/06/2014
  2276 00003ACA [1A610000]          <1> 	dd sysmsg	; 35 ; Retro UNIX 386 v1 feature only !
  2277                              <1> 			     ; 01/07/2015
  2278 00003ACE [F2610000]          <1> 	dd sysgeterr	; 36 ; Retro UNIX 386 v1 feature only !
  2279                              <1> 			     ; 21/09/2015 - get last error number
  2280                              <1> end_of_syscalls:
  2281                              <1> 
  2282                              <1> error:
  2283                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2284                              <1> 	; 17/09/2015
  2285                              <1> 	; 03/09/2015
  2286                              <1> 	; 01/09/2015
  2287                              <1> 	; 09/06/2015
  2288                              <1> 	; 13/05/2015
  2289                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2290                              <1> 	; 10/04/2013 - 07/08/2013 (Retro UNIX 8086 v1)
  2291                              <1> 	;
  2292                              <1> 	; 'error' merely sets the error bit off the processor status (c-bit)
  2293                              <1> 	; then falls right into the 'sysret', 'sysrele' return sequence.
  2294                              <1> 	;
  2295                              <1> 	; INPUTS -> none
  2296                              <1> 	; OUTPUTS ->
  2297                              <1> 	;	processor status - carry (c) bit is set (means error)
  2298                              <1> 	;
  2299                              <1> 	; 26/05/2013 (Stack pointer must be reset here! 
  2300                              <1> 	; 	      Because, jumps to error procedure
  2301                              <1> 	;	      disrupts push-pop nesting balance)
  2302                              <1> 	;
  2303 00003AD2 8B2D[906E0000]      <1> 	mov	ebp, [u.sp] ; interrupt (system call) return (iretd) address
  2304 00003AD8 804D0801            <1> 	or	byte [ebp+8], 1  ; set carry bit of flags register
  2305                              <1> 				 ; (system call will return with cf = 1)
  2306                              <1> 		; bis $1,20.(r1) / set c bit in processor status word below
  2307                              <1> 		               ; / users stack
  2308                              <1> 	; 17/09/2015
  2309 00003ADC 83ED30              <1> 	sub	ebp, ESPACE ; 48 ; total size of stack frame ('sysdefs.inc')
  2310                              <1> 				 ; for saving/restoring user registers	
  2311                              <1> 	;cmp	ebp, [u.usp]
  2312                              <1> 	;je	short err0	
  2313 00003ADF 892D[946E0000]      <1> 	mov	[u.usp], ebp
  2314                              <1> ;err0:
  2315                              <1> 	; 01/09/2015
  2316 00003AE5 8B25[946E0000]      <1> 	mov	esp, [u.usp] 	    ; Retro Unix 8086 v1 modification!
  2317                              <1> 				    ; 10/04/2013
  2318                              <1> 				    ; (If an I/O error occurs during disk I/O,
  2319                              <1> 				    ; related procedures will jump to 'error'
  2320                              <1> 				    ; procedure directly without returning to 
  2321                              <1> 				    ; the caller procedure. So, stack pointer
  2322                              <1>                                     ; must be restored here.)
  2323                              <1> 	; 13/05/2015
  2324                              <1> 	; NOTE: (The last) error code is in 'u.error', it can be retrieved by
  2325                              <1> 	;	'get last error' system call later. 	
  2326                              <1> 
  2327                              <1> 	; 03/09/2015 - 09/06/2015 - 07/08/2013
  2328 00003AEB C605[FF6E0000]00    <1> 	mov 	byte [u.kcall], 0 ; namei_r, mkdir_w reset
  2329                              <1> 
  2330                              <1> sysret: ; < return from system call>
  2331                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2332                              <1> 	; 10/09/2015
  2333                              <1> 	; 29/07/2015
  2334                              <1> 	; 25/06/2015
  2335                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2336                              <1> 	; 10/04/2013 - 23/02/2014 (Retro UNIX 8086 v1)
  2337                              <1> 	;
  2338                              <1> 	; 'sysret' first checks to see if process is about to be 
  2339                              <1> 	; terminated (u.bsys). If it is, 'sysexit' is called.
  2340                              <1> 	; If not, following happens:	 
  2341                              <1> 	; 	1) The user's stack pointer is restored.
  2342                              <1> 	;	2) r1=0 and 'iget' is called to see if last mentioned
  2343                              <1> 	;	   i-node has been modified. If it has, it is written out
  2344                              <1> 	;	   via 'ppoke'.
  2345                              <1> 	;	3) If the super block has been modified, it is written out
  2346                              <1> 	;	   via 'ppoke'.				
  2347                              <1> 	;	4) If the dismountable file system's super block has been
  2348                              <1> 	;	   modified, it is written out to the specified device
  2349                              <1> 	;	   via 'ppoke'.
  2350                              <1> 	;	5) A check is made if user's time quantum (uquant) ran out
  2351                              <1> 	;	   during his execution. If so, 'tswap' is called to give
  2352                              <1> 	;	   another user a chance to run.
  2353                              <1> 	;	6) 'sysret' now goes into 'sysrele'. 
  2354                              <1> 	;	    (See 'sysrele' for conclusion.)		
  2355                              <1> 	;
  2356                              <1> 	; Calling sequence:
  2357                              <1> 	;	jump table or 'br sysret'
  2358                              <1> 	; Arguments: 
  2359                              <1> 	;	-	
  2360                              <1> 	; ...............................................................
  2361                              <1> 	;	
  2362                              <1> 	; ((AX=r1 for 'iget' input))
  2363                              <1> 	;	
  2364                              <1> 	;xor	ax, ax ; 04/05/2013
  2365                              <1> 	; 24/12/2021
  2366 00003AF2 31C0                <1> 	xor	eax, eax
  2367                              <1> sysret0: ; 29/07/2015 (eax = 0, jump from sysexec)
  2368 00003AF4 FEC0                <1> 	inc	al ; 04/05/2013
  2369 00003AF6 3805[E66E0000]      <1> 	cmp	[u.bsys], al ; 1
  2370                              <1> 		; tstb u.bsys / is a process about to be terminated because
  2371                              <1> 	;jnb	sysexit ; 04/05/2013
  2372                              <1> 	;	; bne sysexit / of an error? yes, go to sysexit
  2373                              <1> 	; 24/12/2021
  2374 00003AFC 720F                <1> 	jb	short _3
  2375 00003AFE C705[ED6E0000]0100- <1> 	mov	dword [u.error], ERR_INV_FUNC ; 1 ; 'invalid system call !'
  2375 00003B06 0000                <1>
  2376 00003B08 E9E9000000          <1> 	jmp	sysexit
  2377                              <1> _3:
  2378                              <1> 	;mov	esp, [u.usp] ; 24/05/2013 (that is not needed here)
  2379                              <1> 		; mov u.sp,sp / no point stack to users stack
  2380 00003B0D FEC8                <1> 	dec 	al ; mov ax, 0
  2381                              <1> 		; clr r1 / zero r1 to check last mentioned i-node
  2382 00003B0F E881160000          <1> 	call	iget
  2383                              <1> 		; jsr r0,iget / if last mentioned i-node has been modified
  2384                              <1> 		            ; / it is written out
  2385                              <1> 	;xor 	ax, ax ; 0
  2386                              <1> 	; 24/12/2021
  2387 00003B14 31C0                <1> 	xor	eax, eax
  2388 00003B16 3805[8D6E0000]      <1> 	cmp	[smod], al ; 0
  2389                              <1> 		; tstb	smod / has the super block been modified
  2390 00003B1C 7614                <1> 	jna	short sysret1
  2391                              <1> 		; beq	1f / no, 1f
  2392 00003B1E A2[8D6E0000]        <1> 	mov	[smod], al ; 0
  2393                              <1> 		; clrb smod / yes, clear smod
  2394 00003B23 BB[507B0000]        <1> 	mov	ebx, sb0 ;; 07/08//2013
  2395 00003B28 66810B0002          <1>    	or	word [ebx], 200h ;;
  2396                              <1> 	;or	word [sb0], 200h ; write bit, bit 9
  2397                              <1> 		; bis $1000,sb0 / set write bit in I/O queue for super block
  2398                              <1> 		      	      ; / output
  2399                              <1> 	; AX = 0
  2400 00003B2D E800220000          <1> 	call 	poke ; 07/08/2013
  2401                              <1> 	; call	ppoke
  2402                              <1> 	; AX = 0
  2403                              <1> 		; jsr r0,ppoke / write out modified super block to disk
  2404                              <1> sysret1: ;1:
  2405 00003B32 3805[8E6E0000]      <1> 	cmp	[mmod], al ; 0
  2406                              <1> 		; tstb	mmod / has the super block for the dismountable file
  2407                              <1> 		           ; / system
  2408 00003B38 7614                <1> 	jna	short sysrel0
  2409                              <1> 		; beq 1f / been modified?  no, 1f
  2410 00003B3A A2[8E6E0000]        <1> 	mov	[mmod], al ; 0	
  2411                              <1> 		; clrb	mmod / yes, clear mmod
  2412                              <1>         ;mov    ax, [mntd]
  2413                              <1>         ;;mov   al, [mdev] ; 26/04/2013
  2414 00003B3F BB[587D0000]        <1> 	mov	ebx, sb1 ;; 07/08//2013
  2415                              <1>         ;;mov	[ebx], al
  2416                              <1> 	;mov    [sb1], al
  2417                              <1> 		; movb	mntd,sb1 / set the I/O queue
  2418 00003B44 66810B0002          <1> 	or	word [ebx], 200h
  2419                              <1> 	;or	word [sb1], 200h ; write bit, bit 9
  2420                              <1> 		; bis $1000,sb1 / set write bit in I/O queue for detached sb
  2421 00003B49 E8E4210000          <1> 	call	poke ; 07/08/2013
  2422                              <1> 	;call	ppoke 
  2423                              <1> 		; jsr r0,ppoke / write it out to its device
  2424                              <1>         ;xor    al, al ; 26/04/2013       
  2425                              <1> ;1:
  2426                              <1> 		; tstb uquant / is the time quantum 0?
  2427                              <1> 		; bne 1f / no, don't swap it out
  2428                              <1> 
  2429                              <1> sysrele: ; < release >
  2430                              <1> 	; 14/10/2015
  2431                              <1> 	; 01/09/2015
  2432                              <1> 	; 24/07/2015
  2433                              <1> 	; 14/05/2015
  2434                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2435                              <1> 	; 10/04/2013 - 07/03/2014 (Retro UNIX 8086 v1)
  2436                              <1> 	;
  2437                              <1> 	; 'sysrele' first calls 'tswap' if the time quantum for a user is
  2438                              <1> 	;  zero (see 'sysret'). It then restores the user's registers and
  2439                              <1> 	; turns off the system flag. It then checked to see if there is
  2440                              <1> 	; an interrupt from the user by calling 'isintr'. If there is, 
  2441                              <1> 	; the output gets flashed (see isintr) and interrupt action is
  2442                              <1> 	; taken by a branch to 'intract'. If there is no interrupt from
  2443                              <1> 	; the user, a rti is made.
  2444                              <1> 	;
  2445                              <1> 	; Calling sequence:
  2446                              <1> 	;	Fall through a 'bne' in 'sysret' & ?
  2447                              <1> 	; Arguments:
  2448                              <1> 	;	-	
  2449                              <1> 	; ...............................................................
  2450                              <1> 	;	
  2451                              <1> 	; 23/02/2014 (swapret)
  2452                              <1> 	; 22/09/2013
  2453                              <1> sysrel0: ;1:
  2454 00003B4E 803D[DA6E0000]00    <1> 	cmp	byte [u.quant], 0 ; 16/05/2013
  2455                              <1> 		; tstb uquant / is the time quantum 0?
  2456 00003B55 7705                <1>         ja      short swapret
  2457                              <1> 		; bne 1f / no, don't swap it out
  2458                              <1> sysrelease: ; 07/12/2013 (jump from 'clock')
  2459 00003B57 E8D1120000          <1> 	call	tswap
  2460                              <1> 		; jsr r0,tswap / yes, swap it out
  2461                              <1> ;
  2462                              <1> ; Retro Unix 8086 v1 feature: return from 'swap' to 'swapret' address.
  2463                              <1> swapret: ;1:
  2464                              <1> 	; 10/09/2015
  2465                              <1> 	; 01/09/2015
  2466                              <1> 	; 14/05/2015
  2467                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - 32 bit, pm modifications)
  2468                              <1> 	; 26/05/2013 (Retro UNIX 8086 v1)
  2469                              <1> 	; cli
  2470                              <1> 	; 24/07/2015
  2471                              <1> 	;
  2472                              <1> 	;; 'esp' must be already equal to '[u.usp]' here ! 
  2473                              <1> 	;; mov	esp, [u.usp]
  2474                              <1> 
  2475                              <1> 	; 22/09/2013
  2476 00003B5C E8A3140000          <1> 	call	isintr
  2477                              <1> 	; 20/10/2013
  2478 00003B61 7405                <1> 	jz	short sysrel1
  2479 00003B63 E877000000          <1> 	call	intract
  2480                              <1> 		; jsr r0,isintr / is there an interrupt from the user
  2481                              <1> 		;     br intract / yes, output gets flushed, take interrupt
  2482                              <1> 		               ; / action
  2483                              <1> sysrel1:
  2484 00003B68 FA                  <1> 	cli ; 14/10/2015
  2485 00003B69 FE0D[8F6E0000]      <1> 	dec	byte [sysflg]
  2486                              <1> 		; decb sysflg / turn system flag off
  2487 00003B6F A1[F16E0000]        <1> 	mov     eax, [u.pgdir]
  2488 00003B74 0F22D8              <1> 	mov	cr3, eax  ; 1st PDE points to Kernel Page Table 0 (1st 4 MB)
  2489                              <1> 			  ; (others are different than kernel page tables) 
  2490                              <1> 	; 10/09/2015
  2491 00003B77 61                  <1> 	popad ; edi, esi, ebp, temp (icrement esp by 4), ebx, edx, ecx, eax
  2492                              <1> 		; mov (sp)+,sc / restore user registers
  2493                              <1> 		; mov (sp)+,mq
  2494                              <1> 		; mov (sp)+,ac
  2495                              <1> 		; mov (sp)+,r5
  2496                              <1> 		; mov (sp)+,r4
  2497                              <1> 		; mov (sp)+,r3
  2498                              <1> 		; mov (sp)+,r2
  2499                              <1> 	;
  2500 00003B78 A1[986E0000]        <1> 	mov	eax, [u.r0]  ; ((return value in EAX))
  2501 00003B7D 0FA9                <1> 	pop	gs
  2502 00003B7F 0FA1                <1> 	pop	fs
  2503 00003B81 07                  <1> 	pop	es
  2504 00003B82 1F                  <1> 	pop	ds
  2505 00003B83 CF                  <1> 	iretd	
  2506                              <1> 		; rti / no, return from interrupt
  2507                              <1> 
  2508                              <1> badsys:
  2509                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2510                              <1> 	; (Major Modification: 'core' dumping procedure in
  2511                              <1>         ;       original UNIX v1 and Retro UNIX 8086 v1
  2512                              <1> 	;	has been changed to print 'Invalid System Call !'
  2513                              <1> 	;	message on the user's console tty.)
  2514                              <1> 	; (EIP, EAX values will be shown on screen with error message)
  2515                              <1> 	; (EIP = Return address just after the system call -INT 30h-)
  2516                              <1> 	; (EAX = Function number)  
  2517                              <1> 	;
  2518 00003B84 FE05[E66E0000]      <1> 	inc	byte [u.bsys]
  2519                              <1> 	;
  2520 00003B8A 8B1D[906E0000]      <1> 	mov	ebx, [u.sp] ; esp at the beginning of 'sysent'
  2521 00003B90 8B03                <1> 	mov	eax, [ebx] ; EIP (return address, not 'INT 30h' address)
  2522 00003B92 E861DBFFFF          <1> 	call	dwordtohex
  2523 00003B97 8915[34680000]      <1> 	mov	[bsys_msg_eip], edx
  2524 00003B9D A3[38680000]        <1> 	mov	[bsys_msg_eip+4], eax
  2525 00003BA2 A1[986E0000]        <1> 	mov	eax, [u.r0]
  2526 00003BA7 E84CDBFFFF          <1> 	call	dwordtohex
  2527 00003BAC 8915[24680000]      <1> 	mov	[bsys_msg_eax], edx
  2528 00003BB2 A3[28680000]        <1> 	mov	[bsys_msg_eax+4], eax
  2529                              <1> 	; 24/12/2021
  2530                              <1> 	;xor	eax, eax
  2531                              <1> 	;mov	dword [u.base], badsys_msg ; "Invalid System Call !"
  2532                              <1> 	;mov	ebx, [u.fofp]
  2533                              <1> 	;mov	[ebx], eax
  2534                              <1> 	;;mov	eax, 1 ; inode number of console tty (for user)	
  2535                              <1> 	;inc	eax
  2536                              <1> 	;mov	dword [u.count], BSYS_M_SIZE
  2537                              <1> 		; writei
  2538                              <1> 		; INPUTS ->
  2539                              <1> 		;    r1 - inode number
  2540                              <1> 		;    u.count - byte count to be written
  2541                              <1> 		;    u.base - points to user buffer
  2542                              <1> 		;    u.fofp - points to word with current file offset
  2543                              <1> 		; OUTPUTS ->
  2544                              <1> 		;    u.count - cleared
  2545                              <1> 		;    u.nread - accumulates total bytes passed back	
  2546                              <1> 		;
  2547                              <1> 		; ((Modified registers: EDX, EBX, ECX, ESI, EDI, EBP)) 	
  2548                              <1> 	;call	writei
  2549                              <1> 	;;mov	eax, 1
  2550                              <1> 	;jmp	sysexit
  2551                              <1> 
  2552                              <1> 	; 24/12/2021 - Retro UNIX 386 v1.1
  2553 00003BB7 BE[05680000]        <1> 	mov	esi, badsys_msg ; "Invalid System Call !"
  2554 00003BBC 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2555 00003BC3 8A83[F76B0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2556 00003BC9 C605[076B0000]0F    <1> 	mov	byte [ccolor], 0Fh ; white (message) color
  2557 00003BD0 A2[EC6E0000]        <1> 	mov 	[u.ttyn], al ; current (active) tty (for user)
  2558 00003BD5 E8FD250000          <1> 	call	print_cmsg
  2559                              <1> 	;mov	dword [u.error], ERR_INV_FUNC ; 1 ; 'invalid system call !'
  2560 00003BDA E9F3FEFFFF          <1> 	jmp	error
  2561                              <1> 
  2562                              <1> 		; incb u.bsys / turn on the user's bad-system flag
  2563                              <1> 		; mov $3f,u.namep / point u.namep to "core\0\0"
  2564                              <1> 		; jsr r0,namei / get the i-number for the core image file
  2565                              <1> 		; br 1f / error
  2566                              <1> 		; neg r1 / negate the i-number to open the core image file
  2567                              <1> 		       ; / for writing
  2568                              <1> 		; jsr r0,iopen / open the core image file
  2569                              <1> 		; jsr r0,itrunc / free all associated blocks
  2570                              <1> 		; br 2f
  2571                              <1> ;1:
  2572                              <1> 		; mov $17,r1 / put i-node mode (17) in r1
  2573                              <1> 		; jsr r0,maknod / make an i-node
  2574                              <1> 		; mov u.dirbuf,r1 / put i-node number in r1
  2575                              <1> ;2:
  2576                              <1> 		; mov $core,u.base / move address core to u.base
  2577                              <1> 		; mov $ecore-core,u.count / put the byte count in u.count
  2578                              <1> 		; mov $u.off,u.fofp / more user offset to u.fofp
  2579                              <1> 		; clr u.off / clear user offset
  2580                              <1> 		; jsr r0,writei / write out the core image to the user
  2581                              <1> 		; mov $user,u.base / pt. u.base to user
  2582                              <1> 		; mov $64.,u.count / u.count = 64
  2583                              <1> 		; jsr r0,writei / write out all the user parameters
  2584                              <1> 		; neg r1 / make i-number positive
  2585                              <1> 		; jsr r0,iclose / close the core image file
  2586                              <1> 		; br sysexit /
  2587                              <1> ;3:
  2588                              <1> 		; <core\0\0>
  2589                              <1> 
  2590                              <1> intract: ; / interrupt action
  2591                              <1> 	; 14/10/2015
  2592                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2593                              <1> 	; 09/05/2013 - 07/12/2013 (Retro UNIX 8086 v1)
  2594                              <1> 	;
  2595                              <1> 	; Retro UNIX 8086 v1 modification !
  2596                              <1> 	; (Process/task switching and quit routine by using
  2597                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2598                              <1> 	;
  2599                              <1> 	; input -> 'u.quit'  (also value of 'u.intr' > 0)
  2600                              <1> 	; output -> If value of 'u.quit' = FFFFh ('ctrl+brk' sign)
  2601                              <1> 	;		'intract' will jump to 'sysexit'.
  2602                              <1> 	;	    Intract will return to the caller 
  2603                              <1> 	;		if value of 'u.quit' <> FFFFh. 	 
  2604                              <1> 	; 14/10/2015
  2605 00003BDF FB                  <1> 	sti
  2606                              <1> 	; 07/12/2013	
  2607 00003BE0 66FF05[DE6E0000]    <1> 	inc 	word [u.quit]
  2608 00003BE7 7408                <1> 	jz	short intrct0 ; FFFFh -> 0
  2609 00003BE9 66FF0D[DE6E0000]    <1> 	dec	word [u.quit]
  2610                              <1> 	; 16/04/2015
  2611 00003BF0 C3                  <1> 	retn
  2612                              <1> intrct0:	
  2613 00003BF1 58                  <1> 	pop	eax ; call intract -> retn
  2614                              <1> 	;
  2615 00003BF2 31C0                <1> 	xor 	eax, eax
  2616 00003BF4 FEC0                <1> 	inc	al  ; mov ax, 1
  2617                              <1> ;;;
  2618                              <1> 	; UNIX v1 original 'intract' routine... 
  2619                              <1> 	; / interrupt action
  2620                              <1> 		;cmp *(sp),$rti / are you in a clock interrupt?
  2621                              <1> 		; bne 1f / no, 1f
  2622                              <1> 		; cmp (sp)+,(sp)+ / pop clock pointer
  2623                              <1> 	; 1: / now in user area
  2624                              <1> 		; mov r1,-(sp) / save r1
  2625                              <1> 		; mov u.ttyp,r1 
  2626                              <1> 			; / pointer to tty buffer in control-to r1
  2627                              <1> 		; cmpb 6(r1),$177
  2628                              <1> 			; / is the interrupt char equal to "del"
  2629                              <1> 		; beq 1f / yes, 1f
  2630                              <1> 		; clrb 6(r1) 
  2631                              <1> 		        ; / no, clear the byte 
  2632                              <1> 			; / (must be a quit character)
  2633                              <1> 		; mov (sp)+,r1 / restore r1
  2634                              <1> 		; clr u.quit / clear quit flag
  2635                              <1> 		; bis $20,2(sp) 
  2636                              <1> 		    	; / set trace for quit (sets t bit of 
  2637                              <1> 			; / ps-trace trap)
  2638                              <1> 		; rti   ;  / return from interrupt
  2639                              <1> 	; 1: / interrupt char = del
  2640                              <1> 		; clrb 6(r1) / clear the interrupt byte 
  2641                              <1> 			   ; / in the buffer
  2642                              <1> 		; mov (sp)+,r1 / restore r1
  2643                              <1> 		; cmp u.intr,$core / should control be 
  2644                              <1> 				; / transferred to loc core?
  2645                              <1> 		; blo 1f
  2646                              <1> 		; jmp *u.intr / user to do rti yes, 
  2647                              <1> 				; / transfer to loc core
  2648                              <1> 	; 1:
  2649                              <1> 		; sys 1 / exit
  2650                              <1> 
  2651                              <1> sysexit: ; <terminate process>
  2652                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2653                              <1> 	; 01/09/2015
  2654                              <1> 	; 31/08/2015
  2655                              <1> 	; 14/05/2015
  2656                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2657                              <1> 	; 19/04/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2658                              <1> 	;
  2659                              <1> 	; 'sysexit' terminates a process. First each file that
  2660                              <1> 	; the process has opened is closed by 'flose'. The process
  2661                              <1> 	; status is then set to unused. The 'p.pid' table is then
  2662                              <1> 	; searched to find children of the dying process. If any of
  2663                              <1> 	; children are zombies (died by not waited for), they are
  2664                              <1> 	; set free. The 'p.pid' table is then searched to find the
  2665                              <1> 	; dying process's parent. When the parent is found, it is
  2666                              <1> 	; checked to see if it is free or it is a zombie. If it is
  2667                              <1> 	; one of these, the dying process just dies. If it is waiting
  2668                              <1> 	; for a child process to die, it notified that it doesn't 
  2669                              <1> 	; have to wait anymore by setting it's status from 2 to 1
  2670                              <1> 	; (waiting to active). It is awakened and put on runq by
  2671                              <1> 	; 'putlu'. The dying process enters a zombie state in which
  2672                              <1> 	; it will never be run again but stays around until a 'wait'
  2673                              <1> 	; is completed by it's parent process. If the parent is not
  2674                              <1> 	; found, process just dies. This means 'swap' is called with
  2675                              <1> 	; 'u.uno=0'. What this does is the 'wswap' is not called
  2676                              <1> 	; to write out the process and 'rswap' reads the new process
  2677                              <1> 	; over the one that dies..i.e., the dying process is 
  2678                              <1> 	; overwritten and destroyed.	
  2679                              <1>  	;
  2680                              <1> 	; Calling sequence:
  2681                              <1> 	;	sysexit or conditional branch.
  2682                              <1> 	; Arguments:
  2683                              <1> 	;	-	
  2684                              <1> 	; ...............................................................
  2685                              <1> 	;	
  2686                              <1> 	; Retro UNIX 8086 v1 modification: 
  2687                              <1> 	;       System call number (=1) is in EAX register.
  2688                              <1> 	;
  2689                              <1> 	;       Other parameters are in EDX, EBX, ECX, ESI, EDI, EBP
  2690                              <1> 	;       registers depending of function details.
  2691                              <1> 	;
  2692                              <1> 	; ('swap' procedure is mostly different than original UNIX v1.)
  2693                              <1> 	;
  2694                              <1> ; / terminate process
  2695                              <1> 	; AX = 1
  2696                              <1> 	;dec 	ax ; 0
  2697                              <1> 	; 24/12/2021
  2698 00003BF6 48                  <1> 	dec	eax ; 0
  2699                              <1> 	;dec 	ax ; 0
  2700 00003BF7 66A3[DC6E0000]      <1> 	mov	[u.intr], ax ; 0
  2701                              <1> 		; clr u.intr / clear interrupt control word
  2702                              <1> 		; clr r1 / clear r1
  2703                              <1> 	; AX = 0
  2704                              <1> sysexit_1: ; 1:
  2705                              <1> 	; AX = File descriptor
  2706                              <1> 		; / r1 has file descriptor (index to u.fp list)
  2707                              <1> 		; / Search the whole list
  2708 00003BFD E85A0D0000          <1> 	call	fclose
  2709                              <1> 		; jsr r0,fclose / close all files the process opened
  2710                              <1> 	;; ignore error return
  2711                              <1> 		; br .+2 / ignore error return
  2712                              <1> 	;inc	ax
  2713 00003C02 FEC0                <1> 	inc	al
  2714                              <1> 		; inc r1 / increment file descriptor
  2715                              <1> 	;cmp	ax, 10
  2716 00003C04 3C0A                <1> 	cmp	al, 10
  2717                              <1> 		; cmp r1,$10. / end of u.fp list?
  2718 00003C06 72F5                <1> 	jb	short sysexit_1
  2719                              <1> 		; blt 1b / no, go back
  2720 00003C08 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; 01/09/2015
  2721                              <1> 		; movb	u.uno,r1 / yes, move dying process's number to r1
  2722 00003C0F 88A3[176C0000]      <1> 	mov	[ebx+p.stat-1], ah ; 0, SFREE, 05/02/2014
  2723                              <1> 		; clrb p.stat-1(r1) / free the process
  2724                              <1> 	;shl	bx, 1
  2725 00003C15 D0E3                <1> 	shl	bl, 1
  2726                              <1> 		; asl r1 / use r1 for index into the below tables
  2727 00003C17 668B8B[B66B0000]    <1> 	mov	cx, [ebx+p.pid-2]
  2728                              <1> 		; mov p.pid-2(r1),r3 / move dying process's name to r3
  2729 00003C1E 668B93[D66B0000]    <1> 	mov	dx, [ebx+p.ppid-2]
  2730                              <1> 		; mov p.ppid-2(r1),r4 / move its parents name to r4
  2731                              <1> 	; xor 	bx, bx ; 0
  2732 00003C25 30DB                <1> 	xor	bl, bl ; 0
  2733                              <1> 		; clr r2
  2734 00003C27 31F6                <1> 	xor	esi, esi ; 0
  2735                              <1> 		; clr r5 / initialize reg
  2736                              <1> sysexit_2: ; 1:
  2737                              <1> 	        ; / find children of this dying process, 
  2738                              <1> 		; / if they are zombies, free them
  2739                              <1> 	;add	bx, 2
  2740 00003C29 80C302              <1> 	add	bl, 2
  2741                              <1> 		; add $2,r2 / search parent process table 
  2742                              <1> 		          ; / for dying process's name
  2743 00003C2C 66398B[D66B0000]    <1> 	cmp	[ebx+p.ppid-2], cx
  2744                              <1> 		; cmp p.ppid-2(r2),r3 / found it?
  2745 00003C33 7513                <1> 	jne	short sysexit_4
  2746                              <1> 		; bne 3f / no
  2747                              <1> 	;shr	bx, 1
  2748 00003C35 D0EB                <1> 	shr	bl, 1
  2749                              <1> 		; asr r2 / yes, it is a parent
  2750 00003C37 80BB[176C0000]03    <1> 	cmp	byte [ebx+p.stat-1], 3 ; SZOMB, 05/02/2014
  2751                              <1> 		; cmpb p.stat-1(r2),$3 / is the child of this 
  2752                              <1> 				     ; / dying process a zombie
  2753 00003C3E 7506                <1> 	jne	short sysexit_3 
  2754                              <1> 		; bne 2f / no
  2755 00003C40 88A3[176C0000]      <1> 	mov	[ebx+p.stat-1], ah ; 0, SFREE, 05/02/2014
  2756                              <1> 		; clrb p.stat-1(r2) / yes, free the child process
  2757                              <1> sysexit_3: ; 2:
  2758                              <1> 	;shr	bx, 1
  2759 00003C46 D0E3                <1> 	shl	bl, 1
  2760                              <1> 		; asl r2
  2761                              <1> sysexit_4: ; 3:
  2762                              <1> 		; / search the process name table 
  2763                              <1> 		; / for the dying process's parent
  2764 00003C48 663993[B66B0000]    <1> 	cmp	[ebx+p.pid-2], dx ; 17/09/2013	
  2765                              <1> 		; cmp p.pid-2(r2),r4 / found it?
  2766 00003C4F 7502                <1> 	jne	short sysexit_5
  2767                              <1> 		; bne 3f / no
  2768 00003C51 89DE                <1> 	mov	esi, ebx
  2769                              <1> 		; mov r2,r5 / yes, put index to p.pid table (parents
  2770                              <1> 		          ; / process # x2) in r5
  2771                              <1> sysexit_5: ; 3:
  2772                              <1> 	;cmp	bx, nproc + nproc
  2773 00003C53 80FB20              <1> 	cmp	bl, nproc + nproc
  2774                              <1> 		; cmp r2,$nproc+nproc / has whole table been searched?
  2775 00003C56 72D1                <1> 	jb	short sysexit_2
  2776                              <1> 		; blt 1b / no, go back
  2777                              <1> 		; mov r5,r1 / yes, r1 now has parents process # x2
  2778 00003C58 21F6                <1> 	and	esi, esi ; r5=r1
  2779 00003C5A 7431                <1> 	jz	short sysexit_6
  2780                              <1> 		; beq 2f / no parent has been found. 
  2781                              <1> 		       ; / The process just dies
  2782 00003C5C 66D1EE              <1> 	shr	si, 1
  2783                              <1> 		; asr r1 / set up index to p.stat
  2784 00003C5F 8A86[176C0000]      <1> 	mov	al, [esi+p.stat-1]
  2785                              <1> 		; movb p.stat-1(r1),r2 / move status of parent to r2
  2786 00003C65 20C0                <1> 	and	al, al
  2787 00003C67 7424                <1> 	jz	short sysexit_6
  2788                              <1> 		; beq 2f / if its been freed, 2f
  2789 00003C69 3C03                <1> 	cmp	al, 3
  2790                              <1> 		; cmp r2,$3 / is parent a zombie?
  2791 00003C6B 7420                <1> 	je	short sysexit_6
  2792                              <1> 		; beq 2f / yes, 2f
  2793                              <1> 	; BH = 0
  2794 00003C6D 8A1D[E76E0000]      <1> 	mov	bl, [u.uno]
  2795                              <1> 		; movb u.uno,r3 / move dying process's number to r3
  2796 00003C73 C683[176C0000]03    <1> 	mov	byte [ebx+p.stat-1], 3  ; SZOMB, 05/02/2014
  2797                              <1> 		; movb $3,p.stat-1(r3) / make the process a zombie
  2798                              <1> 	; 05/02/2014
  2799 00003C7A 3C01                <1> 	cmp	al, 1 ; SRUN
  2800 00003C7C 740F                <1> 	je	short sysexit_6
  2801                              <1> 	;cmp	al, 2
  2802                              <1> 		; cmp r2,$2 / is the parent waiting for 
  2803                              <1> 			  ; / this child to die
  2804                              <1> 	;jne	short sysexit_6	
  2805                              <1> 		; bne 2f / yes, notify parent not to wait any more
  2806                              <1> 	; 05/02/2014
  2807                              <1> 	; p.stat = 2 --> waiting
  2808                              <1> 	; p.stat = 4 --> sleeping
  2809 00003C7E C686[176C0000]01    <1> 	mov	byte [esi+p.stat-1], 1 ; SRUN ; 05/02/2014
  2810                              <1> 	;dec	byte [esi+p.stat-1]
  2811                              <1> 		; decb	p.stat-1(r1) / awaken it by putting it (parent)
  2812 00003C85 6689F0              <1> 	mov	ax, si ; r1  (process number in AL)
  2813                              <1> 	; 
  2814                              <1> 	;mov	ebx, runq + 4
  2815                              <1> 		; mov $runq+4,r2 / on the runq
  2816 00003C88 E877120000          <1> 	call	putlu
  2817                              <1> 		; jsr r0, putlu
  2818                              <1> sysexit_6: ; 2:
  2819                              <1> 	; 31/08/2015
  2820                              <1> 		; / the process dies
  2821 00003C8D C605[E76E0000]00    <1> 	mov	byte [u.uno], 0
  2822                              <1> 		; clrb u.uno / put zero as the process number, 
  2823                              <1> 	           ; / so "swap" will
  2824 00003C94 E89E110000          <1> 	call	swap
  2825                              <1> 		; jsr r0,swap / overwrite process with another process
  2826                              <1> hlt_sys:
  2827                              <1> 	;sti ; 18/01/2014
  2828                              <1> hlts0:
  2829 00003C99 F4                  <1> 	hlt
  2830 00003C9A EBFD                <1> 	jmp	short hlts0
  2831                              <1> 		; 0 / and thereby kill it; halt?
  2832                              <1> 
  2833                              <1> 
  2834                              <1> syswait: ; < wait for a processs to die >
  2835                              <1> 	; 09/02/2022
  2836                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1)
  2837                              <1> 	; 17/09/2015
  2838                              <1> 	; 02/09/2015
  2839                              <1> 	; 01/09/2015
  2840                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2841                              <1> 	; 24/05/2013 - 05/02/2014 (Retro UNIX 8086 v1)
  2842                              <1> 	;
  2843                              <1> 	; 'syswait' waits for a process die. 
  2844                              <1> 	; It works in following way:
  2845                              <1> 	;    1) From the parent process number, the parent's 
  2846                              <1> 	; 	process name is found. The p.ppid table of parent
  2847                              <1> 	;	names is then searched for this process name.
  2848                              <1> 	;	If a match occurs, r2 contains child's process
  2849                              <1> 	;	number. The child status is checked to see if it is
  2850                              <1> 	;	a zombie, i.e; dead but not waited for (p.stat=3)
  2851                              <1> 	;	If it is, the child process is freed and it's name
  2852                              <1> 	;	is put in (u.r0). A return is then made via 'sysret'.
  2853                              <1> 	;	If the child is not a zombie, nothing happens and
  2854                              <1> 	;	the search goes on through the p.ppid table until
  2855                              <1> 	;	all processes are checked or a zombie is found.
  2856                              <1> 	;    2) If no zombies are found, a check is made to see if
  2857                              <1> 	;	there are any children at all. If there are none,
  2858                              <1> 	;	an error return is made. If there are, the parent's
  2859                              <1> 	;	status is set to 2 (waiting for child to die),
  2860                              <1> 	;	the parent is swapped out, and a branch to 'syswait'
  2861                              <1> 	;	is made to wait on the next process.
  2862                              <1> 	;
  2863                              <1> 	; Calling sequence:
  2864                              <1> 	;	?
  2865                              <1> 	; Arguments:
  2866                              <1> 	;	-
  2867                              <1> 	; Inputs: - 
  2868                              <1> 	; Outputs: if zombie found, it's name put in u.r0.	
  2869                              <1> 	; ...............................................................
  2870                              <1> 	;				
  2871                              <1> 	
  2872                              <1> ; / wait for a process to die
  2873                              <1> 
  2874                              <1> syswait_0:
  2875 00003C9C 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; 01/09/2015
  2876                              <1> 		; movb u.uno,r1 / put parents process number in r1
  2877 00003CA3 D0E3                <1> 	shl	bl, 1
  2878                              <1> 	;shl	bx, 1
  2879                              <1> 		; asl r1 / x2 to get index into p.pid table
  2880 00003CA5 668B83[B66B0000]    <1> 	mov	ax, [ebx+p.pid-2]
  2881                              <1> 		; mov p.pid-2(r1),r1 / get the name of this process
  2882 00003CAC 31F6                <1> 	xor	esi, esi
  2883                              <1> 		; clr r2
  2884 00003CAE 31C9                <1> 	xor	ecx, ecx ; 30/10/2013
  2885                              <1> 	;xor 	cl, cl
  2886                              <1> 		; clr r3 / initialize reg 3
  2887                              <1> syswait_1: ; 1:
  2888                              <1> 	; 09/02/2022
  2889 00003CB0 46                  <1> 	inc	esi
  2890 00003CB1 46                  <1> 	inc	esi
  2891                              <1> 	;add	si, 2
  2892                              <1> 		; add $2,r2 / use r2 for index into p.ppid table
  2893                              <1> 			  ; / search table of parent processes 
  2894                              <1> 			  ; / for this process name
  2895 00003CB2 663B86[D66B0000]    <1> 	cmp	ax, [esi+p.ppid-2]
  2896                              <1> 		; cmp p.ppid-2(r2),r1 / r2 will contain the childs 
  2897                              <1> 			            ; / process number
  2898 00003CB9 7531                <1> 	jne	short syswait_3
  2899                              <1> 		;bne 3f / branch if no match of parent process name
  2900                              <1> 	;inc	cx
  2901 00003CBB FEC1                <1> 	inc	cl
  2902                              <1> 		;inc r3 / yes, a match, r3 indicates number of children
  2903                              <1> 	; 09/02/2022
  2904 00003CBD D1EE                <1> 	shr	esi, 1
  2905                              <1> 	;shr	si, 1
  2906                              <1> 		; asr r2 / r2/2 to get index to p.stat table
  2907                              <1> 	; The possible states ('p.stat' values) of a process are:
  2908                              <1> 	;	0 = free or unused
  2909                              <1> 	;	1 = active
  2910                              <1> 	;	2 = waiting for a child process to die
  2911                              <1> 	;	3 = terminated, but not yet waited for (zombie).	
  2912 00003CBF 80BE[176C0000]03    <1> 	cmp	byte [esi+p.stat-1], 3 ; SZOMB, 05/02/2014
  2913                              <1> 		; cmpb p.stat-1(r2),$3 / is the child process a zombie?
  2914 00003CC6 7522                <1> 	jne	short syswait_2
  2915                              <1> 		; bne 2f / no, skip it
  2916 00003CC8 88BE[176C0000]      <1> 	mov	[esi+p.stat-1], bh ; 0
  2917                              <1> 		; clrb p.stat-1(r2) / yes, free it
  2918                              <1> 	; 09/02/2022
  2919 00003CCE D1E6                <1> 	shl	esi, 1
  2920                              <1> 	;shl	si, 1
  2921                              <1> 		; asl r2 / r2x2 to get index into p.pid table
  2922 00003CD0 0FB786[B66B0000]    <1> 	movzx	eax, word [esi+p.pid-2]
  2923 00003CD7 A3[986E0000]        <1> 	mov	[u.r0], eax
  2924                              <1> 		; mov p.pid-2(r2),*u.r0 
  2925                              <1> 			      ; / put childs process name in (u.r0)
  2926                              <1> 	;
  2927                              <1> 	; Retro UNIX 386 v1 modification ! (17/09/2015)
  2928                              <1> 	;
  2929                              <1> 	; Parent process ID -p.ppid- field (of the child process)
  2930                              <1> 	; must be cleared in order to prevent infinitive 'syswait'
  2931                              <1> 	; system call loop from the application/program if it calls
  2932                              <1> 	; 'syswait' again (mistakenly) while there is not a zombie
  2933                              <1> 	; or running child process to wait. ('forktest.s', 17/09/2015)
  2934                              <1> 	;
  2935                              <1> 	; Note: syswait will return with error if there is not a
  2936                              <1> 	;       zombie or running process to wait.	
  2937                              <1> 	;
  2938                              <1> 	;sub	ax, ax
  2939                              <1> 	; 08/01/2022
  2940 00003CDC 29C0                <1> 	sub	eax, eax
  2941 00003CDE 668986[D66B0000]    <1> 	mov 	[esi+p.ppid-2], ax ; 0 ; 17/09/2015
  2942 00003CE5 E90AFEFFFF          <1> 	jmp	sysret0 ; ax = 0
  2943                              <1> 	;
  2944                              <1> 	;jmp	sysret
  2945                              <1> 		; br sysret1 / return cause child is dead
  2946                              <1> syswait_2: ; 2:
  2947                              <1> 	; 09/02/2022
  2948 00003CEA D1E6                <1> 	shl	esi, 1
  2949                              <1> 	;shl	si, 1
  2950                              <1> 		; asl r2 / r2x2 to get index into p.ppid table
  2951                              <1> syswait_3: ; 3:
  2952 00003CEC 6683FE20            <1> 	cmp	si, nproc+nproc
  2953                              <1> 		; cmp r2,$nproc+nproc / have all processes been checked?
  2954 00003CF0 72BE                <1> 	jb	short syswait_1
  2955                              <1> 		; blt 1b / no, continue search
  2956                              <1> 	;and	cx, cx
  2957 00003CF2 20C9                <1> 	and	cl, cl
  2958                              <1> 		; tst r3 / one gets here if there are no children 
  2959                              <1> 		       ; / or children that are still active
  2960                              <1> 	; 30/10/2013
  2961 00003CF4 7515                <1> 	jnz	short syswait_4
  2962                              <1> 	;jz	error
  2963                              <1> 		; beq error1 / there are no children, error
  2964 00003CF6 890D[986E0000]      <1> 	mov	[u.r0], ecx ; 0
  2965                              <1> 	; 09/02/2022
  2966 00003CFC C705[ED6E0000]1B00- <1> 	mov	dword [u.error], ERR_MISC ; 27
  2966 00003D04 0000                <1>
  2967                              <1> 			; miscellaneous/other errors
  2968 00003D06 E9C7FDFFFF          <1> 	jmp	error
  2969                              <1> syswait_4:
  2970 00003D0B 8A1D[E76E0000]      <1> 	mov	bl, [u.uno]
  2971                              <1> 		; movb u.uno,r1 / there are children so put 
  2972                              <1> 			      ; / parent process number in r1
  2973 00003D11 FE83[176C0000]      <1> 	inc	byte [ebx+p.stat-1] ; 2, SWAIT, 05/02/2014
  2974                              <1> 		; incb p.stat-1(r1) / it is waiting for 
  2975                              <1> 				  ; / other children to die
  2976                              <1> 	; 04/11/2013
  2977 00003D17 E81B110000          <1> 	call	swap
  2978                              <1> 		; jsr r0,swap / swap it out, because it's waiting
  2979 00003D1C E97BFFFFFF          <1> 	jmp	syswait_0
  2980                              <1> 		; br syswait / wait on next process
  2981                              <1> 
  2982                              <1> sysfork: ; < create a new process >
  2983                              <1> 	; 26/02/2022
  2984                              <1> 	; 25/02/2022
  2985                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1)
  2986                              <1> 	; 18/09/2015
  2987                              <1> 	; 04/09/2015
  2988                              <1> 	; 02/09/2015
  2989                              <1> 	; 01/09/2015
  2990                              <1> 	; 28/08/2015
  2991                              <1> 	; 14/05/2015
  2992                              <1> 	; 10/05/2015
  2993                              <1> 	; 09/05/2015
  2994                              <1> 	; 06/05/2015 (Retro UNIX 386 v1 - Beginning)
  2995                              <1> 	; 24/05/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2996                              <1> 	;
  2997                              <1> 	; 'sysfork' creates a new process. This process is referred
  2998                              <1> 	; to as the child process. This new process core image is
  2999                              <1> 	; a copy of that of the caller of 'sysfork'. The only
  3000                              <1> 	; distinction is the return location and the fact that (u.r0)
  3001                              <1> 	; in the old process (parent) contains the process id (p.pid)
  3002                              <1> 	; of the new process (child). This id is used by 'syswait'.
  3003                              <1> 	; 'sysfork' works in the following manner: 	
  3004                              <1> 	;    1) The process status table (p.stat) is searched to find
  3005                              <1> 	;	a process number that is unused. If none are found
  3006                              <1> 	;	an error occurs.
  3007                              <1> 	;    2) when one is found, it becomes the child process number
  3008                              <1> 	;	and it's status (p.stat) is set to active.
  3009                              <1> 	;    3) If the parent had a control tty, the interrupt 
  3010                              <1> 	;	character in that tty buffer is cleared.
  3011                              <1> 	;    4) The child process is put on the lowest priority run 
  3012                              <1> 	;	queue via 'putlu'.
  3013                              <1> 	;    5) A new process name is gotten from 'mpid' (actually 
  3014                              <1> 	;	it is a unique number) and is put in the child's unique
  3015                              <1> 	;	identifier; process id (p.pid).
  3016                              <1> 	;    6) The process name of the parent is then obtained and
  3017                              <1> 	;	placed in the unique identifier of the parent process
  3018                              <1> 	;	name is then put in 'u.r0'.	
  3019                              <1> 	;    7) The child process is then written out on disk by
  3020                              <1> 	;	'wswap',i.e., the parent process is copied onto disk
  3021                              <1> 	;	and the child is born. (The child process is written 
  3022                              <1> 	;	out on disk/drum with 'u.uno' being the child process
  3023                              <1> 	;	number.)
  3024                              <1> 	;    8) The parent process number is then restored to 'u.uno'.
  3025                              <1> 	;    9) The child process name is put in 'u.r0'.
  3026                              <1> 	;   10) The pc on the stack sp + 18 is incremented by 2 to
  3027                              <1> 	;	create the return address for the parent process.
  3028                              <1> 	;   11) The 'u.fp' list as then searched to see what files
  3029                              <1> 	;	the parent has opened. For each file the parent has
  3030                              <1> 	;	opened, the corresponding 'fsp' entry must be updated
  3031                              <1> 	;	to indicate that the child process also has opened
  3032                              <1> 	;	the file. A branch to 'sysret' is then made.	 			 				
  3033                              <1> 	;
  3034                              <1> 	; Calling sequence:
  3035                              <1> 	;	from shell ?
  3036                              <1> 	; Arguments:
  3037                              <1> 	;	-
  3038                              <1> 	; Inputs: -
  3039                              <1> 	; Outputs: *u.r0 - child process name
  3040                              <1> 	; ...............................................................
  3041                              <1> 	;	
  3042                              <1> 	; Retro UNIX 8086 v1 modification: 
  3043                              <1> 	;	AX = r0 = PID (>0) (at the return of 'sysfork')
  3044                              <1> 	;	= process id of child a parent process returns
  3045                              <1> 	;	= process id of parent when a child process returns
  3046                              <1> 	;
  3047                              <1> 	;       In original UNIX v1, sysfork is called and returns as
  3048                              <1> 	;	in following manner: (with an example: c library, fork)
  3049                              <1> 	;	
  3050                              <1> 	;	1:
  3051                              <1> 	;		sys	fork
  3052                              <1> 	;			br 1f  / child process returns here
  3053                              <1> 	;		bes	2f     / parent process returns here
  3054                              <1> 	;		/ pid of new process in r0
  3055                              <1> 	;		rts	pc
  3056                              <1> 	;	2: / parent process condionally branches here
  3057                              <1> 	;		mov	$-1,r0 / pid = -1 means error return
  3058                              <1> 	;		rts	pc
  3059                              <1> 	;
  3060                              <1> 	;	1: / child process brances here
  3061                              <1> 	;		clr	r0   / pid = 0 in child process
  3062                              <1> 	;		rts	pc
  3063                              <1> 	;
  3064                              <1> 	;	In UNIX v7x86 (386) by Robert Nordier (1999)
  3065                              <1> 	;		// pid = fork();
  3066                              <1> 	;		//
  3067                              <1> 	;		// pid == 0 in child process; 
  3068                              <1> 	;		// pid == -1 means error return
  3069                              <1> 	;		// in child, 
  3070                              <1> 	;		//	parents id is in par_uid if needed
  3071                              <1> 	;		
  3072                              <1> 	;		_fork:
  3073                              <1> 	;			mov	$.fork,eax
  3074                              <1> 	;			int	$0x30
  3075                              <1> 	;			jmp	1f
  3076                              <1> 	;			jnc	2f
  3077                              <1> 	;			jmp	cerror
  3078                              <1> 	;		1:
  3079                              <1> 	;			mov	eax,_par_uid
  3080                              <1> 	;			xor	eax,eax
  3081                              <1> 	;		2:
  3082                              <1> 	;			ret
  3083                              <1> 	;
  3084                              <1> 	;	In Retro UNIX 8086 v1,
  3085                              <1> 	;	'sysfork' returns in following manner:
  3086                              <1> 	;	
  3087                              <1> 	;		mov	ax, sys_fork
  3088                              <1> 	;		mov	bx, offset @f ; routine for child
  3089                              <1> 	;		int	20h
  3090                              <1> 	;		jc	error
  3091                              <1> 	;		
  3092                              <1> 	;	; Routine for parent process here (just after 'jc')
  3093                              <1> 	;		mov	word ptr [pid_of_child], ax
  3094                              <1> 	;		jmp	next_routine_for_parent	
  3095                              <1> 	;
  3096                              <1> 	;	@@: ; routine for child process here				
  3097                              <1> 	;		....	
  3098                              <1> 	;	NOTE: 'sysfork' returns to specified offset
  3099                              <1> 	;	       for child process by using BX input.
  3100                              <1> 	;	      (at first, parent process will return then 
  3101                              <1> 	;	      child process will return -after swapped in-
  3102                              <1> 	;	      'syswait' is needed in parent process
  3103                              <1> 	;	      if return from child process will be waited for.)
  3104                              <1> 	;	  				
  3105                              <1> 	
  3106                              <1> ; / create a new process
  3107                              <1> 	; EBX = return address for child process 
  3108                              <1> 	     ; (Retro UNIX 8086 v1 modification !)
  3109 00003D21 31F6                <1> 	xor 	esi, esi
  3110                              <1> 		; clr r1
  3111                              <1> sysfork_1: ; 1: / search p.stat table for unused process number
  3112 00003D23 46                  <1> 	inc	esi
  3113                              <1> 		; inc r1
  3114 00003D24 80BE[176C0000]00    <1> 	cmp	byte [esi+p.stat-1], 0 ; SFREE, 05/02/2014
  3115                              <1> 		; tstb p.stat-1(r1) / is process active, unused, dead
  3116 00003D2B 760B                <1> 	jna	short sysfork_2	
  3117                              <1> 		; beq 1f / it's unused so branch
  3118 00003D2D 6683FE10            <1> 	cmp	si, nproc
  3119                              <1> 		; cmp r1,$nproc / all processes checked
  3120 00003D31 72F0                <1> 	jb	short sysfork_1
  3121                              <1> 		; blt 1b / no, branch back
  3122                              <1> 	;
  3123                              <1> 	; Retro UNIX 8086 v1. modification:
  3124                              <1> 	;	Parent process returns from 'sysfork' to address 
  3125                              <1> 	;	which is just after 'sysfork' system call in parent
  3126                              <1> 	;	process. Child process returns to address which is put
  3127                              <1> 	;	in BX register by parent process for 'sysfork'. 
  3128                              <1> 	;
  3129                              <1> 		;add $2,18.(sp) / add 2 to pc when trap occured, points
  3130                              <1> 		             ; / to old process return
  3131                              <1> 		; br error1 / no room for a new process
  3132                              <1> sysfork_0:
  3133 00003D33 E99AFDFFFF          <1> 	jmp	error
  3134                              <1> sysfork_2: ; 1:
  3135 00003D38 E879F0FFFF          <1> 	call	allocate_page
  3136                              <1> 	;jc	error
  3137                              <1> 	; 08/01/2022
  3138 00003D3D 72F4                <1> 	jc	short sysfork_0
  3139                              <1> 
  3140 00003D3F 50                  <1> 	push	eax   ; UPAGE (user structure page) address
  3141                              <1> 	; Retro UNIX 386 v1 modification!
  3142 00003D40 E86AF2FFFF          <1> 	call	duplicate_page_dir
  3143                              <1> 		; EAX = New page directory 
  3144 00003D45 7308                <1> 	jnc	short sysfork_3
  3145 00003D47 58                  <1> 	pop	eax   ; UPAGE (user structure page) address
  3146 00003D48 E831F2FFFF          <1> 	call 	deallocate_page
  3147                              <1> 	;jmp	error
  3148                              <1> 	; 08/01/2022
  3149 00003D4D EBE4                <1> 	jmp	short sysfork_0 ; error
  3150                              <1> sysfork_3:
  3151                              <1> 	; Retro UNIX 386 v1 modification !
  3152 00003D4F 56                  <1> 	push	esi
  3153 00003D50 E859110000          <1> 	call	wswap ; save current user (u) structure, user registers
  3154                              <1> 		      ; and interrupt return components (for IRET)
  3155 00003D55 8705[F16E0000]      <1> 	xchg	eax, [u.pgdir] ; page directory of the child process
  3156 00003D5B A3[F56E0000]        <1> 	mov	[u.ppgdir], eax ; page directory of the parent process
  3157 00003D60 5E                  <1> 	pop	esi
  3158 00003D61 58                  <1> 	pop	eax   ; UPAGE (user structure page) address
  3159                              <1> 		; [u.usp] = esp
  3160 00003D62 89F7                <1> 	mov	edi, esi
  3161                              <1> 	;shl	di, 2
  3162                              <1> 	; 08/01/2022
  3163 00003D64 C1E702              <1> 	shl	edi, 2
  3164 00003D67 8987[246C0000]      <1> 	mov	[edi+p.upage-4], eax ; memory page for 'user' struct
  3165 00003D6D A3[E86E0000]        <1> 	mov	[u.upage], eax ; memory page for 'user' struct (child)
  3166                              <1> 	; 28/08/2015
  3167 00003D72 0FB605[E76E0000]    <1> 	movzx	eax, byte [u.uno] ; parent process number
  3168                              <1> 		; movb u.uno,-(sp) / save parent process number
  3169 00003D79 89C7                <1> 	mov	edi, eax
  3170 00003D7B 50                  <1>         push	eax ; ** 
  3171 00003D7C 8A87[F76B0000]      <1> 	mov     al, [edi+p.ttyc-1] ; console tty (parent)
  3172                              <1> 		; 18/09/2015
  3173 00003D82 8886[F76B0000]      <1> 	mov     [esi+p.ttyc-1], al ; set child's console tty
  3174                              <1> 	; 26/02/2022 (p.waitc is not used)
  3175                              <1> 	;mov	[esi+p.waitc-1], ah ; 0 ; reset child's wait channel
  3176                              <1> 	; 25/02/2022 (BugFix)
  3177                              <1> 	;mov	[esi+p.ttyc-1], ax ; al - set child's console tty
  3178                              <1> 	;			   ; ah - reset child's wait channel	
  3179 00003D88 89F0                <1> 	mov	eax, esi
  3180 00003D8A A2[E76E0000]        <1> 	mov	[u.uno], al ; child process number
  3181                              <1> 		;movb r1,u.uno / set child process number to r1
  3182 00003D8F FE86[176C0000]      <1>         inc     byte [esi+p.stat-1] ; 1, SRUN, 05/02/2014
  3183                              <1> 		; incb p.stat-1(r1) / set p.stat entry for child 
  3184                              <1> 				; / process to active status
  3185                              <1> 		; mov u.ttyp,r2 / put pointer to parent process' 
  3186                              <1> 			      ; / control tty buffer in r2
  3187                              <1>                 ; beq 2f / branch, if no such tty assigned
  3188                              <1> 		; clrb 6(r2) / clear interrupt character in tty buffer
  3189                              <1> 	; 2:
  3190 00003D95 53                  <1> 	push	ebx  ; * return address for the child process
  3191                              <1> 		     ; * Retro UNIX 8086 v1 feature only !	
  3192                              <1> 	; (Retro UNIX 8086 v1 modification!)
  3193                              <1> 		; mov $runq+4,r2
  3194 00003D96 E869110000          <1> 	call	putlu 
  3195                              <1>  		; jsr r0,putlu / put child process on lowest priority 
  3196                              <1> 			   ; / run queue
  3197                              <1> 	; 08/01/2022
  3198 00003D9B D1E6                <1> 	shl	esi, 1
  3199                              <1> 	;shl	si, 1
  3200                              <1> 		; asl r1 / multiply r1 by 2 to get index 
  3201                              <1> 		       ; / into p.pid table
  3202 00003D9D 66FF05[866E0000]    <1> 	inc	word [mpid]
  3203                              <1> 		; inc mpid / increment m.pid; get a new process name
  3204 00003DA4 66A1[866E0000]      <1> 	mov	ax, [mpid]
  3205 00003DAA 668986[B66B0000]    <1> 	mov	[esi+p.pid-2], ax
  3206                              <1> 		;mov mpid,p.pid-2(r1) / put new process name 
  3207                              <1> 				    ; / in child process' name slot
  3208 00003DB1 5A                  <1> 	pop	edx  ; * return address for the child process
  3209                              <1> 		     ; * Retro UNIX 8086 v1 feature only !	
  3210 00003DB2 5B                  <1>   	pop	ebx  ; **
  3211                              <1> 	;mov	ebx, [esp] ; ** parent process number
  3212                              <1> 		; movb (sp),r2 / put parent process number in r2
  3213                              <1> 	; 08/01/2022
  3214 00003DB3 D1E3                <1> 	shl	ebx, 1
  3215                              <1> 	;shl 	bx, 1
  3216                              <1> 		; asl r2 / multiply by 2 to get index into below tables
  3217                              <1> 	;movzx eax, word [ebx+p.pid-2]
  3218 00003DB5 668B83[B66B0000]    <1> 	mov	ax, [ebx+p.pid-2]
  3219                              <1> 		; mov p.pid-2(r2),r2 / get process name of parent
  3220                              <1> 				   ; / process
  3221 00003DBC 668986[D66B0000]    <1> 	mov	[esi+p.ppid-2], ax
  3222                              <1> 		; mov r2,p.ppid-2(r1) / put parent process name 
  3223                              <1> 			  ; / in parent process slot for child
  3224 00003DC3 A3[986E0000]        <1> 	mov	[u.r0], eax	
  3225                              <1> 		; mov r2,*u.r0 / put parent process name on stack 
  3226                              <1> 			     ; / at location where r0 was saved
  3227 00003DC8 8B2D[906E0000]      <1> 	mov 	ebp, [u.sp] ; points to return address (EIP for IRET)
  3228 00003DCE 895500              <1> 	mov	[ebp], edx ; *, CS:EIP -> EIP
  3229                              <1> 			   ; * return address for the child process
  3230                              <1> 		; mov $sysret1,-(sp) /
  3231                              <1> 		; mov sp,u.usp / contents of sp at the time when 
  3232                              <1> 			      ; / user is swapped out
  3233                              <1> 		; mov $sstack,sp / point sp to swapping stack space
  3234                              <1> 	; 04/09/2015 - 01/09/2015
  3235                              <1> 	; [u.usp] = esp
  3236 00003DD1 68[F23A0000]        <1> 	push	sysret ; ***
  3237 00003DD6 8925[946E0000]      <1> 	mov	[u.usp], esp ; points to 'sysret' address (***)
  3238                              <1> 			     ; (for child process)	
  3239 00003DDC 31C0                <1> 	xor 	eax, eax
  3240 00003DDE 66A3[C86E0000]      <1> 	mov 	[u.ttyp], ax ; 0
  3241                              <1> 	;
  3242 00003DE4 E8C5100000          <1> 	call	wswap ; Retro UNIX 8086 v1 modification !
  3243                              <1> 		;jsr r0,wswap / put child process out on drum
  3244                              <1> 		;jsr r0,unpack / unpack user stack
  3245                              <1> 		;mov u.usp,sp / restore user stack pointer
  3246                              <1> 		; tst (sp)+ / bump stack pointer
  3247                              <1> 	; Retro UNIX 386 v1 modification !
  3248 00003DE9 58                  <1> 	pop	eax ; ***
  3249                              <1> 	; 08/01/2022
  3250 00003DEA D1E3                <1> 	shl	ebx, 1
  3251                              <1> 	;shl 	bx, 1
  3252 00003DEC 8B83[246C0000]      <1> 	mov     eax, [ebx+p.upage-4] ; UPAGE address ; 14/05/2015
  3253 00003DF2 E8E0100000          <1> 	call	rswap ; restore parent process 'u' structure, 
  3254                              <1> 		      ; registers and return address (for IRET)
  3255                              <1> 		;movb (sp)+,u.uno / put parent process number in u.uno
  3256 00003DF7 0FB705[866E0000]    <1>         movzx   eax, word [mpid]
  3257 00003DFE A3[986E0000]        <1> 	mov	[u.r0], eax
  3258                              <1> 		; mov mpid,*u.r0 / put child process name on stack 
  3259                              <1> 			       ; / where r0 was saved
  3260                              <1> 		; add $2,18.(sp) / add 2 to pc on stack; gives parent
  3261                              <1> 			          ; / process return
  3262                              <1> 	;xor	ebx, ebx
  3263 00003E03 31F6                <1> 	xor     esi, esi
  3264                              <1> 		;clr r1
  3265                              <1> sysfork_4: ; 1: / search u.fp list to find the files 
  3266                              <1> 	      ; / opened by the parent process
  3267                              <1> 	; 01/09/2015
  3268                              <1> 	;xor	bh, bh
  3269                              <1> 	;mov 	bl, [esi+u.fp]
  3270 00003E05 8A86[9E6E0000]      <1> 	mov 	al, [esi+u.fp]
  3271                              <1> 		; movb u.fp(r1),r2 / get an open file for this process
  3272                              <1>         ;or	bl, bl
  3273 00003E0B 08C0                <1> 	or	al, al
  3274 00003E0D 740C                <1> 	jz	short sysfork_5	
  3275                              <1> 		; beq 2f / file has not been opened by parent, 
  3276                              <1> 		       ; / so branch
  3277 00003E0F B40A                <1> 	mov	ah, 10 ; Retro UNIX 386 v1 fsp structure size = 10 bytes
  3278 00003E11 F6E4                <1> 	mul	ah
  3279                              <1> 	;;movzx	ebx, ax
  3280                              <1> 	;mov	bx, ax
  3281 00003E13 89C3                <1> 	mov	ebx, eax ; 08/01/2022
  3282                              <1> 	;shl	bx, 3
  3283                              <1> 		; asl r2 / multiply by 8
  3284                              <1>        		; asl r2 / to get index into fsp table
  3285                              <1>        		; asl r2
  3286 00003E15 FE83[666C0000]      <1>   	inc     byte [ebx+fsp-2]
  3287                              <1> 		; incb fsp-2(r2) / increment number of processes
  3288                              <1> 			     ; / using file, because child will now be
  3289                              <1> 			     ; / using this file
  3290                              <1> sysfork_5: ; 2:
  3291 00003E1B 46                  <1>         inc     esi
  3292                              <1> 		; inc r1 / get next open file
  3293 00003E1C 6683FE0A            <1>         cmp     si, 10
  3294                              <1> 		; cmp r1,$10. / 10. files is the maximum number which
  3295                              <1> 			  ; / can be opened
  3296 00003E20 72E3                <1> 	jb	short sysfork_4	
  3297                              <1> 		; blt 1b / check next entry
  3298 00003E22 E9CBFCFFFF          <1> 	jmp	sysret
  3299                              <1> 		; br sysret1
  3300                              <1> 
  3301                              <1> sysread: ; < read from file >
  3302                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3303                              <1> 	; 13/05/2015
  3304                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3305                              <1> 	; 23/05/2013 (Retro UNIX 8086 v1)
  3306                              <1> 	;
  3307                              <1> 	; 'sysread' is given a buffer to read into and the number of
  3308                              <1> 	; characters to be read. If finds the file from the file
  3309                              <1> 	; descriptor located in *u.r0 (r0). This file descriptor
  3310                              <1> 	; is returned from a successful open call (sysopen).
  3311                              <1> 	; The i-number of file is obtained via 'rw1' and the data
  3312                              <1> 	; is read into core via 'readi'.
  3313                              <1> 	;
  3314                              <1> 	; Calling sequence:
  3315                              <1> 	;	sysread; buffer; nchars
  3316                              <1> 	; Arguments:
  3317                              <1> 	;	buffer - location of contiguous bytes where 
  3318                              <1> 	;		 input will be placed.
  3319                              <1> 	;	nchars - number of bytes or characters to be read.
  3320                              <1> 	; Inputs: *u.r0 - file descriptor (& arguments)
  3321                              <1> 	; Outputs: *u.r0 - number of bytes read.	
  3322                              <1> 	; ...............................................................
  3323                              <1> 	;				
  3324                              <1> 	; Retro UNIX 8086 v1 modification: 
  3325                              <1> 	;       'sysread' system call has three arguments; so,
  3326                              <1> 	;	* 1st argument, file descriptor is in BX register
  3327                              <1> 	;	* 2nd argument, buffer address/offset in CX register
  3328                              <1> 	;	* 3rd argument, number of bytes is in DX register
  3329                              <1> 	;
  3330                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3331                              <1> 	;	to the user with number of bytes read. 
  3332                              <1> 	;
  3333 00003E27 E840000000          <1> 	call	rw1
  3334                              <1> 	;jc	error ; 13/05/2015, ax < 1
  3335                              <1> 	;	; jsr r0,rw1 / get i-number of file to be read into r1
  3336                              <1>        	; 24/12/2021
  3337 00003E2C 7239                <1> 	jc	short sysread_err
  3338 00003E2E F6C480              <1> 	test	ah, 80h
  3339                              <1> 		; tst r1 / negative i-number?
  3340 00003E31 752A                <1> 	jnz	short rw3 ; 24/12/2021
  3341                              <1> 	;jnz	error
  3342                              <1> 		; ble error1 / yes, error 1 to read
  3343                              <1> 			   ; / it should be positive
  3344 00003E33 E831150000          <1> 	call	readi
  3345                              <1> 		; jsr r0,readi / read data into core
  3346 00003E38 EB14                <1> 	jmp	short rw0
  3347                              <1> 		; br 1f
  3348                              <1> 
  3349                              <1> syswrite: ; < write to file >
  3350                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3351                              <1> 	; 13/05/2015
  3352                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3353                              <1> 	; 23/05/2013 (Retro UNIX 8086 v1)
  3354                              <1> 	;
  3355                              <1> 	; 'syswrite' is given a buffer to write onto an output file
  3356                              <1> 	; and the number of characters to write. If finds the file
  3357                              <1> 	; from the file descriptor located in *u.r0 (r0). This file 
  3358                              <1> 	; descriptor is returned from a successful open or create call
  3359                              <1> 	; (sysopen or syscreat). The i-number of file is obtained via
  3360                              <1> 	; 'rw1' and buffer is written on the output file via 'write'.
  3361                              <1> 	;
  3362                              <1> 	; Calling sequence:
  3363                              <1> 	;	syswrite; buffer; nchars
  3364                              <1> 	; Arguments:
  3365                              <1> 	;	buffer - location of contiguous bytes to be writtten.
  3366                              <1> 	;	nchars - number of characters to be written.
  3367                              <1> 	; Inputs: *u.r0 - file descriptor (& arguments)
  3368                              <1> 	; Outputs: *u.r0 - number of bytes written.	
  3369                              <1> 	; ...............................................................
  3370                              <1> 	;				
  3371                              <1> 	; Retro UNIX 8086 v1 modification: 
  3372                              <1> 	;       'syswrite' system call has three arguments; so,
  3373                              <1> 	;	* 1st argument, file descriptor is in BX register
  3374                              <1> 	;	* 2nd argument, buffer address/offset in CX register
  3375                              <1> 	;	* 3rd argument, number of bytes is in DX register
  3376                              <1> 	;
  3377                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3378                              <1> 	;	to the user with number of bytes written. 
  3379                              <1> 	;
  3380 00003E3A E82D000000          <1> 	call	rw1
  3381                              <1> 	;jc	error ; 13/05/2015, ax < 1
  3382                              <1> 	;	; jsr r0,rw1 / get i-number in r1 of file to write
  3383                              <1>        	; 24/12/2021
  3384 00003E3F 7226                <1> 	jc	short syswrite_err
  3385 00003E41 F6C480              <1>         test	ah, 80h
  3386                              <1> 		; tst r1 / positive i-number ?
  3387 00003E44 7417                <1>         jz	short rw3 ; 13/05/2015
  3388                              <1> 	;jz	error
  3389                              <1> 		; bge error1 / yes, error 1 
  3390                              <1> 			   ; / negative i-number means write
  3391 00003E46 66F7D8              <1>         neg	ax
  3392                              <1> 		; neg r1 / make it positive
  3393 00003E49 E809170000          <1> 	call	writei
  3394                              <1>         	; jsr r0,writei / write data
  3395                              <1> rw0: ; 1:
  3396 00003E4E A1[C06E0000]        <1>         mov	eax, [u.nread]
  3397 00003E53 A3[986E0000]        <1> 	mov	[u.r0], eax
  3398                              <1> 		; mov u.nread,*u.r0 / put no. of bytes transferred
  3399                              <1> 				  ; / into (u.r0)
  3400 00003E58 E995FCFFFF          <1> 	jmp	sysret
  3401                              <1>         	; br sysret1
  3402                              <1> 
  3403                              <1> rw3: 
  3404                              <1> 	; 13/05/2015
  3405 00003E5D C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  3405 00003E65 0000                <1>
  3406                              <1> 	;stc
  3407                              <1> 	;retn
  3408                              <1> 	; 24/12/2021 (BugFix)
  3409                              <1> sysread_err:
  3410                              <1> syswrite_err:
  3411 00003E67 E966FCFFFF          <1> 	jmp	error
  3412                              <1> 
  3413                              <1> rw1:	
  3414                              <1> 	; 14/05/2015
  3415                              <1> 	; 13/05/2015
  3416                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3417                              <1> 	; 23/05/2013 - 24/05/2013 (Retro UNIX 8086 v1)
  3418                              <1> 	; System call registers: bx, cx, dx (through 'sysenter')
  3419                              <1> 	;
  3420                              <1> 	;mov	[u.base], ecx 	; buffer address/offset 
  3421                              <1> 				;(in the user's virtual memory space)
  3422                              <1> 	;mov	[u.count], edx 
  3423                              <1> 		; jsr r0,arg; u.base / get buffer pointer
  3424                              <1>         	; jsr r0,arg; u.count / get no. of characters
  3425                              <1> 	;;mov	eax, ebx ; file descriptor
  3426                              <1> 		; mov *u.r0,r1 / put file descriptor 
  3427                              <1> 		             ; / (index to u.fp table) in r1
  3428                              <1> 	; 13/05/2015
  3429 00003E6C C705[986E0000]0000- <1> 	mov	dword [u.r0], 0 ; r/w transfer count = 0 (reset)
  3429 00003E74 0000                <1>
  3430                              <1> 	;
  3431                              <1> 	;; call	getf
  3432                              <1>         ; eBX = File descriptor
  3433 00003E76 E8240B0000          <1> 	call	getf1 ; calling point in 'getf' from 'rw1'
  3434                              <1> 		; jsr r0,getf / get i-number of the file in r1
  3435                              <1> 	; AX = I-number of the file ; negative i-number means write
  3436                              <1> 	; 13/05/2015
  3437 00003E7B 6683F801            <1> 	cmp 	ax, 1
  3438 00003E7F 7217                <1> 	jb	short rw2
  3439                              <1> 	;
  3440 00003E81 890D[B86E0000]      <1> 	mov	[u.base], ecx 	; buffer address/offset 
  3441                              <1> 				;(in the user's virtual memory space)
  3442 00003E87 8915[BC6E0000]      <1> 	mov	[u.count], edx 
  3443                              <1> 	; 14/05/2015
  3444 00003E8D C705[ED6E0000]0000- <1>         mov     dword [u.error], 0 ; reset the last error code
  3444 00003E95 0000                <1>
  3445 00003E97 C3                  <1> 	retn
  3446                              <1>         	; rts r0
  3447                              <1> rw2:
  3448                              <1> 	; 13/05/2015
  3449 00003E98 C705[ED6E0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN ; file not open !
  3449 00003EA0 0000                <1>
  3450 00003EA2 C3                  <1> 	retn
  3451                              <1> 
  3452                              <1> sysopen: ;<open file>
  3453                              <1> 	; 09/01/2022
  3454                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3455                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3456                              <1> 	; 22/05/2013 - 27/05/2013 (Retro UNIX 8086 v1)
  3457                              <1> 	;
  3458                              <1> 	; 'sysopen' opens a file in following manner:
  3459                              <1> 	;    1) The second argument in a sysopen says whether to
  3460                              <1> 	;	open the file ro read (0) or write (>0).
  3461                              <1> 	;    2) I-node of the particular file is obtained via 'namei'.
  3462                              <1> 	;    3) The file is opened by 'iopen'.
  3463                              <1> 	;    4) Next housekeeping is performed on the fsp table
  3464                              <1> 	;	and the user's open file list - u.fp.
  3465                              <1> 	;	a) u.fp and fsp are scanned for the next available slot.
  3466                              <1> 	;	b) An entry for the file is created in the fsp table.
  3467                              <1> 	;	c) The number of this entry is put on u.fp list.
  3468                              <1> 	;	d) The file descriptor index to u.fp list is pointed
  3469                              <1> 	;	   to by u.r0.
  3470                              <1> 	;
  3471                              <1> 	; Calling sequence:
  3472                              <1> 	;	sysopen; name; mode
  3473                              <1> 	; Arguments:
  3474                              <1> 	;	name - file name or path name
  3475                              <1> 	;	mode - 0 to open for reading
  3476                              <1> 	;	       1 to open for writing
  3477                              <1> 	; Inputs: (arguments)
  3478                              <1> 	; Outputs: *u.r0 - index to u.fp list (the file descriptor)
  3479                              <1> 	;		  is put into r0's location on the stack.	
  3480                              <1> 	; ...............................................................
  3481                              <1> 	;				
  3482                              <1> 	; Retro UNIX 8086 v1 modification: 
  3483                              <1> 	;       'sysopen' system call has two arguments; so,
  3484                              <1> 	;	* 1st argument, name is pointed to by BX register
  3485                              <1> 	;	* 2nd argument, mode is in CX register
  3486                              <1> 	;
  3487                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3488                              <1> 	;	to the user with the file descriptor/number 
  3489                              <1> 	;	(index to u.fp list).
  3490                              <1> 	;
  3491                              <1> 	;call	arg2
  3492                              <1> 	; * name - 'u.namep' points to address of file/path name
  3493                              <1> 	;          in the user's program segment ('u.segmnt')
  3494                              <1> 	;          with offset in BX register (as sysopen argument 1).
  3495                              <1> 	; * mode - sysopen argument 2 is in CX register 
  3496                              <1> 	;          which is on top of stack.
  3497                              <1> 	;
  3498                              <1> 	; jsr r0,arg2 / get sys args into u.namep and on stack
  3499                              <1> 	;
  3500                              <1>        	; system call registers: ebx, ecx (through 'sysenter')
  3501                              <1> 
  3502 00003EA3 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  3503                              <1> 	; 24/12/2021 (cx -> ecx)
  3504 00003EA9 51                  <1> 	push	ecx ; * 
  3505 00003EAA E8210B0000          <1> 	call	namei
  3506                              <1> 		; jsr r0,namei / i-number of file in r1
  3507                              <1>      	;and	ax, ax
  3508                              <1> 	;jz	error ; File not found
  3509 00003EAF 7239                <1> 	jc	short fnotfound ; 14/05/2015
  3510                              <1> 	;jc	error ; 27/05/2013
  3511                              <1> 		; br  error2 / file not found
  3512                              <1>    	; 24/12/2021
  3513                              <1> 	;pop	edx ; * ; mode
  3514                              <1> 	;push	edx ; *
  3515 00003EB1 8B1424              <1> 	mov	edx, [esp] ; *
  3516                              <1> 	; edx = open mode (0 or 1)
  3517                              <1> 	;or	dx, dx
  3518 00003EB4 08D2                <1> 	or	dl, dl
  3519                              <1> 		; tst (sp) / is mode = 0 (2nd arg of call; 
  3520                              <1> 		         ; / 0 means, open for read)
  3521 00003EB6 7403                <1> 	jz	short sysopen_0
  3522                              <1> 		; beq 1f / yes, leave i-number positive
  3523                              <1> syscreat_0: ; 27/12/2015
  3524 00003EB8 66F7D8              <1> 	neg	ax
  3525                              <1>         	; neg r1 / open for writing so make i-number negative
  3526                              <1> sysopen_0: ;1:
  3527 00003EBB E8591A0000          <1> 	call	iopen
  3528                              <1> 		;jsr r0,iopen / open file whose i-number is in r1
  3529 00003EC0 5A                  <1> 	pop	edx ; * ; mode ; 24/12/2021
  3530                              <1> 	;and	dx, dx
  3531 00003EC1 20D2                <1> 	and	dl, dl
  3532                              <1>         	; tst (sp)+ / pop the stack and test the mode
  3533 00003EC3 7403                <1> 	jz	short sysopen_2
  3534                              <1>         	; beq op1 / is open for read op1
  3535                              <1> sysopen_1: ;op0:
  3536 00003EC5 66F7D8              <1> 	neg	ax
  3537                              <1>         	; neg r1 
  3538                              <1> 	;; NOTE: iopen always make i-number positive.
  3539                              <1> 	;; Here i-number becomes negative again. [22/05/2013]
  3540                              <1> sysopen_2: ;op1:
  3541 00003EC8 31F6                <1>         xor     esi, esi
  3542                              <1>         	; clr r2 / clear registers
  3543 00003ECA 31DB                <1>         xor     ebx, ebx
  3544                              <1> 		; clr r3
  3545                              <1> sysopen_3: ;1: / scan the list of entries in fsp table
  3546 00003ECC 389E[9E6E0000]      <1>         cmp     [esi+u.fp], bl ; 0
  3547                              <1> 		; tstb u.fp(r2) / test the entry in the u.fp list
  3548 00003ED2 7625                <1>         jna      short sysopen_4
  3549                              <1> 		; beq 1f / if byte in list is 0 branch
  3550 00003ED4 46                  <1>         inc     esi
  3551                              <1> 		; inc r2 / bump r2 so next byte can be checked
  3552 00003ED5 6683FE0A            <1>         cmp     si, 10  ; OPENFILES
  3553                              <1> 		; cmp r2,$10. / reached end of list?
  3554 00003ED9 72F1                <1> 	jb	short sysopen_3
  3555                              <1> 		; blt 1b / no, go back
  3556                              <1> toomanyf:
  3557                              <1> 	; 14/05/2015
  3558 00003EDB C705[ED6E0000]0D00- <1> 	mov	dword [u.error], ERR_TOO_MANY_FILES ; too many open files !
  3558 00003EE3 0000                <1>
  3559 00003EE5 E9E8FBFFFF          <1> 	jmp	error
  3560                              <1>         	; br error2 / yes, error (no files open)
  3561                              <1> fnotfound: 
  3562                              <1> 	; 14/05/2015
  3563 00003EEA C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; file not found !
  3563 00003EF2 0000                <1>
  3564 00003EF4 E9D9FBFFFF          <1> 	jmp	error
  3565                              <1> 
  3566                              <1> sysopen_4: ; 1:
  3567 00003EF9 6683BB[686C0000]00  <1>         cmp     word [ebx+fsp], 0
  3568                              <1> 		; tst fsp(r3) / scan fsp entries
  3569 00003F01 760D                <1>         jna     short sysopen_5
  3570                              <1> 		; beq 1f / if 0 branch
  3571                              <1> 	; 14/05/2015 - Retro UNIX 386 v1 modification !
  3572 00003F03 6683C30A            <1>         add     bx, 10 ; fsp structure size = 10 bytes/entry
  3573                              <1> 		; add $8.,r3 / add 8 to r3 
  3574                              <1> 			; / to bump it to next entry mfsp table
  3575 00003F07 6681FBF401          <1>         cmp     bx, nfiles*10
  3576                              <1> 		; cmp r3,$[nfiles*8.] / done scanning
  3577 00003F0C 72EB                <1> 	jb	short sysopen_4
  3578                              <1>        		; blt 1b / no, back
  3579                              <1> 	;jmp	error
  3580                              <1>         ;	; br error2 / yes, error
  3581                              <1> 	; 24/12/2021
  3582 00003F0E EBCB                <1> 	jmp	short toomanyf
  3583                              <1> 
  3584                              <1> sysopen_5: ; 1: / r2 has index to u.fp list; r3, has index to fsp table
  3585 00003F10 668983[686C0000]    <1>         mov     [ebx+fsp], ax
  3586                              <1> 		; mov r1,fsp(r3) / put i-number of open file 
  3587                              <1> 			; / into next available entry in fsp table,
  3588                              <1> 	; 09/01/2022
  3589                              <1> 	;mov	di, [cdev] ; word ? byte ?
  3590                              <1>         ;mov	[ebx+fsp+2], di ; device number
  3591                              <1> 		; mov cdev,fsp+2(r3) / put # of device in next word
  3592                              <1> 	;xor	edi, edi
  3593                              <1>         ;mov	[ebx+fsp+4], edi ; offset pointer (0)
  3594                              <1> 	;	; clr fsp+4(r3)
  3595                              <1>         ;mov	[ebx+fsp+8], di ; open count (0), deleted flag (0)
  3596                              <1>        	;	; clr fsp+6(r3) / clear the next two words
  3597 00003F17 31C0                <1> 	xor	eax, eax
  3598 00003F19 8983[6C6C0000]      <1> 	mov	[ebx+fsp+4], eax ; offset pointer (0)
  3599 00003F1F 668983[706C0000]    <1> 	mov	[ebx+fsp+8], ax ; open count (0), deleted flag (0)
  3600                              <1> 
  3601 00003F26 A0[7F6E0000]        <1> 	mov	al, [cdev]
  3602 00003F2B 668983[6A6C0000]    <1> 	mov	[ebx+fsp+2], ax ; device number
  3603                              <1> 
  3604 00003F32 89D8                <1>   	mov	eax, ebx
  3605 00003F34 B30A                <1> 	mov	bl, 10
  3606 00003F36 F6F3                <1> 	div	bl 
  3607                              <1> 		; asr r3
  3608                              <1> 		; asr r3 / divide by 8 
  3609                              <1> 		; asr r3 ; / to get number of the fsp entry-1
  3610 00003F38 FEC0                <1> 	inc	al
  3611                              <1>         	; inc r3 / add 1 to get fsp entry number
  3612 00003F3A 8886[9E6E0000]      <1>         mov     [esi+u.fp], al
  3613                              <1> 		; movb r3,u.fp(r2) / move entry number into 
  3614                              <1> 			; / next available slot in u.fp list
  3615 00003F40 8935[986E0000]      <1>         mov     [u.r0], esi
  3616                              <1> 		; mov r2,*u.r0 / move index to u.fp list 
  3617                              <1> 			     ; / into r0 loc on stack
  3618 00003F46 E9A7FBFFFF          <1>         jmp	sysret
  3619                              <1> 		; br sysret2
  3620                              <1> 
  3621                              <1> 	;
  3622                              <1> 	; 'fsp' table (10 bytes/entry)
  3623                              <1> 	; bit 15				   bit 0
  3624                              <1> 	; ---|-------------------------------------------
  3625                              <1> 	; r/w|		i-number of open file
  3626                              <1> 	; ---|-------------------------------------------
  3627                              <1> 	;		   device number
  3628                              <1> 	; -----------------------------------------------
  3629                              <1> 	; offset pointer, r/w pointer to file (bit 0-15)
  3630                              <1> 	; -----------------------------------------------
  3631                              <1> 	; offset pointer, r/w pointer to file (bit 16-31)
  3632                              <1> 	; ----------------------|------------------------
  3633                              <1> 	;  flag that says file 	| number of processes
  3634                              <1> 	;   has been deleted	| that have file open 
  3635                              <1> 	; ----------------------|------------------------
  3636                              <1> 	;
  3637                              <1> 
  3638                              <1> syscreat: ; < create file >
  3639                              <1> 	; 24/12/2021
  3640                              <1> 	; 27/12/2015 (Retro UNIX 386 v1.1)
  3641                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3642                              <1> 	; 27/05/2013 (Retro UNIX 8086 v1)
  3643                              <1> 	;
  3644                              <1> 	; 'syscreat' called with two arguments; name and mode.
  3645                              <1> 	; u.namep points to name of the file and mode is put
  3646                              <1> 	; on the stack. 'namei' is called to get i-number of the file.		
  3647                              <1> 	; If the file aready exists, it's mode and owner remain 
  3648                              <1> 	; unchanged, but it is truncated to zero length. If the file
  3649                              <1> 	; did not exist, an i-node is created with the new mode via
  3650                              <1> 	; 'maknod' whether or not the file already existed, it is
  3651                              <1> 	; open for writing. The fsp table is then searched for a free
  3652                              <1> 	; entry. When a free entry is found, proper data is placed
  3653                              <1> 	; in it and the number of this entry is put in the u.fp list.
  3654                              <1> 	; The index to the u.fp (also know as the file descriptor)
  3655                              <1> 	; is put in the user's r0. 			
  3656                              <1> 	;
  3657                              <1> 	; Calling sequence:
  3658                              <1> 	;	syscreate; name; mode
  3659                              <1> 	; Arguments:
  3660                              <1> 	;	name - name of the file to be created
  3661                              <1> 	;	mode - mode of the file to be created
  3662                              <1> 	; Inputs: (arguments)
  3663                              <1> 	; Outputs: *u.r0 - index to u.fp list 
  3664                              <1> 	;		   (the file descriptor of new file)
  3665                              <1> 	; ...............................................................
  3666                              <1> 	;				
  3667                              <1> 	; Retro UNIX 8086 v1 modification: 
  3668                              <1> 	;       'syscreate' system call has two arguments; so,
  3669                              <1> 	;	* 1st argument, name is pointed to by BX register
  3670                              <1> 	;	* 2nd argument, mode is in CX register
  3671                              <1> 	;
  3672                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3673                              <1> 	;	to the user with the file descriptor/number 
  3674                              <1> 	;	(index to u.fp list).
  3675                              <1> 	;
  3676                              <1> 	;call	arg2
  3677                              <1> 	; * name - 'u.namep' points to address of file/path name
  3678                              <1> 	;          in the user's program segment ('u.segmnt')
  3679                              <1> 	;          with offset in BX register (as sysopen argument 1).
  3680                              <1> 	; * mode - sysopen argument 2 is in CX register 
  3681                              <1> 	;          which is on top of stack.
  3682                              <1> 	;
  3683                              <1>         	; jsr r0,arg2 / put file name in u.namep put mode 
  3684                              <1> 			    ; / on stack
  3685 00003F4B 891D[B06E0000]      <1> 	mov	[u.namep], ebx ; file name address
  3686                              <1> 	;push	cx ; mode
  3687                              <1> 	; 24/12/2021
  3688 00003F51 51                  <1> 	push	ecx ; cx = mode (permission flags)
  3689 00003F52 E8790A0000          <1> 	call 	namei        	
  3690                              <1> 		; jsr r0,namei / get the i-number
  3691                              <1>         ;and	ax, ax
  3692                              <1> 	;jz	short syscreat_2	       	
  3693 00003F57 721B                <1> 	jc	short syscreat_2
  3694                              <1> 		; br  2f / if file doesn't exist 2f
  3695                              <1> 	; 27/12/2015
  3696 00003F59 6683F829            <1> 	cmp	ax, 41 ; device inode ?
  3697                              <1>         ;jb	syscreat_0 ; yes
  3698                              <1> 	; 24/12/2021
  3699 00003F5D 7305                <1> 	jnb	short syscreat_1
  3700 00003F5F E954FFFFFF          <1> 	jmp	syscreat_0
  3701                              <1> syscreat_1:
  3702 00003F64 66F7D8              <1> 	neg 	ax
  3703                              <1>         	; neg r1 / if file already exists make i-number 
  3704                              <1> 		       ; / negative (open for writing)
  3705 00003F67 E8AD190000          <1> 	call	iopen
  3706                              <1>         	; jsr r0,iopen /
  3707 00003F6C E850130000          <1> 	call	itrunc
  3708                              <1>         	; jsr r0,itrunc / truncate to 0 length
  3709                              <1> 	;pop	cx ; pop mode (did not exist in original Unix v1 !?)
  3710                              <1> 	; 04/12/2021
  3711 00003F71 59                  <1> 	pop	ecx
  3712                              <1> 	; 08/01/2022
  3713 00003F72 EB0E                <1> 	jmp	short syscreat_3
  3714                              <1>         ;jmp	sysopen_1
  3715                              <1>         	; br op0
  3716                              <1> syscreat_2: ; 2: / file doesn't exist
  3717                              <1> 	;pop	ax
  3718                              <1>         ;	; mov (sp)+,r1 / put the mode in r1
  3719                              <1> 	; 24/12/2021
  3720 00003F74 58                  <1> 	pop	eax  ; ax = mode (permission flags)
  3721 00003F75 30E4                <1> 	xor	ah, ah	
  3722                              <1>         	; bic $!377,r1 / clear upper byte
  3723 00003F77 E8170D0000          <1> 	call 	maknod
  3724                              <1>         	; jsr r0,maknod / make an i-node for this file
  3725 00003F7C 66A1[CA6E0000]      <1> 	mov	ax, [u.dirbuf]
  3726                              <1>         	; mov u.dirbuf,r1 / put i-number 
  3727                              <1> 			        ; / for this new file in r1
  3728                              <1> syscreat_3:
  3729 00003F82 E93EFFFFFF          <1>         jmp     sysopen_1
  3730                              <1>         	; br op0 / open the file
  3731                              <1> 
  3732                              <1> sysmkdir: ; < make directory >
  3733                              <1> 	; 26/02/2022
  3734                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3735                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3736                              <1> 	; 27/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  3737                              <1> 	;
  3738                              <1> 	; 'sysmkdir' creates an empty directory whose name is
  3739                              <1> 	; pointed to by arg 1. The mode of the directory is arg 2.	
  3740                              <1> 	; The special entries '.' and '..' are not present.
  3741                              <1> 	; Errors are indicated if the directory already exists or		
  3742                              <1> 	; user is not the super user. 
  3743                              <1> 	;
  3744                              <1> 	; Calling sequence:
  3745                              <1> 	;	sysmkdir; name; mode
  3746                              <1> 	; Arguments:
  3747                              <1> 	;	name - points to the name of the directory
  3748                              <1> 	;	mode - mode of the directory
  3749                              <1> 	; Inputs: (arguments)
  3750                              <1> 	; Outputs: -
  3751                              <1> 	;    (sets 'directory' flag to 1; 
  3752                              <1> 	;    'set user id on execution' and 'executable' flags to 0)
  3753                              <1> 	; ...............................................................
  3754                              <1> 	;				
  3755                              <1> 	; Retro UNIX 8086 v1 modification: 
  3756                              <1> 	;       'sysmkdir' system call has two arguments; so,
  3757                              <1> 	;	* 1st argument, name is pointed to by BX register
  3758                              <1> 	;	* 2nd argument, mode is in CX register
  3759                              <1> 	;
  3760                              <1> 		
  3761                              <1> ; / make a directory
  3762                              <1> 
  3763                              <1> 	;call	arg2
  3764                              <1> 	; * name - 'u.namep' points to address of file/path name
  3765                              <1> 	;          in the user's program segment ('u.segmnt')
  3766                              <1> 	;          with offset in BX register (as sysopen argument 1).
  3767                              <1> 	; * mode - sysopen argument 2 is in CX register 
  3768                              <1> 	;          which is on top of stack.
  3769                              <1> 
  3770                              <1> 		; jsr r0,arg2 / put file name in u.namep put mode 
  3771                              <1> 			    ; / on stack
  3772 00003F87 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  3773                              <1> 	;push	cx ; mode
  3774                              <1> 	; 24/12/2021
  3775 00003F8D 51                  <1> 	push	ecx ; cx = mode
  3776 00003F8E E83D0A0000          <1> 	call	namei
  3777                              <1>         	; jsr r0,namei / get the i-number
  3778                              <1>         	;     br .+4 / if file not found branch around error
  3779                              <1>         ;xor 	ax, ax
  3780                              <1> 	;jnz	error
  3781 00003F93 731B                <1> 	jnc	short dir_exists ; 14/05/2015
  3782                              <1> 	;jnc	error	
  3783                              <1> 		; br  error2 / directory already exists (error)
  3784 00003F95 803D[E46E0000]00    <1> 	cmp	byte [u.uid], 0 ; 02/08/2013
  3785                              <1>         	;tstb u.uid / is user the super user
  3786                              <1> 	;jna	short dir_access_err ; 14/05/2015
  3787                              <1> 	;;jna	error
  3788                              <1> 	; 26/02/2022 (BugFix)
  3789 00003F9C 7721                <1> 	ja	short dir_access_err
  3790                              <1>         	;bne error2 / no, not allowed
  3791                              <1> 	;pop	ax
  3792                              <1>         ;	;mov (sp)+,r1 / put the mode in r1
  3793                              <1> 	; 24/12/2021
  3794 00003F9E 58                  <1> 	pop	eax  ; ax = mode
  3795 00003F9F 6683E0CF            <1> 	and	ax, 0FFCFh ; 1111111111001111b
  3796                              <1>         	;bic $!317,r1 / all but su and ex
  3797                              <1> 	;or	ax, 4000h ; 1011111111111111b
  3798 00003FA3 80CC40              <1> 	or	ah, 40h ; Set bit 14 to 1
  3799                              <1>         	;bis $40000,r1 / directory flag
  3800 00003FA6 E8E80C0000          <1> 	call	maknod
  3801                              <1>         	;jsr r0,maknod / make the i-node for the directory
  3802                              <1> ;sysclose_sysret: ; 26/02/2022
  3803 00003FAB E942FBFFFF          <1> 	jmp	sysret
  3804                              <1>         	;br sysret2 /
  3805                              <1> dir_exists:
  3806                              <1> 	; 14/05/2015
  3807 00003FB0 C705[ED6E0000]0E00- <1> 	mov	dword [u.error], ERR_DIR_EXISTS ; dir. already exists !
  3807 00003FB8 0000                <1>
  3808 00003FBA E913FBFFFF          <1> 	jmp	error
  3809                              <1> dir_access_err:
  3810                              <1> 	; 14/05/2015
  3811 00003FBF C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_DIR_ACCESS ; permission denied !
  3811 00003FC7 0000                <1>
  3812 00003FC9 E904FBFFFF          <1> 	jmp	error
  3813                              <1> 
  3814                              <1> sysclose: ;<close file>
  3815                              <1> 	; 26/02/2022
  3816                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3817                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3818                              <1> 	; 22/05/2013 - 26/05/2013 (Retro UNIX 8086 v1)
  3819                              <1> 	;
  3820                              <1> 	; 'sysclose', given a file descriptor in 'u.r0', closes the
  3821                              <1> 	; associated file. The file descriptor (index to 'u.fp' list)
  3822                              <1> 	; is put in r1 and 'fclose' is called.
  3823                              <1> 	;
  3824                              <1> 	; Calling sequence:
  3825                              <1> 	;	sysclose
  3826                              <1> 	; Arguments:
  3827                              <1> 	;	-  
  3828                              <1> 	; Inputs: *u.r0 - file descriptor
  3829                              <1> 	; Outputs: -
  3830                              <1> 	; ...............................................................
  3831                              <1> 	;				
  3832                              <1> 	; Retro UNIX 8086 v1 modification:
  3833                              <1> 	;	 The user/application program puts file descriptor
  3834                              <1> 	;        in BX register as 'sysclose' system call argument.
  3835                              <1> 	; 	 (argument transfer method 1)
  3836                              <1> 
  3837                              <1> 	; / close the file
  3838                              <1> 	
  3839 00003FCE 89D8                <1> 	mov 	eax, ebx
  3840 00003FD0 E887090000          <1> 	call 	fclose
  3841                              <1> 		; mov *u.r0,r1 / move index to u.fp list into r1
  3842                              <1> 		; jsr r0,fclose / close the file
  3843                              <1>                	; br error2 / unknown file descriptor
  3844                              <1> 		; br sysret2
  3845                              <1> 	; 14/05/2015
  3846                              <1> 	;jnc	sysret
  3847                              <1> 	; 04/12/2021
  3848 00003FD5 7205                <1> 	jc	short sysclose_err
  3849 00003FD7 E916FBFFFF          <1> 	jmp	sysret
  3850                              <1> 	; 26/02/2022
  3851                              <1> 	;jnc	short sysclose_sysret
  3852                              <1> sysclose_err:
  3853 00003FDC C705[ED6E0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN ; file not open !
  3853 00003FE4 0000                <1>
  3854 00003FE6 E9E7FAFFFF          <1> 	jmp	error
  3855                              <1> 
  3856                              <1> sysemt:
  3857                              <1> 	; 26/02/2022
  3858                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3859                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3860                              <1> 	; 10/12/2013 - 20/04/2014 (Retro UNIX 8086 v1)
  3861                              <1> 	;
  3862                              <1> 	; Retro UNIX 8086 v1 modification: 
  3863                              <1> 	;	'Enable Multi Tasking'  system call instead 
  3864                              <1> 	;	of 'Emulator Trap' in original UNIX v1 for PDP-11.
  3865                              <1> 	;
  3866                              <1> 	; Retro UNIX 8086 v1 feature only!
  3867                              <1> 	;	Using purpose: Kernel will start without time-out
  3868                              <1> 	;	(internal clock/timer) functionality.
  3869                              <1> 	;	Then etc/init will enable clock/timer for
  3870                              <1> 	;	multi tasking. (Then it will not be disabled again
  3871                              <1> 	;	except hardware reset/restart.)
  3872                              <1> 	;
  3873                              <1> 
  3874 00003FEB 803D[E46E0000]00    <1> 	cmp	byte [u.uid], 0 ; root ?
  3875                              <1> 	;;ja	error
  3876                              <1> 	;ja	badsys ; 14/05/2015
  3877                              <1> 	; 24/12/2021
  3878 00003FF2 7605                <1> 	jna	short emt_0 
  3879 00003FF4 E98BFBFFFF          <1> 	jmp	badsys
  3880                              <1> emt_0:
  3881                              <1> 	; 24/12/2021
  3882                              <1> 	;cli
  3883 00003FF9 21DB                <1> 	and	ebx, ebx
  3884 00003FFB 7429                <1> 	jz	short emt_2
  3885                              <1> 	; Enable multi tasking -time sharing-
  3886 00003FFD B8[4C4F0000]        <1> 	mov	eax, clock
  3887                              <1> 	; 26/02/2022
  3888 00004002 BA[4C0A0000]        <1> 	mov	edx, rtci_default ; disable rtc (digital) printing
  3889                              <1> emt_1:
  3890 00004007 A3[11070000]        <1> 	mov	[x_timer], eax
  3891                              <1> 	; 26/02/2022 (Temporary)
  3892 0000400C 8915[15070000]      <1> 	mov	[x_rtci], edx
  3893 00004012 B306                <1> 	mov	bl, 6  ; timer interrupt page, video page 6
  3894 00004014 E851020000          <1> 	call	wttyc  ; clear video page
  3895 00004019 B307                <1> 	mov	bl, 7  ; rtc interrupt page, video page 7
  3896 0000401B E84A020000          <1> 	call	wttyc  ; clear video page
  3897                              <1> 	;
  3898 00004020 FB                  <1> 	sti
  3899 00004021 E9CCFAFFFF          <1> 	jmp	sysret
  3900                              <1> emt_2:
  3901                              <1> 	; Disable multi tasking -time sharing-
  3902 00004026 B8[1D070000]        <1> 	mov	eax, u_timer ; enable timer tick printing
  3903                              <1> 	; 26/02/2022
  3904 0000402B BA[530A0000]        <1> 	mov	edx, rtc_p   ; enable rtc (digital) printing
  3905                              <1> 	;
  3906 00004030 EBD5                <1> 	jmp	short emt_1
  3907                              <1> 
  3908                              <1> 	; Original UNIX v1 'sysemt' routine
  3909                              <1> ;sysemt:
  3910                              <1>         ;
  3911                              <1> 	;jsr    r0,arg; 30 / put the argument of the sysemt call 
  3912                              <1> 			 ; / in loc 30
  3913                              <1>         ;cmp    30,$core / was the argument a lower address 
  3914                              <1> 			; / than core
  3915                              <1>         ;blo    1f / yes, rtssym
  3916                              <1>         ;cmp    30,$ecore / no, was it higher than "core" 
  3917                              <1> 			; / and less than "ecore"
  3918                              <1>         ;blo    2f / yes, sysret2
  3919                              <1> ;1:
  3920                              <1>         ;mov    $rtssym,30
  3921                              <1> ;2:
  3922                              <1>         ;br     sysret2
  3923                              <1> 
  3924                              <1> sysilgins:
  3925                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3926                              <1> 	; 03/06/2013
  3927                              <1> 	; Retro UNIX 8086 v1 modification: 
  3928                              <1> 	;	not a valid system call ! (not in use)
  3929                              <1> 	;
  3930 00004032 E94DFBFFFF          <1> 	jmp	badsys
  3931                              <1> 	;jmp	error
  3932                              <1> 	;;jmp 	sysret
  3933                              <1> 
  3934                              <1> 	; Original UNIX v1 'sysemt' routine
  3935                              <1> ;sysilgins: / calculate proper illegal instruction trap address
  3936                              <1>         ;jsr    r0,arg; 10 / take address from sysilgins call
  3937                              <1> 			  ;/ put it in loc 8.,
  3938                              <1>         ;cmp    10,$core / making it the illegal instruction 
  3939                              <1> 		       ; / trap address
  3940                              <1>         ;blo    1f / is the address a user core address?  
  3941                              <1> 		; / yes, go to 2f
  3942                              <1>         ;cmp    10,$ecore
  3943                              <1>         ;blo    2f
  3944                              <1> ;1:
  3945                              <1>         ;mov    $fpsym,10 / no, make 'fpsum' the illegal 
  3946                              <1> 		    ; / instruction trap address for the system
  3947                              <1> ;2:
  3948                              <1>         ;br     sysret2 / return to the caller via 'sysret'
  3949                              <1> 
  3950                              <1> sysmdate: ; < change the modification time of a file >
  3951                              <1> 	; 23/02/2022 (Retro UNIX 386 v1 feature/modification)
  3952                              <1> 	;	(ECX input)
  3953                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3954                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  3955                              <1> 	; 03/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  3956                              <1> 	;
  3957                              <1> 	; 'sysmdate' is given a file name. It gets inode of this 
  3958                              <1> 	; file into core. The user is checked if he is the owner 
  3959                              <1> 	; or super user. If he is neither an error occurs.
  3960                              <1> 	; 'setimod' is then called to set the i-node modification
  3961                              <1> 	; byte and the modification time, but the modification time
  3962                              <1> 	; is overwritten by whatever get put on the stack during
  3963                              <1> 	; a 'systime' system call. This calls are restricted to
  3964                              <1> 	; the super user.		
  3965                              <1> 	;
  3966                              <1> 	; Calling sequence:
  3967                              <1> 	;	sysmdate; name
  3968                              <1> 	; Arguments:
  3969                              <1> 	;	name - points to the name of file
  3970                              <1> 	; Inputs: (arguments)
  3971                              <1> 	; Outputs: -
  3972                              <1> 	; ...............................................................
  3973                              <1> 	;				
  3974                              <1> 	; Retro UNIX 8086 v1 modification: 
  3975                              <1> 	;	 The user/application program puts address 
  3976                              <1> 	;	 of the file name in BX register 
  3977                              <1> 	;	 as 'sysmdate' system call argument.
  3978                              <1> 	;
  3979                              <1> ; / change the modification time of a file
  3980                              <1> 		; jsr r0,arg; u.namep / point u.namep to the file name
  3981 00004037 891D[B06E0000]      <1>         mov	[u.namep], ebx
  3982                              <1> 	; 23/02/2022 - (Retro UNIX 386 v1 modification on unix v1 code)
  3983 0000403D 890D[206B0000]      <1> 	mov	[p_time], ecx ; save new modification time to be set 
  3984 00004043 E888090000          <1> 	call	namei
  3985                              <1> 		; jsr r0,namei / get its i-number
  3986                              <1> 	;;jc	error       
  3987                              <1> 	;	; br error2 / no, such file
  3988                              <1> 	;jc	fnotfound ; file not found !
  3989                              <1> 	; 24/12/2021
  3990 00004048 7305                <1> 	jnc	short mdate_0
  3991 0000404A E99BFEFFFF          <1> 	jmp	fnotfound
  3992                              <1> mdate_0:
  3993 0000404F E841110000          <1> 	call	iget
  3994                              <1> 		; jsr r0,iget / get i-node into core
  3995 00004054 A0[E46E0000]        <1> 	mov	al, [u.uid]
  3996 00004059 3A05[9B6B0000]      <1> 	cmp	al, [i.uid]
  3997                              <1>         	; cmpb u.uid,i.uid / is user same as owner
  3998 0000405F 7413                <1> 	je	short mdate_1
  3999                              <1>         	; beq 1f / yes
  4000 00004061 20C0                <1> 	and	al, al
  4001                              <1> 		; tstb u.uid / no, is user the super user
  4002                              <1> 	;jnz	error
  4003                              <1> 		; bne error2 / no, error
  4004 00004063 740F                <1> 	jz	short mdate_1
  4005 00004065 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  4005 0000406D 0000                <1>
  4006                              <1> sysstty_err:	; 04/02/2022
  4007 0000406F E95EFAFFFF          <1> 	jmp	error
  4008                              <1> mdate_1: ;1:
  4009 00004074 E826120000          <1> 	call	setimod
  4010                              <1>         	; jsr r0,setimod / fill in modification data,
  4011                              <1> 		               ; / time etc.
  4012 00004079 BE[206B0000]        <1> 	mov	esi, p_time
  4013 0000407E BF[B26B0000]        <1> 	mov	edi, i.mtim
  4014 00004083 A5                  <1> 	movsd
  4015                              <1> 		; mov 4(sp),i.mtim / move present time to
  4016                              <1>         	; mov 2(sp),i.mtim+2 / modification time
  4017 00004084 E969FAFFFF          <1>         jmp	sysret
  4018                              <1> 		; br sysret2
  4019                              <1> 
  4020                              <1> 	; 04/02/2022
  4021                              <1> sysstty_err_s:
  4022 00004089 880D[986E0000]      <1> 	mov	byte [u.r0], cl ; serial port's tty number
  4023 0000408F EBDE                <1> 	jmp	short sysstty_err
  4024                              <1> 
  4025                              <1> sysstty: ; < set tty status and mode >
  4026                              <1> 	; 26/02/2022
  4027                              <1> 	; 04/02/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  4028                              <1> 	; 02/02/2022 (Retro UNIX 386 v1, Kernel v0.2.0.18)
  4029                              <1> 	; 01/02/2022 (Retro UNIX 386 v1) -clear screen-
  4030                              <1> 	; 17/11/2015
  4031                              <1> 	; 12/11/2015
  4032                              <1> 	; 29/10/2015
  4033                              <1> 	; 17/10/2015
  4034                              <1> 	; 13/10/2015
  4035                              <1> 	; 29/06/2015
  4036                              <1> 	; 27/06/2015 (Retro UNIX 386 v1 - Beginning)
  4037                              <1> 	; 02/06/2013 - 12/07/2014 (Retro UNIX 8086 v1)
  4038                              <1> 	;
  4039                              <1> 	; 'sysstty' sets the status and mode of the typewriter 
  4040                              <1> 	; whose file descriptor is in (u.r0).
  4041                              <1> 	;
  4042                              <1> 	; Calling sequence:
  4043                              <1> 	;	sysstty; arg
  4044                              <1> 	; Arguments:
  4045                              <1> 	;	arg - address of 3 consequitive words that contain
  4046                              <1> 	;	      the source of status data	
  4047                              <1> 	; Inputs: ((*u.r0 - file descriptor & argument))
  4048                              <1> 	; Outputs: ((status in address which is pointed to by arg))
  4049                              <1> 	; ...............................................................
  4050                              <1> 	;	
  4051                              <1> 	; Retro UNIX 8086 v1 modification: 
  4052                              <1> 	;	'sysstty' system call will set the tty
  4053                              <1> 	;	(clear keyboard buffer and set cursor position)
  4054                              <1> 	;	 in following manner:
  4055                              <1> 	;   NOTE: All of tty setting functions are here (16/01/2014)
  4056                              <1> 	;
  4057                              <1> 	; Inputs:
  4058                              <1> 	;	BX = 0 --> means
  4059                              <1> 	;	   If CL = FFh (& DX <> 0FFFFh) ; 01/02/2022
  4060                              <1> 	;	      set cursor position for console tty, only 
  4061                              <1> 	;	      CH will be ignored (char. will not be written)	
  4062                              <1> 	;	   If CH = 0 (& DX <> 0FFFFh & CL < FFh) ; 01/02/20222
  4063                              <1> 	;	      set console tty for (current) process
  4064                              <1> 	;	      CL = tty number (0 to 9)
  4065                              <1> 	;	      (If CH = 0, character will not be written)			
  4066                              <1> 	;          If CH > 0 (CL < FFh)	
  4067                              <1> 	;             CL = tty number (0 to 9)
  4068                              <1> 	;	      CH = character will be written
  4069                              <1> 	;	        at requested cursor position (in DX)	
  4070                              <1> 	;	   DX = cursor position for tty number 0 to 7.	
  4071                              <1>   	;		(only tty number 0 to 7) 
  4072                              <1> 	;          DL = communication parameters (for serial ports) 
  4073                              <1> 	;	        (only for COM1 and COM2 serial ports)
  4074                              <1> 	;	   DH < 0FFh -> DL is valid, initialize serial port
  4075                              <1> 	;			or set cursor position	
  4076                              <1> 	;	   DH = 0FFh -> DL is not valid
  4077                              <1> 	;		do not set serial port parameters 
  4078                              <1> 	;		or do not set cursor position
  4079                              <1> 	;
  4080                              <1> 	;	BX > 0 --> points to name of tty
  4081                              <1> 	;    	   CH > 0 -->
  4082                              <1> 	;		CH = character will be written in current 
  4083                              <1> 	;            	cursor position (for tty number from 0 to 7)
  4084                              <1> 	;	     	or character will be sent to serial port
  4085                              <1> 	;	     	(for tty number 8 or 9)
  4086                              <1> 	;		CL = color of the character if tty number < 8.
  4087                              <1> 	;    	   CH = 0 --> Do not write a character, 
  4088                              <1> 	;		set mode (tty 8 to 9) or 
  4089                              <1> 	;		set current cursor positions (tty 0 to 7) only.
  4090                              <1> 	;   	   DX = cursor position for tty number 0 to 7.
  4091                              <1> 	;    	   DH = FFh --> Do not set cursor pos (or comm. params.)
  4092                              <1> 	;		(DL is not valid)
  4093                              <1> 	;	   DL = communication parameters 
  4094                              <1> 	;		for tty number 8 or 9 (COM1 or COM2).
  4095                              <1> 	;
  4096                              <1> 	;	01/02/2022 - Retro UNIX 386 v1 - 2022 modification
  4097                              <1> 	;	(30/01/2022 - Retro UNIX 8086 - 2022 modification)
  4098                              <1> 	;	If CH = 0 & DX = 0FFFFh -> 
  4099                              <1> 	;	   clear screen (video page) & set cursor pos to 0,0.
  4100                              <1> 	;	   (for tty number 0 to 7, CL <= 7)
  4101                              <1> 	;	   (if CL = 0FFh -> clear console tty)	
  4102                              <1> 	;
  4103                              <1> 	; Outputs:
  4104                              <1> 	;	cf = 0 -> OK
  4105                              <1> 	;	     AL = tty number (0 to 9)
  4106                              <1> 	;	     AH = line status if tty number is 8 or 9
  4107                              <1> 	;	     AH = process number (of the caller) 	
  4108                              <1> 	;	cf = 1 means error (requested tty is not ready)
  4109                              <1> 	;	     AH = FFh if the tty is locked 
  4110                              <1> 	;		  (owned by another process)
  4111                              <1> 	;	        = process number (of the caller) 
  4112                              <1> 	;		  (if < FFh and tty number < 8)
  4113                              <1> 	;	     AL = tty number (0FFh if it does not exist)
  4114                              <1> 	;	     AH = line status if tty number is 8 or 9
  4115                              <1> 	;	NOTE: Video page will be cleared if cf = 0.
  4116                              <1> 	;	
  4117                              <1> 
  4118                              <1> 	; 27/06/2015 (32 bit modifications)
  4119                              <1> 	; 14/01/2014
  4120 00004091 31C0                <1> 	xor 	eax, eax
  4121 00004093 6648                <1> 	dec	ax ; 17/10/2015
  4122 00004095 A3[986E0000]        <1> 	mov	[u.r0], eax ; 0FFFFh
  4123                              <1> 	;;;
  4124                              <1> 	; 01/02/2022
  4125 0000409A FEC1                <1> 	inc	cl  ; 0FFh -> 0, 7 -> 8
  4126 0000409C 39C2                <1> 	cmp	edx, eax
  4127                              <1> 	;cmp	dx, ax ; 0FFFFh
  4128 0000409E 7521                <1> 	jne	short sysstty_18
  4129                              <1> 	; clear video page
  4130                              <1> 	; (CH must be 0)
  4131 000040A0 08ED                <1> 	or	ch, ch
  4132 000040A2 75CB                <1> 	jnz	short sysstty_err ; invalid parameters
  4133 000040A4 80F908              <1> 	cmp	cl, 8 ; > tty7 (serial port?)
  4134 000040A7 77C6                <1> 	ja	short sysstty_err ; invalid parameters
  4135 000040A9 20C9                <1> 	and	cl, cl
  4136 000040AB 7514                <1> 	jnz	short sysstty_18 ; actual tty (video page) num + 1
  4137 000040AD 0FB635[E76E0000]    <1> 	movzx	esi, byte [u.uno]
  4138 000040B4 8A8E[F76B0000]      <1> 	mov	cl, byte [esi+p.ttyc-1] ; current/console tty
  4139 000040BA 80F907              <1> 	cmp	cl, 7
  4140 000040BD 77CA                <1> 	ja	short sysstty_err_s ; serial port !	 
  4141                              <1> 	; here CL contains (actual) tty number (tty0 to tty7) 
  4142 000040BF FEC1                <1> 	inc	cl  ; 0 -> 1, 7 -> 8 
  4143                              <1> sysstty_18:
  4144 000040C1 FEC9                <1> 	dec	cl  ; 8 -> 7, 1 -> 0
  4145                              <1> 	; cl = video page (tty) number		
  4146                              <1> 	;;;
  4147 000040C3 21DB                <1> 	and	ebx, ebx
  4148                              <1> 	;jnz	sysstty_6
  4149                              <1> 	; 01/02/2022
  4150 000040C5 7405                <1> 	jz	short sysstty_19
  4151 000040C7 E9C2000000          <1> 	jmp	sysstty_6
  4152                              <1> sysstty_19:
  4153                              <1> 	; set console tty
  4154                              <1> 	; 29/10/2015
  4155                              <1> 	; 17/01/2014 
  4156 000040CC 80F909              <1> 	cmp	cl, 9
  4157 000040CF 7613                <1> 	jna	short sysstty_0
  4158                              <1> 	; 17/11/2015
  4159 000040D1 80F9FF              <1> 	cmp	cl, 0FFh
  4160 000040D4 7202                <1> 	jb	short sysstty_13
  4161 000040D6 88CD                <1> 	mov	ch, cl ; force CH value to FFh 
  4162                              <1> sysstty_13:
  4163 000040D8 8A1D[E76E0000]      <1> 	mov	bl, [u.uno] ; process number
  4164 000040DE 8A8B[F76B0000]      <1> 	mov	cl, [ebx+p.ttyc-1] ; current/console tty
  4165                              <1> sysstty_0:
  4166                              <1> 	; 29/06/2015
  4167                              <1> 	;push	dx
  4168                              <1> 	;push	cx
  4169                              <1> 	; 01/02/2022
  4170 000040E4 52                  <1> 	push	edx
  4171 000040E5 51                  <1> 	push	ecx
  4172 000040E6 30D2                <1> 	xor 	dl, dl	; sysstty call sign
  4173 000040E8 88C8                <1> 	mov	al, cl
  4174 000040EA A2[986E0000]        <1> 	mov	[u.r0], al ; tty number (0 to 9)
  4175 000040EF E8BF180000          <1> 	call	ottyp
  4176                              <1> 	; 01/02/2022
  4177 000040F4 59                  <1> 	pop	ecx
  4178 000040F5 5A                  <1> 	pop	edx
  4179                              <1> 	;pop	cx
  4180                              <1> 	;pop	dx
  4181                              <1> 	;
  4182 000040F6 7220                <1> 	jc	short sysstty_pd_err
  4183                              <1> 	;
  4184                              <1> 	; 26/02/2022 (Bug! BugFix)
  4185                              <1> 	; (ebx = ?, modified in ottyp, it may be > 255)
  4186                              <1> 	;
  4187 000040F8 80F908              <1> 	cmp	cl, 8
  4188 000040FB 720C                <1> 	jb	short sysstty_2
  4189                              <1> 	;
  4190 000040FD 80FEFF              <1> 	cmp	dh, 0FFh
  4191 00004100 7407                <1> 	je	short sysstty_2
  4192                              <1> 		; set communication parameters for serial ports
  4193                              <1> 
  4194                              <1> ; 01/02/2022
  4195                              <1> ;	; 29/10/2015
  4196                              <1> ;	mov	ah, dl ; communication parameters
  4197                              <1> ;		; ah = 0E3h = 11100011b = 115200 baud,
  4198                              <1> ;		;			 THRE int + RDA int 
  4199                              <1> ;		; ah = 23h = 00100011b = 9600 baud,
  4200                              <1> ;		;			 THRE int + RDA int 
  4201                              <1> ;	sub	al, al ; 0
  4202                              <1> ;	; 12/07/2014
  4203                              <1> ;	cmp	cl, 9
  4204                              <1> ;	jb	short sysstty_1
  4205                              <1> ;	inc	al
  4206                              <1> ;sysstty_1:
  4207                              <1> ;	; 01/02/2022
  4208                              <1> ;	push	ecx
  4209                              <1> ;	;push	cx
  4210                              <1> ;	; 29/06/2015	
  4211                              <1> ;	call 	sp_setp ; Set serial port communication parameters
  4212                              <1> ;	mov	[u.r0+1], cx ; Line status (ah)
  4213                              <1> ;			     ; Modem status (EAX bits 16 to 23)
  4214                              <1> ;	; 01/02/2022
  4215                              <1> ;	pop	ecx	
  4216                              <1> ;	;pop	cx
  4217                              <1> ;       jc      short sysstty_tmout_err ; 29/10/2015
  4218                              <1> 
  4219                              <1> 	; 01/02/2022
  4220 00004102 E830010000          <1> 	call	sysstty_scp
  4221 00004107 7276                <1>         jc      short sysstty_tmout_err ; 29/10/2015
  4222                              <1> 
  4223                              <1> sysstty_2:
  4224                              <1> 	; 17/01/2014
  4225 00004109 20ED                <1> 	and	ch, ch 	; set cursor position 
  4226                              <1> 			; or comm. parameters ONLY
  4227 0000410B 7527                <1> 	jnz	short sysstty_3
  4228                              <1> 	; 01/02/2022
  4229 0000410D 6683FAFF            <1> 	cmp	dx, 0FFFFh
  4230 00004111 7214                <1> 	jb	short sysstty_20
  4231                              <1> 	; clear screen (video page)
  4232 00004113 E93B010000          <1> 	jmp	sysstty_14
  4233                              <1> 
  4234                              <1> sysstty_pd_err: ; 29/06/2015
  4235                              <1> 	; 'permission denied !' error
  4236 00004118 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_OWNER
  4236 00004120 0000                <1>
  4237 00004122 E9ABF9FFFF          <1> 	jmp	error
  4238                              <1> 
  4239                              <1> sysstty_20:
  4240 00004127 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  4241 0000412E 888B[F76B0000]      <1> 	mov	[ebx+p.ttyc-1], cl ; console tty
  4242                              <1> sysstty_3:
  4243                              <1> 	; 16/01/2014
  4244 00004134 88E8                <1> 	mov	al, ch ; character ; 0 to FFh
  4245                              <1> 	; 17/11/2015
  4246 00004136 B507                <1> 	mov 	ch, 7  ; Default color (light gray)
  4247 00004138 38E9                <1> 	cmp	cl, ch ; 7 (tty number)
  4248                              <1> 	;jna	sysstty_9
  4249                              <1> 	; 01/02/2022
  4250 0000413A 7705                <1> 	ja	short sysstty_12
  4251 0000413C E9C5000000          <1> 	jmp	sysstty_9
  4252                              <1> 
  4253                              <1> sysstty_12:
  4254                              <1> 	;; BX = 0, CL = 8 or CL = 9
  4255                              <1> 	; (Set specified serial port as console tty port)
  4256                              <1> 	; CH = character to be written
  4257                              <1> 	; 15/04/2014
  4258                              <1> 	; CH = 0 --> initialization only
  4259                              <1> 	; AL = character
  4260                              <1> 	; 26/06/2014
  4261 00004141 880D[EC6E0000]      <1> 	mov	[u.ttyn], cl
  4262                              <1> 	; 12/07/2014
  4263 00004147 88CC                <1> 	mov	ah, cl ; tty number (8 or 9)
  4264                              <1> 	; 02/02/2022
  4265 00004149 FEC0                <1> 	inc	al  ; 0FFh -> 0, 0 -> 1
  4266 0000414B 740B                <1> 	jz	short sysstty_4 ; al = ch = 0	
  4267 0000414D FEC8                <1> 	dec	al  ; 1 -> 0	
  4268                              <1> 	;and	al, al
  4269 0000414F 7407                <1> 	jz	short sysstty_4 ; al = ch = 0
  4270                              <1>  	; 04/07/2014
  4271 00004151 E8991E0000          <1> 	call 	sndc
  4272                              <1> 	; 12/07/2014
  4273 00004156 EB0C                <1> 	jmp	short sysstty_5
  4274                              <1> 
  4275                              <1> sysstty_4:
  4276                              <1> 	; 12/07/2014
  4277                              <1> 	;xchg 	ah, al ; al = 0 -> al = ah, ah = 0
  4278 00004158 88E0                <1> 	mov	al, ah ; 29/06/2015
  4279 0000415A 2C08                <1> 	sub	al, 8
  4280                              <1> 	; 27/06/2015
  4281 0000415C E819F4FFFF          <1> 	call	sp_status ; get serial port status
  4282                              <1> 	; AL = Line status, AH = Modem status
  4283                              <1> 	; 12/11/2015
  4284 00004161 3C80                <1> 	cmp	al, 80h
  4285 00004163 F5                  <1> 	cmc
  4286                              <1> sysstty_5:
  4287 00004164 66A3[996E0000]      <1> 	mov	[u.r0+1], ax ; ah = line status
  4288                              <1> 		; EAX bits 16-23 = modem status	
  4289 0000416A 9C                  <1> 	pushf
  4290 0000416B 30D2                <1> 	xor	dl, dl ; sysstty call sign
  4291 0000416D A0[EC6E0000]        <1> 	mov	al, [u.ttyn] ; 26/06/2014
  4292 00004172 E85F190000          <1> 	call	cttyp
  4293 00004177 9D                  <1> 	popf
  4294                              <1> 	;jnc	sysret ; time out error 
  4295                              <1> 	; 01/02/2022
  4296 00004178 7205                <1> 	jc	short sysstty_tmout_err
  4297 0000417A E973F9FFFF          <1> 	jmp	sysret
  4298                              <1> 
  4299                              <1> sysstty_tmout_err:
  4300 0000417F C705[ED6E0000]1900- <1> 	mov	dword [u.error], ERR_TIME_OUT
  4300 00004187 0000                <1>
  4301 00004189 E944F9FFFF          <1> 	jmp	error
  4302                              <1> 
  4303                              <1> sysstty_6:
  4304                              <1> 	;push	dx
  4305                              <1> 	;push	cx
  4306                              <1> 	; 01/02/2022
  4307 0000418E 52                  <1> 	push	edx
  4308 0000418F 51                  <1> 	push	ecx
  4309 00004190 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  4310 00004196 E835080000          <1> 	call	namei
  4311                              <1> 	; 01/02/2022
  4312 0000419B 59                  <1> 	pop	ecx
  4313 0000419C 5A                  <1> 	pop	edx
  4314                              <1> 	;pop	cx
  4315                              <1> 	;pop	dx
  4316 0000419D 7258                <1> 	jc	short sysstty_inv_dn
  4317                              <1> 	;
  4318 0000419F 6683F813            <1> 	cmp	ax, 19  ; inode number of /dev/COM2
  4319 000041A3 7752                <1> 	ja	short sysstty_inv_dn ; 27/06/2015
  4320                              <1> 	;
  4321 000041A5 3C0A                <1> 	cmp	al, 10 ; /dev/tty0 .. /dev/tty7
  4322                              <1> 		       ; /dev/COM1, /dev/COM2
  4323 000041A7 7204                <1> 	jb	short sysstty_7
  4324 000041A9 2C0A                <1> 	sub	al, 10
  4325 000041AB EB11                <1> 	jmp	short sysstty_8
  4326                              <1> 
  4327                              <1> sysstty_7:
  4328 000041AD 3C01                <1> 	cmp	al, 1 ; /dev/tty
  4329 000041AF 7546                <1> 	jne	short sysstty_inv_dn ; 27/06/2015
  4330 000041B1 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  4331 000041B8 8A83[F76B0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; console tty
  4332                              <1> sysstty_8:
  4333                              <1> 	; 26/02/2022
  4334                              <1> 	; (ebx < 256)	
  4335 000041BE A2[986E0000]        <1> 	mov	[u.r0], al
  4336                              <1> 	; 01/02/2022
  4337                              <1> 	;push	dx
  4338                              <1> 	;push	ax
  4339                              <1> 	;push	cx
  4340 000041C3 52                  <1> 	push	edx
  4341 000041C4 50                  <1> 	push	eax
  4342 000041C5 51                  <1> 	push	ecx	
  4343 000041C6 E8E8170000          <1> 	call	ottyp
  4344 000041CB 59                  <1> 	pop	ecx
  4345 000041CC 58                  <1> 	pop	eax
  4346 000041CD 5A                  <1> 	pop	edx
  4347                              <1> 	;pop	cx
  4348                              <1> 	;pop	ax
  4349                              <1> 	;pop	dx
  4350                              <1>         ;jc	sysstty_pd_err ; 'permission denied !'
  4351                              <1> 	; 01/02/2022
  4352 000041CE 7305                <1> 	jnc	short sysstty_21
  4353 000041D0 E943FFFFFF          <1> 	jmp	sysstty_pd_err ; 'permission denied !'
  4354                              <1> sysstty_21:
  4355                              <1> 	; 29/10/2015
  4356 000041D5 86E9                <1> 	xchg 	ch, cl
  4357                              <1> 		; cl = character, ch = color code
  4358 000041D7 86C1                <1> 	xchg	al, cl
  4359                              <1> 		; al = character, cl = tty number
  4360 000041D9 80F907              <1> 	cmp	cl, 7
  4361                              <1> 	;ja	sysstty_12
  4362                              <1> 	; 01/02/2022
  4363 000041DC 7628                <1> 	jna	short sysstty_16
  4364                              <1> ;;
  4365 000041DE 80FEFF              <1> 	cmp	dh, 0FFh
  4366 000041E1 740B                <1> 	je	short sysstty_22 ; do not set comm. parameters
  4367                              <1> 
  4368                              <1> ; 01/02/2022
  4369                              <1> ;	; 29/10/2015
  4370                              <1> ;	mov	ah, dl ; communication parameters
  4371                              <1> ;		; ah = 0E3h = 11100011b = 115200 baud,
  4372                              <1> ;		;			 THRE int + RDA int 
  4373                              <1> ;		; ah = 23h = 00100011b = 9600 baud,
  4374                              <1> ;		;			 THRE int + RDA int 
  4375                              <1> ;	sub	al, al ; 0
  4376                              <1> ;	; 12/07/2014
  4377                              <1> ;	cmp	cl, 9
  4378                              <1> ;	jb	short sysstty_1
  4379                              <1> ;	inc	al
  4380                              <1> ;sysstty_1:
  4381                              <1> ;	; 01/02/2022
  4382                              <1> ;	push	ecx
  4383                              <1> ;	;push	cx
  4384                              <1> ;	; 29/06/2015	
  4385                              <1> ;	call 	sp_setp ; Set serial port communication parameters
  4386                              <1> ;	mov	[u.r0+1], cx ; Line status (ah)
  4387                              <1> ;			     ; Modem status (EAX bits 16 to 23)
  4388                              <1> ;	; 01/02/2022
  4389                              <1> ;	pop	ecx	
  4390                              <1> ;	;pop	cx
  4391                              <1> ;       jc      short sysstty_tmout_err ; 29/10/2015
  4392                              <1> 
  4393                              <1> 	; 02/02/2022
  4394 000041E3 88C5                <1> 	mov	ch, al ; save char
  4395                              <1> 	; 01/02/2022
  4396 000041E5 E84D000000          <1> 	call	sysstty_scp
  4397 000041EA 7293                <1>         jc      short sysstty_tmout_err ; 29/10/2015
  4398                              <1> 	; 02/02/2022
  4399 000041EC 88E8                <1> 	mov	al, ch ; restore char
  4400                              <1> sysstty_22:
  4401                              <1> 	; 01/02/2022
  4402 000041EE 08ED                <1> 	or	ch, ch
  4403 000041F0 7437                <1> 	jz	short sysstty_11 ; do not send char to terminal
  4404                              <1> 	; send char to (serial port) terminal
  4405                              <1> 	; al = character
  4406                              <1> 	; cl = tty number (8 or 9)
  4407 000041F2 E94AFFFFFF          <1> 	jmp	sysstty_12 ; (tty8 or tty9)
  4408                              <1> 
  4409                              <1> sysstty_inv_dn: 
  4410                              <1> 	; 27/06/2015
  4411                              <1> 	; Invalid device name (not a tty) ! error
  4412                              <1> 	; (Device is not a tty or device name not found)
  4413 000041F7 C705[ED6E0000]1800- <1> 	mov	dword [u.error], ERR_INV_DEV_NAME
  4413 000041FF 0000                <1>
  4414 00004201 E9CCF8FFFF          <1> 	jmp	error 
  4415                              <1> 
  4416                              <1> sysstty_16:
  4417                              <1> 	; 26/02/2022
  4418                              <1> 	; 16/01/2014
  4419                              <1> 	;xor	bh, bh
  4420                              <1> 	; 02/02/2022
  4421                              <1> sysstty_9: 	; tty 0 to tty 7
  4422                              <1> 	; al = character
  4423                              <1> 	; ch = color/attribute ; 01/02/2022
  4424                              <1> 	;
  4425                              <1> 	; 26/02/2022 (BugFix)
  4426                              <1> 	; (ebx may be > 255 here!? due to 'ottyp')
  4427 00004206 29DB                <1> 	sub	ebx, ebx ; *
  4428 00004208 80FEFF              <1> 	cmp	dh, 0FFh ; Do not set cursor position
  4429 0000420B 740B                <1> 	je	short sysstty_10
  4430                              <1> 	; 02/02/2022
  4431 0000420D 51                  <1> 	push	ecx
  4432 0000420E 50                  <1> 	push	eax
  4433                              <1> 	;push	cx
  4434                              <1> 	;push	ax	
  4435                              <1> 	;movzx	ebx, cl
  4436 0000420F 88CB                <1> 	mov	bl, cl ; (tty number = video page number)
  4437 00004211 E8BAD2FFFF          <1> 	call	set_cpos
  4438                              <1> 	;pop	ax
  4439                              <1> 	;pop	cx
  4440                              <1> 	; 02/02/2022
  4441 00004216 58                  <1> 	pop	eax
  4442 00004217 59                  <1> 	pop	ecx
  4443                              <1> sysstty_10: 
  4444                              <1> 	; 29/10/2015
  4445 00004218 08C0                <1> 	or	al, al ; character
  4446 0000421A 740D                <1> 	jz      short sysstty_11 ; al = 0
  4447                              <1> 	; 17/11/2015
  4448 0000421C 3CFF                <1> 	cmp	al, 0FFh
  4449 0000421E 7309                <1> 	jnb	short sysstty_11
  4450                              <1> 		; ch > 0 and ch < FFh
  4451                              <1> 	; write a character at current cursor position
  4452 00004220 88EC                <1> 	mov	ah, ch ; color/attribute
  4453                              <1> 	; 12/07/2014
  4454                              <1> 	;push	cx
  4455                              <1> 	; 02/02/2022
  4456 00004222 51                  <1> 	push	ecx
  4457 00004223 E894D3FFFF          <1> 	call	write_c_current
  4458                              <1> 	;pop	cx
  4459                              <1> 	; 02/02/2022
  4460 00004228 59                  <1> 	pop	ecx
  4461                              <1> sysstty_11:
  4462                              <1> 	; 14/01/2014
  4463 00004229 30D2                <1> 	xor	dl, dl ; sysstty call sign
  4464                              <1> 	; 18/01/2014
  4465                              <1> 	;movzx	eax, cl ; 27/06/2015
  4466 0000422B 88C8                <1> 	mov	al, cl
  4467 0000422D E8A4180000          <1> 	call	cttyp
  4468 00004232 E9BBF8FFFF          <1> 	jmp	sysret
  4469                              <1> 
  4470                              <1> sysstty_scp:
  4471                              <1> 	; 02/02/2022
  4472                              <1> 	; set communication parameters (for COM1 or COM2)
  4473                              <1> 	; 01/02/2022
  4474                              <1> 	;
  4475                              <1> 	; 29/10/2015
  4476 00004237 88D4                <1> 	mov	ah, dl ; communication parameters
  4477                              <1> 		; ah = 0E3h = 11100011b = 115200 baud,
  4478                              <1> 		;			 THRE int + RDA int 
  4479                              <1> 		; ah = 23h = 00100011b = 9600 baud,
  4480                              <1> 		;			 THRE int + RDA int 
  4481 00004239 28C0                <1> 	sub	al, al ; 0
  4482                              <1> 	; 12/07/2014
  4483 0000423B 80F909              <1> 	cmp	cl, 9
  4484 0000423E 7202                <1> 	jb	short sysstty_1
  4485 00004240 FEC0                <1> 	inc	al
  4486                              <1> sysstty_1:
  4487                              <1> 	; 02/02/2022
  4488 00004242 52                  <1> 	push	edx
  4489                              <1> 	; 01/02/2022
  4490 00004243 51                  <1> 	push	ecx
  4491                              <1> 	;push	cx
  4492                              <1> 	; 29/06/2015	
  4493 00004244 E839F3FFFF          <1> 	call 	sp_setp ; Set serial port communication parameters
  4494 00004249 66890D[996E0000]    <1> 	mov	[u.r0+1], cx ; Line status (ah)
  4495                              <1> 			     ; Modem status (EAX bits 16 to 23)
  4496                              <1> 	; 01/02/2022
  4497 00004250 59                  <1> 	pop	ecx	
  4498                              <1> 	;pop	cx
  4499 00004251 5A                  <1> 	pop	edx ; 02/02/2022
  4500                              <1> 	; 01/02/2022
  4501                              <1> 	; if cf = 1 -> sysstty_tmout_err
  4502 00004252 C3                  <1> 	retn
  4503                              <1> 
  4504                              <1> sysstty_14:
  4505                              <1> 	; 26/02/2022
  4506                              <1> 	; 02/02/2022
  4507                              <1> 	; ch = 0
  4508                              <1> 	; cl = video page
  4509                              <1> 	;
  4510                              <1> 	; dx = 0FFFFh
  4511                              <1> 	; clear screen (video page)
  4512                              <1> 	;
  4513                              <1> 
  4514                              <1> 	; 02/02/2022
  4515                              <1> 	; clear screen
  4516                              <1> 	;
  4517                              <1> 	; (modified registers: eax, ebx, ecx, edx, esi, edi)
  4518                              <1> 	; clear video page
  4519                              <1> 
  4520                              <1> 	; 26/02/2022
  4521 00004253 88CB                <1> 	mov 	bl, cl ; CL = tty number (0 to 7)
  4522                              <1> 
  4523                              <1> 	; clear video page
  4524 00004255 E810000000          <1> 	call	wttyc ; 26/02/2022
  4525                              <1> 
  4526                              <1> 	; 26/02/2022
  4527 0000425A 88D8                <1> 	mov	al, bl
  4528 0000425C 8A25[E76E0000]      <1> 	mov	ah, [u.uno]
  4529 00004262 66A3[986E0000]      <1> 	mov	[u.r0], ax
  4530 00004268 EBBF                <1> 	jmp	short sysstty_11
  4531                              <1> 
  4532                              <1> vp_clr:	; 27/02/2022
  4533                              <1> wttyc:
  4534                              <1> 	; 23/02/2022
  4535                              <1> 	; (clear video page)
  4536                              <1> 	; INPUT:
  4537                              <1> 	;  bl = video page (0 to 7)
  4538                              <1> 	;
  4539                              <1> 	; Modified registers: eax, ecx, edx, esi, edi
  4540                              <1> 
  4541                              <1> 	;xor	dx, dx ; column 0, row 0
  4542                              <1> 	;;inc	dx ; 0 ; 23/02/2022
  4543                              <1> 	;
  4544                              <1> ;	movzx	ebx, cl
  4545                              <1> ;	mov 	bl, cl ; CL = tty number (0 to 7) ; 23/02/2022
  4546                              <1> 
  4547                              <1> ;	shl 	bl, 1 
  4548                              <1> ;	mov 	al, byte ptr [ebx+ttyl]
  4549                              <1> ;		; AL = lock value (0 or process number)
  4550                              <1> ;	or	al, al
  4551                              <1> ;	jz	short @f
  4552                              <1> ;	cmp	al, byte ptr [u.uno] ; process number
  4553                              <1> ;	jne	short sysstty_15
  4554                              <1> ;		; only the owner can clear its video page
  4555                              <1> ;	xor	al, al ; 0
  4556                              <1> ;@@:
  4557                              <1> ;	;mov	bl, cl		
  4558                              <1> ;	shr	bl, 1 
  4559                              <1> 
  4560 0000426A 30C0                <1> 	xor	al, al	; 0
  4561 0000426C B407                <1> 	mov 	ah, 07h	; attribute/color (default)
  4562                              <1> 
  4563                              <1> 	; scroll_up input:
  4564                              <1> 	;
  4565                              <1> 	; al = line count (0 or 1) ((0 == clear video page))
  4566                              <1> 	; 	((al = 1 for write_tty (putc) procedure))
  4567                              <1> 	; ah = attribute to be used on blanked line
  4568                              <1> 	; bl = video page number (0 to 7)
  4569                              <1> 
  4570 0000426E E8E7D2FFFF          <1> 	call	scroll_up ; clear video page (al=0)
  4571                              <1> 
  4572                              <1> 	; (modified registers: eax, ecx, edx, esi, edi)
  4573                              <1> 
  4574                              <1> 	; bl = video page number (0 to 7)
  4575                              <1> 	;xor	dx, dx ; column 0, row 0
  4576                              <1> 	; 02/02/2022
  4577 00004273 31D2                <1> 	xor	edx, edx
  4578                              <1> 	; 26/02/2022
  4579                              <1> 	;call	set_cpos
  4580                              <1> 	;retn
  4581 00004275 E956D2FFFF          <1> 	jmp	set_cpos
  4582                              <1> 
  4583                              <1> 	;mov	al, bl
  4584                              <1> 	;mov	ah, [u.uno]
  4585                              <1> 	;mov	[u.r0], ax
  4586                              <1> 	;jmp	short sysstty_11
  4587                              <1> 
  4588                              <1> ;sysstty_15:
  4589                              <1> ;	; 30/01/2022
  4590                              <1> ;	; permission (denied) error
  4591                              <1> ;	;xor	dl, dl ; sysstty call sign
  4592                              <1> ;	mov	al, cl
  4593                              <1> ;	sub	ah, ah ; 0
  4594                              <1> ;	call	cttyp
  4595                              <1> ;	jmp	error
  4596                              <1> 
  4597                              <1> ; Original UNIX v1 'sysstty' routine:
  4598                              <1> ; gtty:
  4599                              <1> ;sysstty: / set mode of typewriter; 3 consequtive word arguments
  4600                              <1>         ;jsr    r0,gtty / r1 will have offset to tty block, 
  4601                              <1> 	; 		/ r2 has source
  4602                              <1>         ;mov    r2,-(sp)
  4603                              <1>         ;mov    r1,-(sp) / put r1 and r2 on the stack
  4604                              <1> ;1: / flush the clist wait till typewriter is quiescent
  4605                              <1>         ;mov    (sp),r1 / restore r1 to tty block offset
  4606                              <1>         ;movb   tty+3(r1),0f / put cc offset into getc argument
  4607                              <1>         ;mov    $240,*$ps / set processor priority to 5
  4608                              <1>         ;jsr    r0,getc; 0:../ put character from clist in r1
  4609                              <1>         ;       br .+4 / list empty, skip branch
  4610                              <1>         ;br     1b / get another character until list is empty
  4611                              <1>         ;mov    0b,r1 / move cc offset to r1
  4612                              <1>         ;inc    r1 / bump it for output clist
  4613                              <1>         ;tstb   cc(r1) / is it 0
  4614                              <1>         ;beq    1f / yes, no characters to output
  4615                              <1>  	;mov    r1,0f / no, put offset in sleep arg
  4616                              <1>         ;jsr    r0,sleep; 0:.. / put tty output process to sleep
  4617                              <1>         ;br     1b / try to calm it down again
  4618                              <1> ;1:
  4619                              <1>         ;mov    (sp)+,r1
  4620                              <1>         ;mov    (sp)+,r2 / restore registers
  4621                              <1> 	;mov    (r2)+,r3 / put reader control status in r3
  4622                              <1>         ;beq    1f / if 0, 1f
  4623                              <1>         ;mov    r3,rcsr(r1) / move r.c. status to reader
  4624                              <1>         ;                   / control status register
  4625                              <1> ;1:
  4626                              <1>         ;mov    (r2)+,r3 / move pointer control status to r3
  4627                              <1>         ;beq    1f / if 0 1f
  4628                              <1>         ;mov    r3,tcsr(r1) / move p.c. status to printer 
  4629                              <1> 	;		    / control status reg
  4630                              <1> ;1:
  4631                              <1>         ;mov    (r2)+,tty+4(r1) / move to flag byte of tty block
  4632                              <1>         ;jmp     sysret2 / return to user
  4633                              <1> 
  4634                              <1> sysgtty: ; < get tty status >
  4635                              <1> 	; 26/02/2022
  4636                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4637                              <1> 	;	    ((32 bit reg push/pop))
  4638                              <1> 	; 23/11/2015
  4639                              <1> 	; 29/10/2015
  4640                              <1> 	; 17/10/2015
  4641                              <1> 	; 28/06/2015 (Retro UNIX 386 v1 - Beginning)
  4642                              <1> 	; 30/05/2013 - 12/07/2014 (Retro UNIX 8086 v1)
  4643                              <1> 	;
  4644                              <1> 	; 'sysgtty' gets the status of tty in question. 
  4645                              <1> 	; It stores in the three words addressed by it's argument
  4646                              <1> 	; the status of the typewriter whose file descriptor
  4647                              <1> 	; in (u.r0).
  4648                              <1> 	;
  4649                              <1> 	; Calling sequence:
  4650                              <1> 	;	sysgtty; arg
  4651                              <1> 	; Arguments:
  4652                              <1> 	;	arg - address of 3 words destination of the status
  4653                              <1> 	; Inputs: ((*u.r0 - file descriptor))
  4654                              <1> 	; Outputs: ((status in address which is pointed to by arg))
  4655                              <1> 	; ...............................................................
  4656                              <1> 	;	
  4657                              <1> 	; Retro UNIX 8086 v1 modification: 
  4658                              <1> 	;	'sysgtty' system call will return status of tty
  4659                              <1> 	;	(keyboard, serial port and video page status)
  4660                              <1> 	;	 in following manner:
  4661                              <1> 	;
  4662                              <1> 	; Inputs:
  4663                              <1> 	;	BX = 0 --> means 
  4664                              <1> 	;	     CH = 0 -->	'return status of the console tty' 
  4665                              <1> 	;	                 for (current) process
  4666                              <1> 	;	     CL = 0 --> return keyboard status (tty 0 to 9)
  4667                              <1> 	;	     CL = 1 --> return video page status (tty 0 to 7)
  4668                              <1> 	;	     CL = 1 --> return serial port status (tty 8 & 9)		
  4669                              <1> 	;	     CH > 0 -->	tty number + 1
  4670                              <1> 	;
  4671                              <1> 	;	BX > 0 --> points to name of tty
  4672                              <1> 	;	     CL = 0 --> return keyboard status
  4673                              <1> 	;	     CL = 1 --> return video page status
  4674                              <1> 	;	     CH = undefined		 
  4675                              <1> 	;
  4676                              <1> 	; Outputs:
  4677                              <1> 	;	cf = 0 ->
  4678                              <1> 	;
  4679                              <1> 	;	     AL = tty number from 0 to 9
  4680                              <1> 	;		  (0 to 7 is also the video page of the tty)	
  4681                              <1> 	;	     AH = 0 if the tty is free/unused
  4682                              <1> 	;	     AH = the process number of the caller 
  4683                              <1>  	;	     AH = FFh if the tty is locked by another process
  4684                              <1> 	;
  4685                              <1> 	;	  (if calling is for serial port status)
  4686                              <1> 	;	     BX = serial port status if tty number is 8 or 9
  4687                              <1> 	;		  (BH = modem status, BL = Line status)
  4688                              <1> 	;	     CX = 0FFFFh (if data is ready)
  4689                              <1> 	;	     CX = 0 (if data is not ready or undefined)		
  4690                              <1> 	;
  4691                              <1> 	;	  (if calling is for keyboard status)
  4692                              <1> 	;	     BX = current character in tty/keyboard buffer
  4693                              <1> 	;		  (BH = scan code, BL = ascii code)
  4694                              <1> 	;		  (BX=0 if there is not a waiting character)
  4695                              <1> 	;	     CX  is undefined
  4696                              <1> 	;
  4697                              <1> 	;	  (if calling is for video page status)	
  4698                              <1> 	;	     BX = cursor position on the video page
  4699                              <1> 	;		  if tty number < 8
  4700                              <1> 	;		  (BH = row, BL = column)
  4701                              <1> 	;	     CX = current character (in cursor position)
  4702                              <1> 	;		  on the video page of the tty 
  4703                              <1> 	;		  if tty number < 8
  4704                              <1> 	;		  (CH = color, CL = character)
  4705                              <1> 	;	
  4706                              <1> 	;	cf = 1 means error (requested tty is not ready)
  4707                              <1> 	;
  4708                              <1> 	;	     AH = FFh if the caller is not owner of
  4709                              <1> 	;		  specified tty or console tty
  4710                              <1> 	;	     AL = tty number (0FFh if it does not exist)
  4711                              <1> 	;	     BX, CX are undefined if cf = 1
  4712                              <1> 	;
  4713                              <1> 	;	  (If tty number is 8 or 9)
  4714                              <1> 	;	     AL = tty number 
  4715                              <1> 	;	     AH = the process number of the caller 
  4716                              <1> 	;	     BX = serial port status
  4717                              <1> 	;  		 (BH = modem status, BL = Line status)
  4718                              <1> 	;	     CX = 0
  4719                              <1> 	;
  4720                              <1> 		
  4721                              <1> gtty:   ; get (requested) tty number
  4722                              <1> 	; 26/02/2022
  4723                              <1> 	; 17/10/2015
  4724                              <1> 	; 28/06/2015 (Retro UNIX 386 v1 - 32 bit modifications)
  4725                              <1> 	; 30/05/2013 - 12/07/2014
  4726                              <1> 	; Retro UNIX 8086 v1 modification ! 
  4727                              <1> 	;
  4728                              <1> 	; ((Modified regs: eAX, eBX, eCX, eDX, eSI, eDI, eBP))
  4729                              <1> 	;
  4730                              <1> 	; 28/06/2015 (32 bit modifications)
  4731                              <1> 	; 16/01/2014
  4732 0000427A 31C0                <1> 	xor 	eax, eax
  4733 0000427C 6648                <1> 	dec	ax ; 17/10/2015
  4734 0000427E A3[986E0000]        <1> 	mov 	[u.r0], eax ; 0FFFFh
  4735 00004283 80F901              <1> 	cmp	cl, 1
  4736 00004286 760F                <1> 	jna	short sysgtty_0
  4737                              <1> sysgtty_invp:
  4738                              <1> 	; 28/06/2015
  4739 00004288 C705[ED6E0000]1700- <1>         mov     dword [u.error], ERR_INV_PARAMETER ; 'invalid parameter !' 
  4739 00004290 0000                <1>
  4740 00004292 E93BF8FFFF          <1> 	jmp	error
  4741                              <1> sysgtty_0:	
  4742 00004297 21DB                <1> 	and	ebx, ebx
  4743 00004299 742E                <1> 	jz	short sysgtty_1
  4744                              <1> 	;
  4745 0000429B 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  4746                              <1> 	;push	cx ; 23/11/2015
  4747 000042A1 51                  <1> 	push	ecx ; 24/12/2021
  4748 000042A2 E829070000          <1> 	call	namei
  4749 000042A7 59                  <1> 	pop	ecx
  4750                              <1> 	;pop	cx ; 23/11/2015
  4751 000042A8 7210                <1> 	jc 	short sysgtty_inv_dn ; 28/06/2015
  4752                              <1> 	;
  4753 000042AA 6683F801            <1> 	cmp	ax, 1
  4754 000042AE 7622                <1> 	jna	short sysgtty_2
  4755                              <1> 	; 26/02/2022
  4756 000042B0 20E4                <1> 	and	ah, ah
  4757 000042B2 7506                <1> 	jnz	short sysgtty_inv_dn
  4758                              <1> 	;sub	ax, 10
  4759 000042B4 2C0A                <1> 	sub	al, 10
  4760 000042B6 3C09                <1> 	cmp	al, 9
  4761                              <1> 	;cmp	ax, 9
  4762                              <1> 	;ja	short sysgtty_inv_dn
  4763                              <1> 	;mov	ch, al
  4764                              <1> 	;jmp	short sysgtty_4
  4765                              <1> 	; 23/11/2015
  4766 000042B8 7629                <1> 	jna	short sysgtty_4
  4767                              <1> sysgtty_inv_dn: 
  4768                              <1> 	; 28/06/2015
  4769                              <1> 	; Invalid device name (not a tty) ! error
  4770                              <1> 	; (Device is not a tty or device name not found)
  4771 000042BA C705[ED6E0000]1800- <1> 	mov	dword [u.error], ERR_INV_DEV_NAME
  4771 000042C2 0000                <1>
  4772 000042C4 E909F8FFFF          <1> 	jmp	error 
  4773                              <1> sysgtty_1:
  4774                              <1> 	; 16/01/2014
  4775 000042C9 80FD0A              <1> 	cmp	ch, 10
  4776 000042CC 77BA                <1> 	ja	short sysgtty_invp ; 28/06/2015
  4777 000042CE FECD                <1> 	dec	ch ; 0 -> FFh (negative)
  4778 000042D0 790F                <1> 	jns	short sysgtty_3 ; not negative
  4779                              <1> 	;
  4780                              <1> sysgtty_2:
  4781                              <1> 	; get tty number of console tty
  4782 000042D2 8A25[E76E0000]      <1> 	mov	ah, [u.uno]
  4783                              <1>  	; 28/06/2015
  4784 000042D8 0FB6DC              <1> 	movzx 	ebx, ah
  4785 000042DB 8AAB[F76B0000]      <1> 	mov	ch, [ebx+p.ttyc-1]
  4786                              <1> sysgtty_3:
  4787 000042E1 88E8                <1> 	mov	al, ch
  4788                              <1> sysgtty_4:
  4789 000042E3 A2[986E0000]        <1> 	mov	[u.r0], al
  4790                              <1>  	; 28/06/2015
  4791                              <1> 	;cmp	al, 9
  4792                              <1> 	;ja	short sysgtty_invp
  4793 000042E8 8B2D[946E0000]      <1> 	mov	ebp, [u.usp]
  4794                              <1> 	; 23/11/2015
  4795 000042EE 20C9                <1> 	and	cl, cl
  4796 000042F0 7432                <1> 	jz	short sysgtty_6 ; keyboard status
  4797 000042F2 3C08                <1> 	cmp	al, 8 ; cmp ch, 8
  4798 000042F4 722E                <1> 	jb	short sysgtty_6 ; video page status
  4799                              <1> 	; serial port status
  4800                              <1> 	; 12/07/2014
  4801                              <1> 	;mov	dx, 0
  4802                              <1> 	;je	short sysgtty_5
  4803                              <1> 	;inc	dl
  4804                              <1> ;sysgtty_5:
  4805                              <1> 	; 28/06/2015
  4806 000042F6 2C08                <1> 	sub	al, 8
  4807 000042F8 E87DF2FFFF          <1> 	call	sp_status ; serial (COM) port (line) status
  4808                              <1> 	; AL = Line status, AH = Modem status
  4809 000042FD 66894510            <1> 	mov	[ebp+16], ax ; serial port status (in EBX)
  4810 00004301 8A25[E76E0000]      <1> 	mov	ah, [u.uno]
  4811 00004307 8825[996E0000]      <1>         mov     [u.r0+1], ah
  4812                              <1> 	; 24/12/2021
  4813 0000430D 66C745180000        <1> 	mov	word [ebp+24], 0 ; data status (0 = not ready)
  4814                              <1> 				; (in ECX)
  4815 00004313 A880                <1> 	test	al, 80h
  4816 00004315 7561                <1> 	jnz	short sysgtty_dnr_err ; 29/06/2015
  4817 00004317 A801                <1> 	test	al, 1
  4818                              <1> 	;jz	sysret
  4819 00004319 7404                <1> 	jz	short sysgtty_10
  4820 0000431B 66FF4D18            <1> 	dec	word [ebp+24] ; data status (FFFFh = ready)
  4821                              <1> sysgtty_10:
  4822 0000431F E9CEF7FFFF          <1> 	jmp	sysret
  4823                              <1> sysgtty_6:
  4824 00004324 A2[EC6E0000]        <1> 	mov	[u.ttyn], al ; tty number
  4825                              <1> 	;movzx	ebx, al
  4826 00004329 88C3                <1> 	mov 	bl, al ; tty number (0 to 9)
  4827 0000432B D0E3                <1> 	shl 	bl, 1  ; aligned to word
  4828                              <1> 	; 22/04/2014 - 29/06/2015
  4829 0000432D 81C3[246B0000]      <1>         add     ebx, ttyl
  4830 00004333 8A23                <1>  	mov	ah, [ebx]
  4831 00004335 3A25[E76E0000]      <1> 	cmp	ah, [u.uno]
  4832 0000433B 7404                <1> 	je	short sysgtty_7
  4833 0000433D 20E4                <1> 	and	ah, ah
  4834                              <1> 	;jz	short sysgtty_7
  4835 0000433F 7506                <1> 	jnz	short sysgtty_8
  4836                              <1> 	;mov	ah, 0FFh
  4837                              <1> sysgtty_7:
  4838 00004341 8825[996E0000]      <1>         mov     [u.r0+1], ah
  4839                              <1> sysgtty_8:
  4840 00004347 08C9                <1> 	or	cl, cl
  4841 00004349 7510                <1> 	jnz	short sysgtty_9
  4842 0000434B B001                <1> 	mov	al, 1  ; test a key is available
  4843 0000434D E8201C0000          <1> 	call	getc
  4844 00004352 66894510            <1> 	mov	[ebp+16], ax ; bx, character
  4845 00004356 E997F7FFFF          <1> 	jmp	sysret
  4846                              <1> sysgtty_9:
  4847 0000435B 8A1D[EC6E0000]      <1> 	mov	bl, [u.ttyn]
  4848                              <1> 	; bl = video page number
  4849 00004361 E87D1D0000          <1> 	call 	get_cpos
  4850                              <1> 	; dx = cursor position
  4851 00004366 66895510            <1> 	mov	[ebp+16], dx ; bx
  4852                              <1> 	;mov	bl, [u.ttyn]
  4853                              <1> 	; bl = video page number
  4854 0000436A E8851D0000          <1> 	call	read_ac_current
  4855                              <1> 	; ax = character and attribute/color
  4856 0000436F 66894518            <1> 	mov	[ebp+24], ax ; cx
  4857 00004373 E97AF7FFFF          <1> 	jmp	sysret
  4858                              <1> sysgtty_dnr_err:
  4859                              <1> 	; 'device not responding !' error	
  4860                              <1> 	;mov 	dword [u.error], ERR_TIME_OUT ; 25
  4861 00004378 C705[ED6E0000]1900- <1> 	mov 	dword [u.error], ERR_DEV_NOT_RESP ; 25
  4861 00004380 0000                <1>
  4862 00004382 E94BF7FFFF          <1> 	jmp	error	
  4863                              <1> 
  4864                              <1> ; Original UNIX v1 'sysgtty' routine:
  4865                              <1> ; sysgtty:
  4866                              <1>         ;jsr    r0,gtty / r1 will have offset to tty block,
  4867                              <1> 	;	       / r2 has destination
  4868                              <1>         ;mov    rcsr(r1),(r2)+ / put reader control status 
  4869                              <1> 	;                     / in 1st word of dest
  4870                              <1>         ;mov    tcsr(r1),(r2)+ / put printer control status
  4871                              <1> 	;                     / in 2nd word of dest
  4872                              <1>         ;mov    tty+4(r1),(r2)+ / put mode in 3rd word
  4873                              <1>         ;jmp    sysret2 / return to user
  4874                              <1> 	
  4875                              <1> ; Original UNIX v1 'gtty' routine:
  4876                              <1> ; gtty:
  4877                              <1>         ;jsr    r0,arg; u.off / put first arg in u.off
  4878                              <1>         ;mov    *u.r0,r1 / put file descriptor in r1
  4879                              <1>         ;jsr    r0,getf / get the i-number of the file
  4880                              <1>         ;tst    r1 / is it open for reading
  4881                              <1>         ;bgt    1f / yes
  4882                              <1>         ;neg    r1 / no, i-number is negative, 
  4883                              <1> 	;          / so make it positive
  4884                              <1> ;1:
  4885                              <1>         ;sub    $14.,r1 / get i-number of tty0
  4886                              <1>         ;cmp    r1,$ntty-1 / is there such a typewriter
  4887                              <1>         ;bhis   error9 / no, error
  4888                              <1>         ;asl    r1 / 0%2
  4889                              <1>         ;asl    r1 / 0%4 / yes
  4890                              <1>         ;asl    r1 / 0%8 / multiply by 8 so r1 points to 
  4891                              <1> 	;	       ; / tty block
  4892                              <1>         ;mov    u.off,r2 / put argument in r2
  4893                              <1>         ;rts    r0 / return
  2093                                  %include 'u2.s'        ; 11/05/2015
  2094                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS2.INC
  2095                              <1> ; Last Modification: 11/02/2022
  2096                              <1> ; ----------------------------------------------------------------------------
  2097                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2098                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2099                              <1> ;
  2100                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2101                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2102                              <1> ; <Bell Laboratories (17/3/1972)>
  2103                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2104                              <1> ;
  2105                              <1> ; Retro UNIX 8086 v1 - U2.ASM (24/03/2014) //// UNIX v1 -> u2.s
  2106                              <1> ;
  2107                              <1> ; ****************************************************************************
  2108                              <1> 
  2109                              <1> syslink:
  2110                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2111                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2112                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  2113                              <1> 	;
  2114                              <1> 	; 'syslink' is given two arguments, name 1 and name 2.
  2115                              <1> 	; name 1 is a file that already exists. name 2 is the name
  2116                              <1> 	; given to the entry that will go in the current directory.
  2117                              <1> 	; name2 will then be a link to the name 1 file. The i-number
  2118                              <1> 	; in the name 2 entry of current directory is the same
  2119                              <1> 	; i-number for the name 1 file.
  2120                              <1> 	;
  2121                              <1> 	; Calling sequence:
  2122                              <1> 	;	syslink; name 1; name 2
  2123                              <1> 	; Arguments:
  2124                              <1> 	;	name 1 - file name to which link will be created.
  2125                              <1> 	;	name 2 - name of entry in current directory that
  2126                              <1> 	;		 links to name 1.
  2127                              <1> 	; Inputs: -
  2128                              <1> 	; Outputs: -
  2129                              <1> 	; ...............................................................
  2130                              <1> 	;	
  2131                              <1> 	; Retro UNIX 8086 v1 modification: 
  2132                              <1> 	;       'syslink' system call has two arguments; so,
  2133                              <1> 	;	* 1st argument, name 1 is pointed to by BX register
  2134                              <1> 	;	* 2nd argument, name 2 is pointed to by CX register
  2135                              <1> 	;
  2136                              <1> 		; / name1, name2
  2137                              <1> 		;jsr r0,arg2 / u.namep has 1st arg u.off has 2nd
  2138 00004387 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  2139 0000438D 51                  <1> 	push	ecx
  2140 0000438E E83D060000          <1> 	call	namei
  2141                              <1> 		; jsr r0,namei / find the i-number associated with
  2142                              <1> 			     ; / the 1st path name
  2143                              <1>      	;;and	ax, ax
  2144                              <1> 	;;jz	error ; File not found
  2145                              <1> 	;jc	error 
  2146                              <1> 		; br error9 / cannot be found
  2147 00004393 730F                <1> 	jnc	short syslink0
  2148                              <1> 	;pop 	ecx
  2149                              <1> 	; 'file not found !' error
  2150 00004395 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  2150 0000439D 0000                <1>
  2151 0000439F E92EF7FFFF          <1> 	jmp	error
  2152                              <1> syslink0:
  2153 000043A4 E8EC0D0000          <1> 	call	iget
  2154                              <1> 		; jsr r0,iget / get the i-node into core
  2155 000043A9 8F05[B06E0000]      <1> 	pop	dword [u.namep] ; ecx
  2156                              <1> 		; mov (sp)+,u.namep / u.namep points to 2nd name
  2157                              <1> 	; 24/12/2021
  2158 000043AF 50                  <1> 	push	eax ; *
  2159                              <1> 	;push	ax
  2160                              <1> 		; mov r1,-(sp) / put i-number of name1 on the stack
  2161                              <1> 			    ; / (a link to this file is to be created)
  2162                              <1> 	; 24/12/2021
  2163 000043B0 8A0D[7F6E0000]      <1> 	mov	cl, [cdev]
  2164 000043B6 51                  <1> 	push	ecx ; **
  2165                              <1> 	;push	word [cdev]
  2166                              <1> 		; mov cdev,-(sp) / put i-nodes device on the stack
  2167 000043B7 E852000000          <1> 	call	isdir
  2168                              <1> 		; jsr r0,isdir / is it a directory
  2169 000043BC E80F060000          <1> 	call	namei
  2170                              <1> 		; jsr r0,namei / no, get i-number of name2
  2171                              <1> 	;jnc	error
  2172                              <1> 		; br .+4   / not found 
  2173                              <1> 			 ; / so r1 = i-number of current directory
  2174                              <1> 			 ; / ii = i-number of current directory
  2175                              <1> 		; br error9 / file already exists., error
  2176 000043C1 720F                <1> 	jc	short syslink1
  2177                              <1> 	; pop eax ; 24/12/2021
  2178                              <1> 	; pop eax
  2179                              <1> 	; 'file exists !' error
  2180 000043C3 C705[ED6E0000]0E00- <1> 	mov	dword [u.error], ERR_FILE_EXISTS ; 14
  2180 000043CB 0000                <1>
  2181 000043CD E900F7FFFF          <1> 	jmp	error
  2182                              <1> syslink1:
  2183                              <1> 	;pop	cx
  2184                              <1> 	; 24/12/2021
  2185 000043D2 59                  <1> 	pop	ecx ; **
  2186                              <1> 	;cmp	cx, [cdev]
  2187 000043D3 3A0D[7F6E0000]      <1> 	cmp	cl, [cdev]
  2188                              <1> 	;jne	error
  2189                              <1> 		; cmp (sp)+,cdev / u.dirp now points to 
  2190                              <1> 			       ; / end of current directory
  2191                              <1> 	        ; bne error9
  2192 000043D9 740F                <1> 	je	short syslink2
  2193                              <1> 	; 'not same drive !' error
  2194 000043DB C705[ED6E0000]1500- <1> 	mov	dword [u.error],  ERR_DRV_NOT_SAME ; 21
  2194 000043E3 0000                <1>
  2195 000043E5 E9E8F6FFFF          <1> 	jmp	error
  2196                              <1> syslink2:
  2197                              <1> 	;pop	eax ; 24/12/2021
  2198                              <1> 	;push	eax
  2199                              <1> 	; 24/12/2021
  2200 000043EA 8B0424              <1> 	mov	eax, [esp] ; *
  2201 000043ED 66A3[CA6E0000]      <1> 	mov	[u.dirbuf], ax
  2202                              <1> 		; mov (sp),u.dirbuf / i-number of name1 into u.dirbuf
  2203 000043F3 E89E000000          <1> 	call	mkdir
  2204                              <1> 		; jsr r0,mkdir / make directory entry for name2 
  2205                              <1> 		 	     ; / in current directory
  2206                              <1> 	; 24/12/2021
  2207 000043F8 58                  <1> 	pop	eax ; *
  2208                              <1> 	;pop	ax
  2209                              <1> 		; mov (sp)+,r1 / r1 has i-number of name1
  2210 000043F9 E8970D0000          <1> 	call	iget
  2211                              <1> 		; jsr r0,iget / get i-node into core
  2212 000043FE FE05[9A6B0000]      <1> 	inc	byte [i.nlks]
  2213                              <1> 		; incb i.nlks / add 1 to its number of links
  2214 00004404 E8960E0000          <1> 	call	setimod
  2215                              <1> 		; jsr r0,setimod / set the i-node modified flag
  2216 00004409 E9E4F6FFFF          <1> 	jmp	sysret
  2217                              <1> 
  2218                              <1> isdir:
  2219                              <1> 	; 03/02/2022
  2220                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  2221                              <1> 	; 04/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  2222                              <1> 	;
  2223                              <1> 	; 'isdir' check to see if the i-node whose i-number is in r1
  2224                              <1> 	;  is a directory. If it is, an error occurs, because 'isdir'
  2225                              <1> 	;  called by syslink and sysunlink to make sure directories
  2226                              <1> 	;  are not linked. If the user is the super user (u.uid=0),
  2227                              <1> 	; 'isdir' does not bother checking. The current i-node
  2228                              <1> 	;  is not disturbed.			
  2229                              <1> 	;		
  2230                              <1> 	; INPUTS ->
  2231                              <1> 	;    r1 - contains the i-number whose i-node is being checked.
  2232                              <1> 	;    u.uid - user id
  2233                              <1> 	; OUTPUTS ->
  2234                              <1> 	;    r1 - contains current i-number upon exit
  2235                              <1> 	;    	 (current i-node back in core) 
  2236                              <1> 	;	
  2237                              <1> 	; ((AX = R1))
  2238                              <1> 	;
  2239                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  2240                              <1> 	;
  2241                              <1> 
  2242                              <1> 	; / if the i-node whose i-number is in r1 is a directory 
  2243                              <1> 	; / there is an error unless super user made the call
  2244                              <1> 	
  2245 0000440E 803D[E46E0000]00    <1> 	cmp	byte [u.uid], 0 
  2246                              <1> 		; tstb u.uid / super user
  2247 00004415 762B                <1> 	jna	short isdir1
  2248                              <1> 		; beq 1f / yes, don't care
  2249 00004417 66FF35[7C6E0000]    <1> 	push	word [ii]
  2250                              <1> 		; mov ii,-(sp) / put current i-number on stack
  2251 0000441E E8720D0000          <1> 	call	iget
  2252                              <1> 		; jsr r0,iget / get i-node into core (i-number in r1)
  2253                              <1> 	; 03/02/2022
  2254 00004423 F605[996B0000]40    <1> 	test	byte [i.flgs+1], 40h
  2255                              <1> 	;test 	word [i.flgs], 4000h ; Bit 14 : Directory flag
  2256                              <1> 		; bit $40000,i.flgs / is it a directory
  2257                              <1> 	;jnz	error
  2258                              <1> 		; bne error9 / yes, error
  2259 0000442A 740F                <1> 	jz	short isdir0
  2260 0000442C C705[ED6E0000]0B00- <1> 	mov 	dword [u.error], ERR_NOT_FILE  ; 11 ; ERR_DIR_ACCESS 
  2260 00004434 0000                <1>
  2261                              <1> 				; 'permission denied !' error
  2262                              <1> 	; pop	ax
  2263 00004436 E997F6FFFF          <1> 	jmp	error	
  2264                              <1> isdir0:	
  2265 0000443B 6658                <1> 	pop	ax
  2266                              <1> 		; mov (sp)+,r1 / no, put current i-number in r1 (ii)
  2267 0000443D E8530D0000          <1> 	call	iget
  2268                              <1> 		; jsr r0,iget / get it back in
  2269                              <1> isdir1: ; 1:
  2270 00004442 C3                  <1> 	retn
  2271                              <1> 		; rts r0
  2272                              <1> 
  2273                              <1> sysunlink:
  2274                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2275                              <1> 	; 04/12/2015 (14 byte file names)
  2276                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2277                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  2278                              <1> 	;
  2279                              <1> 	; 'sysunlink' removes the entry for the file pointed to by
  2280                              <1> 	; name from its directory. If this entry was the last link
  2281                              <1> 	; to the file, the contents of the file are freed and the
  2282                              <1> 	; file is destroyed. If, however, the file was open in any
  2283                              <1> 	; process, the actual destruction is delayed until it is 
  2284                              <1> 	; closed, even though the directory entry has disappeared.
  2285                              <1> 	; 
  2286                              <1> 	; The error bit (e-bit) is set to indicate that the file	
  2287                              <1> 	; does not exist or that its directory can not be written.
  2288                              <1> 	; Write permission is not required on the file itself.
  2289                              <1> 	; It is also illegal to unlink a directory (except for
  2290                              <1> 	; the superuser).
  2291                              <1> 	;
  2292                              <1> 	; Calling sequence:
  2293                              <1> 	;	sysunlink; name
  2294                              <1> 	; Arguments:
  2295                              <1> 	;	name - name of directory entry to be removed 
  2296                              <1> 	; Inputs: -
  2297                              <1> 	; Outputs: -
  2298                              <1> 	; ...............................................................
  2299                              <1> 	;				
  2300                              <1> 	; Retro UNIX 8086 v1 modification:
  2301                              <1> 	;	 The user/application program puts address of the name
  2302                              <1> 	;        in BX register as 'sysunlink' system call argument.
  2303                              <1> 
  2304                              <1> 	; / name - remove link name
  2305 00004443 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  2306                              <1> 		;jsr r0,arg; u.namep / u.namep points to name
  2307 00004449 E882050000          <1> 	call	namei
  2308                              <1> 		; jsr r0,namei / find the i-number associated 
  2309                              <1> 			     ; / with the path name
  2310                              <1> 	;jc	error
  2311                              <1> 		; br error9 / not found
  2312 0000444E 730F                <1> 	jnc	short sysunlink1
  2313                              <1> 	; 'file not found !' error
  2314 00004450 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  2314 00004458 0000                <1>
  2315 0000445A E973F6FFFF          <1> 	jmp	error
  2316                              <1> sysunlink1:
  2317 0000445F 50                  <1> 	push	eax ; 24/12/2021
  2318                              <1> 	;push	ax
  2319                              <1> 		; mov r1,-(sp) / put its i-number on the stack
  2320 00004460 E8A9FFFFFF          <1> 	call	isdir
  2321                              <1> 		; jsr r0,isdir / is it a directory
  2322                              <1> 	;xor 	ax, ax
  2323                              <1> 	; 24/12/2021
  2324 00004465 31C0                <1> 	xor	eax, eax
  2325 00004467 66A3[CA6E0000]      <1> 	mov	[u.dirbuf], ax ; 0
  2326                              <1> 		; clr u.dirbuf / no, clear the location that will
  2327                              <1> 			   ; / get written into the i-number portion
  2328                              <1> 			 ; / of the entry
  2329 0000446D 832D[B46E0000]10    <1> 	sub	dword [u.off], 16 ; 04/12/2015 (10 -> 16) 
  2330                              <1> 		; sub $10.,u.off / move u.off back 1 directory entry
  2331 00004474 E868000000          <1> 	call	wdir
  2332                              <1> 		; jsr r0,wdir / free the directory entry
  2333 00004479 58                  <1> 	pop	eax ; 24/12/2021
  2334                              <1> 	;pop	ax
  2335                              <1> 		; mov (sp)+,r1 / get i-number back
  2336 0000447A E8160D0000          <1> 	call	iget
  2337                              <1> 		; jsr r0,iget / get i-node
  2338 0000447F E81B0E0000          <1> 	call	setimod
  2339                              <1> 		; jsr r0,setimod / set modified flag
  2340 00004484 FE0D[9A6B0000]      <1> 	dec	byte [i.nlks]
  2341                              <1> 		; decb i.nlks / decrement the number of links
  2342                              <1> 	; 24/12/2021
  2343 0000448A 7505                <1> 	jnz	short sysunlink_2
  2344                              <1> 	;jnz	sysret
  2345                              <1> 		; bgt sysret9 / if this was not the last link
  2346                              <1> 			    ; / to file return
  2347                              <1> 	; AX = r1 = i-number
  2348 0000448C E85B090000          <1> 	call	anyi
  2349                              <1> 		; jsr r0,anyi / if it was, see if anyone has it open.
  2350                              <1> 			 ; / Then free contents of file and destroy it.
  2351                              <1> sysunlink_2:
  2352 00004491 E95CF6FFFF          <1> 	jmp	sysret
  2353                              <1> 		; br sysret9
  2354                              <1> 
  2355                              <1> mkdir:
  2356                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2357                              <1> 	; 04/12/2015 (14 byte directory names)
  2358                              <1> 	; 12/10/2015
  2359                              <1> 	; 17/06/2015 (Retro UNIX 386 v1 - Beginning)
  2360                              <1> 	; 29/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2361                              <1> 	;
  2362                              <1> 	; 'mkdir' makes a directory entry from the name pointed to
  2363                              <1> 	; by u.namep into the current directory.
  2364                              <1> 	;
  2365                              <1> 	; INPUTS ->
  2366                              <1> 	;    u.namep - points to a file name 
  2367                              <1> 	;	           that is about to be a directory entry.
  2368                              <1> 	;    ii - current directory's i-number.	
  2369                              <1> 	; OUTPUTS ->
  2370                              <1> 	;    u.dirbuf+2 - u.dirbuf+10 - contains file name. 
  2371                              <1> 	;    u.off - points to entry to be filled 
  2372                              <1> 	;	     in the current directory		
  2373                              <1> 	;    u.base - points to start of u.dirbuf.
  2374                              <1> 	;    r1 - contains i-number of current directory 
  2375                              <1> 	;	
  2376                              <1> 	; ((AX = R1)) output
  2377                              <1> 	;
  2378                              <1> 	;    (Retro UNIX Prototype : 11/11/2012, UNIXCOPY.ASM)
  2379                              <1>         ;    ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  2380                              <1> 	;
  2381                              <1> 
  2382                              <1> 	; 17/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  2383 00004496 31C0                <1> 	xor 	eax, eax
  2384 00004498 BF[CC6E0000]        <1> 	mov     edi, u.dirbuf+2
  2385 0000449D 89FE                <1> 	mov	esi, edi
  2386 0000449F AB                  <1> 	stosd
  2387 000044A0 AB                  <1> 	stosd
  2388                              <1> 	; 04/12/2015 (14 byte directory names)
  2389 000044A1 AB                  <1> 	stosd
  2390 000044A2 66AB                <1> 	stosw
  2391                              <1> 		; jsr r0,copyz; u.dirbuf+2; u.dirbuf+10. / clear this
  2392 000044A4 89F7                <1> 	mov	edi, esi ; offset to u.dirbuf
  2393                              <1> 	; 12/10/2015 ([u.namep] -> ebp)
  2394                              <1> 	;mov 	ebp, [u.namep]
  2395 000044A6 E85E060000          <1> 	call	trans_addr_nmbp ; convert virtual address to physical
  2396                              <1> 		; esi = physical address (page start + offset)
  2397                              <1> 		; ecx = byte count in the page (1 - 4096)
  2398                              <1> 	; edi = offset to u.dirbuf (edi is not modified in trans_addr_nm)
  2399                              <1> 		; mov u.namep,r2 / r2 points to name of directory entry
  2400                              <1> 		; mov $u.dirbuf+2,r3 / r3 points to u.dirbuf+2
  2401                              <1> mkdir_1: ; 1: 
  2402 000044AB 45                  <1> 	inc	ebp ; 12/10/2015
  2403                              <1> 	;
  2404                              <1> 	; / put characters in the directory name in u.dirbuf+2 - u.dirbuf+10
  2405                              <1> 	 ; 01/08/2013
  2406 000044AC AC                  <1> 	lodsb
  2407                              <1> 		; movb (r2)+,r1 / move character in name to r1
  2408 000044AD 20C0                <1> 	and 	al, al
  2409 000044AF 7426                <1> 	jz 	short mkdir_3 	  
  2410                              <1> 		; beq 1f / if null, done
  2411 000044B1 3C2F                <1> 	cmp	al, '/'
  2412                              <1> 		; cmp r1,$'/ / is it a "/"?
  2413 000044B3 7413                <1> 	je	short mkdir_err
  2414                              <1> 	;je	error
  2415                              <1> 		; beq error9 / yes, error
  2416                              <1> 	; 12/10/2015
  2417                              <1> 	;dec	cx
  2418 000044B5 49                  <1> 	dec	ecx ; 24/12/2021
  2419 000044B6 7505                <1> 	jnz	short mkdir_2
  2420                              <1> 	; 12/10/2015 ([u.namep] -> ebp)
  2421 000044B8 E852060000          <1> 	call	trans_addr_nm ; convert virtual address to physical
  2422                              <1> 		; esi = physical address (page start + offset)
  2423                              <1> 		; ecx = byte count in the page
  2424                              <1> 	; edi = offset to u.dirbuf (edi is not modified in trans_addr_nm)
  2425                              <1> mkdir_2:
  2426 000044BD 81FF[DA6E0000]      <1> 	cmp     edi, u.dirbuf+16 ; ; 04/12/2015 (10 -> 16) 
  2427                              <1> 		; cmp r3,$u.dirbuf+10. / have we reached the last slot for
  2428                              <1> 				     ; / a char?
  2429 000044C3 74E6                <1> 	je	short mkdir_1
  2430                              <1> 		; beq 1b / yes, go back
  2431 000044C5 AA                  <1> 	stosb
  2432                              <1> 		; movb r1,(r3)+ / no, put the char in the u.dirbuf
  2433 000044C6 EBE3                <1> 	jmp 	short mkdir_1
  2434                              <1> 		; br 1b / get next char
  2435                              <1> mkdir_err:
  2436                              <1> 	; 17/06/2015
  2437 000044C8 C705[ED6E0000]1300- <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a valid directory !'
  2437 000044D0 0000                <1>
  2438 000044D2 E9FBF5FFFF          <1> 	jmp	error
  2439                              <1> 
  2440                              <1> mkdir_3: ; 1:
  2441 000044D7 A1[AC6E0000]        <1> 	mov	eax, [u.dirp]
  2442 000044DC A3[B46E0000]        <1> 	mov	[u.off], eax
  2443                              <1> 		; mov u.dirp,u.off / pointer to empty current directory
  2444                              <1> 				 ; / slot to u.off
  2445                              <1> wdir: 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2446                              <1> 	; 29/04/2013
  2447 000044E1 C705[B86E0000]-     <1>         mov     dword [u.base], u.dirbuf
  2447 000044E7 [CA6E0000]          <1>
  2448                              <1> 		; mov $u.dirbuf,u.base / u.base points to created file name
  2449 000044EB C705[BC6E0000]1000- <1>         mov     dword [u.count], 16 ; 04/12/2015 (10 -> 16) 
  2449 000044F3 0000                <1>
  2450                              <1> 		; mov $10.,u.count / u.count = 10
  2451 000044F5 66A1[7C6E0000]      <1> 	mov	ax, [ii] 
  2452                              <1> 		; mov ii,r1 / r1 has i-number of current directory
  2453 000044FB B201                <1> 	mov	dl, 1 ; owner flag mask ; RETRO UNIX 8086 v1 modification !
  2454 000044FD E8670D0000          <1> 	call 	access
  2455                              <1> 		; jsr r0,access; 1 / get i-node and set its file up 
  2456                              <1> 				 ; / for writing
  2457                              <1> 	; AX = i-number of current directory
  2458                              <1> 	; 01/08/2013
  2459 00004502 FE05[FF6E0000]      <1> 	inc     byte [u.kcall] ; the caller is 'mkdir' sign	
  2460                              <1> 	;call	writei
  2461                              <1> 	;	; jsr r0,writei / write into directory
  2462                              <1> 	;retn	
  2463                              <1> 	;	; rts r0
  2464                              <1> 	; 24/12/2021
  2465 00004508 E94A100000          <1> 	jmp	writei
  2466                              <1> 
  2467                              <1> sysexec:
  2468                              <1> 	; 03/02/2022
  2469                              <1> 	; 12/01/2022
  2470                              <1> 	; 08/01/2022
  2471                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2472                              <1> 	; 23/10/2015
  2473                              <1> 	; 19/10/2015
  2474                              <1> 	; 10/10/2015, 18/10/2015
  2475                              <1> 	; 29/07/2015, 05/08/2015, 26/08/2015
  2476                              <1> 	; 21/07/2015, 24/07/2015, 25/07/2015
  2477                              <1> 	; 01/07/2015, 02/07/2015, 20/07/2015
  2478                              <1> 	; 24/06/2015, 25/06/2015
  2479                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2480                              <1> 	; 03/06/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2481                              <1> 	;
  2482                              <1> 	; 'sysexec' initiates execution of a file whose path name if
  2483                              <1> 	; pointed to by 'name' in the sysexec call. 
  2484                              <1> 	; 'sysexec' performs the following operations:
  2485                              <1> 	;    1. obtains i-number of file to be executed via 'namei'.
  2486                              <1> 	;    2. obtains i-node of file to be exceuted via 'iget'.
  2487                              <1> 	;    3. sets trap vectors to system routines.
  2488                              <1> 	;    4. loads arguments to be passed to executing file into
  2489                              <1> 	;	highest locations of user's core
  2490                              <1> 	;    5. puts pointers to arguments in locations immediately
  2491                              <1> 	;	following arguments.
  2492                              <1> 	;    6.	saves number of arguments in next location.
  2493                              <1> 	;    7. initializes user's stack area so that all registers
  2494                              <1> 	;	will be zeroed and the PS is cleared and the PC set
  2495                              <1> 	;	to core when 'sysret' restores registers 
  2496                              <1> 	;	and does an rti.
  2497                              <1> 	;    8. inializes u.r0 and u.sp
  2498                              <1> 	;    9. zeros user's core down to u.r0
  2499                              <1> 	;   10.	reads executable file from storage device into core
  2500                              <1> 	;	starting at location 'core'.
  2501                              <1> 	;   11.	sets u.break to point to end of user's code with
  2502                              <1> 	;	data area appended.
  2503                              <1> 	;   12.	calls 'sysret' which returns control at location
  2504                              <1> 	;	'core' via 'rti' instruction. 		  		
  2505                              <1> 	;
  2506                              <1> 	; Calling sequence:
  2507                              <1> 	;	sysexec; namep; argp
  2508                              <1> 	; Arguments:
  2509                              <1> 	;	namep - points to pathname of file to be executed
  2510                              <1> 	;	argp  - address of table of argument pointers
  2511                              <1> 	;	argp1... argpn - table of argument pointers
  2512                              <1> 	;	argp1:<...0> ... argpn:<...0> - argument strings
  2513                              <1> 	; Inputs: (arguments)
  2514                              <1> 	; Outputs: -	
  2515                              <1> 	; ...............................................................
  2516                              <1> 	;
  2517                              <1> 	; Retro UNIX 386 v1 modification: 
  2518                              <1> 	;	User application runs in it's own virtual space 
  2519                              <1> 	;	which is izolated from kernel memory (and other
  2520                              <1> 	;	memory pages) via 80386	paging in ring 3 
  2521                              <1> 	;	privilige mode. Virtual start address is always 0.
  2522                              <1> 	;	User's core memory starts at linear address 400000h
  2523                              <1> 	;	(the end of the 1st 4MB).
  2524                              <1> 	;
  2525                              <1> 	; Retro UNIX 8086 v1 modification: 
  2526                              <1> 	;	user/application segment and system/kernel segment
  2527                              <1> 	;	are different and sysenter/sysret/sysrele routines
  2528                              <1> 	;	are different (user's registers are saved to 
  2529                              <1> 	;	and then restored from system's stack.)
  2530                              <1> 	;
  2531                              <1> 	;	NOTE: Retro UNIX 8086 v1 'arg2' routine gets these
  2532                              <1> 	;	      arguments which were in these registers;
  2533                              <1> 	;	      but, it returns by putting the 1st argument
  2534                              <1> 	;	      in 'u.namep' and the 2nd argument
  2535                              <1> 	;	      on top of stack. (1st argument is offset of the
  2536                              <1> 	;	      file/path name in the user's program segment.)		 	
  2537                              <1> 	
  2538                              <1> 	;call	arg2
  2539                              <1> 	; * name - 'u.namep' points to address of file/path name
  2540                              <1> 	;          in the user's program segment ('u.segmnt')
  2541                              <1> 	;          with offset in BX register (as sysopen argument 1).
  2542                              <1> 	; * argp - sysexec argument 2 is in CX register 
  2543                              <1> 	;          which is on top of stack.
  2544                              <1> 	;
  2545                              <1> 		; jsr r0,arg2 / arg0 in u.namep,arg1 on top of stack
  2546                              <1> 
  2547                              <1> 	; 23/06/2015 (32 bit modifications)
  2548                              <1> 
  2549 0000450D 891D[B06E0000]      <1> 	mov	[u.namep], ebx ; argument 1
  2550                              <1>         ; 18/10/2015
  2551 00004513 890D[186F0000]      <1> 	mov     [argv], ecx  ; * ; argument 2
  2552 00004519 E8B2040000          <1> 	call	namei
  2553                              <1> 		; jsr r0,namei / namei returns i-number of file 
  2554                              <1> 			     ; / named in sysexec call in r1
  2555                              <1> 	;jc	error
  2556                              <1> 		; br error9
  2557 0000451E 731E                <1> 	jnc	short sysexec_0
  2558                              <1> 	;
  2559                              <1> 	; 'file not found !' error
  2560 00004520 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND
  2560 00004528 0000                <1>
  2561 0000452A E9A3F5FFFF          <1> 	jmp	error 
  2562                              <1> sysexec_not_exf:
  2563                              <1> 	; 'not executable file !' error
  2564 0000452F C705[ED6E0000]1600- <1> 	mov	dword [u.error], ERR_NOT_EXECUTABLE
  2564 00004537 0000                <1>
  2565 00004539 E994F5FFFF          <1> 	jmp	error 
  2566                              <1> sysexec_0:
  2567 0000453E E8520C0000          <1> 	call	iget
  2568                              <1> 		; jsr r0,iget / get i-node for file to be executed
  2569                              <1> 	; 24/12/2021
  2570 00004543 F605[986B0000]10    <1> 	test	byte [i.flgs], 10h
  2571                              <1> 	;test	word [i.flgs], 10h
  2572                              <1> 	;	; bit $20,i.flgs / is file executable
  2573 0000454A 74E3                <1> 	jz	short sysexec_not_exf
  2574                              <1> 	;jz	error
  2575                              <1> 		; beq error9
  2576                              <1> 	;;
  2577 0000454C E8C8130000          <1> 	call	iopen
  2578                              <1> 		; jsr r0,iopen / gets i-node for file with i-number
  2579                              <1> 			     ; / given in r1 (opens file)
  2580                              <1> 	; AX = i-number of the file
  2581                              <1> 	; 24/12/2021
  2582 00004551 F605[986B0000]20    <1> 	test	byte [i.flgs], 20h
  2583                              <1> 	;test	word [i.flgs], 20h
  2584                              <1> 		; bit $40,i.flgs / test user id on execution bit
  2585 00004558 7415                <1> 	jz	short sysexec_1
  2586                              <1> 		; beq 1f
  2587 0000455A 803D[E46E0000]00    <1> 	cmp 	byte [u.uid], 0 ; 02/08/2013
  2588                              <1> 		; tstb u.uid / test user id
  2589 00004561 760C                <1> 	jna	short sysexec_1
  2590                              <1> 		; beq 1f / super user
  2591 00004563 8A0D[9B6B0000]      <1> 	mov	cl, [i.uid]
  2592 00004569 880D[E46E0000]      <1> 	mov	[u.uid], cl ; 02/08/2013
  2593                              <1> 		; movb i.uid,u.uid / put user id of owner of file
  2594                              <1> 				 ; / as process user id
  2595                              <1> sysexec_1:
  2596                              <1> 	; 03/02/2022
  2597                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2598                              <1> 	; 18/10/2215
  2599                              <1> 	; 10/10/2015
  2600                              <1> 	; 21/07/2015, 24/07/2015
  2601                              <1> 	; 24/06/2015, 25/06/2015
  2602                              <1>         ; Moving arguments to the end of [u.upage]
  2603                              <1> 	; (by regarding page borders in user's memory space)
  2604                              <1> 	;
  2605                              <1> 	; 10/10/2015
  2606                              <1> 	; 21/07/2015
  2607 0000456F 89E5                <1> 	mov	ebp, esp ; (**)
  2608                              <1> 	; 18/10/2015
  2609 00004571 89EF                <1> 	mov 	edi, ebp
  2610 00004573 B900010000          <1> 	mov 	ecx, MAX_ARG_LEN ; 256
  2611                              <1> 	;sub	edi, MAX_ARG_LEN ; 256
  2612 00004578 29CF                <1> 	sub	edi, ecx
  2613 0000457A 89FC                <1> 	mov	esp, edi
  2614 0000457C 31C0                <1> 	xor	eax, eax
  2615 0000457E A3[C06E0000]        <1> 	mov 	[u.nread], eax ; 0
  2616                              <1> 	; 12/01/2022
  2617                              <1> 	; ([argc] must be cleared because previous 'sysexec'
  2618                              <1> 	; may leave it with any value after an error))
  2619                              <1> 	;mov	[argc], ax
  2620 00004583 A2[166F0000]        <1> 	mov	[argc], al ; 0
  2621                              <1> 	;
  2622 00004588 49                  <1> 	dec	ecx ; 256 - 1
  2623 00004589 890D[BC6E0000]      <1> 	mov 	[u.count], ecx ; MAX_ARG_LEN - 1 ; 255
  2624                              <1> 	;mov 	dword [u.count], MAX_ARG_LEN - 1 ; 255
  2625                              <1> sysexec_2:
  2626 0000458F 8B35[186F0000]      <1> 	mov	esi, [argv] ; 18/10/2015 
  2627 00004595 E860020000          <1> 	call	get_argp
  2628                              <1> 	;mov	ecx, 4 
  2629                              <1> 	; 03/02/2022
  2630 0000459A 31C9                <1> 	xor	ecx, ecx
  2631 0000459C B104                <1> 	mov	cl, 4
  2632                              <1> sysexec_3:
  2633 0000459E 21C0                <1> 	and	eax, eax
  2634 000045A0 7455                <1> 	jz	short sysexec_6
  2635                              <1> 	; 18/10/2015
  2636 000045A2 010D[186F0000]      <1> 	add	[argv], ecx ; 4
  2637                              <1> 	;inc	word [argc]
  2638                              <1> 	; 12/01/2022 ; ([argc] < 32)
  2639 000045A8 FE05[166F0000]      <1> 	inc	byte [argc]
  2640                              <1> 	;
  2641 000045AE A3[B86E0000]        <1> 	mov	[u.base], eax
  2642                              <1>  	; 23/10/2015
  2643 000045B3 66C705[FD6E0000]00- <1> 	mov	word [u.pcount], 0
  2643 000045BB 00                  <1>
  2644                              <1> sysexec_4:
  2645 000045BC E84B110000          <1> 	call	cpass ; get a character from user's core memory
  2646 000045C1 750B                <1>         jnz	short sysexec_5
  2647                              <1> 		; (max. 255 chars + null)
  2648                              <1> 	; 18/10/2015
  2649 000045C3 28C0                <1> 	sub 	al, al
  2650 000045C5 AA                  <1> 	stosb
  2651 000045C6 FF05[C06E0000]      <1> 	inc	dword [u.nread]
  2652 000045CC EB29                <1> 	jmp	short sysexec_6
  2653                              <1> sysexec_5:
  2654 000045CE AA                  <1> 	stosb
  2655 000045CF 20C0                <1> 	and 	al, al
  2656 000045D1 75E9                <1> 	jnz	short sysexec_4
  2657                              <1> 	;mov	ecx, 4
  2658                              <1> 	; 24/12/2021
  2659 000045D3 29C9                <1> 	sub	ecx, ecx
  2660 000045D5 B104                <1> 	mov	cl, 4
  2661                              <1> 	;cmp	[ncount], ecx ; 4
  2662                              <1> 	; 24/12/2021
  2663 000045D7 66390D[146F0000]    <1> 	cmp	[ncount], cx ; 4
  2664 000045DE 72AF                <1> 	jb	short sysexec_2
  2665 000045E0 8B35[106F0000]      <1> 	mov	esi, [nbase]
  2666 000045E6 010D[106F0000]      <1> 	add	[nbase], ecx ; 4	
  2667 000045EC 66290D[146F0000]    <1> 	sub	[ncount], cx 
  2668 000045F3 8B06                <1> 	mov	eax, [esi]
  2669 000045F5 EBA7                <1> 	jmp	short sysexec_3
  2670                              <1> sysexec_6:
  2671                              <1> 	; 18/10/2015
  2672                              <1> 	; argument list transfer from user's core memory to
  2673                              <1> 	; kernel stack frame is OK here.
  2674                              <1> 	; [u.nread] = ; argument list length
  2675                              <1> 	;mov	[argv], esp ; start address of argument list 	
  2676                              <1> 	;
  2677                              <1> 	; 18/10/2015
  2678                              <1> 	; 24/07/2015
  2679                              <1>         ; 21/07/2015
  2680                              <1> 	; 02/07/2015
  2681                              <1> 	; 25/06/2015
  2682                              <1> 	; 24/06/2015
  2683                              <1> 	; 23/06/2015
  2684                              <1> 	;
  2685 000045F7 8B1D[F56E0000]      <1> 	mov	ebx, [u.ppgdir] ; parent's page directory
  2686 000045FD 21DB                <1> 	and 	ebx, ebx  ; /etc/init ? (u.ppgdir = 0)	
  2687 000045FF 740A                <1> 	jz	short sysexec_7
  2688 00004601 A1[F16E0000]        <1> 	mov	eax, [u.pgdir] ; physical address of page directory
  2689 00004606 E8DBE8FFFF          <1> 	call	deallocate_page_dir
  2690                              <1> sysexec_7:
  2691 0000460B E80BE8FFFF          <1> 	call	make_page_dir
  2692                              <1> 	;jc	short sysexec_14
  2693                              <1> 	;jc	panic  ; allocation error 
  2694                              <1> 		       ; after a deallocation would be nonsence !?
  2695                              <1> 	; 08/01/2022
  2696 00004610 7243                <1> 	jc	short sysexec_panic
  2697                              <1> 
  2698                              <1> 	; 24/07/2015
  2699                              <1> 	; map kernel pages (1st 4MB) to PDE 0
  2700                              <1> 	;     of the user's page directory
  2701                              <1> 	;     (It is needed for interrupts!)
  2702                              <1> 	; 18/10/2015
  2703 00004612 8B15[D86A0000]      <1> 	mov	edx, [k_page_dir] ; Kernel's page directory
  2704 00004618 8B02                <1> 	mov	eax, [edx] ; physical address of
  2705                              <1> 			   ; kernel's first page table (1st 4 MB)
  2706                              <1> 			   ; (PDE 0 of kernel's page directory)
  2707 0000461A 8B15[F16E0000]      <1> 	mov 	edx, [u.pgdir]
  2708 00004620 8902                <1> 	mov	[edx], eax ; PDE 0 (1st 4MB)
  2709                              <1> 	;
  2710                              <1> 	; 20/07/2015
  2711 00004622 BB00004000          <1> 	mov	ebx, CORE ; start address = 0 (virtual) + CORE
  2712                              <1> 	; 18/10/2015
  2713 00004627 BE[086F0000]        <1> 	mov	esi, pcore ; physical start address
  2714                              <1> sysexec_8:	
  2715 0000462C B907000000          <1> 	mov	ecx, PDE_A_USER + PDE_A_WRITE + PDE_A_PRESENT
  2716 00004631 E803E8FFFF          <1> 	call	make_page_table
  2717                              <1> 	;jc	panic
  2718                              <1> 	; 24/12/2021
  2719 00004636 721D                <1> 	jc	short sysexec_panic
  2720                              <1> 	;mov	ecx, PTE_A_USER + PTE_A_WRITE + PTE_A_PRESENT
  2721 00004638 E80AE8FFFF          <1> 	call	make_page ; make new page, clear and set the pte 
  2722                              <1> 	;jc	panic
  2723                              <1> 	; 24/12/2021
  2724 0000463D 7216                <1> 	jc	short sysexec_panic
  2725                              <1> 	;
  2726 0000463F 8906                <1> 	mov	[esi], eax ; 24/06/2015
  2727                              <1> 	; ebx = virtual address (24/07/2015)
  2728                              <1> 	; 24/12/2021
  2729                              <1> 	;call 	add_to_swap_queue
  2730                              <1> 	; 18/10/2015
  2731 00004641 81FE[0C6F0000]      <1> 	cmp	esi, ecore ; user's stack (last) page ?
  2732 00004647 7411                <1> 	je	short sysexec_9 ; yes
  2733 00004649 BE[0C6F0000]        <1> 	mov	esi, ecore  ; physical address of the last page 
  2734                              <1> 	; 20/07/2015
  2735 0000464E BB00F0FFFF          <1> 	mov	ebx, (ECORE - PAGE_SIZE) + CORE
  2736                              <1> 	; ebx = virtual end address + segment base address - 4K
  2737 00004653 EBD7                <1>         jmp     short sysexec_8
  2738                              <1> 
  2739                              <1> sysexec_panic:
  2740                              <1> 	; 26/03/2021
  2741 00004655 E92CEDFFFF          <1> 	jmp	panic
  2742                              <1> 
  2743                              <1> sysexec_9:
  2744                              <1> 	; 18/10/2015
  2745                              <1> 	; 26/08/2015
  2746                              <1> 	; 25/06/2015
  2747                              <1> 	; move arguments from kernel stack to [ecore]
  2748                              <1> 	; (argument list/line will be copied from kernel stack
  2749                              <1> 	; frame to the last (stack) page of user's core memory)
  2750                              <1> 	; 18/10/2015
  2751 0000465A 8B3D[0C6F0000]      <1> 	mov	edi, [ecore]
  2752 00004660 81C700100000        <1> 	add	edi, PAGE_SIZE
  2753                              <1> 	;movzx	eax, word [argc]
  2754                              <1> 	; 12/01/2022
  2755 00004666 31C0                <1> 	xor	eax, eax
  2756 00004668 A0[166F0000]        <1> 	mov	al, [argc]
  2757 0000466D 08C0                <1> 	or	al, al
  2758                              <1> 	;or	eax, eax
  2759 0000466F 7509                <1> 	jnz	short sysexec_10
  2760 00004671 89FB                <1> 	mov 	ebx, edi
  2761 00004673 83EB04              <1> 	sub	ebx, 4 
  2762 00004676 8903                <1> 	mov	[ebx], eax ; 0
  2763 00004678 EB40                <1> 	jmp 	short sysexec_13
  2764                              <1> sysexec_10:
  2765 0000467A 8B0D[C06E0000]      <1> 	mov	ecx, [u.nread]
  2766                              <1> 	;mov 	esi, [argv]
  2767 00004680 89E6                <1> 	mov	esi, esp ; start address of argument list
  2768 00004682 29CF                <1> 	sub	edi, ecx ; page end address - argument list length
  2769 00004684 89C2                <1> 	mov	edx, eax
  2770                              <1> 	; 12/01/2022 ; ([argc] < 32)
  2771 00004686 FEC2                <1> 	inc	dl ; argument count + 1 for argc value  
  2772 00004688 C0E202              <1> 	shl 	dl, 2  ; 4 * (argument count + 1)
  2773                              <1> 	; edx <= 128
  2774 0000468B 89FB                <1> 	mov	ebx, edi
  2775 0000468D 80E3FC              <1> 	and	bl, 0FCh ; 32 bit (dword) alignment
  2776 00004690 29D3                <1> 	sub 	ebx, edx
  2777 00004692 89FA                <1> 	mov	edx, edi
  2778 00004694 F3A4                <1> 	rep	movsb
  2779 00004696 89D6                <1> 	mov 	esi, edx
  2780 00004698 89DF                <1> 	mov 	edi, ebx
  2781 0000469A BA00F0BFFF          <1> 	mov	edx, ECORE - PAGE_SIZE ; virtual addr. of the last page
  2782 0000469F 2B15[0C6F0000]      <1> 	sub 	edx, [ecore] ; difference (virtual - physical) 
  2783 000046A5 AB                  <1> 	stosd	; eax = argument count	
  2784                              <1> sysexec_11:
  2785 000046A6 89F0                <1> 	mov	eax, esi
  2786 000046A8 01D0                <1> 	add	eax, edx
  2787 000046AA AB                  <1> 	stosd  ; eax = virtual address
  2788 000046AB FE0D[166F0000]      <1> 	dec	byte [argc]
  2789 000046B1 7407                <1> 	jz	short sysexec_13
  2790                              <1> sysexec_12:
  2791 000046B3 AC                  <1> 	lodsb
  2792 000046B4 20C0                <1> 	and	al, al
  2793 000046B6 75FB                <1> 	jnz	short sysexec_12
  2794 000046B8 EBEC                <1> 	jmp	short sysexec_11
  2795                              <1> 	;
  2796                              <1> 	; 1:
  2797                              <1> 		; mov (sp)+,r5 / r5 now contains address of list of 
  2798                              <1> 			     ; / pointers to arguments to be passed
  2799                              <1> 		; mov $1,u.quit / u.quit determines handling of quits;
  2800                              <1> 			      ; / u.quit = 1 take quit
  2801                              <1> 		; mov $1,u.intr / u.intr determines handling of 
  2802                              <1> 			     ; / interrupts; u.intr = 1 take interrupt
  2803                              <1> 		; mov $rtssym,30 / emt trap vector set to take 
  2804                              <1> 			       ; / system routine
  2805                              <1> 		; mov $fpsym,*10 / reserved instruction trap vector 
  2806                              <1> 			       ; / set to take system routine
  2807                              <1> 		; mov $sstack,sp / stack space used during swapping
  2808                              <1> 		; mov r5,-(sp) / save arguments pointer on stack
  2809                              <1> 		; mov $ecore,r5 / r5 has end of core
  2810                              <1> 		; mov $core,r4 / r4 has start of users core
  2811                              <1> 		; mov r4,u.base / u.base has start of users core
  2812                              <1> 		; mov (sp),r2 / move arguments list pointer into r2
  2813                              <1> 	; 1:
  2814                              <1> 		; tst (r2)+ / argument char = "nul"
  2815                              <1> 		; bne 1b
  2816                              <1> 		; tst -(r2) / decrement r2 by 2; r2 has addr of 
  2817                              <1> 			  ; / end of argument pointer list
  2818                              <1> 	; 1:
  2819                              <1> 	     ; / move arguments to bottom of users core
  2820                              <1> 		; mov -(r2),r3 / (r3) last non zero argument ptr
  2821                              <1> 		; cmp r2,(sp) / is r2 = beginning of argument
  2822                              <1> 			    ; / ptr list
  2823                              <1> 		; blo 1f / branch to 1f when all arguments
  2824                              <1> 		       ; / are moved
  2825                              <1> 		; mov -(r2),r3 / (r3) last non zero argument ptr
  2826                              <1> 	; 2:
  2827                              <1> 		; tstb (r3)+
  2828                              <1> 		; bne 2b / scan argument for \0 (nul)
  2829                              <1> 
  2830                              <1> 	; 2:
  2831                              <1> 		; movb -(r3),-(r5) / move argument char 
  2832                              <1> 				 ; / by char starting at "ecore"
  2833                              <1> 		; cmp r3,(r2) / moved all characters in 
  2834                              <1> 			    ; / this argument
  2835                              <1> 		; bhi 2b / branch 2b if not
  2836                              <1> 		; mov r5,(r4)+ / move r5 into top of users core;
  2837                              <1> 			     ; / r5 has pointer to nth arg
  2838                              <1> 		; br 1b / string
  2839                              <1> 	; 1:
  2840                              <1> 		; clrb -(r5)
  2841                              <1> 		; bic $1,r5 / make r5 even, r5 points to 
  2842                              <1> 			; / last word of argument strings
  2843                              <1> 		; mov $core,r2
  2844                              <1> 	
  2845                              <1> 	; 1: / move argument pointers into core following 
  2846                              <1> 	      ; / argument strings
  2847                              <1> 		; cmp r2,r4
  2848                              <1> 		; bhis 1f / branch to 1f when all pointers
  2849                              <1> 			; / are moved
  2850                              <1> 		; mov (r2)+,-(r5)
  2851                              <1> 		; br 1b
  2852                              <1> 	; 1:
  2853                              <1> 		; sub $core,r4 / gives number of arguments *2
  2854                              <1> 		; asr r4 / divide r4 by 2 to calculate 
  2855                              <1> 		       ; / the number of args stored
  2856                              <1> 		; mov r4,-(r5) / save number of arguments ahead
  2857                              <1> 			     ; / of the argument pointers
  2858                              <1> sysexec_13:
  2859                              <1> 	; 19/10/2015
  2860                              <1> 	; 18/10/2015
  2861                              <1> 	; 29/07/2015
  2862                              <1> 	; 25/07/2015
  2863                              <1> 	; 24/07/2015
  2864                              <1> 	; 20/07/2015
  2865                              <1> 	; 25/06/2015
  2866                              <1> 	; 24/06/2015
  2867                              <1> 	; 23/06/2015
  2868                              <1> 	;
  2869                              <1> 	; moving arguments to [ecore] is OK here..
  2870                              <1> 	; 18/10/2015
  2871 000046BA 89EC                <1> 	mov 	esp, ebp ; (**) restore kernel stack pointer
  2872                              <1> 	; ebx = beginning addres of argument list pointers
  2873                              <1> 	;	in user's stack
  2874                              <1> 	; 19/10/2015
  2875 000046BC 2B1D[0C6F0000]      <1> 	sub 	ebx, [ecore]
  2876 000046C2 81C300F0BFFF        <1> 	add     ebx, (ECORE - PAGE_SIZE)
  2877                              <1> 			; end of core - 4096 (last page)
  2878                              <1> 			; (virtual address)
  2879 000046C8 891D[186F0000]      <1> 	mov	[argv], ebx
  2880 000046CE 891D[C46E0000]      <1> 	mov	[u.break], ebx ; available user memory
  2881                              <1> 	;
  2882 000046D4 29C0                <1> 	sub	eax, eax
  2883 000046D6 C705[BC6E0000]2000- <1> 	mov	dword [u.count], 32 ; Executable file header size
  2883 000046DE 0000                <1>
  2884                              <1> 		; mov $14,u.count
  2885 000046E0 C705[A86E0000]-     <1> 	mov	dword [u.fofp], u.off
  2885 000046E6 [B46E0000]          <1>
  2886                              <1> 		; mov $u.off,u.fofp
  2887 000046EA A3[B46E0000]        <1> 	mov	[u.off], eax ; 0
  2888                              <1> 		; clr u.off / set offset in file to be read to zero
  2889                              <1> 	; 25/07/2015
  2890 000046EF A3[B86E0000]        <1> 	mov	[u.base], eax ; 0, start of user's core (virtual)
  2891                              <1> 	; 25/06/2015 
  2892 000046F4 66A1[7C6E0000]      <1> 	mov	ax, [ii]
  2893                              <1> 	; AX = i-number of the executable file
  2894 000046FA E86A0C0000          <1> 	call	readi
  2895                              <1> 		; jsr r0,readi / read in first six words of 
  2896                              <1> 			; / user's file, starting at $core
  2897                              <1> 		; mov sp,r5 / put users stack address in r5
  2898                              <1> 		; sub $core+40.,r5 / subtract $core +40, 
  2899                              <1> 				; / from r5 (leaves number of words
  2900                              <1> 				; / less 26 available for
  2901                              <1> 			     	; / program in user core
  2902                              <1> 		; mov r5,u.count /
  2903                              <1> 	; 25/06/2015
  2904 000046FF 8B0D[C46E0000]      <1> 	mov	ecx, [u.break] ; top of user's stack (physical addr.)
  2905 00004705 890D[BC6E0000]      <1> 	mov	[u.count], ecx ; save for overrun check
  2906                              <1> 	;
  2907 0000470B 8B0D[C06E0000]      <1> 	mov	ecx, [u.nread]
  2908 00004711 890D[C46E0000]      <1> 	mov	[u.break], ecx ; virtual address (offset from start)
  2909 00004717 80F920              <1> 	cmp	cl, 32
  2910 0000471A 7540                <1>         jne     short sysexec_15
  2911                              <1> 	;:
  2912                              <1> 	; 25/06/2015
  2913                              <1> 	; Retro UNIX 386 v1 (32 bit) executable file header format
  2914                              <1> 	; 18/10/2015
  2915 0000471C 8B35[086F0000]      <1> 	mov	esi, [pcore] ; start address of user's core memory 
  2916                              <1> 		             ; (phys. start addr. of the exec. file)
  2917 00004722 AD                  <1> 	lodsd
  2918 00004723 663DEB1E            <1> 	cmp	ax, 1EEBh ; EBH, 1Eh -> jump to +32
  2919 00004727 7533                <1> 	jne	short sysexec_15
  2920                              <1> 		; cmp core,$405 / br .+14 is first instruction 
  2921                              <1> 			      ; / if file is standard a.out format
  2922                              <1> 		; bne 1f / branch, if not standard format
  2923 00004729 AD                  <1> 	lodsd
  2924 0000472A 89C1                <1> 	mov	ecx, eax ; text (code) section size
  2925 0000472C AD                  <1> 	lodsd
  2926 0000472D 01C1                <1> 	add	ecx, eax ; + data section size (initialized data)
  2927                              <1> 		; mov core+2,r5 / put 2nd word of users program in r5;
  2928                              <1> 		              ; / number of bytes in program text	
  2929                              <1> 		; sub $14,r5 / subtract 12
  2930 0000472F 89CB                <1> 	mov	ebx, ecx
  2931                              <1> 	;
  2932                              <1> 	; 25/06/2015
  2933                              <1> 	; NOTE: These are for next versions of Retro UNIX 386
  2934                              <1> 	;	and SINGLIX operating systems (as code template).
  2935                              <1> 	;	Current Retro UNIX 386 v1 files can be max. 64KB
  2936                              <1> 	;	due to RUFS (floppy disk file system) restriction...
  2937                              <1> 	;	Overrun is not possible for current version. 	
  2938                              <1> 	;
  2939 00004731 AD                  <1> 	lodsd	
  2940 00004732 01C3                <1> 	add	ebx, eax ; + bss section size (for overrun checking)
  2941 00004734 3B1D[BC6E0000]      <1> 	cmp	ebx, [u.count]
  2942 0000473A 7711                <1> 	ja	short sysexec_14  ; program overruns stack !
  2943                              <1> 	;
  2944                              <1> 	; 24/07/2015
  2945                              <1> 	; add bss section size to [u.break]
  2946 0000473C 0105[C46E0000]      <1> 	add 	[u.break], eax
  2947                              <1> 	;
  2948 00004742 83E920              <1> 	sub	ecx, 32  ; header size (already loaded)
  2949                              <1> 	;cmp	ecx, [u.count]
  2950                              <1> 	;jnb	short sysexec_16
  2951                              <1> 		; cmp r5,u.count /
  2952                              <1> 		; bgt 1f / branch if r5 greater than u.count
  2953 00004745 890D[BC6E0000]      <1> 	mov	[u.count], ecx ; required read count
  2954                              <1> 		; mov r5,u.count
  2955                              <1> 	;
  2956 0000474B EB2A                <1> 	jmp	short sysexec_16
  2957                              <1> 	;
  2958                              <1> sysexec_14:
  2959                              <1> 	; 23/06/2015
  2960                              <1> 	; insufficient (out of) memory
  2961 0000474D C705[ED6E0000]0400- <1> 	mov	dword [u.error], ERR_MINOR_IM ; 1
  2961 00004755 0000                <1>
  2962 00004757 E976F3FFFF          <1> 	jmp	error
  2963                              <1> 	;
  2964                              <1> sysexec_15:
  2965                              <1> 	; 25/06/2015
  2966 0000475C 0FB715[9C6B0000]    <1>         movzx   edx, word [i.size] ; file size
  2967 00004763 29CA                <1> 	sub	edx, ecx ; file size - loaded bytes
  2968 00004765 7627                <1> 	jna	short sysexec_17 ; no need to next read
  2969 00004767 01D1                <1> 	add	ecx, edx ; [i.size]
  2970 00004769 3B0D[BC6E0000]      <1> 	cmp	ecx, [u.count] ; overrun check (!)
  2971 0000476F 77DC                <1> 	ja	short sysexec_14
  2972 00004771 8915[BC6E0000]      <1> 	mov	[u.count], edx
  2973                              <1> sysexec_16:
  2974 00004777 66A1[7C6E0000]      <1> 	mov	ax, [ii] ; i-number
  2975 0000477D E8E70B0000          <1> 	call	readi
  2976                              <1> 		; add core+10,u.nread / add size of user data area 
  2977                              <1> 		                    ; / to u.nread
  2978                              <1> 		; br 2f
  2979                              <1> 	; 1:
  2980                              <1> 		; jsr r0,readi / read in rest of file
  2981                              <1> 	; 2:
  2982 00004782 8B0D[C06E0000]      <1> 	mov	ecx, [u.nread]
  2983 00004788 010D[C46E0000]      <1> 	add	[u.break], ecx
  2984                              <1> 		; mov u.nread,u.break / set users program break to end of 
  2985                              <1> 				    ; / user code
  2986                              <1> 		; add $core+14,u.break / plus data area
  2987                              <1> sysexec_17: ; 20/07/2015
  2988                              <1> 	; 08/01/2022 - Retro UNIX 386 v1.1 (Kernel v0.2.1.2)
  2989                              <1> 	; ('iclose' is not needed for regular files, from now on)
  2990                              <1> 	;;mov	ax, [ii] ; i-number
  2991                              <1> 	;call	iclose
  2992                              <1> 	;	; jsr r0,iclose / does nothing
  2993 0000478E 31C0                <1>         xor     eax, eax
  2994 00004790 FEC0                <1> 	inc	al
  2995 00004792 66A3[DC6E0000]      <1> 	mov	[u.intr], ax ; 1 (interrupt/time-out is enabled)
  2996 00004798 66A3[DE6E0000]      <1> 	mov	[u.quit], ax ; 1 ('crtl+brk' signal is enabled) 
  2997                              <1> 	; 02/07/2015
  2998 0000479E 833D[F56E0000]00    <1>         cmp	dword [u.ppgdir], 0  ; is the caller sys_init (kernel) ?
  2999 000047A5 770C                <1> 	ja	short sysexec_18 ; no, the caller is user process
  3000                              <1> 	; If the caller is kernel (sys_init), 'sysexec' will come here
  3001 000047A7 8B15[D86A0000]      <1> 	mov	edx, [k_page_dir] ; kernel's page directory
  3002 000047AD 8915[F56E0000]      <1> 	mov	[u.ppgdir], edx ; next time 'sysexec' must not come here 
  3003                              <1> sysexec_18:
  3004                              <1> 	; 18/10/2015
  3005                              <1> 	; 05/08/2015
  3006                              <1> 	; 29/07/2015
  3007 000047B3 8B2D[186F0000]      <1> 	mov	ebp, [argv] ; user's stack pointer must point to argument
  3008                              <1> 			    ; list pointers (argument count)
  3009 000047B9 FA                  <1> 	cli
  3010 000047BA 8B25[746A0000]      <1>         mov     esp, [tss.esp0]  ; ring 0 (kernel) stack pointer
  3011                              <1> 	;mov   	esp, [u.sp] ; Restore Kernel stack
  3012                              <1> 			    ; for this process	 
  3013                              <1> 	;add	esp, 20 ; --> EIP, CS, EFLAGS, ESP, SS
  3014                              <1> 	;xor	eax, eax ; 0
  3015 000047C0 FEC8                <1> 	dec	al ; eax = 0
  3016 000047C2 66BA2300            <1> 	mov	dx, UDATA
  3017 000047C6 6652                <1> 	push	dx  ; user's stack segment
  3018 000047C8 55                  <1> 	push	ebp ; user's stack pointer
  3019                              <1> 		    ; (points to number of arguments)
  3020 000047C9 FB                  <1> 	sti
  3021 000047CA 9C                  <1> 	pushfd	; EFLAGS
  3022                              <1> 		; Set IF for enabling interrupts in user mode	
  3023                              <1> 	;or	dword [esp], 200h 
  3024                              <1> 	;
  3025                              <1> 	;mov	bx, UCODE
  3026                              <1> 	;push	bx ; user's code segment
  3027 000047CB 6A1B                <1> 	push	UCODE
  3028                              <1> 	;push	0
  3029 000047CD 50                  <1> 	push	eax ; EIP (=0) - start address -	
  3030                              <1> 		; clr -(r5) / popped into ps when rti in 
  3031                              <1> 			  ; / sysrele is executed
  3032                              <1> 		; mov $core,-(r5) / popped into pc when rti 
  3033                              <1> 		                ; / in sysrele is executed
  3034                              <1> 		;mov r5,0f / load second copyz argument
  3035                              <1> 		;tst -(r5) / decrement r5
  3036 000047CE 8925[906E0000]      <1> 	mov	[u.sp], esp ; 29/07/2015
  3037                              <1> 	; 05/08/2015
  3038                              <1> 	; Remedy of a General Protection Fault during 'iretd' is here !
  3039                              <1> 	; ('push dx' would cause to general protection fault, 
  3040                              <1> 	; after 'pop ds' etc.)
  3041                              <1> 	;
  3042                              <1> 	;; push dx ; ds (UDATA)
  3043                              <1> 	;; push dx ; es (UDATA)
  3044                              <1> 	;; push dx ; fs (UDATA)
  3045                              <1> 	;; push dx ; gs (UDATA)
  3046                              <1> 	;
  3047                              <1> 	; This is a trick to prevent general protection fault
  3048                              <1> 	; during 'iretd' intruction at the end of 'sysrele' (in u1.s):
  3049 000047D4 8EC2                <1> 	mov 	es, dx ; UDATA
  3050 000047D6 06                  <1> 	push 	es ; ds (UDATA)
  3051 000047D7 06                  <1> 	push 	es ; es (UDATA)
  3052 000047D8 06                  <1> 	push 	es ; fs (UDATA)
  3053 000047D9 06                  <1> 	push	es ; gs (UDATA)
  3054 000047DA 66BA1000            <1> 	mov	dx, KDATA
  3055 000047DE 8EC2                <1> 	mov	es, dx
  3056                              <1> 	;
  3057                              <1> 	;; pushad simulation
  3058 000047E0 89E5                <1> 	mov	ebp, esp ; esp before pushad
  3059 000047E2 50                  <1> 	push	eax ; eax (0)
  3060 000047E3 50                  <1> 	push	eax ; ecx (0)
  3061 000047E4 50                  <1> 	push	eax ; edx (0)
  3062 000047E5 50                  <1> 	push	eax ; ebx (0)
  3063 000047E6 55                  <1> 	push	ebp ; esp before pushad
  3064 000047E7 50                  <1> 	push	eax ; ebp (0)
  3065 000047E8 50                  <1> 	push	eax ; esi (0)		
  3066 000047E9 50                  <1> 	push	eax ; edi (0)	
  3067                              <1> 	;
  3068 000047EA A3[986E0000]        <1> 	mov	[u.r0], eax ; eax = 0
  3069 000047EF 8925[946E0000]      <1> 	mov	[u.usp], esp
  3070                              <1> 		; mov r5,u.r0 /
  3071                              <1> 		; sub $16.,r5 / skip 8 words
  3072                              <1> 		; mov r5,u.sp / assign user stack pointer value, 
  3073                              <1> 		;             / effectively zeroes all regs
  3074                              <1> 			    ; / when sysrele is executed
  3075                              <1> 		; jsr r0,copyz; core; 0:0 / zero user's core
  3076                              <1> 		; clr u.break
  3077                              <1> 		; mov r5,sp / point sp to user's stack
  3078                              <1> 	;
  3079 000047F5 E9FAF2FFFF          <1> 	jmp	sysret0
  3080                              <1> 	;jmp	sysret
  3081                              <1> 		; br sysret3 / return to core image at $core
  3082                              <1> 
  3083                              <1> get_argp:
  3084                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3085                              <1> 	; 18/10/2015 (nbase, ncount)
  3086                              <1> 	; 21/07/2015
  3087                              <1> 	; 24/06/2015 (Retro UNIX 386 v1)
  3088                              <1> 	; Get (virtual) address of argument from user's core memory
  3089                              <1> 	;
  3090                              <1> 	; INPUT:
  3091                              <1> 	;	esi = virtual address of argument pointer
  3092                              <1> 	; OUTPUT:
  3093                              <1> 	;	eax = virtual address of argument
  3094                              <1> 	;
  3095                              <1> 	; Modified registers: EAX, EBX, ECX, EDX, ESI 
  3096                              <1> 	;
  3097 000047FA 833D[F56E0000]00    <1>  	cmp     dword [u.ppgdir], 0 ; /etc/init ?
  3098                              <1> 				    ; (the caller is kernel)
  3099                              <1> 	;jna	short get_argpk 
  3100                              <1> 	; 24/12/2021
  3101 00004801 7719                <1> 	ja	short get_argp5
  3102                              <1> get_argpk:
  3103                              <1> 	; Argument is in kernel's memory space
  3104 00004803 66C705[146F0000]00- <1> 	mov	word [ncount], PAGE_SIZE ; 4096
  3104 0000480B 10                  <1>
  3105 0000480C 8935[106F0000]      <1> 	mov	[nbase], esi
  3106 00004812 8305[106F0000]04    <1> 	add	dword [nbase], 4
  3107 00004819 8B06                <1> 	mov	eax, [esi] ; virtual addr. = physcal addr.
  3108 0000481B C3                  <1> 	retn
  3109                              <1> get_argp5:
  3110 0000481C 89F3                <1>      	mov	ebx, esi
  3111 0000481E E87FE9FFFF          <1> 	call	get_physical_addr ; get physical address
  3112 00004823 7257                <1>         jc      short get_argp_err ; 24/12/2021 (short jump)
  3113 00004825 A3[106F0000]        <1> 	mov 	[nbase], eax ; physical address	
  3114 0000482A 66890D[146F0000]    <1> 	mov	[ncount], cx ; remain byte count in page (1-4096)
  3115 00004831 B804000000          <1> 	mov	eax, 4 ; 21/07/2015
  3116                              <1> 	;cmp	cx, ax ; 4
  3117 00004836 39C1                <1> 	cmp	ecx, eax ; 24/12/2021
  3118 00004838 734C                <1> 	jnb	short get_argp2
  3119 0000483A 89F3                <1> 	mov	ebx, esi
  3120 0000483C 01CB                <1> 	add	ebx, ecx
  3121 0000483E E85FE9FFFF          <1> 	call	get_physical_addr ; get physical address
  3122 00004843 7237                <1> 	jc	short get_argp_err
  3123                              <1> 	;push	esi
  3124 00004845 89C6                <1> 	mov	esi, eax
  3125 00004847 66870D[146F0000]    <1> 	xchg	cx, [ncount]
  3126 0000484E 8735[106F0000]      <1> 	xchg	esi, [nbase]
  3127 00004854 B504                <1> 	mov	ch, 4
  3128 00004856 28CD                <1> 	sub	ch, cl
  3129                              <1> get_argp0:
  3130 00004858 AC                  <1> 	lodsb
  3131                              <1> 	;push	ax
  3132                              <1> 	; 24/12/2021
  3133 00004859 50                  <1> 	push	eax
  3134 0000485A FEC9                <1> 	dec	cl
  3135 0000485C 75FA                <1>         jnz     short get_argp0
  3136 0000485E 8B35[106F0000]      <1> 	mov	esi, [nbase]
  3137                              <1> 	; 21/07/2015
  3138 00004864 0FB6C5              <1> 	movzx	eax, ch
  3139 00004867 0105[106F0000]      <1> 	add	[nbase], eax
  3140 0000486D 662905[146F0000]    <1> 	sub	[ncount], ax
  3141                              <1> get_argp1:
  3142 00004874 AC                  <1> 	lodsb
  3143 00004875 FECD                <1> 	dec	ch
  3144 00004877 7423                <1>         jz      short get_argp3
  3145                              <1> 	;push	ax
  3146                              <1> 	; 24/12/2021
  3147 00004879 50                  <1> 	push	eax
  3148 0000487A EBF8                <1> 	jmp     short get_argp1
  3149                              <1> 	; 24/12/2021
  3150                              <1> get_argp_err:
  3151 0000487C A3[ED6E0000]        <1> 	mov	[u.error], eax
  3152 00004881 E94CF2FFFF          <1> 	jmp	error
  3153                              <1> get_argp2:
  3154                              <1> 	; 21/07/2015
  3155                              <1> 	;mov	eax, 4
  3156 00004886 8B15[106F0000]      <1> 	mov 	edx, [nbase] ; 18/10/2015
  3157 0000488C 0105[106F0000]      <1> 	add	[nbase], eax
  3158 00004892 662905[146F0000]    <1> 	sub	[ncount], ax
  3159                              <1> 	;
  3160 00004899 8B02                <1> 	mov	eax, [edx]
  3161 0000489B C3                  <1> 	retn
  3162                              <1> get_argp3:
  3163 0000489C B103                <1> 	mov	cl, 3
  3164                              <1> get_argp4:
  3165 0000489E C1E008              <1> 	shl	eax, 8
  3166                              <1> 	;pop	dx
  3167                              <1> 	; 24/12/2021
  3168 000048A1 5A                  <1> 	pop	edx
  3169 000048A2 88D0                <1> 	mov 	al, dl
  3170 000048A4 E2F8                <1>         loop    get_argp4
  3171                              <1> 	;pop	esi
  3172 000048A6 C3                  <1> 	retn	
  3173                              <1> 
  3174                              <1> sysfstat:
  3175                              <1> 	; 03/02/2022
  3176                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3177                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  3178                              <1> 	;
  3179                              <1> 	; 'sysfstat' is identical to 'sysstat' except that it operates
  3180                              <1> 	; on open files instead of files given by name. It puts the
  3181                              <1> 	; buffer address on the stack, gets the i-number and
  3182                              <1> 	; checks to see if the file is open for reading or writing.
  3183                              <1> 	; If the file is open for writing (i-number is negative)
  3184                              <1> 	; the i-number is set positive and a branch into 'sysstat'
  3185                              <1> 	; is made.	
  3186                              <1> 	;
  3187                              <1> 	; Calling sequence:
  3188                              <1> 	;	sysfstat; buf
  3189                              <1> 	; Arguments:
  3190                              <1> 	;	buf - buffer address
  3191                              <1> 	;
  3192                              <1> 	; Inputs: *u.r0 - file descriptor
  3193                              <1> 	; Outputs: buffer is loaded with file information
  3194                              <1> 	; ...............................................................
  3195                              <1> 	;				
  3196                              <1> 	; Retro UNIX 8086 v1 modification:
  3197                              <1> 	;       'sysfstat' system call has two arguments; so,
  3198                              <1> 	;	* 1st argument, file descriptor is in BX register
  3199                              <1> 	;	* 2nd argument, buf is pointed to by CX register
  3200                              <1> 
  3201                              <1> 	; / set status of open file
  3202                              <1> 		; jsr r0,arg; u.off / put buffer address in u.off
  3203 000048A7 51                  <1> 	push	ecx
  3204                              <1> 		; mov u.off,-(sp) / put buffer address on the stack
  3205                              <1> 		; mov *u.r0,r1 / put file descriptor in r1
  3206                              <1> 		; jsr r0,getf / get the files i-number
  3207                              <1> 	; BX = file descriptor (file number)
  3208 000048A8 E8F2000000          <1> 	call	getf1
  3209                              <1> 	; 03/02/2022
  3210 000048AD 21C0                <1> 	and	eax, eax
  3211                              <1> 	;and	ax, ax ; i-number of the file
  3212                              <1> 		; tst	r1 / is it 0?
  3213                              <1> 	;jz	error
  3214                              <1> 		; beq error3 / yes, error
  3215 000048AF 750F                <1> 	jnz	short sysfstat1
  3216 000048B1 C705[ED6E0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN  ; 'file not open !'
  3216 000048B9 0000                <1>
  3217 000048BB E912F2FFFF          <1> 	jmp	error
  3218                              <1> sysfstat1:
  3219 000048C0 80FC80              <1> 	cmp	ah, 80h
  3220 000048C3 7222                <1>         jb      short sysstat1
  3221                              <1> 		; bgt 1f / if i-number is negative (open for writing)
  3222 000048C5 66F7D8              <1> 	neg	ax
  3223                              <1> 		; neg r1 / make it positive, then branch
  3224 000048C8 EB1D                <1> 	jmp	short sysstat1
  3225                              <1> 		; br 1f / to 1f
  3226                              <1> sysstat:
  3227                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3228                              <1> 	; 18/10/2015
  3229                              <1> 	; 07/10/2015
  3230                              <1> 	; 02/09/2015
  3231                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3232                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  3233                              <1> 	;
  3234                              <1> 	; 'sysstat' gets the status of a file. Its arguments are the
  3235                              <1> 	; name of the file and buffer address. The buffer is 34 bytes
  3236                              <1> 	; long and information about the file placed in it.	
  3237                              <1> 	; sysstat calls 'namei' to get the i-number of the file.
  3238                              <1> 	; Then 'iget' is called to get i-node in core. The buffer
  3239                              <1> 	; is then loaded and the results are given in the UNIX
  3240                              <1> 	; Programmers Manual sysstat (II).	
  3241                              <1> 	;
  3242                              <1> 	; Calling sequence:
  3243                              <1> 	;	sysstat; name; buf
  3244                              <1> 	; Arguments:
  3245                              <1> 	;	name - points to the name of the file
  3246                              <1> 	;	buf - address of a 34 bytes buffer
  3247                              <1> 	; Inputs: -
  3248                              <1> 	; Outputs: buffer is loaded with file information
  3249                              <1> 	; ...............................................................
  3250                              <1> 	;				
  3251                              <1> 	; Retro UNIX 8086 v1 modification: 
  3252                              <1> 	;       'sysstat' system call has two arguments; so,
  3253                              <1> 	;	Retro UNIX 8086 v1 argument transfer method 2 is used
  3254                              <1> 	;	to get sysstat system call arguments from the user;
  3255                              <1> 	;	* 1st argument, name is pointed to by BX register
  3256                              <1> 	;	* 2nd argument, buf is pointed to by CX register
  3257                              <1> 	;
  3258                              <1> 	;	NOTE: Retro UNIX 8086 v1 'arg2' routine gets these
  3259                              <1> 	;	      arguments which were in these registers;
  3260                              <1> 	;	      but, it returns by putting the 1st argument
  3261                              <1> 	;	      in 'u.namep' and the 2nd argument
  3262                              <1> 	;	      on top of stack. (1st argument is offset of the
  3263                              <1> 	;	      file/path name in the user's program segment.)		 	
  3264                              <1> 	
  3265                              <1> 	; / ; name of file; buffer - get files status
  3266                              <1> 		; jsr r0,arg2 / get the 2 arguments
  3267 000048CA 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  3268 000048D0 51                  <1> 	push	ecx
  3269 000048D1 E8FA000000          <1> 	call	namei
  3270                              <1> 		; jsr r0,namei / get the i-number for the file
  3271                              <1> 	;jc	error
  3272                              <1> 		; br error3 / no such file, error
  3273 000048D6 730F                <1> 	jnc	short sysstat1
  3274                              <1> 	; pop 	ecx
  3275                              <1> sysstat_err0:
  3276                              <1> 	; 'file not found !' error
  3277 000048D8 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  3277 000048E0 0000                <1>
  3278 000048E2 E9EBF1FFFF          <1> 	jmp	error
  3279                              <1> 
  3280                              <1> ;statx: db 0
  3281                              <1> 
  3282                              <1> sysstat1: ; 1:
  3283 000048E7 E8A9080000          <1> 	call	iget
  3284                              <1> 		; jsr r0,iget / get the i-node into core
  3285                              <1> 	; 07/10/2015 (ax = [ii], inode number)
  3286                              <1> 	; 02/09/2015
  3287 000048EC 8F05[B86E0000]      <1> 	pop	dword [u.base]
  3288                              <1> 		; mov (sp)+,r3 / move u.off to r3 (points to buffer)
  3289 000048F2 E855000000          <1> 	call	sysstat_gpa ; get physical address
  3290 000048F7 730A                <1> 	jnc 	short sysstat2
  3291                              <1> sysstat_err1:
  3292 000048F9 A3[ED6E0000]        <1> 	mov	dword [u.error], eax ; error code
  3293 000048FE E9CFF1FFFF          <1> 	jmp	error
  3294                              <1> sysstat2:
  3295 00004903 A0[7C6E0000]        <1> 	mov 	al, [ii] ; 07/10/2015 (result of 'iget' call, above)
  3296 00004908 AA                  <1> 	stosb
  3297 00004909 FF05[B86E0000]      <1> 	inc 	dword [u.base]
  3298                              <1> 	;dec 	cx
  3299                              <1> 	; 24/12/2021
  3300 0000490F 49                  <1> 	dec	ecx
  3301 00004910 7505                <1> 	jnz	short sysstat3
  3302 00004912 E835000000          <1> 	call	sysstat_gpa
  3303                              <1> 	;jc	short sysstat_err1
  3304                              <1> sysstat3:
  3305 00004917 A0[7D6E0000]        <1> 	mov 	al, [ii+1] ; 07/10/2015 (result of 'iget' call, above)
  3306 0000491C AA                  <1> 	stosb
  3307                              <1> 		; mov r1,(r3)+ / put i-number in 1st word of buffer
  3308 0000491D FF05[B86E0000]      <1> 	inc 	dword [u.base]
  3309                              <1> 	;;dec 	word [u.pcount]
  3310                              <1> 	;dec	cx
  3311 00004923 49                  <1> 	dec	ecx ; 24/12/2021
  3312 00004924 7505                <1> 	jnz	short sysstat4
  3313 00004926 E821000000          <1> 	call	sysstat_gpa
  3314                              <1> 	;jc	short sysstat_err1	
  3315                              <1> sysstat4:
  3316 0000492B BE[986B0000]        <1> 	mov	esi, inode
  3317                              <1> 		; mov $inode,r2 / r2 points to i-node
  3318                              <1> sysstat5: ; 1:
  3319 00004930 A4                  <1> 	movsb
  3320                              <1> 		; mov (r2)+,(r3)+ / move rest of i-node to buffer
  3321 00004931 FF05[B86E0000]      <1> 	inc 	dword [u.base]
  3322                              <1> 	;;dec 	word [u.pcount]
  3323                              <1> 	;dec 	cx
  3324                              <1> 	; 24/12/2021
  3325 00004937 49                  <1> 	dec	ecx
  3326 00004938 7505                <1> 	jnz	short sysstat6
  3327 0000493A E80D000000          <1> 	call	sysstat_gpa
  3328                              <1> 	;jc	short sysstat_err1
  3329                              <1> sysstat6:		
  3330 0000493F 81FE[B86B0000]      <1> 	cmp	esi, inode + 32
  3331                              <1> 		; cmp r2,$inode+32 / done?
  3332 00004945 75E9                <1> 	jne	short sysstat5
  3333                              <1> 		; bne 1b / no, go back
  3334 00004947 E9A6F1FFFF          <1> 	jmp	sysret
  3335                              <1> 		; br sysret3 / return through sysret
  3336                              <1> 	;
  3337                              <1> sysstat_gpa: ; get physical address of file status buffer
  3338                              <1> 	; 02/09/2015
  3339 0000494C 8B1D[B86E0000]      <1> 	mov 	ebx, [u.base]
  3340                              <1> 	; 07/10/2015
  3341 00004952 E84BE8FFFF          <1> 	call	get_physical_addr ; get physical address
  3342                              <1> 	;jc	short sysstat_gpa1
  3343 00004957 72A0                <1> 	jc	short sysstat_err1
  3344                              <1> 	; 18/10/2015
  3345 00004959 89C7                <1> 	mov	edi, eax ; physical address
  3346                              <1> 	;mov	[u.pcount], cx ; remain bytes in page
  3347                              <1> ;sysstat_gpa1:
  3348 0000495B C3                  <1> 	retn
  3349                              <1> 
  3350                              <1> fclose:
  3351                              <1> 	; 08/01/2022
  3352                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3353                              <1> 	; 18/06/2015 (Retro UNIX 386 v1 - Beginning)
  3354                              <1> 	;            (32 bit offset pointer modification)
  3355                              <1> 	; 19/04/2013 - 12/01/2014 (Retro UNIX 8086 v1)
  3356                              <1> 	;
  3357                              <1> 	; Given the file descriptor (index to the u.fp list)
  3358                              <1> 	; 'fclose' first gets the i-number of the file via 'getf'.
  3359                              <1> 	; If i-node is active (i-number > 0) the entry in 
  3360                              <1> 	; u.fp list is cleared. If all the processes that opened
  3361                              <1> 	; that file close it, then fsp etry is freed and the file
  3362                              <1> 	; is closed. If not a return is taken. 
  3363                              <1> 	; If the file has been deleted while open, 'anyi' is called
  3364                              <1> 	; to see anyone else has it open, i.e., see if it is appears
  3365                              <1> 	; in another entry in the fsp table. Upon return from 'anyi'
  3366                              <1> 	; a check is made to see if the file is special.	
  3367                              <1> 	;
  3368                              <1> 	; INPUTS ->
  3369                              <1> 	;    r1 - contains the file descriptor (value=0,1,2...)
  3370                              <1> 	;    u.fp - list of entries in the fsp table
  3371                              <1> 	;    fsp - table of entries (4 words/entry) of open files.	 
  3372                              <1> 	; OUTPUTS ->
  3373                              <1> 	;    r1 - contains the same file descriptor
  3374                              <1> 	;    r2 - contains i-number
  3375                              <1> 	;
  3376                              <1> 	; ((AX = R1))
  3377                              <1> 	; ((Modified registers: eDX, eBX, eCX, eSI, eDI, eBP))
  3378                              <1> 	;
  3379                              <1> 	; Retro UNIX 8086 v1 modification : CF = 1
  3380                              <1> 	;              if i-number of the file is 0. (error)  	
  3381                              <1> 
  3382                              <1> 	;movzx	edx, ax ; **
  3383                              <1> 	; 24/12/2021
  3384                              <1> 	;movzx	edx, al
  3385 0000495C 89C2                <1> 	mov	edx, eax ; eax <= 10 ; 24/12/2021
  3386 0000495E 50                  <1> 	push	eax ; ***
  3387                              <1> 	;push	ax ; ***
  3388                              <1> 		; mov r1,-(sp) / put r1 on the stack (it contains 
  3389                              <1> 			     ; / the index to u.fp list)
  3390 0000495F E839000000          <1> 	call	getf
  3391                              <1> 		; jsr r0,getf / r1 contains i-number, 
  3392                              <1> 			    ; / cdev has device =, u.fofp 
  3393                              <1> 			    ; / points to 3rd word of fsp entry
  3394 00004964 6683F801            <1> 	cmp	ax, 1 ; r1
  3395                              <1> 		; tst r1 / is i-number 0?
  3396 00004968 7231                <1> 	jb	short fclose_2
  3397                              <1> 		; beq 1f / yes, i-node not active so return
  3398                              <1> 		; tst (r0)+ / no, jump over error return
  3399 0000496A 89D3                <1> 	mov	ebx, edx ; **
  3400                              <1> 	; 24/12/2021
  3401 0000496C 89C2                <1> 	mov	edx, eax ; *
  3402                              <1> 	;mov 	dx, ax ; *
  3403                              <1> 		; mov r1,r2 / move i-number to r2 ;*
  3404                              <1> 		; mov (sp),r1 / restore value of r1 from the stack
  3405                              <1> 			    ; / which is index to u.fp ; **
  3406 0000496E C683[9E6E0000]00    <1> 	mov	byte [ebx+u.fp], 0
  3407                              <1> 		; clrb u.fp(r1) / clear that entry in the u.fp list
  3408 00004975 8B1D[A86E0000]      <1> 	mov	ebx, [u.fofp]
  3409                              <1> 		; mov u.fofp,r1 / r1 points to 3rd word in fsp entry
  3410                              <1> fclose_0:
  3411 0000497B FE4B04              <1> 	dec	byte [ebx+4] ; 18/06/2015
  3412                              <1> 		; decb 2(r1) / decrement the number of processes 
  3413                              <1> 			   ; / that have opened the file
  3414 0000497E 791B                <1> 	jns	short fclose_2 ; jump if not negative (jump if bit 7 is 0)	 
  3415                              <1> 		; bge 1f / if all processes haven't closed the file, return
  3416                              <1> 	;
  3417                              <1> 	; 24/12/2021
  3418 00004980 52                  <1> 	push	edx ; *
  3419                              <1> 	;push	dx ; *
  3420                              <1> 		; mov r2,-(sp) / put r2 on the stack (i-number)
  3421                              <1> 	;xor	ax, ax ; 0
  3422                              <1> 	; 24/12/2021
  3423 00004981 31C0                <1> 	xor	eax, eax
  3424 00004983 668943FC            <1> 	mov	[ebx-4], ax ; 0
  3425                              <1> 		; clr -4(r1) / clear 1st word of fsp entry
  3426 00004987 8A4305              <1> 	mov	al, [ebx+5] ; 18/06/2015
  3427                              <1> 		; tstb	3(r1) / has this file been deleted
  3428 0000498A 20C0                <1> 	and	al, al
  3429 0000498C 7407                <1> 	jz	short fclose_1
  3430                              <1> 		; beq 2f / no, branch
  3431                              <1> 	; 08/01/2022
  3432 0000498E 89D0                <1> 	mov	eax, edx
  3433                              <1> 	;mov	ax, dx ; *
  3434                              <1> 		; mov r2,r1 / yes, put i-number back into r1
  3435                              <1> 	; AX = inode number
  3436 00004990 E857040000          <1> 	call	anyi
  3437                              <1> 		; jsr r0,anyi / free all blocks related to i-number
  3438                              <1> 			    ; / check if file appears in fsp again
  3439                              <1> fclose_1: ; 2:
  3440                              <1> 	; 24/12/2021
  3441 00004995 58                  <1> 	pop	eax ; * 
  3442                              <1> 	;pop	ax ; *
  3443                              <1> 		; mov (sp)+,r1 / put i-number back into r1
  3444 00004996 E8BD100000          <1> 	call	iclose ; close if it is special file 
  3445                              <1> 		; jsr r0,iclose / check to see if its a special file
  3446                              <1> fclose_2: ; 1:
  3447                              <1> 	; 24/12/2021
  3448 0000499B 58                  <1> 	pop	eax ; ***
  3449                              <1> 	;pop	ax ; ***
  3450                              <1> 		; mov (sp)+,r1 / put index to u.fp back into r1
  3451 0000499C C3                  <1> 	retn
  3452                              <1> 		; rts r0
  3453                              <1> 
  3454                              <1> 	; 09/01/2022
  3455                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1. - Kernel v0.2.1.2)
  3456                              <1> getf:	; / get the device number and the i-number of an open file
  3457                              <1> 	; 13/05/2015
  3458                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3459                              <1> 	; 19/04/2013 - 18/11/2013 (Retro UNIX 8086 v1)
  3460                              <1> 	;
  3461 0000499D 89C3                <1> 	mov	ebx, eax
  3462                              <1> getf1: ;; Calling point from 'rw1' (23/05/2013)
  3463                              <1> 	; 08/01/2022
  3464 0000499F 29C0                <1> 	sub	eax, eax
  3465                              <1> 	;
  3466 000049A1 83FB0A              <1> 	cmp	ebx, 10
  3467                              <1> 		; cmp r1,$10. / user limited to 10 open files
  3468 000049A4 7329                <1>         jnb	short getf2 ; 13/05/2015
  3469                              <1> 	;jnb	error
  3470                              <1> 		; bhis error3 / u.fp is table of users open files, 
  3471                              <1> 			    ; / index in fsp table
  3472                              <1> 	; 08/01/2022
  3473 000049A6 8A83[9E6E0000]      <1> 	mov	al, [ebx+u.fp]
  3474                              <1> 	;mov	bl, [ebx+u.fp]
  3475                              <1> 		; movb	u.fp(r1),r1 / r1 contains number of entry 
  3476                              <1> 		                  ; / in fsp table
  3477                              <1> 	; 08/01/2022
  3478 000049AC 08C0                <1> 	or	al, al
  3479 000049AE 741F                <1> 	jz	short getf2	
  3480                              <1> 	;or	bl, bl
  3481                              <1> 	;jnz	short getf3
  3482                              <1> 	;;jz	short getf4
  3483                              <1> 		; beq 1f / if its zero return
  3484                              <1> ;getf2:
  3485                              <1> ;	; 08/01/2022
  3486                              <1> ;	; 'File not open !' error (ax=0)
  3487                              <1> ;	;sub	eax, eax
  3488                              <1> ;	retn
  3489                              <1> 
  3490                              <1> getf3:	
  3491                              <1> 	; Retro UNIX 386 v1 modification ! (11/05/2015)
  3492                              <1> 	;
  3493                              <1> 	; 'fsp' table (10 bytes/entry)
  3494                              <1> 	; bit 15				   bit 0
  3495                              <1> 	; ---|-------------------------------------------
  3496                              <1> 	; r/w|		i-number of open file
  3497                              <1> 	; ---|-------------------------------------------
  3498                              <1> 	;		   device number
  3499                              <1> 	; -----------------------------------------------
  3500                              <1> 	; offset pointer, r/w pointer to file (bit 0-15)
  3501                              <1> 	; -----------------------------------------------
  3502                              <1> 	; offset pointer, r/w pointer to file (bit 16-31)
  3503                              <1> 	; ----------------------|------------------------
  3504                              <1> 	;  flag that says file 	| number of processes
  3505                              <1> 	;   has been deleted	| that have file open 
  3506                              <1> 	; ----------------------|------------------------
  3507                              <1> 	;
  3508                              <1> 	;mov	eax, 10
  3509                              <1> 	; 08/01/2022
  3510 000049B0 B30A                <1> 	mov	bl, 10
  3511 000049B2 F6E3                <1> 	mul	bl
  3512 000049B4 BB[626C0000]        <1> 	mov	ebx, fsp-6 ; the 3rd word in the fsp entry
  3513 000049B9 01C3                <1> 	add	ebx, eax
  3514                              <1> 		; asl r1
  3515                              <1> 		; asl r1 / multiply by 8 to get index into 
  3516                              <1> 		       ; / fsp table entry
  3517                              <1> 		; asl r1
  3518                              <1> 		; add $fsp-4,r1 / r1 is pointing at the 3rd word 
  3519                              <1> 			      ; / in the fsp entry
  3520 000049BB 891D[A86E0000]      <1> 	mov	[u.fofp], ebx
  3521                              <1> 		; mov r1,u.fofp / save address of 3rd word 
  3522                              <1> 			      ; / in fsp entry in u.fofp
  3523 000049C1 4B                  <1> 	dec	ebx
  3524 000049C2 4B                  <1> 	dec	ebx
  3525                              <1> 	;mov	ax, [ebx]
  3526                              <1> 	; 09/01/2022
  3527 000049C3 8A03                <1> 	mov	al, [ebx]
  3528 000049C5 A2[7F6E0000]        <1> 	mov	[cdev], al ; ;;Retro UNIX 8086 v1 ! 
  3529                              <1> 	;mov	[cdev], ax ; ;;in fact (!) 
  3530                              <1> 			     ;;dev number is in 1 byte
  3531                              <1> 		; mov -(r1),cdev / remove the device number cdev
  3532 000049CA 4B                  <1> 	dec	ebx
  3533 000049CB 4B                  <1> 	dec	ebx
  3534 000049CC 668B03              <1> 	mov	ax, [ebx]
  3535                              <1> 		; mov -(r1),r1 / and the i-number  r1
  3536                              <1> getf2:	; 08/01/2022
  3537                              <1> getf4:	; 1:
  3538 000049CF C3                  <1> 	retn
  3539                              <1> 		; rts r0
  3540                              <1> 
  3541                              <1> namei:
  3542                              <1> 	; 03/02/2022
  3543                              <1> 	; 09/01/2022
  3544                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  3545                              <1> 	; 04/12/2015 (Retro UNIX 386 v1.1, 14 byte file names)
  3546                              <1> 	; 18/10/2015 (nbase, ncount)
  3547                              <1> 	; 12/10/2015
  3548                              <1> 	; 21/08/2015
  3549                              <1> 	; 18/07/2015
  3550                              <1> 	; 02/07/2015
  3551                              <1> 	; 17/06/2015
  3552                              <1> 	; 16/06/2015 (Retro UNIX 386 v1 - Beginning)
  3553                              <1> 	; 24/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  3554                              <1> 	;
  3555                              <1> 	; 'namei' takes a file path name and returns i-number of
  3556                              <1> 	; the file in the current directory or the root directory
  3557                              <1> 	; (if the first character of the pathname is '/').	
  3558                              <1> 	;
  3559                              <1> 	; INPUTS ->
  3560                              <1> 	;    u.namep - points to a file path name
  3561                              <1> 	;    u.cdir - i-number of users directory
  3562                              <1> 	;    u.cdev - device number on which user directory resides	
  3563                              <1> 	; OUTPUTS ->
  3564                              <1> 	;    r1 - i-number of file
  3565                              <1> 	;    cdev
  3566                              <1> 	;    u.dirbuf - points to directory entry where a match 
  3567                              <1> 	;               occurs in the search for file path name.
  3568                              <1> 	;	        If no match u.dirb points to the end of 
  3569                              <1> 	;               the directory and r1 = i-number of the current
  3570                              <1> 	;	        directory.	
  3571                              <1> 	; ((AX = R1))
  3572                              <1> 	;
  3573                              <1> 	; (Retro UNIX Prototype : 07/10/2012 - 05/01/2013, UNIXCOPY.ASM)
  3574                              <1>         ; ((Modified registers: eDX, eBX, eCX, eSI, eDI, eBP))  
  3575                              <1> 	;
  3576                              <1> 
  3577 000049D0 66A1[9C6E0000]      <1> 	mov	ax, [u.cdir]
  3578                              <1> 		; mov u.cdir,r1 / put the i-number of current directory
  3579                              <1> 			      ; / in r1
  3580                              <1> 	; 09/01/2022
  3581 000049D6 8A15[E26E0000]      <1> 	mov	dl, [u.cdrv]
  3582 000049DC 8815[7F6E0000]      <1> 	mov	[cdev], dl
  3583                              <1> 	;mov	dx, [u.cdrv]
  3584                              <1> 	;mov	[cdev], dx 	    ; NOTE: Retro UNIX 8086 v1 
  3585                              <1> 				    ; device/drive number is in 1 byte, 
  3586                              <1> 				    ; not in 1 word!
  3587                              <1> 		; mov u.cdev,cdev / device number for users directory 
  3588                              <1> 				; / into cdev
  3589                              <1> 	; 12/10/2015
  3590                              <1> 	; 16/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  3591                              <1>       	 ; convert virtual (pathname) addr to physical address
  3592 000049E2 E822010000          <1> 	call    trans_addr_nmbp ; 12/10/2015
  3593                              <1> 		; esi = physical address of [u.namep]
  3594                              <1> 		; ecx = byte count in the page
  3595 000049E7 803E2F              <1> 	cmp	byte [esi], '/'
  3596                              <1> 		; cmpb *u.namep,$'/ / is first char in file name a /
  3597 000049EA 751D                <1> 	jne	short namei_1
  3598                              <1> 		; bne 1f
  3599 000049EC FF05[B06E0000]      <1> 	inc	dword [u.namep]
  3600                              <1> 		; inc u.namep / go to next char
  3601                              <1> 	;dec	cx ; remain byte count in the page
  3602                              <1> 	; 24/12/2021
  3603 000049F2 49                  <1> 	dec	ecx
  3604 000049F3 7506                <1> 	jnz	short namei_0
  3605                              <1> 	; 12/10/2015
  3606 000049F5 E80F010000          <1> 	call	trans_addr_nmbp ; convert virtual address to physical
  3607                              <1> 		; esi = physical address (page start + offset)
  3608                              <1> 		; ecx = byte count in the page
  3609 000049FA 4E                  <1> 	dec	esi
  3610                              <1> namei_0:
  3611 000049FB 46                  <1> 	inc 	esi  ; go to next char
  3612 000049FC 66A1[886E0000]      <1> 	mov	ax, [rootdir] ; 09/07/2013
  3613                              <1> 		; mov rootdir,r1 / put i-number of rootdirectory in r1
  3614 00004A02 C605[7F6E0000]00    <1> 	mov	byte [cdev], 0
  3615                              <1> 		; clr cdev / clear device number
  3616                              <1> namei_1: ; 1:
  3617 00004A09 F606FF              <1> 	test	byte [esi], 0FFh
  3618                              <1> namei_10: ; 24/12/2021 (jump from namei_8)
  3619 00004A0C 74C1                <1> 	jz	short getf4
  3620                              <1> 	;jz	nig
  3621                              <1> 		; tstb *u.namep / is the character in file name a nul
  3622                              <1> 		; beq nig / yes, end of file name reached; 
  3623                              <1> 			; / branch to "nig"
  3624                              <1> namei_2: ; 1:
  3625                              <1> 	; 18/10/2015
  3626 00004A0E 8935[106F0000]      <1> 	mov 	[nbase], esi
  3627 00004A14 66890D[146F0000]    <1> 	mov 	[ncount], cx
  3628                              <1> 	;
  3629                              <1> 	;mov	dx, 2
  3630 00004A1B B202                <1> 	mov	dl, 2 ; user flag (read, non-owner)
  3631 00004A1D E847080000          <1> 	call	access
  3632                              <1> 		; jsr r0,access; 2 / get i-node with i-number r1
  3633                              <1> 	; 'access' will not return here if user has not "r" permission !
  3634                              <1> 	; 03/02/2022
  3635 00004A22 F605[996B0000]40    <1> 	test	byte [i.flgs+1], 40h
  3636                              <1> 	;test 	word [i.flgs], 4000h
  3637                              <1> 		; bit $40000,i.flgs / directory i-node?
  3638 00004A29 746A                <1>         jz      short namei_err
  3639                              <1> 		; beq error3 / no, got an error
  3640                              <1> 	; 16/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  3641 00004A2B 31C0                <1> 	xor	eax, eax
  3642 00004A2D A3[B46E0000]        <1> 	mov	[u.off], eax ; 0
  3643 00004A32 66A1[9C6B0000]      <1> 	mov	ax, [i.size]
  3644 00004A38 A3[AC6E0000]        <1> 	mov	[u.dirp], eax
  3645                              <1> 		; mov i.size,u.dirp / put size of directory in u.dirp
  3646                              <1> 		; clr u.off / u.off is file offset used by user
  3647 00004A3D C705[A86E0000]-     <1> 	mov	dword [u.fofp], u.off
  3647 00004A43 [B46E0000]          <1>
  3648                              <1> 		; mov $u.off,u.fofp / u.fofp is a pointer to 
  3649                              <1> 				  ; / the offset portion of fsp entry
  3650                              <1> namei_3: ; 2:
  3651 00004A47 C705[B86E0000]-     <1> 	mov	dword [u.base], u.dirbuf
  3651 00004A4D [CA6E0000]          <1>
  3652                              <1> 		; mov $u.dirbuf,u.base / u.dirbuf holds a file name 
  3653                              <1> 				    ; / copied from a directory
  3654 00004A51 C705[BC6E0000]1000- <1> 	mov 	dword [u.count], 16 ; 04/12/2015 (10 -> 16) 	
  3654 00004A59 0000                <1>
  3655                              <1>  		; mov $10.,u.count / u.count is byte count 
  3656                              <1> 				 ; / for reads and writes
  3657 00004A5B 66A1[7C6E0000]      <1> 	mov 	ax, [ii]
  3658                              <1> 	; 31/07/2013 ('namei_r') - 16/06/2015 ('u.kcall')
  3659 00004A61 FE05[FF6E0000]      <1>  	inc     byte [u.kcall] ; the caller is 'namei' sign	
  3660 00004A67 E8FD080000          <1>     	call	readi
  3661                              <1> 		; jsr r0,readi / read 10. bytes of file 
  3662                              <1> 		      ; with i-number (r1); i.e. read a directory entry
  3663 00004A6C 8B0D[C06E0000]      <1> 	mov 	ecx, [u.nread]
  3664 00004A72 09C9                <1> 	or 	ecx, ecx
  3665                              <1> 		; tst u.nread
  3666 00004A74 741B                <1> 	jz	short nib
  3667                              <1> 		; ble nib / gives error return
  3668                              <1> 	;
  3669 00004A76 668B1D[CA6E0000]    <1> 	mov 	bx, [u.dirbuf]
  3670 00004A7D 6621DB              <1> 	and 	bx, bx       
  3671                              <1> 		; tst u.dirbuf /
  3672 00004A80 7522                <1> 	jnz	short namei_4
  3673                              <1> 		; bne 3f / branch when active directory entry 
  3674                              <1> 		       ; / (i-node word in entry non zero)
  3675 00004A82 A1[B46E0000]        <1> 	mov	eax, [u.off]
  3676 00004A87 83E810              <1> 	sub	eax, 16 ; 04/12/2015 (10 -> 16) 
  3677 00004A8A A3[AC6E0000]        <1> 	mov	[u.dirp], eax
  3678                              <1> 		; mov u.off,u.dirp
  3679                              <1> 		; sub $10.,u.dirp
  3680 00004A8F EBB6                <1> 	jmp	short namei_3
  3681                              <1> 		; br 2b
  3682                              <1> 
  3683                              <1> 	; 18/07/2013
  3684                              <1> nib: 
  3685 00004A91 31C0                <1> 	xor	eax, eax  ; xor ax, ax ; ax = 0 -> file not found 
  3686 00004A93 F9                  <1> 	stc
  3687                              <1> nig:
  3688 00004A94 C3                  <1> 	retn
  3689                              <1> 
  3690                              <1> namei_err:
  3691                              <1> 	; 16/06/2015
  3692 00004A95 C705[ED6E0000]1300- <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a directory !' error
  3692 00004A9D 0000                <1>
  3693 00004A9F E92EF0FFFF          <1> 	jmp	error
  3694                              <1> 
  3695                              <1> namei_4: ; 3:
  3696                              <1> 	; 18/10/2015
  3697                              <1> 	; 12/10/2015
  3698                              <1> 	; 21/08/2015
  3699                              <1> 	; 18/07/2015
  3700 00004AA4 8B2D[B06E0000]      <1> 	mov	ebp, [u.namep]
  3701                              <1> 		; mov u.namep,r2 / u.namep points into a file name string
  3702 00004AAA BF[CC6E0000]        <1> 	mov 	edi, u.dirbuf + 2
  3703                              <1> 		; mov $u.dirbuf+2,r3 / points to file name of directory entry
  3704                              <1> 	; 18/10/2015
  3705 00004AAF 8B35[106F0000]      <1> 	mov	esi, [nbase]	
  3706 00004AB5 668B0D[146F0000]    <1> 	mov	cx, [ncount]
  3707                              <1> 	;
  3708 00004ABC 6621C9              <1> 	and	cx, cx
  3709 00004ABF 7505                <1> 	jnz	short namei_5	
  3710                              <1> 	;
  3711 00004AC1 E849000000          <1> 	call	trans_addr_nm ; convert virtual address to physical
  3712                              <1> 		; esi = physical address (page start + offset)
  3713                              <1> 		; ecx = byte count in the page
  3714                              <1> namei_5: ; 3:
  3715 00004AC6 45                  <1> 	inc	ebp ; 18/07/2015
  3716 00004AC7 AC                  <1> 	lodsb   ; mov al, [esi] ; inc esi (al = r4)
  3717                              <1> 		; movb (r2)+,r4 / move a character from u.namep string into r4
  3718 00004AC8 08C0                <1> 	or 	al, al
  3719 00004ACA 741C                <1> 	jz 	short namei_7
  3720                              <1> 		; beq 3f / if char is nul, then the last char in string
  3721                              <1> 			; / has been moved
  3722 00004ACC 3C2F                <1> 	cmp	al, '/'
  3723                              <1> 		; cmp r4,$'/ / is char a </>
  3724 00004ACE 7418                <1> 	je 	short namei_7
  3725                              <1> 		; beq 3f	
  3726                              <1> 	; 24/12/2021
  3727 00004AD0 49                  <1> 	dec	ecx
  3728                              <1> 	; 12/10/2015
  3729                              <1> 	;dec	cx ; remain byte count in the page
  3730 00004AD1 7505                <1> 	jnz	short namei_6
  3731 00004AD3 E837000000          <1> 	call	trans_addr_nm ; convert virtual address to physical
  3732                              <1> 		; esi = physical address (page start + offset)
  3733                              <1> 		; ecx = byte count in the page
  3734                              <1> namei_6:
  3735 00004AD8 81FF[DA6E0000]      <1>         cmp     edi, u.dirbuf + 16 ; 04/12/2015 (10 -> 16) 
  3736                              <1> 		; cmp r3,$u.dirbuf+10. / have I checked
  3737                              <1> 				     ; / all 8 bytes of file name
  3738 00004ADE 74E6                <1> 	je	short namei_5
  3739                              <1> 		; beq 3b
  3740 00004AE0 AE                  <1> 	scasb	
  3741                              <1> 		; cmpb (r3)+,r4 / compare char in u.namep string to file name 
  3742                              <1> 			      ; / char read from directory
  3743 00004AE1 74E3                <1> 	je 	short namei_5
  3744                              <1> 		; beq 3b / branch if chars match
  3745                              <1> namei_9:
  3746 00004AE3 E95FFFFFFF          <1>         jmp	namei_3 ; 2b
  3747                              <1> 		; br 2b / file names do not match go to next directory entry
  3748                              <1> namei_7: ; 3:
  3749 00004AE8 81FF[DA6E0000]      <1> 	cmp	edi, u.dirbuf + 16 ; 04/12/2015 (10 -> 16) 
  3750                              <1> 		; cmp r3,$u.dirbuf+10. / if equal all 8 bytes were matched
  3751 00004AEE 7406                <1> 	je	short namei_8
  3752                              <1> 		; beq 3f
  3753 00004AF0 8A27                <1> 	mov 	ah, [edi]
  3754                              <1> 	;inc 	edi 
  3755 00004AF2 20E4                <1> 	and 	ah, ah
  3756                              <1> 		; tstb (r3)+ /
  3757                              <1>         ;jnz	namei_3
  3758                              <1> 		; bne 2b
  3759                              <1> 	; 24/12/2021
  3760 00004AF4 75ED                <1> 	jnz	short namei_9	
  3761                              <1> namei_8: ; 3
  3762 00004AF6 892D[B06E0000]      <1> 	mov	[u.namep], ebp ; 18/07/2015
  3763                              <1> 		; mov r2,u.namep / u.namep points to char 
  3764                              <1> 			       ; / following a / or nul
  3765                              <1> 	;mov	bx, [u.dirbuf]
  3766                              <1> 		; mov u.dirbuf,r1 / move i-node number in directory 
  3767                              <1> 				; / entry to r1
  3768 00004AFC 20C0                <1> 	and 	al, al
  3769                              <1> 		; tst r4 / if r4 = 0 the end of file name reached,
  3770                              <1> 		      ;  / if r4 = </> then go to next directory
  3771                              <1> 	;mov	ax, bx
  3772 00004AFE 66A1[CA6E0000]      <1> 	mov 	ax, [u.dirbuf] ; 17/06/2015
  3773                              <1>   	; 24/12/2021
  3774 00004B04 E903FFFFFF          <1> 	jmp	namei_10 ; (jnz short namei_2, retn)
  3775                              <1> 	;jnz	namei_2 
  3776                              <1> 		; bne 1b
  3777                              <1> 	; AX = i-number of the file
  3778                              <1> ;;nig:
  3779                              <1> 	;retn	; 24/12/2021
  3780                              <1> 		; tst (r0)+ / gives non-error return
  3781                              <1> ;;nib:
  3782                              <1> ;;	xor	ax, ax ; Retro UNIX 8086 v1 modification !
  3783                              <1> 		       ; ax = 0 -> file not found 
  3784                              <1> ;;	stc	; 27/05/2013
  3785                              <1> ;;	retn
  3786                              <1> 		; rts r0
  3787                              <1> 
  3788                              <1> trans_addr_nmbp:
  3789                              <1> 	; 08/01/2022 - Retro UNIX 386 v1.1 (Kernel v0.2.1.2)
  3790                              <1> 	; 18/10/2015
  3791                              <1> 	; 12/10/2015
  3792 00004B09 8B2D[B06E0000]      <1> 	mov 	ebp, [u.namep]
  3793                              <1> trans_addr_nm:
  3794                              <1> 	; 08/01/2022 - Retro UNIX 386 v1.1 (Kernel v0.2.1.2) 
  3795                              <1> 	; Convert virtual (pathname) address to physical address
  3796                              <1> 	; (Retro UNIX 386 v1 feature only !)
  3797                              <1> 	; 18/10/2015
  3798                              <1> 	; 12/10/2015 (u.pnbase & u.pncount has been removed from code)
  3799                              <1> 	; 02/07/2015
  3800                              <1> 	; 17/06/2015
  3801                              <1> 	; 16/06/2015
  3802                              <1> 	;
  3803                              <1> 	; INPUTS: 
  3804                              <1> 	;	ebp = pathname address (virtual) ; [u.namep]
  3805                              <1> 	;	[u.pgdir] = user's page directory
  3806                              <1> 	; OUTPUT:
  3807                              <1> 	;       esi = physical address of the pathname
  3808                              <1> 	;	ecx = remain byte count in the page
  3809                              <1> 	;
  3810                              <1> 	; (Modified registers: EAX, EBX, ECX, EDX, ESI)
  3811                              <1> 	;
  3812                              <1> 
  3813                              <1> 	; 08/01/2022
  3814 00004B0F 29C9                <1> 	sub	ecx, ecx
  3815                              <1> 	;
  3816 00004B11 833D[F56E0000]00    <1>         cmp     dword [u.ppgdir], 0  ; /etc/init ? (sysexec)
  3817 00004B18 7618                <1> 	jna	short trans_addr_nmk ; the caller is os kernel;
  3818                              <1> 				     ; it is already physical address
  3819 00004B1A 50                  <1>    	push	eax	
  3820 00004B1B 89EB                <1> 	mov	ebx, ebp ; [u.namep] ; pathname address (virtual)
  3821 00004B1D E880E6FFFF          <1>        	call	get_physical_addr ; get physical address
  3822 00004B22 7204                <1> 	jc	short tr_addr_nm_err
  3823                              <1> 	; 18/10/2015
  3824                              <1> 	; eax = physical address 
  3825                              <1> 	; cx = remain byte count in page (1-4096) 
  3826                              <1> 		; 12/10/2015 (cx = [u.pncount])
  3827 00004B24 89C6                <1> 	mov	esi, eax ; 12/10/2015 (esi=[u.pnbase])
  3828 00004B26 58                  <1> 	pop	eax 
  3829 00004B27 C3                  <1> 	retn
  3830                              <1> 
  3831                              <1> tr_addr_nm_err:
  3832 00004B28 A3[ED6E0000]        <1> 	mov	[u.error], eax
  3833                              <1> 	;pop 	eax
  3834 00004B2D E9A0EFFFFF          <1> 	jmp	error
  3835                              <1> 
  3836                              <1> trans_addr_nmk:
  3837                              <1> 	; 12/10/2015
  3838                              <1> 	; 02/07/2015
  3839 00004B32 8B35[B06E0000]      <1> 	mov	esi, [u.namep]  ; [u.pnbase]
  3840                              <1> 	;mov	cx, PAGE_SIZE ; 4096 ; [u.pncount]
  3841                              <1> 	; 08/01/2022
  3842 00004B38 B510                <1> 	mov	ch, PAGE_SIZE/256
  3843 00004B3A C3                  <1> 	retn
  3844                              <1> 
  3845                              <1> syschdir:
  3846                              <1> 	; / makes the directory specified in the argument
  3847                              <1> 	; / the current directory
  3848                              <1> 	;
  3849                              <1> 	; 09/01/2022
  3850                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  3851                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3852                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  3853                              <1> 	;
  3854                              <1> 	; 'syschdir' makes the directory specified in its argument
  3855                              <1> 	; the current working directory.
  3856                              <1> 	;
  3857                              <1> 	; Calling sequence:
  3858                              <1> 	;	syschdir; name
  3859                              <1> 	; Arguments:
  3860                              <1> 	;	name - address of the path name of a directory
  3861                              <1> 	;	       terminated by nul byte.	
  3862                              <1> 	; Inputs: -
  3863                              <1> 	; Outputs: -
  3864                              <1> 	; ...............................................................
  3865                              <1> 	;				
  3866                              <1> 	; Retro UNIX 8086 v1 modification:
  3867                              <1> 	;	 The user/application program puts address of 
  3868                              <1> 	;	 the path name in BX register as 'syschdir' 
  3869                              <1> 	; 	 system call argument.
  3870                              <1> 
  3871 00004B3B 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  3872                              <1> 		; jsr r0,arg; u.namep / u.namep points to path name
  3873 00004B41 E88AFEFFFF          <1> 	call	namei
  3874                              <1> 		; jsr r0,namei / find its i-number
  3875                              <1> 	;jc	error
  3876                              <1> 		; br error3
  3877 00004B46 730F                <1> 	jnc	short syschdir0
  3878                              <1> 	; 'directory not found !' error
  3879 00004B48 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_DIR_NOT_FOUND ; 12
  3879 00004B50 0000                <1>
  3880 00004B52 E97BEFFFFF          <1> 	jmp	error
  3881                              <1> syschdir0:
  3882                              <1> 	; 08/01/2022
  3883 00004B57 B202                <1> 	mov	dl, 2  ; read access ; 08/01/2022 (BugFix)
  3884 00004B59 E80B070000          <1> 	call	access
  3885                              <1> 		; jsr r0,access; 2 / get i-node into core
  3886                              <1> 	; 08/01/2022
  3887 00004B5E F605[996B0000]40    <1> 	test	byte [i.flgs+1], 40h
  3888                              <1> 	;test	word [i.flgs], 4000h
  3889                              <1> 		; bit $40000,i.flgs / is it a directory?
  3890                              <1> 	;jz	error 
  3891                              <1> 		; beq error3 / no error
  3892 00004B65 750F                <1> 	jnz	short syschdir1
  3893 00004B67 C705[ED6E0000]1300- <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a valid directory !'
  3893 00004B6F 0000                <1>
  3894 00004B71 E95CEFFFFF          <1> 	jmp	error
  3895                              <1> syschdir1:
  3896 00004B76 66A3[9C6E0000]      <1> 	mov	[u.cdir], ax
  3897                              <1> 		; mov r1,u.cdir / move i-number to users 
  3898                              <1> 			      ; / current directory
  3899                              <1> 	; 09/01/2022
  3900 00004B7C A0[7F6E0000]        <1> 	mov	al, [cdev]
  3901 00004B81 A2[E26E0000]        <1> 	mov	[u.cdrv], al
  3902                              <1> 	;mov	ax, [cdev]
  3903                              <1> 	;mov	[u.cdrv], ax
  3904                              <1> 		; mov cdev,u.cdev / move its device to users 
  3905                              <1> 			        ; / current device
  3906 00004B86 E967EFFFFF          <1> 	jmp	sysret
  3907                              <1> 		; br sysret3
  3908                              <1> 
  3909                              <1> syschmod: ; < change mode of file >
  3910                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  3911                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3912                              <1> 	; 20/06/2013 - 07/07/2013 (Retro UNIX 8086 v1)
  3913                              <1> 	;
  3914                              <1> 	; 'syschmod' changes mode of the file whose name is given as
  3915                              <1> 	; null terminated string pointed to by 'name' has it's mode 
  3916                              <1> 	; changed to 'mode'.
  3917                              <1> 	;
  3918                              <1> 	; Calling sequence:
  3919                              <1> 	;	syschmod; name; mode
  3920                              <1> 	; Arguments:
  3921                              <1> 	;	name - address of the file name
  3922                              <1> 	;	       terminated by null byte.
  3923                              <1> 	;	mode - (new) mode/flags < attributes >
  3924                              <1> 	;	
  3925                              <1> 	; Inputs: -
  3926                              <1> 	; Outputs: -
  3927                              <1> 	; ...............................................................
  3928                              <1> 	;				
  3929                              <1> 	; Retro UNIX 8086 v1 modification: 
  3930                              <1> 	;       'syschmod' system call has two arguments; so,
  3931                              <1> 	;	* 1st argument, name is pointed to by BX register
  3932                              <1> 	;	* 2nd argument, mode is in CX register
  3933                              <1> 	;
  3934                              <1> 	; Mode bits (Flags):
  3935                              <1> 	;	bit 15 - 'i-node is allocated' flag (8000h)
  3936                              <1> 	;	bit 14 - directory flag (4000h)
  3937                              <1> 	;	bit 13 - file has modified flag (always on) (2000h)
  3938                              <1> 	;	bit 12 - large file flag (1000h)
  3939                              <1> 	;	bit 6,7,8,9,10,11 are not used (undefined)
  3940                              <1> 	;	bit 5 - set user ID on execution flag (20h) 
  3941                              <1> 	;	bit 4 - executable flag (10h)
  3942                              <1> 	;	bit 3 - read permission for owner (08h)
  3943                              <1> 	;	bit 2 - write permission for owner (04h)
  3944                              <1> 	;	bit 1 - read permission for non-owner (02h)
  3945                              <1> 	;	bit 0 - write permission for non-owner (01h)
  3946                              <1> 
  3947                              <1> 	; / name; mode
  3948 00004B8B E812000000          <1> 	call	isown
  3949                              <1> 		;jsr r0,isown / get the i-node and check user status
  3950                              <1> 	; 09/01/2022
  3951 00004B90 F605[996B0000]40    <1> 	test	byte [i.flgs+1], 40h
  3952                              <1> 	;test	word [i.flgs], 4000h
  3953                              <1> 		; bit $40000,i.flgs / directory?
  3954 00004B97 7402                <1> 	jz	short syschmod1
  3955                              <1> 		; beq 2f / no
  3956                              <1> 	; AL = (new) mode
  3957 00004B99 24CF                <1> 	and	al, 0CFh ; 11001111b (clears bit 4 & 5)
  3958                              <1> 		; bic $60,r2 / su & ex / yes, clear set user id and 
  3959                              <1> 			   ; / executable modes
  3960                              <1> syschmod1: ; 2:
  3961 00004B9B A2[986B0000]        <1> 	mov	[i.flgs], al	
  3962                              <1> 		; movb r2,i.flgs / move remaining mode to i.flgs
  3963 00004BA0 EB42                <1> 	jmp	short isown1
  3964                              <1> 		; br 1f
  3965                              <1> 
  3966                              <1> isown:
  3967                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  3968                              <1> 	; 04/05/2013 - 07/07/2013 (Retro UNIX 8086 v1)
  3969                              <1> 	;
  3970                              <1> 	; 'isown' is given a file name (the 1st argument).
  3971                              <1> 	;  It find the i-number of that file via 'namei' 
  3972                              <1> 	;  then gets the i-node into core via 'iget'.
  3973                              <1> 	;  It then tests to see if the user is super user. 
  3974                              <1> 	;  If not, it cheks to see if the user is owner of 
  3975                              <1> 	;  the file. If he is not an error occurs.
  3976                              <1> 	;  If user is the owner 'setimod' is called to indicate
  3977                              <1> 	;  the inode has been modified and the 2nd argument of
  3978                              <1> 	;  the call is put in r2.
  3979                              <1> 	;
  3980                              <1> 	; INPUTS ->
  3981                              <1> 	;    arguments of syschmod and syschown calls
  3982                              <1> 	; OUTPUTS ->
  3983                              <1> 	;    u.uid - id of user
  3984                              <1> 	;    imod - set to a 1
  3985                              <1> 	;    r2 - contains second argument of the system call				 	
  3986                              <1> 	;
  3987                              <1> 	;   ((AX=R2) output as 2nd argument)
  3988                              <1> 	;
  3989                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  3990                              <1> 	;
  3991                              <1> 		; jsr r0,arg2 / u.namep points to file name
  3992                              <1> 	;; ! 2nd argument on top of stack !
  3993                              <1> 	;; 22/06/2015 - 32 bit modifications
  3994                              <1> 	;; 07/07/2013
  3995 00004BA2 891D[B06E0000]      <1> 	mov	[u.namep], ebx ;; 1st argument
  3996 00004BA8 51                  <1> 	push 	ecx ;; 2nd argument
  3997                              <1> 	;;
  3998 00004BA9 E822FEFFFF          <1> 	call	namei
  3999                              <1> 		; jsr r0,namei / get its i-number
  4000                              <1>        ; Retro UNIX 8086 v1 modification !
  4001                              <1>        ; ax = 0 -> file not found 
  4002                              <1> 	;and	ax, ax
  4003                              <1> 	;jz	error
  4004                              <1> 	;jc	error ; 27/05/2013
  4005                              <1> 		; br error3
  4006 00004BAE 730F                <1> 	jnc	short isown0
  4007                              <1> 	; 'file not found !' error
  4008 00004BB0 C705[ED6E0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  4008 00004BB8 0000                <1>
  4009 00004BBA E913EFFFFF          <1> 	jmp	error
  4010                              <1> isown0:
  4011 00004BBF E8D1050000          <1> 	call	iget
  4012                              <1> 		; jsr r0,iget / get i-node into core
  4013 00004BC4 A0[E46E0000]        <1> 	mov	al, [u.uid] ; 02/08/2013
  4014 00004BC9 08C0                <1> 	or	al, al
  4015                              <1> 		; tstb u.uid / super user?
  4016 00004BCB 7417                <1> 	jz	short isown1
  4017                              <1> 		; beq 1f / yes, branch
  4018 00004BCD 3A05[9B6B0000]      <1> 	cmp	al, [i.uid]
  4019                              <1> 		; cmpb i.uid,u.uid / no, is this the owner of
  4020                              <1> 				 ; / the file
  4021                              <1> 	;jne	error
  4022                              <1> 		; beq 1f / yes
  4023                              <1> 		; jmp error3 / no, error
  4024 00004BD3 740F                <1> 	je	short isown1
  4025                              <1> 
  4026 00004BD5 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_OWNER  ; 11
  4026 00004BDD 0000                <1>
  4027                              <1> 			;  'permission denied !' error
  4028 00004BDF E9EEEEFFFF          <1> 	jmp	error
  4029                              <1> isown1: ; 1:
  4030 00004BE4 E8B6060000          <1> 	call	setimod
  4031                              <1> 		; jsr r0,setimod / indicates 
  4032                              <1> 		;	       ; / i-node has been modified
  4033 00004BE9 58                  <1> 	pop	eax ; 2nd argument
  4034                              <1> 		; mov (sp)+,r2 / mode is put in r2 
  4035                              <1> 		       ; / (u.off put on stack with 2nd arg)
  4036 00004BEA C3                  <1> 	retn
  4037                              <1> 		; rts r0
  4038                              <1> 
  4039                              <1> ;;arg:  ; < get system call arguments >
  4040                              <1> 	; 'arg' extracts an argument for a routine whose call is 
  4041                              <1> 	; of form:
  4042                              <1> 	;	sys 'routine' ; arg1
  4043                              <1> 	;		or
  4044                              <1> 	;	sys 'routine' ; arg1 ; arg2
  4045                              <1> 	;		or
  4046                              <1> 	;	sys 'routine' ; arg1;...;arg10 (sys exec) 
  4047                              <1> 	;	
  4048                              <1> 	; INPUTS ->
  4049                              <1> 	;    u.sp+18 - contains a pointer to one of arg1..argn
  4050                              <1> 	;	This pointers's value is actually the value of
  4051                              <1> 	;	update pc at the the trap to sysent (unkni) is
  4052                              <1> 	;	made to process the sys instruction
  4053                              <1> 	;    r0 - contains the return address for the routine
  4054                              <1> 	;	that called arg. The data in the word pointer 
  4055                              <1> 	;	to by the return address is used as address
  4056                              <1> 	;	in which the extracted argument is stored   		
  4057                              <1> 	;    	
  4058                              <1> 	; OUTPUTS ->
  4059                              <1> 	;    'address' - contains the extracted argument 
  4060                              <1> 	;    u.sp+18 - is incremented by 2 
  4061                              <1> 	;    r1 - contains the extracted argument
  4062                              <1> 	;    r0 - points to the next instruction to be
  4063                              <1> 	;	 executed in the calling routine.
  4064                              <1> 	;
  4065                              <1>   
  4066                              <1> 	; mov u.sp,r1
  4067                              <1> 	; mov *18.(r1),*(r0)+ / put argument of system call
  4068                              <1> 			; / into argument of arg2
  4069                              <1> 	; add $2,18.(r1) / point pc on stack 
  4070                              <1> 			      ; / to next system argument
  4071                              <1> 	; rts r0
  4072                              <1> 
  4073                              <1> ;;arg2: ; < get system calls arguments - with file name pointer>
  4074                              <1> 	; 'arg2' takes first argument in system call
  4075                              <1> 	;  (pointer to name of the file) and puts it in location
  4076                              <1> 	;  u.namep; takes second argument and puts it in u.off
  4077                              <1> 	;  and on top of the stack
  4078                              <1> 	;	
  4079                              <1> 	; INPUTS ->
  4080                              <1> 	;    u.sp, r0
  4081                              <1> 	;    	
  4082                              <1> 	; OUTPUTS ->
  4083                              <1> 	;    u.namep
  4084                              <1> 	;    u.off 
  4085                              <1> 	;    u.off pushed on stack
  4086                              <1> 	;    r1
  4087                              <1> 	;
  4088                              <1> 
  4089                              <1> 	; jsr	r0,arg; u.namep / u.namep contains value of
  4090                              <1> 				; / first arg in sys call
  4091                              <1> 	; jsr r0,arg; u.off / u.off contains value of 
  4092                              <1> 				; / second arg in sys call
  4093                              <1> 	; mov r0,r1 / r0 points to calling routine
  4094                              <1> 	; mov (sp),r0 / put operation code back in r0
  4095                              <1> 	; mov u.off,(sp) / put pointer to second argument 
  4096                              <1> 			; / on stack
  4097                              <1> 	; jmp (r1) / return to calling routine
  4098                              <1> 
  4099                              <1> syschown: ; < change owner of file >
  4100                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4101                              <1> 	; 20/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4102                              <1> 	;
  4103                              <1> 	; 'syschown' changes the owner of the file whose name is given
  4104                              <1> 	; as null terminated string pointed to by 'name' has it's owner
  4105                              <1> 	; changed to 'owner'
  4106                              <1> 	;
  4107                              <1> 	; Calling sequence:
  4108                              <1> 	;	syschown; name; owner
  4109                              <1> 	; Arguments:
  4110                              <1> 	;	name - address of the file name
  4111                              <1> 	;	       terminated by null byte.
  4112                              <1> 	;	owner - (new) owner (number/ID)
  4113                              <1> 	;	
  4114                              <1> 	; Inputs: -
  4115                              <1> 	; Outputs: -
  4116                              <1> 	; ...............................................................
  4117                              <1> 	;				
  4118                              <1> 	; Retro UNIX 8086 v1 modification: 
  4119                              <1> 	;       'syschown' system call has two arguments; so,
  4120                              <1> 	;	* 1st argument, name is pointed to by BX register
  4121                              <1> 	;	* 2nd argument, owner number is in CX register
  4122                              <1> 	;
  4123                              <1> 	; / name; owner
  4124 00004BEB E8B2FFFFFF          <1> 	call	isown
  4125                              <1> 		; jsr r0,isown / get the i-node and check user status
  4126 00004BF0 803D[E46E0000]00    <1> 	cmp 	byte [u.uid], 0 ; 02/08/2013 
  4127                              <1> 		; tstb u.uid / super user
  4128 00004BF7 7418                <1> 	jz	short syschown1
  4129                              <1> 		; beq 2f / yes, 2f
  4130 00004BF9 F605[986B0000]20    <1>         test    byte [i.flgs], 20h ; 32
  4131                              <1> 		; bit $40,i.flgs / no, set userid on execution?
  4132                              <1> 	;jnz	error
  4133                              <1> 		; bne 3f / yes error, could create Trojan Horses
  4134 00004C00 740F                <1> 	jz	short syschown1
  4135                              <1> 	; 'permission denied !'
  4136 00004C02 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS  ; 11
  4136 00004C0A 0000                <1>
  4137 00004C0C E9C1EEFFFF          <1> 	jmp	error
  4138                              <1> syschown1: ; 2:
  4139                              <1> 	; AL = owner (number/ID)
  4140 00004C11 A2[9B6B0000]        <1> 	mov	[i.uid], al ; 23/06/2015
  4141                              <1> 		;  movb	r2,i.uid / no, put the new owners id 
  4142                              <1> 			       ; / in the i-node
  4143 00004C16 E9D7EEFFFF          <1> 	jmp	sysret
  4144                              <1> 	; 1: 
  4145                              <1> 		; jmp sysret4
  4146                              <1> 	; 3:
  4147                              <1> 		; jmp	error
  4148                              <1> 
  4149                              <1> systime: ; / get time of year
  4150                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4151                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  4152                              <1> 	;
  4153                              <1> 	; 20/06/2013
  4154                              <1> 	; 'systime' gets the time of the year.
  4155                              <1> 	; The present time is put on the stack.
  4156                              <1> 	;
  4157                              <1> 	; Calling sequence:
  4158                              <1> 	;	systime
  4159                              <1> 	; Arguments: -
  4160                              <1> 	;	
  4161                              <1> 	; Inputs: -
  4162                              <1> 	; Outputs: sp+2, sp+4 - present time
  4163                              <1> 	; ...............................................................
  4164                              <1> 	;	
  4165                              <1> 	; Retro UNIX 8086 v1 modification: 
  4166                              <1> 	;       'systime' system call will return to the user
  4167                              <1> 	;	with unix time (epoch) in DX:AX register pair
  4168                              <1> 	;
  4169                              <1> 	; 	!! Major modification on original Unix v1 'systime' 
  4170                              <1> 	;	system call for PC compatibility !!		 	
  4171                              <1> 
  4172 00004C1B E8F5E9FFFF          <1> 	call 	epoch
  4173 00004C20 A3[986E0000]        <1> 	mov 	[u.r0], eax
  4174                              <1> 		; mov s.time,4(sp)
  4175                              <1> 		; mov s.time+2,2(sp) / put the present time 
  4176                              <1> 				   ; / on the stack
  4177                              <1> 		; br sysret4
  4178 00004C25 E9C8EEFFFF          <1> 	jmp	sysret 
  4179                              <1> 
  4180                              <1> sysstime: ; / set time
  4181                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4182                              <1> 	; 20/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4183                              <1> 	;
  4184                              <1> 	; 'sysstime' sets the time. Only super user can use this call.
  4185                              <1> 	;
  4186                              <1> 	; Calling sequence:
  4187                              <1> 	;	sysstime
  4188                              <1> 	; Arguments: -
  4189                              <1> 	;	
  4190                              <1> 	; Inputs: sp+2, sp+4 - time system is to be set to.
  4191                              <1> 	; Outputs: -
  4192                              <1> 	; ...............................................................
  4193                              <1> 	;	
  4194                              <1> 	; Retro UNIX 8086 v1 modification: 
  4195                              <1> 	;	the user calls 'sysstime' with unix (epoch) time
  4196                              <1> 	;	(to be set) is in CX:BX register pair as two arguments.
  4197                              <1> 	; 
  4198                              <1> 	;	Retro UNIX 8086 v1 argument transfer method 2 is used
  4199                              <1> 	;	to get sysstime system call arguments from the user;
  4200                              <1> 	;	* 1st argument, lowword of unix time is in BX register
  4201                              <1> 	;	* 2nd argument, highword of unix time is in CX register		 	
  4202                              <1> 	;
  4203                              <1> 	; 	!! Major modification on original Unix v1 'sysstime' 
  4204                              <1> 	;	system call for PC compatibility !!	
  4205                              <1> 
  4206 00004C2A 803D[E46E0000]00    <1> 	cmp	byte [u.uid], 0
  4207                              <1> 		; tstb u.uid / is user the super user
  4208                              <1> 	;ja	error
  4209                              <1> 		; bne error4 / no, error
  4210 00004C31 760F                <1> 	jna	short systime1
  4211                              <1> 	; 'permission denied !'
  4212 00004C33 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_SUPERUSER  ; 11 
  4212 00004C3B 0000                <1>
  4213 00004C3D E990EEFFFF          <1> 	jmp	error
  4214                              <1> systime1:
  4215                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - 32 bit version)
  4216                              <1> 	; EBX = unix (epoch) time (from user)
  4217 00004C42 89D8                <1> 	mov	eax, ebx
  4218 00004C44 E84CEBFFFF          <1> 	call 	set_date_time
  4219                              <1> 		; mov 4(sp),s.time
  4220                              <1> 		; mov 2(sp),s.time+2 / set the system time
  4221 00004C49 E9A4EEFFFF          <1> 	jmp	sysret
  4222                              <1> 		; br sysret4
  4223                              <1> 
  4224                              <1> sysbreak:
  4225                              <1> 	; 18/10/2015
  4226                              <1> 	; 07/10/2015
  4227                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4228                              <1> 	; 20/06/2013 - 24/03/2014 (Retro UNIX 8086 v1)
  4229                              <1> 	;
  4230                              <1> 	; 'sysbreak' sets the programs break points. 
  4231                              <1> 	; It checks the current break point (u.break) to see if it is
  4232                              <1> 	; between "core" and the stack (sp). If it is, it is made an
  4233                              <1> 	; even address (if it was odd) and the area between u.break
  4234                              <1> 	; and the stack is cleared. The new breakpoint is then put
  4235                              <1> 	; in u.break and control is passed to 'sysret'.
  4236                              <1> 	;
  4237                              <1> 	; Calling sequence:
  4238                              <1> 	;	sysbreak; addr
  4239                              <1> 	; Arguments: -
  4240                              <1> 	;	
  4241                              <1> 	; Inputs: u.break - current breakpoint
  4242                              <1> 	; Outputs: u.break - new breakpoint 
  4243                              <1> 	;	area between old u.break and the stack (sp) is cleared.
  4244                              <1> 	; ...............................................................
  4245                              <1> 	;	
  4246                              <1> 	; Retro UNIX 8086 v1 modification:
  4247                              <1> 	;	The user/application program puts breakpoint address
  4248                              <1> 	;       in BX register as 'sysbreak' system call argument.
  4249                              <1> 	; 	(argument transfer method 1)
  4250                              <1> 	;
  4251                              <1> 	;  NOTE: Beginning of core is 0 in Retro UNIX 8086 v1 !
  4252                              <1> 	; 	((!'sysbreak' is not needed in Retro UNIX 8086 v1!))
  4253                              <1> 	;  NOTE:
  4254                              <1> 	; 	'sysbreak' clears extended part (beyond of previous
  4255                              <1> 	;	'u.break' address) of user's memory for original unix's
  4256                              <1> 	;	'bss' compatibility with Retro UNIX 8086 v1 (19/11/2013)
  4257                              <1> 
  4258                              <1> 		; mov u.break,r1 / move users break point to r1
  4259                              <1> 		; cmp r1,$core / is it the same or lower than core?
  4260                              <1> 		; blos 1f / yes, 1f
  4261                              <1> 	; 23/06/2015
  4262 00004C4E 8B2D[C46E0000]      <1> 	mov	ebp, [u.break] ; virtual address (offset)
  4263                              <1> 	;and	ebp, ebp
  4264                              <1> 	;jz	short sysbreak_3 
  4265                              <1> 	; Retro UNIX 386 v1 NOTE: u.break points to virtual address !!!
  4266                              <1> 	; (Even break point address is not needed for Retro UNIX 386 v1)
  4267 00004C54 8B15[906E0000]      <1> 	mov	edx, [u.sp] ; kernel stack at the beginning of sys call
  4268 00004C5A 83C20C              <1> 	add	edx, 12 ; EIP -4-> CS -4-> EFLAGS -4-> ESP (user) 
  4269                              <1> 	; 07/10/2015
  4270 00004C5D 891D[C46E0000]      <1> 	mov	[u.break], ebx ; virtual address !!!
  4271                              <1> 	;
  4272 00004C63 3B1A                <1> 	cmp	ebx, [edx] ; compare new break point with 
  4273                              <1> 			   ; with top of user's stack (virtual!)
  4274 00004C65 7327                <1> 	jnb	short sysbreak_3
  4275                              <1> 		; cmp r1,sp / is it the same or higher 
  4276                              <1> 			  ; / than the stack?
  4277                              <1> 		; bhis 1f / yes, 1f
  4278 00004C67 89DE                <1> 	mov	esi, ebx
  4279 00004C69 29EE                <1> 	sub	esi, ebp ; new break point - old break point
  4280 00004C6B 7621                <1> 	jna	short sysbreak_3 
  4281                              <1> 	;push	ebx
  4282                              <1> sysbreak_1:
  4283 00004C6D 89EB                <1> 	mov	ebx, ebp  
  4284 00004C6F E82EE5FFFF          <1> 	call	get_physical_addr ; get physical address
  4285 00004C74 0F82AEFEFFFF        <1> 	jc	tr_addr_nm_err
  4286                              <1> 	; 18/10/2015
  4287 00004C7A 89C7                <1> 	mov	edi, eax 
  4288 00004C7C 29C0                <1> 	sub	eax, eax ; 0
  4289                              <1> 		 ; ECX = remain byte count in page (1-4096)
  4290 00004C7E 39CE                <1> 	cmp	esi, ecx
  4291 00004C80 7302                <1> 	jnb	short sysbreak_2
  4292 00004C82 89F1                <1> 	mov	ecx, esi
  4293                              <1> sysbreak_2:
  4294 00004C84 29CE                <1> 	sub	esi, ecx
  4295 00004C86 01CD                <1> 	add	ebp, ecx
  4296 00004C88 F3AA                <1> 	rep 	stosb
  4297 00004C8A 09F6                <1> 	or	esi, esi
  4298 00004C8C 75DF                <1> 	jnz	short sysbreak_1
  4299                              <1> 	;
  4300                              <1> 		; bit $1,r1 / is it an odd address
  4301                              <1> 		; beq 2f / no, its even
  4302                              <1> 		; clrb (r1)+ / yes, make it even
  4303                              <1> 	; 2: / clear area between the break point and the stack
  4304                              <1> 		; cmp r1,sp / is it higher or same than the stack
  4305                              <1> 		; bhis 1f / yes, quit
  4306                              <1> 		; clr (r1)+ / clear word
  4307                              <1> 		; br 2b / go back
  4308                              <1> 	;pop	ebx
  4309                              <1> sysbreak_3: ; 1:
  4310                              <1> 	;mov	[u.break], ebx ; virtual address !!!
  4311                              <1> 		; jsr r0,arg; u.break / put the "address" 
  4312                              <1> 			; / in u.break (set new break point)
  4313                              <1> 		; br sysret4 / br sysret
  4314 00004C8E E95FEEFFFF          <1> 	jmp	sysret
  4315                              <1> 
  4316                              <1> maknod: 
  4317                              <1> 	; 11/02/2022
  4318                              <1> 	; 09/01/2022
  4319                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4320                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4321                              <1> 	; 02/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4322                              <1> 	;
  4323                              <1> 	; 'maknod' creates an i-node and makes a directory entry
  4324                              <1> 	; for this i-node in the current directory.
  4325                              <1> 	;
  4326                              <1> 	; INPUTS ->
  4327                              <1> 	;    r1 - contains mode
  4328                              <1> 	;    ii - current directory's i-number	
  4329                              <1> 	;    	
  4330                              <1> 	; OUTPUTS ->
  4331                              <1> 	;    u.dirbuf - contains i-number of free i-node 
  4332                              <1> 	;    i.flgs - flags in new i-node 
  4333                              <1> 	;    i.uid - filled with u.uid
  4334                              <1> 	;    i.nlks - 1 is put in the number of links
  4335                              <1> 	;    i.ctim - creation time				
  4336                              <1> 	;    i.ctim+2 - modification time
  4337                              <1> 	;    imod - set via call to setimod
  4338                              <1> 	;	
  4339                              <1> 	; ((AX = R1)) input
  4340                              <1> 	;
  4341                              <1> 	; (Retro UNIX Prototype : 
  4342                              <1> 	;	30/10/2012 - 01/03/2013, UNIXCOPY.ASM)
  4343                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  4344                              <1> 
  4345                              <1> 	; / r1 contains the mode
  4346 00004C93 80CC80              <1> 	or 	ah, 80h	; 10000000b
  4347                              <1> 		; bis $100000,r1 / allocate flag set
  4348 00004C96 6650                <1> 	push	ax ; * ; 24/12/2021
  4349                              <1> 		; mov r1,-(sp) / put mode on stack
  4350                              <1> 	; 31/07/2013
  4351 00004C98 66A1[7C6E0000]      <1> 	mov	ax, [ii] ; move current i-number to AX/r1
  4352                              <1> 		; mov ii,r1 / move current i-number to r1
  4353 00004C9E B201                <1> 	mov	dl, 1 ; owner flag mask
  4354 00004CA0 E8C4050000          <1> 	call	access	
  4355                              <1> 		; jsr r0,access; 1 / get its i-node into core
  4356 00004CA5 50                  <1> 	push	eax ; ** ; 24/12/2021
  4357                              <1> 		; mov r1,-(sp) / put i-number on stack
  4358 00004CA6 66B82800            <1> 	mov	ax, 40
  4359                              <1> 		; mov $40.,r1 / r1 = 40
  4360                              <1> maknod1: ; 1: / scan for a free i-node (next 4 instructions)
  4361 00004CAA 6640                <1> 	inc	ax
  4362                              <1> 		; inc r1 / r1 = r1 + 1
  4363 00004CAC E87D060000          <1> 	call	imap
  4364                              <1> 		; jsr r0,imap / get byte address and bit position in 
  4365                              <1> 			    ; /	inode map in r2 & m
  4366                              <1>   
  4367                              <1>         ; DX (MQ) has a 1 in the calculated bit position
  4368                              <1>         ; eBX (R2) has byte address of the byte with allocation bit
  4369                              <1> 
  4370                              <1> 	; 22/06/2015 - NOTE for next Retro UNIX version: 
  4371                              <1> 	;	       Inode count must be checked here
  4372                              <1> 	; (Original UNIX v1 did not check inode count here !?) 	
  4373                              <1> 
  4374                              <1> 	; 11/02/2022 - Retro UNIX 386 v1.1 (Kernel v0.2.1.2)
  4375                              <1> 	; (inode count check)
  4376                              <1> 	; ((if cf=1 --> requested inode number > inode count))
  4377                              <1> 
  4378 00004CB1 730F                <1> 	jnc	short maknod2
  4379                              <1> 
  4380                              <1> 	; no free inode in inode table !
  4381 00004CB3 C705[ED6E0000]1B00- <1> 	mov	 dword [u.error], ERR_MISC ; 27
  4381 00004CBB 0000                <1>
  4382                              <1> 			; miscellaneous/other errors
  4383 00004CBD E910EEFFFF          <1> 	jmp	error	
  4384                              <1> maknod2: 
  4385 00004CC2 8413                <1> 	test	[ebx], dl
  4386                              <1> 		; bitb mq,(r2) / is the i-node active
  4387 00004CC4 75E4                <1> 	jnz	short maknod1
  4388                              <1> 		; bne 1b / yes, try the next one
  4389 00004CC6 0813                <1> 	or	[ebx], dl
  4390                              <1> 		; bisb mq,(r2) / no, make it active 
  4391                              <1> 			     ; / (put a 1 in the bit map)
  4392 00004CC8 E8C8040000          <1> 	call	iget
  4393                              <1> 		; jsr r0,iget / get i-node into core
  4394                              <1> 	; 09/01/2022
  4395 00004CCD F605[996B0000]80    <1> 	test	byte [i.flgs+1], 80h
  4396                              <1> 	;test	word [i.flgs], 8000h 
  4397                              <1> 		; tst i.flgs / is i-node already allocated
  4398 00004CD4 75D4                <1> 	jnz	short maknod1	
  4399                              <1> 		; blt 1b / yes, look for another one
  4400 00004CD6 66A3[CA6E0000]      <1> 	mov	[u.dirbuf], ax
  4401                              <1> 		; mov r1,u.dirbuf / no, put i-number in u.dirbuf
  4402 00004CDC 58                  <1> 	pop	eax ; ** ; 24/12/2021
  4403                              <1> 		; mov (sp)+,r1 / get current i-number back
  4404 00004CDD E8B3040000          <1> 	call	iget
  4405                              <1> 		; jsr r0,iget / get i-node in core
  4406 00004CE2 E8AFF7FFFF          <1> 	call	mkdir
  4407                              <1> 		; jsr r0,mkdir / make a directory entry 
  4408                              <1> 			     ; / in current directory
  4409 00004CE7 66A1[CA6E0000]      <1> 	mov	ax, [u.dirbuf]
  4410                              <1> 		; mov u.dirbuf,r1 / r1 = new inode number
  4411 00004CED E8A3040000          <1> 	call	iget
  4412                              <1> 		; jsr r0,iget / get it into core
  4413                              <1> 		; jsr r0,copyz; inode; inode+32. / 0 it out
  4414                              <1> 	;mov	ecx, 8
  4415                              <1> 	; 09/01/2022 
  4416 00004CF2 29C9                <1> 	sub	ecx, ecx
  4417 00004CF4 B108                <1> 	mov	cl, 8
  4418 00004CF6 31C0                <1> 	xor	eax, eax ; 0
  4419 00004CF8 BF[986B0000]        <1> 	mov	edi, inode 
  4420 00004CFD F3AB                <1> 	rep	stosd
  4421                              <1> 	;
  4422 00004CFF 668F05[986B0000]    <1> 	pop	word [i.flgs] ; * ; 24/12/2021
  4423                              <1> 		; mov (sp)+,i.flgs / fill flags
  4424 00004D06 8A0D[E46E0000]      <1> 	mov 	cl, [u.uid] ; 02/08/2013
  4425 00004D0C 880D[9B6B0000]      <1> 	mov 	[i.uid], cl
  4426                              <1> 		; movb u.uid,i.uid / user id	
  4427 00004D12 C605[9A6B0000]01    <1> 	mov     byte [i.nlks], 1
  4428                              <1> 		; movb $1,i.nlks / 1 link
  4429                              <1> 	;call	epoch ; Retro UNIX 8086 v1 modification !
  4430                              <1> 	;mov	eax, [s.time]
  4431                              <1> 	;mov 	[i.ctim], eax
  4432                              <1> 	 	; mov s.time,i.ctim / time created
  4433                              <1> 	 	; mov s.time+2,i.ctim+2 / time modified
  4434                              <1> 	; Retro UNIX 8086 v1 modification !
  4435                              <1> 	; i.ctime=0, i.ctime+2=0 and
  4436                              <1>         ; 'setimod' will set ctime of file via 'epoch'
  4437                              <1> 	;call	setimod
  4438                              <1> 	;	; jsr r0,setimod / set modified flag
  4439                              <1> 	;retn
  4440                              <1> 	;	; rts r0 / return
  4441                              <1> 	; 24/12/2021
  4442 00004D19 E981050000          <1> 	jmp	setimod
  4443                              <1> 
  4444                              <1> sysseek: ; / moves read write pointer in an fsp entry
  4445                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4446                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4447                              <1> 	;
  4448                              <1> 	; 'sysseek' changes the r/w pointer of (3rd word of in an
  4449                              <1> 	; fsp entry) of an open file whose file descriptor is in u.r0.
  4450                              <1> 	; The file descriptor refers to a file open for reading or
  4451                              <1> 	; writing. The read (or write) pointer is set as follows:
  4452                              <1> 	;	* if 'ptrname' is 0, the pointer is set to offset.
  4453                              <1> 	;	* if 'ptrname' is 1, the pointer is set to its
  4454                              <1> 	;	  current location plus offset.
  4455                              <1> 	;	* if 'ptrname' is 2, the pointer is set to the
  4456                              <1> 	;	  size of file plus offset.
  4457                              <1> 	; The error bit (e-bit) is set for an undefined descriptor.
  4458                              <1> 	;
  4459                              <1> 	; Calling sequence:
  4460                              <1> 	;	sysseek; offset; ptrname
  4461                              <1> 	; Arguments:
  4462                              <1> 	;	offset - number of bytes desired to move 
  4463                              <1> 	;		 the r/w pointer
  4464                              <1> 	;	ptrname - a switch indicated above
  4465                              <1> 	;
  4466                              <1> 	; Inputs: r0 - file descriptor 
  4467                              <1> 	; Outputs: -
  4468                              <1> 	; ...............................................................
  4469                              <1> 	;	
  4470                              <1> 	; Retro UNIX 8086 v1 modification: 
  4471                              <1> 	;       'sysseek' system call has three arguments; so,
  4472                              <1> 	;	* 1st argument, file descriptor is in BX (BL) register
  4473                              <1> 	;	* 2nd argument, offset is in CX register
  4474                              <1> 	;	* 3rd argument, ptrname/switch is in DX (DL) register	
  4475                              <1> 	;	
  4476                              <1> 
  4477 00004D1E E822000000          <1> 	call	seektell
  4478                              <1> 	; AX = u.count
  4479                              <1> 	; BX = *u.fofp
  4480                              <1> 		; jsr r0,seektell / get proper value in u.count
  4481                              <1> 		; add u.base,u.count / add u.base to it
  4482 00004D23 0305[B86E0000]      <1> 	add	eax, [u.base] ; add offset (u.base) to base
  4483 00004D29 8903                <1> 	mov	[ebx], eax
  4484                              <1> 		; mov u.count,*u.fofp / put result into r/w pointer
  4485 00004D2B E9C2EDFFFF          <1> 	jmp	sysret
  4486                              <1> 		; br sysret4
  4487                              <1> 
  4488                              <1> systell: ; / get the r/w pointer
  4489                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4490                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4491                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4492                              <1> 	;
  4493                              <1> 	; Retro UNIX 8086 v1 modification:
  4494                              <1> 	; ! 'systell' does not work in original UNIX v1,
  4495                              <1> 	; 	    it returns with error !
  4496                              <1> 	; Inputs: r0 - file descriptor 
  4497                              <1> 	; Outputs: r0 - file r/w pointer
  4498                              <1> 
  4499                              <1> 	;xor	ecx, ecx ; 0
  4500                              <1> 	;mov	edx, 1 ; 05/08/2013
  4501                              <1> 	; 24/12/2021
  4502 00004D30 29D2                <1> 	sub	edx, edx
  4503 00004D32 FEC2                <1> 	inc	dl
  4504                              <1> 	; edx = 1
  4505                              <1> 	;call 	seektell
  4506 00004D34 E812000000          <1> 	call 	seektell0 ; 05/08/2013
  4507                              <1> 	;mov	ebx, [u.fofp]
  4508 00004D39 8B03                <1> 	mov	eax, [ebx]
  4509 00004D3B A3[986E0000]        <1> 	mov	[u.r0], eax
  4510 00004D40 E9ADEDFFFF          <1> 	jmp	sysret
  4511                              <1> 
  4512                              <1> ; Original unix v1 'systell' system call:
  4513                              <1> 		; jsr r0,seektell
  4514                              <1> 		; br error4
  4515                              <1> 
  4516                              <1> seektell:
  4517                              <1> 	; 03/02/2022
  4518                              <1> 	; 03/01/2016
  4519                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4520                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4521                              <1> 	;
  4522                              <1> 	; 'seektell' puts the arguments from sysseek and systell
  4523                              <1> 	; call in u.base and u.count. It then gets the i-number of
  4524                              <1> 	; the file from the file descriptor in u.r0 and by calling
  4525                              <1> 	; getf. The i-node is brought into core and then u.count
  4526                              <1> 	; is checked to see it is a 0, 1, or 2.
  4527                              <1> 	; If it is 0 - u.count stays the same
  4528                              <1> 	;          1 - u.count = offset (u.fofp)
  4529                              <1> 	;	   2 - u.count = i.size (size of file)
  4530                              <1> 	; 	 		
  4531                              <1> 	; !! Retro UNIX 8086 v1 modification:
  4532                              <1> 	;	Argument 1, file descriptor is in BX;
  4533                              <1> 	;	Argument 2, offset is in CX;
  4534                              <1> 	;	Argument 3, ptrname/switch is in DX register.	
  4535                              <1> 	;
  4536                              <1> 	; mov 	ax, 3 ; Argument transfer method 3 (three arguments)	
  4537                              <1> 	; call 	arg
  4538                              <1> 	;
  4539                              <1> 	; ((Return -> ax = base for offset (position= base+offset))
  4540                              <1> 	;
  4541 00004D45 890D[B86E0000]      <1> 	mov 	[u.base], ecx ; offset
  4542                              <1> 		; jsr r0,arg; u.base / puts offset in u.base
  4543                              <1> seektell0:
  4544 00004D4B 8915[BC6E0000]      <1> 	mov 	[u.count], edx
  4545                              <1> 		; jsr r0,arg; u.count / put ptr name in u.count
  4546                              <1> 	; mov	ax, bx
  4547                              <1> 		; mov *u.r0,r1 / file descriptor in r1 
  4548                              <1> 			     ; / (index in u.fp list)
  4549                              <1> 	; call	getf
  4550                              <1> 		; jsr r0,getf / u.fofp points to 3rd word in fsp entry
  4551                              <1> 	; BX = file descriptor (file number)
  4552 00004D51 E849FCFFFF          <1> 	call	getf1
  4553                              <1> 	; 03/02/2022
  4554 00004D56 09C0                <1> 	or	eax, eax
  4555                              <1> 	;or	ax, ax ; i-number of the file
  4556                              <1> 		; mov r1,-(sp) / r1 has i-number of file, 
  4557                              <1> 		             ; / put it on the stack
  4558                              <1> 	;jz	error
  4559                              <1> 		; beq error4 / if i-number is 0, not active so error
  4560 00004D58 750F                <1> 	jnz	short seektell1
  4561 00004D5A C705[ED6E0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN  ; 'file not open !'
  4561 00004D62 0000                <1>
  4562 00004D64 E969EDFFFF          <1> 	jmp	error
  4563                              <1> seektell1:
  4564                              <1> 	;push	eax
  4565 00004D69 80FC80              <1> 	cmp	ah, 80h
  4566 00004D6C 7203                <1> 	jb	short seektell2
  4567                              <1> 		; bgt .+4 / if its positive jump
  4568 00004D6E 66F7D8              <1> 	neg	ax
  4569                              <1> 		; neg r1 / if not make it positive
  4570                              <1> seektell2:
  4571 00004D71 E81F040000          <1> 	call	iget
  4572                              <1> 		; jsr r0,iget / get its i-node into core
  4573 00004D76 8B1D[A86E0000]      <1>         mov     ebx, [u.fofp] ; 05/08/2013
  4574 00004D7C 803D[BC6E0000]01    <1> 	cmp	byte [u.count], 1
  4575                              <1> 		; cmp u.count,$1 / is ptr name =1
  4576 00004D83 7705                <1> 	ja	short seektell3
  4577                              <1> 		; blt 2f / no its zero
  4578 00004D85 740A                <1> 	je	short seektell_4
  4579                              <1> 		; beq 1f / yes its 1
  4580 00004D87 31C0                <1> 	xor	eax, eax
  4581                              <1> 	;jmp	short seektell_5
  4582 00004D89 C3                  <1> 	retn
  4583                              <1> seektell3:
  4584                              <1> 	; 03/01/2016
  4585                              <1> 	;movzx	eax, word [i.size]
  4586 00004D8A 66A1[9C6B0000]      <1>         mov   	ax, [i.size]
  4587                              <1>                 ; mov i.size,u.count /  put number of bytes 
  4588                              <1>                                    ; / in file in u.count
  4589                              <1> 	;jmp	short seektell_5
  4590                              <1> 		; br 2f
  4591 00004D90 C3                  <1> 	retn
  4592                              <1> seektell_4: ; 1: / ptrname =1
  4593                              <1> 	;mov	ebx, [u.fofp]
  4594 00004D91 8B03                <1> 	mov	eax, [ebx]
  4595                              <1> 		; mov *u.fofp,u.count / put offset in u.count
  4596                              <1> ;seektell_5: ; 2: / ptrname =0
  4597                              <1> 	;mov	[u.count], eax
  4598                              <1> 	;pop	eax 
  4599                              <1> 		; mov (sp)+,r1 / i-number on stack  r1
  4600 00004D93 C3                  <1> 	retn
  4601                              <1> 		; rts r0
  4602                              <1> 
  4603                              <1> sysintr: ; / set interrupt handling
  4604                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4605                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4606                              <1> 	;
  4607                              <1> 	; 'sysintr' sets the interrupt handling value. It puts
  4608                              <1> 	; argument of its call in u.intr then branches into 'sysquit'
  4609                              <1> 	; routine. u.tty is checked if to see if a control tty exists.
  4610                              <1> 	; If one does the interrupt character in the tty buffer is
  4611                              <1> 	; cleared and 'sysret'is called. If one does not exits
  4612                              <1> 	; 'sysret' is just called.	
  4613                              <1> 	;
  4614                              <1> 	; Calling sequence:
  4615                              <1> 	;	sysintr; arg
  4616                              <1> 	; Argument:
  4617                              <1> 	;	arg - if 0, interrupts (ASCII DELETE) are ignored.
  4618                              <1> 	;	    - if 1, intterupts cause their normal result
  4619                              <1> 	;		 i.e force an exit.
  4620                              <1> 	;	    - if arg is a location within the program,
  4621                              <1> 	;		control is passed to that location when
  4622                              <1> 	;		an interrupt occurs.	
  4623                              <1> 	; Inputs: -
  4624                              <1> 	; Outputs: -
  4625                              <1> 	; ...............................................................
  4626                              <1> 	;	
  4627                              <1> 	; Retro UNIX 8086 v1 modification: 
  4628                              <1> 	;       'sysintr' system call sets u.intr to value of BX
  4629                              <1> 	;	then branches into sysquit.
  4630                              <1> 	;
  4631 00004D94 66891D[DC6E0000]    <1> 	mov	[u.intr], bx
  4632                              <1> 		; jsr r0,arg; u.intr / put the argument in u.intr
  4633                              <1> 		; br 1f / go into quit routine
  4634 00004D9B E952EDFFFF          <1> 	jmp	sysret
  4635                              <1> 
  4636                              <1> sysquit:
  4637                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4638                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4639                              <1> 	;
  4640                              <1> 	; 'sysquit' turns off the quit signal. it puts the argument of
  4641                              <1> 	; the call in u.quit. u.tty is checked if to see if a control 
  4642                              <1> 	; tty exists. If one does the interrupt character in the tty
  4643                              <1> 	; buffer is cleared and 'sysret'is called. If one does not exits
  4644                              <1> 	; 'sysret' is just called.	
  4645                              <1> 	;
  4646                              <1> 	; Calling sequence:
  4647                              <1> 	;	sysquit; arg
  4648                              <1> 	; Argument:
  4649                              <1> 	;	arg - if 0, this call diables quit signals from the
  4650                              <1> 	;		typewriter (ASCII FS)
  4651                              <1> 	;	    - if 1, quits are re-enabled and cause execution to
  4652                              <1> 	;		cease and a core image to be produced.
  4653                              <1> 	;		 i.e force an exit.
  4654                              <1> 	;	    - if arg is an addres in the program,
  4655                              <1> 	;		a quit causes control to sent to that
  4656                              <1> 	;		location.	
  4657                              <1> 	; Inputs: -
  4658                              <1> 	; Outputs: -
  4659                              <1> 	; ...............................................................
  4660                              <1> 	;	
  4661                              <1> 	; Retro UNIX 8086 v1 modification: 
  4662                              <1> 	;       'sysquit' system call sets u.quit to value of BX
  4663                              <1> 	;	then branches into 'sysret'.
  4664                              <1> 	;
  4665 00004DA0 66891D[DE6E0000]    <1> 	mov	[u.quit], bx
  4666 00004DA7 E946EDFFFF          <1> 	jmp	sysret
  4667                              <1> 		; jsr r0,arg; u.quit / put argument in u.quit
  4668                              <1> 	;1:
  4669                              <1> 		; mov u.ttyp,r1 / move pointer to control tty buffer
  4670                              <1> 			      ; / to r1
  4671                              <1> 		; beq sysret4 / return to user
  4672                              <1> 		; clrb 6(r1) / clear the interrupt character 
  4673                              <1> 			   ; / in the tty buffer
  4674                              <1> 		; br sysret4 / return to user
  4675                              <1> 
  4676                              <1> syssetuid: ; / set process id
  4677                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4678                              <1> 	; 07/07/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4679                              <1> 	;
  4680                              <1> 	; 'syssetuid' sets the user id (u.uid) of the current process
  4681                              <1> 	; to the process id in (u.r0). Both the effective user and 
  4682                              <1> 	; u.uid and the real user u.ruid are set to this. 
  4683                              <1> 	; Only the super user can make this call.	
  4684                              <1> 	;
  4685                              <1> 	; Calling sequence:
  4686                              <1> 	;	syssetuid
  4687                              <1> 	; Arguments: -
  4688                              <1> 	;
  4689                              <1> 	; Inputs: (u.r0) - contains the process id.
  4690                              <1> 	; Outputs: -
  4691                              <1> 	; ...............................................................
  4692                              <1> 	;	
  4693                              <1> 	; Retro UNIX 8086 v1 modification: 
  4694                              <1> 	;       BL contains the (new) user ID of the current process
  4695                              <1> 
  4696                              <1> 		; movb *u.r0,r1 / move process id (number) to r1
  4697 00004DAC 3A1D[E56E0000]      <1> 	cmp	bl, [u.ruid] 
  4698                              <1> 		; cmpb r1,u.ruid / is it equal to the real user 
  4699                              <1> 			       ; / id number
  4700 00004DB2 741E                <1> 	je	short setuid1
  4701                              <1> 		; beq 1f / yes
  4702 00004DB4 803D[E46E0000]00    <1> 	cmp	byte [u.uid], 0 ; 02/08/2013
  4703                              <1> 		; tstb u.uid / no, is current user the super user?
  4704                              <1> 	;ja	error
  4705                              <1> 		; bne error4 / no, error
  4706 00004DBB 760F                <1> 	jna	short setuid0
  4707 00004DBD C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_SUPERUSER  ; 11
  4707 00004DC5 0000                <1>
  4708                              <1> 				; 'permission denied !' error
  4709 00004DC7 E906EDFFFF          <1> 	jmp	error
  4710                              <1> setuid0:
  4711 00004DCC 881D[E56E0000]      <1> 	mov	[u.ruid], bl
  4712                              <1> setuid1: ; 1:
  4713 00004DD2 881D[E46E0000]      <1> 	mov	[u.uid], bl ; 02/08/2013
  4714                              <1> 		; movb r1,u.uid / put process id in u.uid
  4715                              <1> 		; movb r1,u.ruid / put process id in u.ruid
  4716 00004DD8 E915EDFFFF          <1> 	jmp	sysret
  4717                              <1> 		; br sysret4 / system return
  4718                              <1> 
  4719                              <1> sysgetuid: ; < get user id >
  4720                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  4721                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4722                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4723                              <1> 	;
  4724                              <1> 	; 'sysgetuid' returns the real user ID of the current process.
  4725                              <1> 	; The real user ID identifies the person who is logged in,
  4726                              <1> 	; in contradistinction to the effective user ID, which
  4727                              <1> 	; determines his access permission at each moment. It is thus
  4728                              <1> 	; useful to programs which operate using the 'set user ID'
  4729                              <1> 	; mode, to find out who invoked them.	
  4730                              <1> 	;
  4731                              <1> 	; Calling sequence:
  4732                              <1> 	;	syssetuid
  4733                              <1> 	; Arguments: -
  4734                              <1> 	;
  4735                              <1> 	; Inputs: -
  4736                              <1> 	; Outputs: (u.r0) - contains the real user's id.
  4737                              <1> 	; ...............................................................
  4738                              <1> 	;	
  4739                              <1> 	; Retro UNIX 8086 v1 modification: 
  4740                              <1> 	;       AL contains the real user ID at return.
  4741                              <1> 	;
  4742                              <1> 	;movzx 	eax, byte [u.ruid]
  4743                              <1> 	; 09/01/2022
  4744 00004DDD A0[E56E0000]        <1> 	mov	al, [u.ruid]
  4745 00004DE2 A3[986E0000]        <1> 	mov	[u.r0], eax
  4746                              <1> 		; movb	u.ruid,*u.r0 / move the real user id to (u.r0)
  4747 00004DE7 E906EDFFFF          <1> 	jmp	sysret
  4748                              <1> 		; br sysret4 / systerm return, sysret
  4749                              <1> 
  4750                              <1> anyi: 
  4751                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4752                              <1> 	; 25/04/2013 (Retro UNIX 8086 v1)
  4753                              <1> 	;
  4754                              <1> 	; 'anyi' is called if a file deleted while open.
  4755                              <1> 	; "anyi" checks to see if someone else has opened this file.
  4756                              <1> 	;
  4757                              <1> 	; INPUTS ->
  4758                              <1> 	;    r1 - contains an i-number
  4759                              <1> 	;    fsp - start of table containing open files
  4760                              <1> 	;
  4761                              <1> 	; OUTPUTS ->
  4762                              <1> 	;    "deleted" flag set in fsp entry of another occurrence of
  4763                              <1> 	;	   this file and r2 points 1st word of this fsp entry.
  4764                              <1> 	;    if file not found - bit in i-node map is cleared
  4765                              <1> 	;    			 (i-node is freed)
  4766                              <1> 	;               all blocks related to i-node are freed
  4767                              <1> 	;	        all flags in i-node are cleared
  4768                              <1> 	; ((AX = R1)) input
  4769                              <1> 	;
  4770                              <1> 	;    (Retro UNIX Prototype : 02/12/2012, UNIXCOPY.ASM)
  4771                              <1>         ;    ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  4772                              <1> 	;
  4773                              <1> 		; / r1 contains an i-number
  4774 00004DEC BB[686C0000]        <1> 	mov	ebx, fsp
  4775                              <1> 		; mov $fsp,r2 / move start of fsp table to r2
  4776                              <1> anyi_1: ; 1:
  4777 00004DF1 663B03              <1> 	cmp	ax, [ebx]
  4778                              <1> 		; cmp r1,(r2) / do i-numbers match?
  4779 00004DF4 7433                <1> 	je	short anyi_3
  4780                              <1> 		; beq 1f / yes, 1f
  4781 00004DF6 66F7D8              <1> 	neg	ax
  4782                              <1> 		; neg r1 / no complement r1
  4783 00004DF9 663B03              <1> 	cmp	ax, [ebx]
  4784                              <1> 		; cmp r1,(r2) / do they match now?
  4785 00004DFC 742B                <1> 	je	short anyi_3
  4786                              <1> 		; beq 1f / yes, transfer
  4787                              <1> 		; / i-numbers do not match
  4788 00004DFE 83C30A              <1> 	add	ebx, 10 ; fsp table size is 10 bytes
  4789                              <1> 			; in Retro UNIX 386 v1 (22/06/2015)
  4790                              <1> 		; add $8,r2 / no, bump to next entry in fsp table
  4791 00004E01 81FB[5C6E0000]      <1> 	cmp	ebx, fsp + (nfiles*10) ; 22/06/2015 
  4792                              <1> 		; cmp r2,$fsp+[nfiles*8] 
  4793                              <1> 				; / are we at last entry in the table
  4794 00004E07 72E8                <1> 	jb	short anyi_1
  4795                              <1> 		; blt 1b / no, check next entries i-number
  4796                              <1> 	;cmp	ax, 32768
  4797 00004E09 80FC80              <1> 	cmp	ah, 80h ; negative number check
  4798                              <1> 		; tst r1 / yes, no match
  4799                              <1> 		; bge .+4
  4800 00004E0C 7203                <1> 	jb	short anyi_2
  4801 00004E0E 66F7D8              <1> 	neg	ax
  4802                              <1> 		; neg r1 / make i-number positive
  4803                              <1> anyi_2:	
  4804 00004E11 E818050000          <1> 	call	imap
  4805                              <1> 		; jsr r0,imap / get address of allocation bit 
  4806                              <1> 			    ; / in the i-map in r2
  4807                              <1> 	;; DL/DX (MQ) has a 1 in the calculated bit position
  4808                              <1>         ;; eBX (R2) has address of the byte with allocation bit
  4809                              <1>  	; not	dx
  4810 00004E16 F6D2                <1> 	not 	dl ;; 0 at calculated bit position, other bits are 1
  4811                              <1>         ;and	[ebx], dx
  4812 00004E18 2013                <1> 	and 	[ebx], dl 
  4813                              <1> 		; bicb mq,(r2) / clear bit for i-node in the imap
  4814 00004E1A E8A2040000          <1> 	call	itrunc
  4815                              <1> 		; jsr r0,itrunc / free all blocks related to i-node
  4816 00004E1F 66C705[986B0000]00- <1>  	mov 	word [i.flgs], 0
  4816 00004E27 00                  <1>
  4817                              <1> 		; clr i.flgs / clear all flags in the i-node
  4818 00004E28 C3                  <1> 	retn
  4819                              <1> 		;rts	r0 / return
  4820                              <1> anyi_3: ; 1: / i-numbers match
  4821 00004E29 FE4309              <1> 	inc 	byte [ebx+9] ; 22/06/2015
  4822                              <1> 		;incb 7(r2) / increment upper byte of the 4th word
  4823                              <1> 		   ; / in that fsp entry (deleted flag of fsp entry)
  4824 00004E2C C3                  <1> 	retn
  4825                              <1> 		; rts r0
  2094                                  %include 'u3.s'        ; 10/05/2015
  2095                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.1) - SYS3.INC
  2096                              <1> ; Last Modification: 24/12/2021
  2097                              <1> ; ----------------------------------------------------------------------------
  2098                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2099                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2100                              <1> ;
  2101                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2102                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2103                              <1> ; <Bell Laboratories (17/3/1972)>
  2104                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2105                              <1> ;
  2106                              <1> ; Retro UNIX 8086 v1 - U3.ASM (08/03/2014) //// UNIX v1 -> u3.s
  2107                              <1> ;
  2108                              <1> ; ****************************************************************************
  2109                              <1> 
  2110                              <1> tswitch: ; Retro UNIX 386 v1
  2111                              <1> tswap:
  2112                              <1> 	; 01/09/2015
  2113                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2114                              <1> 	; 14/04/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2115                              <1> 	; time out swap, called when a user times out.
  2116                              <1> 	; the user is put on the low priority queue.
  2117                              <1> 	; This is done by making a link from the last user
  2118                              <1> 	; on the low priority queue to him via a call to 'putlu'.
  2119                              <1> 	; then he is swapped out.
  2120                              <1> 	;
  2121                              <1> 	; Retro UNIX 386 v1 modification ->
  2122                              <1> 	;       swap (software task switch) is performed by changing
  2123                              <1> 	;	user's page directory (u.pgdir) instead of segment change
  2124                              <1> 	;	as in Retro UNIX 8086 v1.
  2125                              <1> 	;
  2126                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2127                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2128                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2129                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2130                              <1> 	;	compatibles was using 1MB segmented memory 
  2131                              <1> 	;	in 8086/8088 times.
  2132                              <1> 	;
  2133                              <1> 	; INPUTS ->
  2134                              <1> 	;    u.uno - users process number
  2135                              <1> 	;    runq+4 - lowest priority queue
  2136                              <1> 	; OUTPUTS ->
  2137                              <1> 	;    r0 - users process number
  2138                              <1> 	;    r2 - lowest priority queue address
  2139                              <1> 	;
  2140                              <1> 	; ((AX = R0, BX = R2)) output
  2141                              <1> 	; ((Modified registers: EDX, EBX, ECX, ESI, EDI))  	
  2142                              <1> 	;
  2143 00004E2D A0[E76E0000]        <1> 	mov 	al, [u.uno]
  2144                              <1> 	       	; movb u.uno,r1 / move users process number to r1
  2145                              <1> 		; mov  $runq+4,r2 
  2146                              <1> 			; / move lowest priority queue address to r2
  2147 00004E32 E8CD000000          <1>         call 	putlu
  2148                              <1> 		; jsr r0,putlu / create link from last user on Q to 
  2149                              <1> 		             ; / u.uno's user
  2150                              <1> 
  2151                              <1> switch: ; Retro UNIX 386 v1
  2152                              <1> swap:
  2153                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2154                              <1> 	; 02/09/2015
  2155                              <1> 	; 01/09/2015
  2156                              <1> 	; 31/08/2015
  2157                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2158                              <1> 	; 14/04/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2159                              <1> 	; 'swap' is routine that controls the swapping of processes
  2160                              <1> 	; in and out of core.
  2161                              <1> 	;
  2162                              <1> 	; Retro UNIX 386 v1 modification ->
  2163                              <1> 	;       swap (software task switch) is performed by changing
  2164                              <1> 	;	user's page directory (u.pgdir) instead of segment change
  2165                              <1> 	;	as in Retro UNIX 8086 v1.
  2166                              <1> 	;
  2167                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2168                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2169                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2170                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2171                              <1> 	;	compatibles was using 1MB segmented memory 
  2172                              <1> 	;	in 8086/8088 times.
  2173                              <1> 	;
  2174                              <1> 	; INPUTS ->
  2175                              <1> 	;    runq table - contains processes to run.
  2176                              <1> 	;    p.link - contains next process in line to be run.
  2177                              <1> 	;    u.uno - process number of process in core	
  2178                              <1> 	;    s.stack - swap stack used as an internal stack for swapping.	
  2179                              <1> 	; OUTPUTS ->
  2180                              <1> 	;    (original unix v1 -> present process to its disk block)
  2181                              <1> 	;    (original unix v1 -> new process into core -> 
  2182                              <1> 	;	   Retro Unix 8086 v1 -> segment registers changed 
  2183                              <1> 	;	   for new process)
  2184                              <1> 	;    u.quant = 3 (Time quantum for a process)
  2185                              <1> 	; 	((INT 1Ch count down speed -> 18.2 times per second)	 	
  2186                              <1> 	;    RETRO UNIX 8086 v1 will use INT 1Ch (18.2 times per second)
  2187                              <1> 	;	 for now, it will swap the process if there is not
  2188                              <1> 	;	 a keyboard event (keystroke) (Int 15h, function 4Fh)
  2189                              <1> 	;	 or will count down from 3 to 0 even if there is a
  2190                              <1> 	;        keyboard event locking due to repetitive key strokes.
  2191                              <1> 	;	 u.quant will be reset to 3 for RETRO UNIX 8086 v1.
  2192                              <1> 	;
  2193                              <1> 	;    u.pri -points to highest priority run Q.
  2194                              <1> 	;    r2 - points to the run queue.
  2195                              <1> 	;    r1 - contains new process number
  2196                              <1> 	;    r0 - points to place in routine or process that called
  2197                              <1> 	;	  swap all user parameters
  2198                              <1> 	;				
  2199                              <1> 	; ((Modified registers: EAX, EDX, EBX, ECX, ESI, EDI))  	
  2200                              <1> 	;
  2201                              <1> swap_0:
  2202                              <1> 		;mov $300,*$ps / processor priority = 6
  2203 00004E37 BE[8A6E0000]        <1> 	mov	esi, runq
  2204                              <1> 		; mov $runq,r2 / r2 points to runq table
  2205                              <1> swap_1: ; 1: / search runq table for highest priority process
  2206 00004E3C 668B06              <1> 	mov	ax, [esi]
  2207 00004E3F 6621C0              <1> 	and 	ax, ax
  2208                              <1>        		; tst (r2)+ / are there any processes to run 
  2209                              <1> 			  ; / in this Q entry
  2210 00004E42 7507                <1> 	jnz	short swap_2
  2211                              <1>        		; bne 1f / yes, process 1f
  2212                              <1> 		; cmp r2,$runq+6 / if zero compare address 
  2213                              <1> 			       ; / to end of table
  2214                              <1> 		; bne 1b / if not at end, go back
  2215 00004E44 E8E0000000          <1> 	call	idle
  2216                              <1> 		; jsr r0,idle; s.idlet+2 / wait for interrupt; 
  2217                              <1> 				       ; / all queues are empty
  2218 00004E49 EBF1                <1> 	jmp	short swap_1
  2219                              <1> 		; br swap
  2220                              <1> swap_2: ; 1:
  2221 00004E4B 0FB6D8              <1> 	movzx	ebx, al ; 02/09/2015
  2222                              <1> 		; tst -(r2) / restore pointer to right Q entry
  2223                              <1>  		; mov r2,u.pri / set present user to this run queue
  2224                              <1> 	        ; movb (r2)+,r1 / move 1st process in queue to r1
  2225 00004E4E 38E0                <1> 	cmp	al, ah
  2226                              <1> 		; cmpb r1,(r2)+ / is there only 1 process 
  2227                              <1> 			      ; / in this Q to be run
  2228 00004E50 740A                <1> 	je	short swap_3
  2229                              <1>        		; beq 1f / yes
  2230                              <1> 		; tst -(r2) / no, pt r2 back to this Q entry
  2231                              <1> 	;movzx	ebx, al
  2232 00004E52 8AA3[076C0000]      <1> 	mov	ah, [ebx+p.link-1] 
  2233 00004E58 8826                <1>        	mov	[esi], ah
  2234                              <1> 		; movb p.link-1(r1),(r2) / move next process 
  2235                              <1> 				       ; / in line into run queue
  2236 00004E5A EB05                <1> 	jmp	short swap_4
  2237                              <1>        		; br 2f
  2238                              <1> swap_3: ; 1:
  2239                              <1> 	;xor	dx, dx
  2240                              <1> 	; 24/12/2021
  2241 00004E5C 31D2                <1> 	xor	edx, edx
  2242 00004E5E 668916              <1> 	mov	[esi], dx
  2243                              <1> 		; clr -(r2) / zero the entry; no processes on the Q
  2244                              <1> swap_4: ; / write out core to appropriate disk area and read 
  2245                              <1>       ; / in new process if required
  2246                              <1>        		; clr *$ps / clear processor status
  2247 00004E61 8A25[E76E0000]      <1> 	mov 	ah, [u.uno]
  2248 00004E67 38C4                <1> 	cmp	ah, al
  2249                              <1> 		; cmpb r1,u.uno / is this process the same as 
  2250                              <1> 			      ; / the process in core?
  2251 00004E69 743B                <1>        	je	short swap_8
  2252                              <1>        		; beq 2f / yes, don't have to swap
  2253                              <1>        		; mov r0,-(sp) / no, write out core; save r0 
  2254                              <1> 			   ; / (address in routine that called swap)
  2255                              <1> 		; mov r1,-(sp) / put r1 (new process #) on the stack
  2256                              <1> 	; 01/09/2015
  2257                              <1> 	;mov	[u.usp], esp
  2258                              <1>        		; mov sp,u.usp / save stack pointer
  2259                              <1> 		; mov $sstack,sp / move swap stack pointer 
  2260                              <1> 			       ; / to the stack pointer
  2261 00004E6B 08E4                <1> 	or	ah, ah
  2262                              <1>        		; tstb u.uno / is the process # = 0
  2263 00004E6D 740D                <1>        	jz	short swap_6 ; 'sysexit'
  2264                              <1> 		; beq 1f / yes, kill process by overwriting
  2265                              <1> 	; 02/09/2015
  2266 00004E6F 8925[946E0000]      <1> 	mov	[u.usp], esp ; return address for 'syswait' & 'sleep'
  2267                              <1> 	;
  2268 00004E75 E834000000          <1> 	call	wswap
  2269                              <1> 		; jsr r0,wswap / write out core to disk
  2270                              <1> 	 ; 31/08/2015
  2271                              <1> 	;movzx	ebx, al ; New (running) process number
  2272 00004E7A EB1C                <1> 	jmp 	short swap_7
  2273                              <1> swap_6:
  2274                              <1> 	; 31/08/2015
  2275                              <1> 	; Deallocate memory pages belong to the process
  2276                              <1> 	; which is being terminated
  2277                              <1> 	; 14/05/2015 ('sysexit')
  2278                              <1>  	; Deallocate memory pages of the process
  2279                              <1> 	; (Retro UNIX 386 v1 modification !)
  2280                              <1> 	;
  2281                              <1> 	; movzx ebx, al
  2282 00004E7C 53                  <1> 	push	ebx
  2283 00004E7D A1[F16E0000]        <1> 	mov 	eax, [u.pgdir]  ; page directory of the process
  2284 00004E82 8B1D[F56E0000]      <1> 	mov	ebx, [u.ppgdir] ; page directory of the parent process
  2285 00004E88 E859E0FFFF          <1> 	call	deallocate_page_dir
  2286 00004E8D A1[E86E0000]        <1> 	mov	eax, [u.upage] ; 'user' structure page of the process
  2287 00004E92 E8E7E0FFFF          <1> 	call	deallocate_page
  2288 00004E97 5B                  <1> 	pop	ebx
  2289                              <1> swap_7: ;1: 
  2290                              <1> 	; 02/09/2015
  2291                              <1> 	; 31/08/2015
  2292                              <1> 	; 14/05/2015
  2293 00004E98 C0E302              <1> 	shl	bl, 2 ; * 4 
  2294 00004E9B 8B83[246C0000]      <1> 	mov	eax, [ebx+p.upage-4] ; the 'u' page of the new process
  2295                              <1> 	;cli
  2296 00004EA1 E831000000          <1> 	call	rswap
  2297                              <1>  		; mov (sp)+,r1 / restore r1 to new process number
  2298                              <1> 		; jsr r0,rswap / read new process into core
  2299                              <1>        		; jsr r0,unpack / unpack the users stack from next
  2300                              <1> 			      ; / to his program to its normal
  2301                              <1> 	; 01/09/2015
  2302                              <1> 	;mov	esp, [u.usp]	
  2303                              <1> 		; mov u.usp,sp / location; restore stack pointer to
  2304                              <1> 			     ; / new process stack
  2305                              <1> 		; mov (sp)+,r0 / put address of where the process 
  2306                              <1> 			     ; / that just got swapped in, left off.,
  2307                              <1> 			     ; / i.e., transfer control to new process
  2308                              <1> 	;sti
  2309                              <1> swap_8: ;2:
  2310                              <1> 	; RETRO UNIX 8086 v1 modification !
  2311 00004EA6 C605[DA6E0000]04    <1> 	mov	byte [u.quant], time_count 
  2312                              <1> 		; movb $30.,uquant / initialize process time quantum
  2313 00004EAD C3                  <1> 	retn
  2314                              <1> 		; rts r0 / return
  2315                              <1> 
  2316                              <1> wswap:  ; < swap out, swap to disk >
  2317                              <1> 	; 09/05/2015 (Retro UNIX 386 v1 - Beginning)
  2318                              <1> 	; 26/05/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2319                              <1> 	; 'wswap' writes out the process that is in core onto its 
  2320                              <1> 	; appropriate disk area.
  2321                              <1> 	;
  2322                              <1> 	; Retro UNIX 386 v1 modification ->
  2323                              <1> 	;       User (u) structure content and the user's register content
  2324                              <1> 	;	will be copied to the process's/user's UPAGE (a page for
  2325                              <1> 	;	saving 'u' structure and user registers for task switching).
  2326                              <1> 	;	u.usp - points to kernel stack address which contains
  2327                              <1> 	;		user's registers while entering system call.  
  2328                              <1> 	;	u.sp  - points to kernel stack address 
  2329                              <1> 	;		to return from system call -for IRET-.
  2330                              <1> 	;	[u.usp]+32+16 = [u.sp] 
  2331                              <1> 	;	[u.usp] -> edi, esi, ebp, esp (= [u.usp]+32), ebx, 
  2332                              <1> 	;		edx, ecx, eax, gs, fs, es, ds, -> [u.sp].
  2333                              <1> 	;
  2334                              <1> 	; Retro UNIX 8086 v1 modification ->
  2335                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2336                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2337                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2338                              <1> 	;	compatibles was using 1MB segmented memory 
  2339                              <1> 	;	in 8086/8088 times.
  2340                              <1> 	;
  2341                              <1> 	; INPUTS ->
  2342                              <1> 	;    u.break - points to end of program
  2343                              <1> 	;    u.usp - stack pointer at the moment of swap
  2344                              <1> 	;    core - beginning of process program		
  2345                              <1> 	;    ecore - end of core 	
  2346                              <1> 	;    user - start of user parameter area		
  2347                              <1> 	;    u.uno - user process number	
  2348                              <1> 	;    p.dska - holds block number of process	
  2349                              <1> 	; OUTPUTS ->
  2350                              <1> 	;    swp I/O queue
  2351                              <1> 	;    p.break - negative word count of process 
  2352                              <1> 	;    r1 - process disk address	
  2353                              <1> 	;    r2 - negative word count
  2354                              <1> 	;
  2355                              <1> 	; RETRO UNIX 8086 v1 input/output:
  2356                              <1> 	;
  2357                              <1> 	; INPUTS ->
  2358                              <1> 	;    u.uno - process number (to be swapped out)
  2359                              <1> 	; OUTPUTS ->
  2360                              <1> 	;    none
  2361                              <1> 	;
  2362                              <1> 	;   ((Modified registers: ECX, ESI, EDI))  
  2363                              <1> 	;
  2364 00004EAE 8B3D[E86E0000]      <1> 	mov	edi, [u.upage] ; process's user (u) structure page addr
  2365 00004EB4 B91E000000          <1> 	mov	ecx, (U_SIZE + 3) / 4
  2366 00004EB9 BE[906E0000]        <1> 	mov	esi, user ; active user (u) structure	
  2367 00004EBE F3A5                <1> 	rep	movsd
  2368                              <1> 	;
  2369 00004EC0 8B35[946E0000]      <1> 	mov	esi, [u.usp] ; esp (system stack pointer, 
  2370                              <1> 			     ;      points to user registers)
  2371 00004EC6 8B0D[906E0000]      <1> 	mov	ecx, [u.sp]  ; return address from the system call
  2372                              <1> 			     ; (for IRET)
  2373                              <1> 			     ; [u.sp] -> EIP (user)
  2374                              <1> 			     ; [u.sp+4]-> CS (user)
  2375                              <1> 			     ; [u.sp+8] -> EFLAGS (user)
  2376                              <1> 			     ; [u.sp+12] -> ESP (user)
  2377                              <1> 			     ; [u.sp+16] -> SS (user)	
  2378 00004ECC 29F1                <1> 	sub	ecx, esi     ; required space for user registers
  2379 00004ECE 83C114              <1> 	add	ecx, 20	     ; +5 dwords to return from system call
  2380                              <1> 			     ; (for IRET) 	
  2381 00004ED1 C1E902              <1> 	shr	ecx, 2	     		
  2382 00004ED4 F3A5                <1> 	rep	movsd
  2383 00004ED6 C3                  <1> 	retn
  2384                              <1> 
  2385                              <1> 	; Original UNIX v1 'wswap' routine:
  2386                              <1> 	; wswap:
  2387                              <1> 		; mov *$30,u.emt / determines handling of emts
  2388                              <1>         	; mov *$10,u.ilgins / determines handling of 
  2389                              <1> 				; / illegal instructions
  2390                              <1> 		; mov u.break,r2 / put process program break address in r2
  2391                              <1> 		; inc r2 / add 1 to it 
  2392                              <1> 		; bic $1,r2 / make it even
  2393                              <1> 		; mov r2,u.break / set break to an even location
  2394                              <1> 		; mov u.usp,r3 / put users stack pointer 
  2395                              <1> 			     ; / at moment of swap in r3
  2396                              <1> 		; cmp r2,$core / is u.break less than $core
  2397                              <1> 		; blos 2f / yes
  2398                              <1> 		; cmp r2,r3 / no, is (u.break) greater than stack ptr.
  2399                              <1>        		; bhis 2f / yes
  2400                              <1> 	; 1:
  2401                              <1>        		; mov (r3)+,(r2)+ / no, pack stack next to users program
  2402                              <1> 		; cmp r3,$ecore / has stack reached end of core
  2403                              <1> 		; bne 1b / no, keep packing
  2404                              <1> 	 	; br 1f / yes
  2405                              <1> 	; 2:
  2406                              <1>        		; mov $ecore,r2 / put end of core in r2 
  2407                              <1> 	; 1:
  2408                              <1>        		; sub  $user,r2 / get number of bytes to write out 
  2409                              <1> 			   ; / (user up to end of stack gets written out)
  2410                              <1> 		; neg r2 / make it negative
  2411                              <1> 		; asr r2 / change bytes to words (divide by 2)
  2412                              <1> 		; mov r2,swp+4 / word count
  2413                              <1> 		; movb u.uno,r1 / move user process number to r1
  2414                              <1> 		; asl r1 / x2 for index
  2415                              <1>       		; mov r2,p.break-2(r1) / put negative of word count 
  2416                              <1> 				     ; / into the p.break table
  2417                              <1>        		; mov p.dska-2(r1),r1 / move disk address of swap area 
  2418                              <1> 				    ; /	for process to r1
  2419                              <1>        		; mov r1,swp+2 / put processes dska address in swp+2 
  2420                              <1> 			     ; / (block number)
  2421                              <1> 		; bis $1000,swp / set it up to write (set bit 9)
  2422                              <1>        		; jsr r0,ppoke / write process out on swap area of disk
  2423                              <1> 	; 1:
  2424                              <1>        		; tstb swp+1 / is lt done writing?
  2425                              <1>        		; bne 1b / no, wait
  2426                              <1> 		; rts r0 / yes, return to swap
  2427                              <1> 
  2428                              <1> rswap:  ; < swap in, swap from disk >
  2429                              <1> 	; 15/09/2015
  2430                              <1> 	; 28/08/2015
  2431                              <1> 	; 14/05/2015
  2432                              <1> 	; 09/05/2015 (Retro UNIX 386 v1 - Beginning)
  2433                              <1> 	; 26/05/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2434                              <1> 	; 'rswap' reads a process whose number is in r1, 
  2435                              <1> 	; from disk into core.
  2436                              <1> 	;
  2437                              <1> 	; Retro UNIX 386 v1 modification ->
  2438                              <1> 	;       User (u) structure content and the user's register content
  2439                              <1> 	;	will be restored from process's/user's UPAGE (a page for
  2440                              <1> 	;	saving 'u' structure and user registers for task switching).
  2441                              <1> 	;	u.usp - points to kernel stack address which contains
  2442                              <1> 	;		user's registers while entering system call.  
  2443                              <1> 	;	u.sp  - points to kernel stack address 
  2444                              <1> 	;		to return from system call -for IRET-.
  2445                              <1> 	;	[u.usp]+32+16 = [u.sp] 
  2446                              <1> 	;	[u.usp] -> edi, esi, ebp, esp (= [u.usp]+32), ebx, 
  2447                              <1> 	;		edx, ecx, eax, gs, fs, es, ds, -> [u.sp].
  2448                              <1> 	;
  2449                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2450                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2451                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2452                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2453                              <1> 	;	compatibles was using 1MB segmented memory 
  2454                              <1> 	;	in 8086/8088 times.
  2455                              <1> 	;
  2456                              <1> 	; INPUTS ->
  2457                              <1> 	;    r1 - process number of process to be read in
  2458                              <1> 	;    p.break - negative of word count of process 
  2459                              <1> 	;    p.dska - disk address of the process		
  2460                              <1> 	;    u.emt - determines handling of emt's 	
  2461                              <1> 	;    u.ilgins - determines handling of illegal instructions		
  2462                              <1> 	; OUTPUTS ->
  2463                              <1> 	;    8 = (u.ilgins)
  2464                              <1> 	;    24 = (u.emt)
  2465                              <1> 	;    swp - bit 10 is set to indicate read 
  2466                              <1> 	;		(bit 15=0 when reading is done)	
  2467                              <1> 	;    swp+2 - disk block address
  2468                              <1> 	;    swp+4 - negative word count 	
  2469                              <1> 	;      ((swp+6 - address of user structure)) 
  2470                              <1> 	;
  2471                              <1> 	; RETRO UNIX 8086 v1 input/output:
  2472                              <1> 	;
  2473                              <1> 	; INPUTS ->
  2474                              <1> 	;    AL	- new process number (to be swapped in)	 
  2475                              <1> 	; OUTPUTS ->
  2476                              <1> 	;    none
  2477                              <1> 	;
  2478                              <1> 	;   ((Modified registers: EAX, ECX, ESI, EDI, ESP)) 
  2479                              <1> 	;
  2480                              <1> 	; Retro UNIX 386 v1 - modification ! 14/05/2015
  2481 00004ED7 89C6                <1> 	mov	esi, eax  ; process's user (u) structure page addr
  2482 00004ED9 B91E000000          <1> 	mov	ecx, (U_SIZE + 3) / 4
  2483 00004EDE BF[906E0000]        <1> 	mov	edi, user ; active user (u) structure	
  2484 00004EE3 F3A5                <1> 	rep	movsd
  2485 00004EE5 58                  <1> 	pop	eax ; 15/09/2015, 'rswap' return address 
  2486 00004EE6 8B3D[946E0000]      <1> 	mov	edi, [u.usp] ; esp (system stack pointer, 
  2487                              <1> 			     ;      points to user registers)
  2488 00004EEC 8B0D[906E0000]      <1> 	mov	ecx, [u.sp]  ; return address from the system call
  2489                              <1> 			     ; (for IRET)
  2490                              <1> 			     ; [u.sp] -> EIP (user)
  2491                              <1> 			     ; [u.sp+4]-> CS (user)
  2492                              <1> 			     ; [u.sp+8] -> EFLAGS (user)
  2493                              <1> 			     ; [u.sp+12] -> ESP (user)
  2494                              <1> 			     ; [u.sp+16] -> SS (user)		
  2495                              <1> 	; 28/08/2015
  2496 00004EF2 29F9                <1> 	sub	ecx, edi     ; required space for user registers
  2497 00004EF4 83C114              <1> 	add	ecx, 20	     ; +5 dwords to return from system call
  2498                              <1> 			     ; (for IRET) 	
  2499 00004EF7 C1E902              <1> 	shr	ecx, 2	       		
  2500 00004EFA F3A5                <1> 	rep	movsd
  2501 00004EFC 8B25[946E0000]      <1> 	mov	esp, [u.usp] ; 15/09/2015
  2502 00004F02 50                  <1> 	push	eax ; 15/09/2015 'rswap' return address
  2503 00004F03 C3                  <1> 	retn
  2504                              <1> 
  2505                              <1> 	; Original UNIX v1 'rswap'  and 'unpack' routines:
  2506                              <1> 	;rswap:
  2507                              <1>        		; asl r1 / process number x2 for index
  2508                              <1>        		; mov p.break-2(r1), swp+4 / word count
  2509                              <1>        		; mov p.dska-2(r1),swp+2 / disk address
  2510                              <1>        		; bis $2000,swp / read
  2511                              <1>        		; jsr r0,ppoke / read it in 
  2512                              <1> 	; 1:
  2513                              <1>        		; tstb swp+1 / done
  2514                              <1>        		; bne 1b / no, wait for bit 15 to clear (inhibit bit)
  2515                              <1>        		; mov u.emt,*$30 / yes move these
  2516                              <1>        		; mov u.ilgins,*$10 / back
  2517                              <1>        		; rts r0 / return
  2518                              <1> 
  2519                              <1> 	;unpack: ; / move stack back to its normal place
  2520                              <1> 		; mov u.break,r2 / r2 points to end of user program
  2521                              <1>        		; cmp r2,$core / at beginning of user program yet?
  2522                              <1> 		; blos 2f / yes, return
  2523                              <1> 		; cmp r2,u.usp / is break_above the stack pointer 
  2524                              <1> 			     ; / before swapping
  2525                              <1> 		; bhis 2f / yes, return
  2526                              <1> 		; mov $ecore,r3 / r3 points to end of core
  2527                              <1> 		; add r3,r2
  2528                              <1> 		; sub u.usp,r2 / end of users stack is in r2
  2529                              <1> 	; 1:
  2530                              <1> 		; mov -(r2),-(r3) / move stack back to its normal place
  2531                              <1> 		; cmp r2,u.break / in core
  2532                              <1> 		; bne 1b
  2533                              <1> 	; 2:
  2534                              <1>        		; rts r0
  2535                              <1> 
  2536                              <1> putlu: 
  2537                              <1> 	; 12/09/2015
  2538                              <1> 	; 02/09/2015
  2539                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2540                              <1> 	; 15/04/2013 - 23/02/2014 (Retro UNIX 8086 v1)
  2541                              <1> 	; 'putlu' is called with a process number in r1 and a pointer
  2542                              <1> 	; to lowest priority Q (runq+4) in r2. A link is created from
  2543                              <1> 	; the last process on the queue to process in r1 by putting
  2544                              <1> 	; the process number in r1 into the last process's link.
  2545                              <1> 	;
  2546                              <1> 	; INPUTS ->
  2547                              <1> 	;    r1 - user process number
  2548                              <1> 	;    r2 - points to lowest priority queue 
  2549                              <1> 	;    p.dska - disk address of the process		
  2550                              <1> 	;    u.emt - determines handling of emt's 	
  2551                              <1> 	;    u.ilgins - determines handling of illegal instructions		
  2552                              <1> 	; OUTPUTS ->
  2553                              <1> 	;    r3 - process number of last process on the queue upon
  2554                              <1> 	;	  entering putlu
  2555                              <1> 	;    p.link-1 + r3 - process number in r1
  2556                              <1> 	;    r2 - points to lowest priority queue
  2557                              <1> 	;
  2558                              <1> 	; ((Modified registers: EDX, EBX)) 
  2559                              <1> 	;
  2560                              <1> 	; / r1 = user process no.; r2 points to lowest priority queue
  2561                              <1> 
  2562                              <1> 	; eBX = r2
  2563                              <1> 	; eAX = r1 (AL=r1b)
  2564                              <1> 
  2565 00004F04 BB[8A6E0000]        <1> 	mov	ebx, runq
  2566 00004F09 0FB613              <1> 	movzx  	edx, byte [ebx]
  2567 00004F0C 43                  <1> 	inc	ebx
  2568 00004F0D 20D2                <1> 	and	dl, dl
  2569                              <1> 		; tstb (r2)+ / is queue empty?
  2570 00004F0F 740A                <1>        	jz	short putlu_1
  2571                              <1> 		; beq 1f / yes, branch
  2572 00004F11 8A13                <1> 	mov 	dl, [ebx] ; 12/09/2015
  2573                              <1> 		; movb (r2),r3 / no, save the "last user" process number
  2574                              <1> 			     ; / in r3
  2575 00004F13 8882[076C0000]      <1>        	mov	[edx+p.link-1], al
  2576                              <1> 		; movb r1,p.link-1(r3) / put pointer to user on 
  2577                              <1> 			     ; / "last users" link
  2578 00004F19 EB03                <1> 	jmp	short putlu_2
  2579                              <1> 		; br 2f /
  2580                              <1> putlu_1: ; 1:
  2581 00004F1B 8843FF              <1> 	mov	[ebx-1], al
  2582                              <1>        		; movb r1,-1(r2) / user is only user; 
  2583                              <1> 			    ; / put process no. at beginning and at end
  2584                              <1> putlu_2: ; 2: 
  2585 00004F1E 8803                <1> 	mov	[ebx], al
  2586                              <1>        		; movb r1,(r2) / user process in r1 is now the last entry
  2587                              <1> 			     ; / on the queue
  2588 00004F20 88C2                <1> 	mov	dl, al
  2589 00004F22 88B2[076C0000]      <1>         mov     [edx+p.link-1], dh ; 0
  2590                              <1> 		; dec r2 / restore r2
  2591 00004F28 C3                  <1>         retn
  2592                              <1> 		; rts r0
  2593                              <1> 
  2594                              <1> ;copyz:
  2595                              <1> ;       mov     r1,-(sp) / put r1 on stack
  2596                              <1> ;       mov     r2,-(sp) / put r2 on stack
  2597                              <1> ;       mov     (r0)+,r1
  2598                              <1> ;       mov     (r0)+,r2
  2599                              <1> ;1:
  2600                              <1> ;       clr     (r1)+ / clear all locations between r1 and r2
  2601                              <1> ;       cmp     r1,r2 
  2602                              <1> ;       blo     1b
  2603                              <1> ;       mov     (sp)+,r2 / restore r2
  2604                              <1> ;       mov     (sp)+,r1 / restore r1
  2605                              <1> ;       rts     r0 
  2606                              <1> 
  2607                              <1> idle:
  2608                              <1> 	; 01/09/2015
  2609                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2610                              <1> 	; 10/04/2013 - 23/10/2013 (Retro UNIX 8086 v1)
  2611                              <1> 	; (idle & wait loop)
  2612                              <1> 	; Retro Unix 8086 v1 modification on original UNIX v1
  2613                              <1> 	; idle procedure!
  2614                              <1>       	;
  2615                              <1>   	; 01/09/2015
  2616 00004F29 FB                  <1> 	sti
  2617                              <1>       	; 29/07/2013
  2618 00004F2A F4                  <1>       	hlt
  2619 00004F2B 90                  <1>       	nop ; 10/10/2013
  2620 00004F2C 90                  <1>       	nop
  2621 00004F2D 90                  <1>       	nop
  2622                              <1>       	; 23/10/2013
  2623 00004F2E 90                  <1>       	nop
  2624 00004F2F 90                  <1>       	nop
  2625 00004F30 90                  <1>       	nop
  2626 00004F31 90                  <1>       	nop
  2627 00004F32 C3                  <1>       	retn      
  2628                              <1> 
  2629                              <1> 	;mov *$ps,-(sp) / save ps on stack
  2630                              <1> 	;clr *$ps / clear ps
  2631                              <1> 	;mov clockp,-(sp) / save clockp on stack
  2632                              <1> 	;mov (r0)+,clockp / arg to idle in clockp
  2633                              <1> 	;1 / wait for interrupt
  2634                              <1> 	;mov (sp)+,clockp / restore clockp, ps
  2635                              <1> 	;mov (sp)+,*$ps
  2636                              <1> 	;rts r0
  2637                              <1> 
  2638                              <1> clear:
  2639                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2640                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2641                              <1> 	; 09/04/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2642                              <1> 	; 'clear' zero's out of a block (whose block number is in r1)
  2643                              <1> 	; on the current device (cdev)
  2644                              <1> 	;	
  2645                              <1> 	; INPUTS ->
  2646                              <1> 	;    r1 - block number of block to be zeroed
  2647                              <1> 	;    cdev - current device number 
  2648                              <1> 	; OUTPUTS ->
  2649                              <1> 	;    a zeroed I/O buffer onto the current device
  2650                              <1> 	;    r1 - points to last entry in the I/O buffer
  2651                              <1> 	;
  2652                              <1> 	; ((AX = R1)) input/output
  2653                              <1> 	;    (Retro UNIX Prototype : 18/11/2012 - 14/11/2012, UNIXCOPY.ASM)
  2654                              <1>         ;    ((Modified registers: EDX, ECX, EBX, ESI, EDI, EBP))  
  2655                              <1> 
  2656 00004F33 E8AB0D0000          <1> 	call 	wslot
  2657                              <1> 		; jsr r0,wslot / get an I/O buffer set bits 9 and 15 in first
  2658                              <1>                    ; / word of I/O queue r5 points to first data word in buffer
  2659 00004F38 89DF                <1> 	mov	edi, ebx ; r5
  2660 00004F3A 89C2                <1> 	mov	edx, eax
  2661 00004F3C B980000000          <1> 	mov	ecx, 128
  2662                              <1> 		; mov $256.,r3
  2663 00004F41 31C0                <1> 	xor	eax, eax
  2664 00004F43 F3AB                <1> 	rep	stosd
  2665 00004F45 89D0                <1> 	mov	eax, edx
  2666                              <1> ; 1: 
  2667                              <1>        		; clr (r5)+ / zero data word in buffer
  2668                              <1>        		; dec r3
  2669                              <1>        		; bgt 1b / branch until all data words in buffer are zero
  2670                              <1> 	;call	dskwr
  2671                              <1> 		; jsr r0,dskwr / write zeroed buffer area out onto physical
  2672                              <1>                              ; / block specified in r1
  2673                              <1> 	; eAX (r1) = block number
  2674                              <1> 	;retn
  2675                              <1> 		; rts r0
  2676                              <1> 	; 24/12/2021
  2677 00004F47 E9B30D0000          <1> 	jmp	dskwr
  2095                                  %include 'u4.s'        ; 15/04/2015
  2096                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS4.INC
  2097                              <1> ; Last Modification: 26/02/2022
  2098                              <1> ; ----------------------------------------------------------------------------
  2099                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2100                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2101                              <1> ;
  2102                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2103                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2104                              <1> ; <Bell Laboratories (17/3/1972)>
  2105                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2106                              <1> ;
  2107                              <1> ; Retro UNIX 8086 v1 - U4.ASM (04/07/2014) //// UNIX v1 -> u4.s
  2108                              <1> ;
  2109                              <1> ; ****************************************************************************
  2110                              <1> 
  2111                              <1> ;setisp:
  2112                              <1>        ;mov     r1,-(sp)
  2113                              <1>        ;mov     r2,-(sp)
  2114                              <1>        ;mov     r3,-(sp)
  2115                              <1>        ;mov     clockp,-(sp)
  2116                              <1>        ;mov     $s.syst+2,clockp
  2117                              <1>        ;jmp     (r0)
  2118                              <1> 
  2119                              <1> clock: ; / interrupt from 60 cycle clock
  2120                              <1> 	
  2121                              <1> 	; 14/10/2015
  2122                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  2123                              <1> 	; 07/12/2013 - 10/04/2014 (Retro UNIX 8086 v1)
  2124                              <1> 
  2125                              <1>        ;mov     r0,-(sp) / save r0
  2126                              <1>        ;tst     *$lks / restart clock?
  2127                              <1>        ;mov     $s.time+2,r0 / increment the time of day
  2128                              <1>        ;inc     (r0)
  2129                              <1>        ;bne     1f
  2130                              <1>        ;inc     -(r0)
  2131                              <1> ;1:
  2132                              <1>        ;mov     clockp,r0 / increment appropriate time category
  2133                              <1>        ;inc     (r0)
  2134                              <1>        ;bne     1f
  2135                              <1>        ;inc     -(r0)
  2136                              <1> ;1:
  2137                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2138                              <1> 
  2139 00004F4C 803D[DA6E0000]00    <1> 	cmp	byte [u.quant], 0
  2140 00004F53 772C                <1> 	ja	short clk_1
  2141                              <1> 	;
  2142 00004F55 803D[8F6E0000]FF    <1>         cmp     byte [sysflg], 0FFh ; user or system space ?
  2143 00004F5C 7529                <1> 	jne	short clk_2 ; system space (sysflg <> 0FFh)
  2144 00004F5E 803D[E76E0000]01    <1> 	cmp     byte [u.uno], 1 ; /etc/init ?
  2145 00004F65 761A                <1> 	jna	short clk_1 ; yes, do not swap out
  2146 00004F67 66833D[DC6E0000]00  <1> 	cmp	word [u.intr], 0
  2147 00004F6F 7616                <1> 	jna	short clk_2
  2148                              <1> clk_0:
  2149                              <1> 	; 14/10/2015
  2150 00004F71 FE05[8F6E0000]      <1> 	inc	byte [sysflg] 	; Now, we are in system space
  2151 00004F77 58                  <1> 	pop	eax ; return address to the timer interrupt
  2152                              <1> 	;
  2153 00004F78 B020                <1> 	MOV	AL,EOI			; GET END OF INTERRUPT MASK
  2154                              <1> 	;CLI				; DISABLE INTERRUPTS TILL STACK CLEARED
  2155 00004F7A E620                <1> 	OUT	INTA00,AL		; END OF INTERRUPT TO 8259 - 1	
  2156                              <1> 	;
  2157 00004F7C E9D6EBFFFF          <1> 	jmp     sysrelease ; 'sys release' by clock/timer
  2158                              <1> clk_1:
  2159 00004F81 FE0D[DA6E0000]      <1> 	dec	byte [u.quant]
  2160                              <1> clk_2:
  2161 00004F87 C3                  <1> 	retn   ; return to (hardware) timer interrupt routine
  2162                              <1> 
  2163                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 
  2164                              <1> 
  2165                              <1>        ;mov     $uquant,r0 / decrement user time quantum
  2166                              <1>        ;decb    (r0)
  2167                              <1>        ;bge     1f / if less than 0
  2168                              <1>        ;clrb    (r0) / make it 0
  2169                              <1> ;1: / decrement time out counts return now if priority was not 0
  2170                              <1>        ;cmp     4(sp),$200 / ps greater than or equal to 200
  2171                              <1>        ;bge     2f / yes, check time outs
  2172                              <1>        ;tstb    (r0) / no, user timed out?
  2173                              <1>        ;bne     1f / no
  2174                              <1>        ;cmpb    sysflg,$-1 / yes, are we outside the system?
  2175                              <1>        ;bne     1f / no, 1f
  2176                              <1>        ;mov     (sp)+,r0 / yes, put users r0 in r0
  2177                              <1>        ;sys     0 / sysrele
  2178                              <1>        ;rti
  2179                              <1> ;2: / priority is high so just decrement time out counts
  2180                              <1>        ;mov     $toutt,r0 / r0 points to beginning of time out table
  2181                              <1> ;2:
  2182                              <1>        ;tstb    (r0) / is the time out?
  2183                              <1>        ;beq     3f / yes, 3f (get next entry)
  2184                              <1>        ;decb    (r0) / no, decrement the time
  2185                              <1>        ;bne     3f / isit zero now?
  2186                              <1>        ;incb    (r0) / yes, increment the time
  2187                              <1> ;3:
  2188                              <1>        ;inc     r0 / next entry
  2189                              <1>        ;cmp     r0,$touts / end of toutt table?
  2190                              <1>        ;blo     2b / no, check this entry
  2191                              <1>        ;mov     (sp)+,r0 / yes, restore r0
  2192                              <1>        ;rti / return from interrupt
  2193                              <1> ;1: / decrement time out counts; if 0 call subroutine
  2194                              <1>        ;mov     (sp)+,r0 / restore r0
  2195                              <1>        ;mov     $240,*$ps / set processor priority to 5
  2196                              <1>        ;jsr     r0,setisp / save registers
  2197                              <1>        ;mov     $touts-toutt-1,r0 / set up r0 as index to decrement thru
  2198                              <1>                                ;  / the table
  2199                              <1> ;1:
  2200                              <1>        ;tstb    toutt(r0) / is the time out for this entry
  2201                              <1>        ;beq     2f / yes
  2202                              <1>        ;decb    toutt(r0) / no, decrement the time
  2203                              <1>        ;bne     2f / is the time 0, now
  2204                              <1>        ;asl     r0 / yes, 2 x r0 to get word index for tout entry
  2205                              <1>        ;jsr     r0,*touts(r0) / go to appropriate routine specified in this
  2206                              <1>        ;asr     r0 / touts entry; set r0 back to toutt index
  2207                              <1> ;2:
  2208                              <1>        ;dec     r0 / set up r0 for next entry
  2209                              <1>        ;bge     1b / finished? , no, go back
  2210                              <1>        ;br      retisp / yes, restore registers and do a rti
  2211                              <1> 
  2212                              <1> ;retisp:
  2213                              <1>        ;mov     (sp)+,clockp / pop values before interrupt off the stack
  2214                              <1>        ;mov     (sp)+,r3
  2215                              <1>        ;mov     (sp)+,r2
  2216                              <1>        ;mov     (sp)+,r1
  2217                              <1>        ;mov     (sp)+,r0
  2218                              <1>        ;rti     / return from interrupt
  2219                              <1> 
  2220                              <1> 
  2221                              <1> wakeup: ; / wakeup processes waiting for an event 
  2222                              <1> 	; / by linking them to the queue
  2223                              <1> 	;
  2224                              <1> 	; 26/02/2022
  2225                              <1> 	; 15/09/2015
  2226                              <1> 	; 29/06/2015
  2227                              <1> 	; 15/04/2015 (Retro UNIX 386 v1 - Beginning)
  2228                              <1> 	;
  2229                              <1> 	; 15/05/2013 - 02/06/2014
  2230                              <1> 	; Retro UNIX 8086 v1 modification !
  2231                              <1> 	; (Process/task switching routine by using
  2232                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.)
  2233                              <1> 	;
  2234                              <1> 	; In original UNIX v1, 'wakeup' is called to wake the process
  2235                              <1> 	; sleeping in the specified wait channel by creating a link 
  2236                              <1> 	; to it from the last user process on the run queue.
  2237                              <1> 	; If there is no process to wake up, nothing happens.
  2238                              <1> 	;
  2239                              <1> 	; In Retro UNIX 8086 v1, Int 09h keyboard interrupt will set
  2240                              <1> 	; 'switching' status of the current process (owns current tty)
  2241                              <1> 	; (via alt + function keys) to a process which has highest
  2242                              <1> 	; priority (on run queue) on the requested tty (0 to 7, except
  2243                              <1> 	; 8 and 9 which are tty identifiers of COM1, COM2 serial ports)
  2244                              <1> 	; as it's console tty. (NOTE: 'p.ttyc' is used to set console
  2245                              <1> 	; tty for tty switching by keyboard.)	 
  2246                              <1> 	; 
  2247                              <1> 	; INPUT -> 
  2248                              <1> 	;	   AL = wait channel (r3) ('tty number' for now)
  2249                              <1> 	;	   ;;EBX = Run queue (r2) offset
  2250                              <1> 	;
  2251                              <1> 	; ((modified registers: EAX, EBX))
  2252                              <1> 	;
  2253 00004F88 0FB6D8              <1> 	movzx	ebx, al ; 29/06/2015
  2254 00004F8B 81C3[386B0000]      <1> 	add	ebx, wlist
  2255 00004F91 8A03                <1> 	mov	al, [ebx] ; waiting list (waiting process number)
  2256 00004F93 20C0                <1> 	and	al, al
  2257 00004F95 741E                <1> 	jz	short wa0 ; nothing to wakeup
  2258                              <1> 	;
  2259 00004F97 30E4                <1> 	xor	ah, ah
  2260 00004F99 8825[DA6E0000]      <1> 	mov 	[u.quant], ah ; 0 ; time quantum = 0	
  2261 00004F9F 8823                <1> 	mov	[ebx], ah ; 0 ; zero wait channel entry
  2262                              <1> 	; 15/09/2015
  2263 00004FA1 0FB6D8              <1> 	movzx	ebx, al
  2264                              <1> 	; 26/02/2022 (p.waitc is not used)
  2265                              <1> 	;mov	[ebx+p.waitc-1], ah ; 0
  2266 00004FA4 FEC4                <1> 	inc	ah
  2267 00004FA6 88A3[176C0000]      <1> 	mov	byte [ebx+p.stat-1], ah ; 1 ; SRUN
  2268                              <1> 	;
  2269 00004FAC 57                  <1> 	push	edi
  2270 00004FAD 52                  <1> 	push	edx
  2271 00004FAE E851FFFFFF          <1> 	call	putlu
  2272 00004FB3 5A                  <1> 	pop	edx
  2273 00004FB4 5F                  <1> 	pop	edi
  2274                              <1> wa0:
  2275 00004FB5 C3                  <1> 	retn
  2276                              <1> 
  2277                              <1> sleep: 
  2278                              <1> 	; 26/02/2022
  2279                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2280                              <1> 	; 15/09/2015
  2281                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2282                              <1> 	;
  2283                              <1> 	; 09/05/2013 - 20/03/2014
  2284                              <1> 	;
  2285                              <1> 	; Retro UNIX 8086 v1 modification !
  2286                              <1> 	; (Process/task switching and quit routine by using
  2287                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2288                              <1> 	;
  2289                              <1> 	; In original UNIX v1, 'sleep' is called to wait for
  2290                              <1> 	; tty and tape output or input becomes available
  2291                              <1> 	; and process is put on waiting channel and swapped out,
  2292                              <1> 	; then -when the tty or tape is ready to write or read-
  2293                              <1> 	; 'wakeup' gets process back to active swapped-in status.)
  2294                              <1> 	;
  2295                              <1> 	; In Retro UNIX 8086 v1, Int 1Bh ctrl+brk interrupt and
  2296                              <1> 	; Int 09h keyboard interrupt will set 'quit' or 'switching'		
  2297                              <1> 	; status of the current process also INT 1Ch will count down
  2298                              <1> 	; 'uquant' value and INT 09h will redirect scancode of keystroke
  2299                              <1> 	; to tty buffer of the current process and kernel will get
  2300                              <1> 	; user input by using tty buffer of the current process
  2301                              <1> 	; (instead of standard INT 16h interrupt).
  2302                              <1> 	; TTY output will be redirected to related video page of text mode
  2303                              <1> 	; (INT 10h will be called with different video page depending
  2304                              <1> 	; on tty assignment of the active process: 0 to 7 for
  2305                              <1> 	; pseudo screens.)
  2306                              <1> 	;
  2307                              <1> 	; In Retro UNIX 8086 v1, 'sleep' will be called to wait for
  2308                              <1> 	; a keystroke from keyboard or wait for reading or writing
  2309                              <1> 	; characters/data on serial port(s).
  2310                              <1> 	;
  2311                              <1> 	; Character/Terminal input/output through COM1 and COM2 will be
  2312                              <1> 	; performed by related routines in addition to pseudo TTY routines.
  2313                              <1> 	; 
  2314                              <1> 	; R1 = AH = wait channel (0-9 for TTYs) ; 05/10/2013 (22/09/2013)
  2315                              <1> 	;
  2316                              <1> 	;; 05/10/2013
  2317                              <1>         ;10/12/2013
  2318                              <1> 	;cmp   byte [u.uno], 1
  2319                              <1>         ;ja    short sleep0
  2320                              <1> 	;retn
  2321                              <1> 
  2322                              <1> 	; 20/03/2014
  2323                              <1> 	;mov	bx, [runq]
  2324                              <1> 	;cmp	bl, bh
  2325                              <1> 	;jne	short sleep0	
  2326                              <1> 	; 25/02/2014
  2327                              <1> 	;cmp word ptr [runq], 0
  2328                              <1> 	;ja short sleep0	
  2329                              <1> 	;retn
  2330                              <1> sleep0:
  2331                              <1> 	;
  2332 00004FB6 E849000000          <1> 	call	isintr
  2333                              <1> 	;jnz	sysret
  2334                              <1> 		; / wait for event
  2335                              <1>        		; jsr r0,isintr / check to see if interrupt 
  2336                              <1> 			      ; / or quit from user
  2337                              <1>                		; br 2f / something happened
  2338                              <1> 			      ; / yes, his interrupt so return
  2339                              <1>                      	      ;	/ to user
  2340                              <1> 	; 24/12/2021
  2341 00004FBB 7405                <1> 	jz	short sleep_2
  2342                              <1> sleep_3:
  2343 00004FBD E930EBFFFF          <1> 	jmp	sysret
  2344                              <1> sleep_2:
  2345                              <1> 	; 30/06/2015
  2346 00004FC2 0FB6DC              <1>     	movzx	ebx, ah ; 30/06/2015
  2347 00004FC5 81C3[386B0000]      <1> 	add	ebx, wlist
  2348 00004FCB 8A03                <1> 	mov	al, [ebx]
  2349 00004FCD 20C0                <1> 	and	al, al
  2350 00004FCF 7407                <1> 	jz	short sleep1
  2351 00004FD1 53                  <1> 	push	ebx
  2352 00004FD2 E82DFFFFFF          <1> 	call	putlu
  2353 00004FD7 5B                  <1> 	pop	ebx
  2354                              <1> sleep1:
  2355 00004FD8 A0[E76E0000]        <1> 	mov	al, [u.uno]    
  2356 00004FDD 8803                <1>   	mov	[ebx], al 	; put the process number
  2357                              <1> 				; in the wait channel
  2358                              <1> 		; mov (r0)+,r1 / put number of wait channel in r1
  2359                              <1> 		; movb wlist(r1),-(sp) / put old process number in there,
  2360                              <1> 				     ; / on the stack
  2361                              <1>        		; movb u.uno,wlist(r1) / put process number of process
  2362                              <1> 				     ; / to put to sleep in there
  2363                              <1>         ; 15/09/2015
  2364 00004FDF 0FB6D8              <1> 	movzx	ebx, al
  2365 00004FE2 C683[176C0000]04    <1>         mov     byte [ebx+p.stat-1], 4 ; SSLEEP
  2366                              <1> 	; 26/02/2022 (p.waitc is not used)
  2367                              <1> 	;inc	ah
  2368                              <1> 	;mov	[ebx+p.waitc-1], ah ; wait channel + 1
  2369                              <1> 	;
  2370 00004FE9 66FF35[7F6E0000]    <1> 	push    word [cdev]
  2371                              <1> 		; mov cdev,-(sp) / nothing happened in isintr so
  2372 00004FF0 E842FEFFFF          <1> 	call	swap
  2373                              <1>        		; jsr r0,swap / swap out process that needs to sleep
  2374 00004FF5 668F05[7F6E0000]    <1>         pop     word [cdev]
  2375                              <1> 		; mov (sp)+,cdev / restore device
  2376 00004FFC E803000000          <1> 	call	isintr
  2377                              <1> 	; 22/09/2013
  2378                              <1> 	;jnz	sysret         
  2379                              <1> 		; jsr r0,isintr / check for interrupt of new process
  2380                              <1>                		; br 2f / yes, return to new user
  2381                              <1> 		; movb (sp)+,r1 / no, r1 = old process number that was 
  2382                              <1> 				; / originally on the wait channel
  2383                              <1>        		; beq 1f / if 0 branch
  2384                              <1>   		; mov $runq+4,r2 / r2 points to lowest priority queue
  2385                              <1>        		; mov $300,*$ps / processor priority = 6
  2386                              <1> 		; jsr r0,putlu / create link to old process number
  2387                              <1>        		; clr *$ps / clear the status; process priority = 0
  2388                              <1> 	; 24/12/2021
  2389 00005001 75BA                <1> 	jnz	short sleep_3 ; jump to sysret
  2390                              <1>      ;1:
  2391 00005003 C3                  <1> 	retn
  2392                              <1> 		; rts r0 / return
  2393                              <1>      ;2:
  2394                              <1>         ;;jmp	sysret
  2395                              <1> 		; jmp sysret / return to user
  2396                              <1> 
  2397                              <1> isintr:
  2398                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2399                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2400                              <1> 	;
  2401                              <1> 	; 09/05/2013 - 30/05/2014
  2402                              <1> 	;
  2403                              <1> 	; Retro UNIX 8086 v1 modification !
  2404                              <1> 	; (Process/task switching and quit routine by using
  2405                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2406                              <1> 	;
  2407                              <1> 	; Retro UNIX 8086 v1 modification:
  2408                              <1> 	; 'isintr' checks if user interrupt request is enabled
  2409                              <1> 	;  and there is a 'quit' request by user;
  2410                              <1> 	;  otherwise, 'isintr' will return with zf=1 that means
  2411                              <1> 	;  "nothing to do". (20/10/2013)
  2412                              <1> 	;
  2413                              <1> 	; 20/10/2013
  2414 00005004 66833D[C86E0000]00  <1> 	cmp 	word [u.ttyp], 0 ; has process got a tty ?
  2415 0000500C 761F                <1> 	jna	short isintr2 ; retn
  2416                              <1> 	; 03/09/2013
  2417                              <1> 	; (nothing to do)
  2418                              <1> 	;retn
  2419                              <1> 	; 22/09/2013
  2420 0000500E 66833D[DC6E0000]00  <1> 	cmp	word [u.intr], 0
  2421 00005016 7615                <1> 	jna	short isintr2 ; retn
  2422                              <1> 	; 30/05/2014
  2423                              <1> 	;push	ax
  2424                              <1> 	; 24/12/2021
  2425 00005018 50                  <1> 	push	eax
  2426 00005019 66A1[DE6E0000]      <1> 	mov	ax, [u.quit]
  2427 0000501F 6609C0              <1> 	or	ax, ax ; 0 ?
  2428 00005022 7408                <1> 	jz	short isintr1 ; zf = 1
  2429 00005024 6683F8FE            <1> 	cmp	ax, 0FFFEh  ; 'ctrl + brk' check
  2430 00005028 7702                <1> 	ja	short isintr1 ; 0FFFFh, zf = 0
  2431                              <1> 	;xor	ax, ax ; zf = 1
  2432                              <1> 	; 24/12/2021
  2433 0000502A 31C0                <1> 	xor	eax, eax ; zf = 1
  2434                              <1> isintr1:
  2435                              <1> 	;pop	ax
  2436                              <1> 	; 24/12/2021
  2437 0000502C 58                  <1> 	pop	eax
  2438                              <1> isintr2: ; 22/09/2013
  2439                              <1> 	; zf=1 -> nothing to do
  2440 0000502D C3                  <1> 	retn
  2441                              <1> 
  2442                              <1> 	; UNIX v1 original 'isintr' routine... 
  2443                              <1>        	;mov     r1,-(sp) / put number of wait channel on the stack
  2444                              <1>        	;mov     r2,-(sp) / save r2
  2445                              <1>        	;mov     u.ttyp,r1 / r1 = pointer to buffer of process control
  2446                              <1>         ;                 / typewriter
  2447                              <1>        	;beq     1f / if 0, do nothing except skip return
  2448                              <1>        	;movb    6(r1),r1 / put interrupt char in the tty buffer in r1
  2449                              <1>        	;beq     1f / if its 0 do nothing except skip return
  2450                              <1>        	;cmp     r1,$177 / is interrupt char = delete?
  2451                              <1>        	;bne     3f / no, so it must be a quit (fs)
  2452                              <1>        	;tst     u.intr / yes, value of u.intr determines handling
  2453                              <1>         ;              / of interrupts
  2454                              <1>        	;bne     2f / if not 0, 2f. If zero do nothing.
  2455                              <1>      ;1:
  2456                              <1>        	;tst     (r0)+ / bump r0 past system return (skip)
  2457                              <1>      ;4:
  2458                              <1>        	;mov     (sp)+,r2 / restore r1 and r2
  2459                              <1>        	;mov     (sp)+,r1
  2460                              <1>        	;rts     r0
  2461                              <1>      ;3: / interrupt char = quit (fs)
  2462                              <1>        	;tst     u.quit / value of u.quit determines handling of quits
  2463                              <1>        	;beq     1b / u.quit = 0 means do nothing
  2464                              <1>      ;2: / get here because either u.intr <> 0 or u.qult <> O
  2465                              <1>        	;mov     $tty+6,r1 / move pointer to tty block into r1
  2466                              <1>      ;1: / find process control tty entry in tty block
  2467                              <1>        	;cmp     (r1),u.ttyp / is this the process control tty buffer?
  2468                              <1>        	;beq     1f / block found go to 1f
  2469                              <1>        	;add     $8,r1 / look at next tty block
  2470                              <1>        	;cmp     r1,$tty+[ntty*8]+6 / are we at end of tty blocks
  2471                              <1>        	;blo     1b / no
  2472                              <1>        	;br      4b / no process control tty found so go to 4b
  2473                              <1>      ;1:
  2474                              <1>        	;mov     $240,*$ps / set processor priority to 5
  2475                              <1>        	;movb    -3(r1),0f / load getc call argument; character llst
  2476                              <1>         ;                  / identifier
  2477                              <1>        	;inc     0f / increment
  2478                              <1>      ;1:
  2479                              <1>        	;jsr     r0,getc; 0:.. / erase output char list for control
  2480                              <1>         ;        br 4b / process tty. This prevents a line of stuff
  2481                              <1>         ;             / being typed out after you hit the interrupt
  2482                              <1>         ;             / key
  2483                              <1>        	;br      1b
  2096                                  %include 'u5.s'        ; 03/06/2015
  2097                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS5.INC
  2098                              <1> ; Last Modification: 11/02/2022
  2099                              <1> ; ----------------------------------------------------------------------------
  2100                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2101                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2102                              <1> ;
  2103                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2104                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2105                              <1> ; <Bell Laboratories (17/3/1972)>
  2106                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2107                              <1> ;
  2108                              <1> ; Retro UNIX 8086 v1 - U5.ASM (07/08/2013) //// UNIX v1 -> u5.s
  2109                              <1> ;
  2110                              <1> ; ****************************************************************************
  2111                              <1> 
  2112                              <1> mget:
  2113                              <1> 	; 09/01/2022
  2114                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2115                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2116                              <1> 	; 22/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2117                              <1> 	;
  2118                              <1> 	; Get existing or (allocate) a new disk block for file
  2119                              <1> 	; 
  2120                              <1> 	; INPUTS ->
  2121                              <1> 	;    u.fofp (file offset pointer)
  2122                              <1> 	;    inode 
  2123                              <1> 	;    u.off (file offset)
  2124                              <1> 	; OUTPUTS ->
  2125                              <1> 	;    r1 (physical block number)
  2126                              <1> 	;    r2, r3, r5 (internal)
  2127                              <1> 	;
  2128                              <1> 	; ((AX = R1)) output
  2129                              <1> 	;    (Retro UNIX Prototype : 05/03/2013 - 14/11/2012, UNIXCOPY.ASM)
  2130                              <1>         ;    ((Modified registers: eDX, eBX, eCX, eSI, eDI, eBP))  
  2131                              <1> 
  2132                              <1> 		; mov *u.fofp,mq / file offset in mq
  2133                              <1> 		; clr ac / later to be high sig
  2134                              <1> 		; mov $-8,lsh   / divide ac/mq by 256.
  2135                              <1> 		; mov mq,r2
  2136                              <1> 		; bit $10000,i.flgs / lg/sm is this a large or small file
  2137                              <1> 		; bne 4f / branch for large file
  2138                              <1> mget_0:	
  2139                              <1> 	; 09/01/2022
  2140 0000502E 29C0                <1> 	sub	eax, eax
  2141 00005030 29D2                <1> 	sub	edx, edx
  2142 00005032 29C9                <1> 	sub	ecx, ecx
  2143 00005034 29DB                <1> 	sub	ebx, ebx
  2144                              <1> 
  2145 00005036 8B35[A86E0000]      <1>         mov     esi, [u.fofp]
  2146                              <1>         ;movzx	ebx, byte [esi+1]
  2147                              <1> 	; 09/01/2022
  2148 0000503C 46                  <1> 	inc	esi
  2149 0000503D 8A1E                <1> 	mov	bl, [esi]
  2150                              <1> 
  2151                              <1> 	; BX = r2
  2152                              <1>         ; 24/12/2021
  2153 0000503F F605[996B0000]10    <1> 	test	byte [i.flgs+1], 10h
  2154                              <1> 	;test 	word [i.flgs], 4096 ; 1000h
  2155                              <1> 				  ; is this a large or small file
  2156 00005046 756A                <1> 	jnz 	short mget_5 ; 4f ; large file
  2157                              <1> 
  2158 00005048 F6C3F0              <1>         test    bl, 0F0h ; !0Fh                    
  2159                              <1> 		; bit $!17,r2
  2160 0000504B 7525                <1> 	jnz 	short mget_2
  2161                              <1> 		; bne 3f / branch if r2 greater than or equal to 16
  2162 0000504D 80E30E              <1>         and     bl, 0Eh  
  2163                              <1> 		; bic $!16,r2 / clear all bits but bits 1,2,3
  2164                              <1> 	; 09/01/2021
  2165 00005050 668B83[9E6B0000]    <1> 	mov	ax, [ebx+i.dskp]
  2166                              <1> 	;movzx 	eax, word [ebx+i.dskp] ; AX = R1, physical block number
  2167                              <1> 		; mov i.dskp(r2),r1 / r1 has physical block number
  2168                              <1> 	; 24/12/2021
  2169 00005057 09C0                <1> 	or	eax, eax
  2170                              <1> 	;or 	ax, ax
  2171 00005059 7516                <1> 	jnz 	short mget_1 
  2172                              <1> 		; bne 2f / if physical block num is zero then need a new block
  2173                              <1> 		       ; / for file
  2174 0000505B E8A4000000          <1> 	call 	alloc
  2175                              <1> 		; jsr r0,alloc / allocate a new block
  2176                              <1>          ; eAX (r1) = Physical block number
  2177 00005060 668983[9E6B0000]    <1> 	mov 	[ebx+i.dskp], ax
  2178                              <1> 		; mov r1,i.dskp(r2) / physical block number stored in i-node
  2179 00005067 E833020000          <1> 	call 	setimod	
  2180                              <1> 		; jsr r0,setimod / set inode modified byte (imod)
  2181 0000506C E8C2FEFFFF          <1> 	call	clear
  2182                              <1> 		; jsr r0,clear / zero out disk/drum block just allocated
  2183                              <1> mget_1: ; 2:
  2184                              <1>         ; eAX (r1) = Physical block number
  2185 00005071 C3                  <1> 	retn 
  2186                              <1> 		; rts r0
  2187                              <1> mget_2: ; 3: / adding on block which changes small file to a large file
  2188 00005072 E88D000000          <1> 	call 	alloc
  2189                              <1> 		; jsr r0,alloc / allocate a new block for this file;
  2190                              <1> 	                     ; / block number in r1
  2191                              <1>         ; eAX (r1) = Physical block number
  2192 00005077 E8670C0000          <1> 	call 	wslot
  2193                              <1> 		; jsr r0,wslot / set up I/O buffer for write, r5 points to 
  2194                              <1> 			     ; / first data word in buffer
  2195                              <1>         ; eAX (r1) = Physical block number
  2196                              <1> 	; 09/01/2022
  2197 0000507C 31C9                <1> 	xor	ecx, ecx
  2198 0000507E B108                <1> 	mov	cl, 8
  2199                              <1> 	;mov 	ecx, 8  ; R3, transfer old physical block pointers
  2200                              <1> 		   ; into new indirect block area for the new
  2201                              <1> 		   ; large file		
  2202 00005080 89DF                <1> 	mov 	edi, ebx ; r5
  2203 00005082 BE[9E6B0000]        <1> 	mov 	esi, i.dskp 
  2204                              <1> 		; mov $8.,r3 / next 6 instructions transfer old physical 
  2205                              <1> 			   ; / block pointers
  2206                              <1> 		; mov $i.dskp,r2 / into new indirect block for the new 
  2207                              <1> 			  ; / large file
  2208                              <1> 	;xor 	ax, ax ; mov ax, 0
  2209                              <1> 	; 24/12/2021
  2210 00005087 31C0                <1> 	xor	eax, eax
  2211                              <1> mget_3: ;1:
  2212 00005089 66A5                <1> 	movsw
  2213                              <1> 		; mov (r2),(r5)+
  2214 0000508B 668946FE            <1> 	mov 	[esi-2], ax
  2215                              <1> 		; clr (r2)+
  2216 0000508F E2F8                <1> 	loop	mget_3 ; 1b
  2217                              <1> 		; dec r3
  2218                              <1> 		; bgt 1b
  2219                              <1> 
  2220 00005091 B1F8                <1> 	mov 	cl, 256-8
  2221                              <1> 		; mov $256.-8.,r3 / clear rest of data buffer
  2222                              <1> mget_4:	; 1
  2223 00005093 F366AB              <1> 	rep 	stosw
  2224                              <1> 		; clr (r5)+
  2225                              <1> 		; dec r3
  2226                              <1> 		; bgt 1b
  2227                              <1> 	; 24/03/2013
  2228                              <1>         ; AX (r1) = Physical block number
  2229 00005096 E8640C0000          <1> 	call	dskwr
  2230                              <1> 		; jsr r0,dskwr / write new indirect block on disk
  2231                              <1>         ; eAX (r1) = Physical block number
  2232 0000509B 66A3[9E6B0000]      <1> 	mov 	[i.dskp], ax
  2233                              <1> 		; mov r1,i.dskp / put pointer to indirect block in i-node
  2234                              <1> 	; 09/01/2022
  2235 000050A1 800D[996B0000]10    <1> 	or	byte [i.flgs+1], 10h
  2236                              <1> 	;or 	word [i.flgs], 4096 ; 1000h
  2237                              <1> 		; bis $10000,i.flgs / set large file bit 
  2238                              <1> 				  ; / in i.flgs word of i-node
  2239 000050A8 E8F2010000          <1> 	call	setimod
  2240                              <1> 		; jsr r0,setimod / set i-node modified flag
  2241 000050AD E97CFFFFFF          <1>         jmp     mget_0 
  2242                              <1> 		; br mget
  2243                              <1> 
  2244                              <1> mget_5:  ; 4 ; large file
  2245                              <1> 		; mov $-8,lsh / divide byte number by 256.
  2246                              <1> 		; bic $!776,r2 / zero all bits but 1,2,3,4,5,6,7,8; gives offset
  2247                              <1> 			    ; / in indirect block
  2248                              <1> 		; mov r2,-(sp) / save on stack (*)
  2249                              <1> 		; mov mq,r2 / calculate offset in i-node for pointer to proper
  2250                              <1>        		          ; / indirect block
  2251                              <1> 		; bic $!16,r2
  2252 000050B2 80E3FE              <1>         and     bl, 0FEh ; bh = 0
  2253 000050B5 53                  <1>         push    ebx  ; i-node pointer offset in indirect block  (*) 
  2254                              <1>         ; 01/03/2013 Max. possible BX (offset) value is 127 (65535/512)
  2255                              <1> 	; 	     for this file system (offset 128 to 255 not in use)
  2256                              <1> 	; There is always 1 indirect block for this file system
  2257                              <1> 	; 09/01/2022
  2258 000050B6 66A1[9E6B0000]      <1> 	mov	ax, [i.dskp]
  2259                              <1> 	;movzx 	eax, word [i.dskp] ; i.dskp[0]
  2260                              <1> 		; mov i.dskp(r2),r1
  2261                              <1> 	; 09/01/2022
  2262 000050BC 09C0                <1> 	or	eax, eax
  2263                              <1> 	;or 	ax, ax ; R1
  2264 000050BE 7515                <1> 	jnz 	short mget_6 ; 2f
  2265                              <1> 		; bne 2f / if no indirect block exists
  2266 000050C0 E83F000000          <1> 	call 	alloc
  2267                              <1> 		; jsr r0,alloc / allocate a new block
  2268 000050C5 66A3[9E6B0000]      <1> 	mov 	[i.dskp], ax  ; 03/03/2013
  2269                              <1> 		; mov r1,i.dskp(r2) / put block number of new block in i-node
  2270 000050CB E8CF010000          <1> 	call 	setimod
  2271                              <1> 		; jsr r0,setimod / set i-node modified byte
  2272                              <1> 	; eAX = new block number
  2273 000050D0 E85EFEFFFF          <1> 	call 	clear
  2274                              <1> 		; jsr r0,clear / clear new block
  2275                              <1> mget_6: ;2
  2276                              <1> 	; 05/03/2013
  2277                              <1> 	; eAX = r1, physical block number (of indirect block)
  2278 000050D5 E8970B0000          <1> 	call 	dskrd ; read indirect block
  2279                              <1> 		; jsr r0,dskrd / read in indirect block
  2280 000050DA 5A                  <1> 	pop 	edx  ; R2, get offset (*)
  2281                              <1> 		; mov (sp)+,r2 / get offset
  2282                              <1> 	; eAX = r1, physical block number (of indirect block)
  2283 000050DB 50                  <1> 	push 	eax ; ** ; 24/03/2013
  2284                              <1> 		; mov r1,-(sp) / save block number of indirect block on stack
  2285                              <1> 	; eBX (r5) = pointer to buffer (indirect block)
  2286 000050DC 01D3                <1> 	add 	ebx, edx ; / r5 points to first word in indirect block, r2
  2287                              <1> 		; add r5,r2 / r5 points to first word in indirect block, r2
  2288                              <1> 	                  ; / points to location of inter
  2289                              <1> 	; 09/01/2022
  2290 000050DE 668B03              <1> 	mov	ax, [ebx]
  2291                              <1> 	;movzx 	eax, word [ebx] ; put physical block no of block
  2292                              <1> 			      ; in file sought in R1 (AX)
  2293                              <1> 		; mov (r2),r1 / put physical block no of block in file
  2294                              <1> 	               	    ; / sought in r1
  2295                              <1> 	; 09/01/2022
  2296 000050E1 09C0                <1> 	or	eax, eax
  2297                              <1> 	;or 	ax, ax
  2298 000050E3 751D                <1>         jnz 	short mget_7 ; 2f
  2299                              <1> 		; bne 2f / if no block exists 
  2300 000050E5 E81A000000          <1> 	call 	alloc
  2301                              <1> 		; jsr r0,alloc / allocate a new block
  2302 000050EA 668903              <1> 	mov 	[ebx], ax ; R1
  2303                              <1> 		; mov r1,(r2) / put new block number into proper location in
  2304                              <1> 	                    ; / indirect block
  2305 000050ED 5A                  <1> 	pop	edx ; ** ; 24/03/2013
  2306                              <1> 		; mov (sp)+,r1 / get block number of indirect block
  2307 000050EE 52                  <1> 	push 	edx ; ** ; 31/07/2013
  2308 000050EF 50                  <1> 	push	eax ; * ; 24/03/2013, 31/07/2013 (new block number)
  2309 000050F0 89D0                <1> 	mov	eax, edx ; 24/03/2013
  2310                              <1> 		; mov (r2),-(sp) / save block number of new block
  2311                              <1> 	; eAX (r1) = physical block number (of indirect block)
  2312 000050F2 E8EC0B0000          <1> 	call 	wslot
  2313                              <1> 		; jsr r0,wslot
  2314                              <1>         ; eAX (r1) = physical block number
  2315                              <1> 	; eBX (r5) = pointer to buffer (indirect block)
  2316 000050F7 E8030C0000          <1> 	call 	dskwr
  2317                              <1> 	; eAX = r1 = physical block number (of indirect block)
  2318                              <1> 		; jsr r0,dskwr / write newly modified indirect block 
  2319                              <1> 			     ; / back out on disk
  2320 000050FC 58                  <1> 	pop	eax ; *  ; 31/07/2013
  2321                              <1> 		; mov (sp),r1 / restore block number of new block	
  2322                              <1> 	; eAX (r1) = physical block number of new block
  2323 000050FD E831FEFFFF          <1> 	call 	clear
  2324                              <1> 		; jsr r0,clear / clear new block	
  2325                              <1> mget_7: ; 2
  2326 00005102 5A                  <1> 	pop 	edx ; **
  2327                              <1> 		; tst (sp)+ / bump stack pointer
  2328                              <1> 	; eAX (r1) = Block number of new block
  2329 00005103 C3                  <1> 	retn
  2330                              <1> 		; rts r0
  2331                              <1> 
  2332                              <1> alloc:
  2333                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2334                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2335                              <1> 	; 01/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2336                              <1> 	;
  2337                              <1> 	; get a free block and 
  2338                              <1> 	; set the corresponding bit in the free storage map
  2339                              <1> 	; 
  2340                              <1> 	; INPUTS ->
  2341                              <1> 	;    cdev (current device)
  2342                              <1> 	;    r2 
  2343                              <1> 	;    r3
  2344                              <1> 	; OUTPUTS ->
  2345                              <1> 	;    r1 (physical block number of block assigned)
  2346                              <1> 	;    smod, mmod, systm (super block), mount (mountable super block)	
  2347                              <1> 	;
  2348                              <1> 	; ((AX = R1)) output
  2349                              <1> 	;    (Retro UNIX Prototype : 14/11/2012 - 21/07/2012, UNIXCOPY.ASM)
  2350                              <1>         ;    ((Modified registers: DX, CX))  
  2351                              <1> 
  2352                              <1> 		;mov r2,-(sp) / save r2, r3 on stack
  2353                              <1> 		;mov r3,-(sp)
  2354                              <1> 	;push 	ecx
  2355 00005104 53                  <1> 	push 	ebx ; R2
  2356                              <1> 	;push 	edx ; R3
  2357 00005105 BB[587B0000]        <1> 	mov 	ebx, systm ; SuperBlock 
  2358                              <1> 		; mov $systm,r2 / start of inode and free storage map for drum
  2359 0000510A 803D[7F6E0000]00    <1> 	cmp 	byte [cdev], 0
  2360                              <1> 		; tst cdev
  2361 00005111 7605                <1> 	jna	short alloc_1
  2362                              <1> 		; beq 1f / drum is device
  2363 00005113 BB[607D0000]        <1> 	mov	ebx, mount
  2364                              <1> 		; mov $mount,r2 / disk or tape is device, start of inode and
  2365                              <1> 			      ; / free storage map
  2366                              <1> alloc_1: ; 1
  2367                              <1> 	; 09/01/2022
  2368                              <1> 	;sub	ecx, ecx
  2369                              <1> 	;sub	edx, edx
  2370                              <1> 	;sub	eax, eax
  2371                              <1> 
  2372 00005118 668B0B              <1>         mov	cx, [ebx]
  2373                              <1> 		; mov (r2)+,r1 / first word contains number of bytes in free
  2374                              <1> 			     ; / storage map
  2375                              <1> 	; 09/01/2022
  2376 0000511B C1E103              <1> 	shl	ecx, 3
  2377                              <1> 	;shl	cx, 3
  2378                              <1> 		; asl r1 / multiply r1 by eight gives 
  2379                              <1> 		; number of blocks in device
  2380                              <1> 		; asl r1
  2381                              <1> 		; asl r1
  2382                              <1> 	;;push	cx ;; 01/08/2013
  2383                              <1> 		; mov r1,-(sp) / save # of blocks in device on stack
  2384 0000511E 31C0                <1> 	xor 	eax, eax ; 0
  2385                              <1> 		; clr r1 / r1 contains bit count of free storage map
  2386                              <1> alloc_2: ; 1
  2387 00005120 43                  <1> 	inc 	ebx ; 18/8/2012
  2388 00005121 43                  <1> 	inc 	ebx ; 
  2389 00005122 668B13              <1> 	mov 	dx, [ebx]
  2390                              <1> 		; mov (r2)+,r3 / word of free storage map in r3 
  2391                              <1> 	; 09/01/2022
  2392 00005125 09D2                <1> 	or	edx, edx
  2393                              <1> 	;or 	dx, dx
  2394 00005127 750D                <1> 	jnz 	short alloc_3 ; 1f
  2395                              <1> 		; bne 1f / branch if any free blocks in this word	
  2396 00005129 6683C010            <1> 	add 	ax, 16
  2397                              <1> 		; add $16.,r1
  2398                              <1> 	; 09/01/2022
  2399 0000512D 39C8                <1> 	cmp	eax, ecx
  2400                              <1> 	;cmp 	ax, cx    
  2401                              <1> 		; cmp r1 ,(sp) / have we examined all free storage bytes
  2402 0000512F 72EF                <1> 	jb 	short alloc_2
  2403                              <1> 		; blo 1b
  2404                              <1> 	; 14/11/2015
  2405                              <1> 	; Note: If the super block buffer has wrong content (zero bytes)
  2406                              <1> 	;	because of a (DMA or another) r/w error, 
  2407                              <1> 	;	we will be here, at 'jmp panic' code address,
  2408                              <1> 	;	even if the (disk) file system space is not full !!!
  2409                              <1> 	;	(cx = 0)	
  2410                              <1> 	;
  2411 00005131 E950E2FFFF          <1> 	jmp     panic 
  2412                              <1> 		; jmp panic / found no free storage
  2413                              <1> alloc_3: ; 1
  2414                              <1> 	; 09/01/2022
  2415 00005136 D1EA                <1> 	shr	edx, 1
  2416                              <1> 	;shr	dx, 1
  2417                              <1> 		; asr r3 / find a free block
  2418 00005138 7203                <1> 	jc	short alloc_4 ; 1f
  2419                              <1> 		; bcs 1f / branch when free block found; bit for block k
  2420                              <1> 		       ; / is in byte k/8 / in bit k (mod 8)
  2421                              <1> 	; 09/01/2022
  2422 0000513A 40                  <1> 	inc	eax
  2423                              <1> 	;inc	ax
  2424                              <1> 		; inc r1 / increment bit count in bit k (mod8)
  2425 0000513B EBF9                <1> 	jmp 	short alloc_3
  2426                              <1> 		; br 1b
  2427                              <1> alloc_4: ; 1:
  2428                              <1> 	;; pop cx ;; 01/08/2013
  2429                              <1> 		; tst (sp)+ / bump sp
  2430                              <1> 	; 02/04/2013 
  2431 0000513D E829000000          <1> 	call	free3
  2432                              <1> 		; jsr r0,3f / have found a free block
  2433                              <1> 	; 21/8/2012
  2434 00005142 66F7D2              <1> 	not 	dx ; masking bit is '0' and others are '1'
  2435 00005145 662113              <1> 	and	[ebx], dx   ;; 0 -> allocated 
  2436                              <1> 		; bic r3,(r2) / set bit for this block 
  2437                              <1> 		            ; / i.e. assign block
  2438                              <1> 		; br 2f
  2439 00005148 EB09                <1> 	jmp 	short alloc_5
  2440                              <1> 
  2441                              <1> free:
  2442                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2443                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2444                              <1> 	; 07/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2445                              <1> 	;
  2446                              <1> 	; calculates byte address and bit position for given block number
  2447                              <1> 	; then sets the corresponding bit in the free storage map
  2448                              <1> 	; 
  2449                              <1> 	; INPUTS ->
  2450                              <1> 	;    r1 - block number for a block structured device
  2451                              <1> 	;    cdev - current device 
  2452                              <1> 	; OUTPUTS ->
  2453                              <1> 	;    free storage map is updated
  2454                              <1> 	;    smod is incremented if cdev is root device (fixed disk)
  2455                              <1> 	;    mmod is incremented if cdev is a removable disk 	
  2456                              <1> 	;
  2457                              <1> 	;  (Retro UNIX Prototype : 01/12/2012, UNIXCOPY.ASM)
  2458                              <1>         ;  ((Modified registers: DX, CX))  
  2459                              <1> 
  2460                              <1> 		;mov r2,-(sp) / save r2, r3
  2461                              <1> 		;mov r3,-(sp)
  2462                              <1> 	;push 	ecx
  2463 0000514A 53                  <1> 	push 	ebx ; R2
  2464                              <1> 	;push 	edx ; R3 
  2465                              <1> 
  2466 0000514B E81B000000          <1>         call    free3
  2467                              <1> 	     	; jsr r0,3f  / set up bit mask and word no. 
  2468                              <1> 				 ; / in free storage map for block
  2469 00005150 660913              <1> 	or 	[ebx], dx  
  2470                              <1> 	  	; bis r3, (r2) / set free storage block bit;
  2471                              <1> 			    ;  / indicates free block	
  2472                              <1> 	; 0 -> allocated, 1 -> free
  2473                              <1> 
  2474                              <1> alloc_5:
  2475                              <1> 	; 07/04/2013
  2476                              <1> free_1: ; 2:
  2477                              <1> 	;pop 	edx
  2478                              <1> 		; mov (sp)+,r3 / restore r2, r3
  2479 00005153 5B                  <1> 	pop	ebx
  2480                              <1> 		; mov (sp)+,r2
  2481                              <1> 	; pop	ecx
  2482 00005154 803D[7F6E0000]00    <1> 	cmp 	byte [cdev], 0
  2483                              <1> 		; tst cdev / cdev = 0, block structured, drum; 
  2484                              <1> 			 ; / cdev = 1, mountable device
  2485 0000515B 7707                <1> 	ja	short alloc_6 ; 1f
  2486                              <1> 		; bne 1f
  2487                              <1> 	;mov	byte [smod], 1
  2488 0000515D FE05[8D6E0000]      <1> 	inc 	byte [smod]
  2489                              <1> 		; incb smod / set super block modified for drum
  2490                              <1> 	; eAX (r1) = block number
  2491 00005163 C3                  <1> 	retn
  2492                              <1> 		; rts r0
  2493                              <1> free_2:
  2494                              <1> alloc_6: ; 1:
  2495                              <1> 	;mov 	byte [mmod], 1
  2496 00005164 FE05[8E6E0000]      <1> 	inc 	byte [mmod]
  2497                              <1> 		; incb	mmod 
  2498                              <1> 		  ; / set super block modified for mountable device
  2499                              <1> 	; eAX (r1) = block number
  2500 0000516A C3                  <1> 	retn	
  2501                              <1> 		; rts r0
  2502                              <1> free3:
  2503                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2504                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2505                              <1> 	; 02/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2506                              <1> 	;
  2507                              <1> 	; free3 is called from 'alloc' and 'free' procedures
  2508                              <1> 	; 
  2509                              <1> alloc_free_3: ; 3
  2510                              <1> 	;mov 	dx, 1
  2511                              <1> 	; 09/01/2022
  2512 0000516B 31D2                <1> 	xor	edx, edx
  2513 0000516D 42                  <1> 	inc	edx
  2514                              <1> 	; edx = 1
  2515 0000516E 88C1                <1> 	mov 	cl, al
  2516                              <1> 		; mov r1,r2 / block number, k, = 1		
  2517 00005170 80E10F              <1> 	and 	cl, 0Fh  ; 0Fh <-- (k) mod 16
  2518                              <1> 		; bic $!7,r2 / clear all bits but 0,1,2; r2 = (k) mod (8)
  2519 00005173 7402                <1> 	jz 	short free4
  2520                              <1> 		; bisb 2f(r2),r3 / use mask to set bit in r3 corresponding to
  2521                              <1> 			       ; / (k) mod 8
  2522                              <1> 	;shl 	dx, cl
  2523                              <1> 	; 09/01/2022
  2524 00005175 D3E2                <1> 	shl	edx, cl
  2525                              <1> free4:
  2526 00005177 0FB7D8              <1> 	movzx 	ebx, ax
  2527                              <1> 		; mov r1,r2 / divide block number by 16
  2528                              <1> 	; 09/01/2022
  2529 0000517A C1EB04              <1> 	shr	ebx, 4
  2530                              <1> 	;shr 	bx, 4
  2531                              <1> 		; asr r2
  2532                              <1> 		; asr r2
  2533                              <1> 		; asr r2
  2534                              <1> 		; asr r2
  2535                              <1> 		; bcc 1f / branch if bit 3 in r1 was 0 i.e., 
  2536                              <1> 		       ; / bit for block is in lower half of word
  2537                              <1> 		; swab r3 / swap bytes in r3; bit in upper half of word in free
  2538                              <1> 		        ; / storage map
  2539                              <1> alloc_free_4: ; 1
  2540                              <1> 	; 09/01/2022
  2541 0000517D D1E3                <1> 	shl	ebx, 1
  2542                              <1> 	;shl 	bx, 1
  2543                              <1> 		; asl r2 / multiply block number by 2; r2 = k/8
  2544 0000517F 81C3[5A7B0000]      <1> 	add 	ebx, systm+2 ; SuperBlock+2
  2545                              <1> 		; add $systm+2,r2 / address of word of free storage map for drum
  2546                              <1> 	    		        ; / with block bit in it 	
  2547 00005185 803D[7F6E0000]00    <1> 	cmp	byte [cdev], 0
  2548                              <1> 		; tst cdev
  2549 0000518C 7606                <1> 	jna	short alloc_free_5
  2550                              <1> 		; beq 1f / cdev = 0 indicates device is drum
  2551 0000518E 81C308020000        <1> 	add	ebx, mount - systm
  2552                              <1> 		; add $mount-systm,r2 / address of word of free storage map for
  2553                              <1> 				    ; / mountable device with bit of block to be
  2554                              <1> 				    ; / freed
  2555                              <1> alloc_free_5: ; 1 
  2556 00005194 C3                  <1> 	retn
  2557                              <1> 		; rts r0 / return to 'free'
  2558                              <1> 	      ; 2
  2559                              <1> 	        ; .byte	1,2,4,10,20,40,100,200 / masks for bits 0,...,7
  2560                              <1> 	
  2561                              <1> iget:
  2562                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2563                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2564                              <1> 	; 07/04/2013 - 07/08/2013 (Retro UNIX 8086 v1)
  2565                              <1> 	;
  2566                              <1> 	; get a new i-node whose i-number in r1 and whose device is in cdev
  2567                              <1> 	;
  2568                              <1> 	; ('iget' returns current i-number in r1, if input value of r1 is 0)
  2569                              <1> 	; 
  2570                              <1> 	; INPUTS ->
  2571                              <1> 	;    ii - current i-number, rootdir
  2572                              <1> 	;    cdev - new i-node device
  2573                              <1> 	;    idev - current i-node device
  2574                              <1> 	;    imod - current i-node modified flag
  2575                              <1> 	;    mnti - cross device file i-number
  2576                              <1> 	;    r1 - i-numbe rof new i-node
  2577                              <1> 	;    mntd - mountable device number		
  2578                              <1> 	; 	 
  2579                              <1> 	; OUTPUTS ->
  2580                              <1> 	;    cdev, idev, imod, ii, r1
  2581                              <1> 	;
  2582                              <1> 	; ((AX = R1)) input/output
  2583                              <1> 	;
  2584                              <1> 	;  (Retro UNIX Prototype : 14/07/2012 - 18/11/2012, UNIXCOPY.ASM)
  2585                              <1>         ;  ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  2586                              <1> 
  2587 00005195 8A15[7F6E0000]      <1> 	mov	dl, [cdev] ; 18/07/2013
  2588 0000519B 8A35[7E6E0000]      <1> 	mov	dh, [idev] ; 07/08/2013
  2589                              <1> 	;
  2590 000051A1 663B05[7C6E0000]    <1> 	cmp 	ax, [ii]
  2591                              <1> 		; cmp r1,ii / r1 = i-number of current file
  2592 000051A8 7504                <1> 	jne 	short iget_1
  2593                              <1> 		; bne 1f
  2594 000051AA 38F2                <1> 	cmp	dl, dh
  2595                              <1> 		; cmp idev,cdev
  2596                              <1> 			  ; / is device number of i-node = current device
  2597 000051AC 7472                <1>         je      short iget_5
  2598                              <1> 		; beq 2f
  2599                              <1> iget_1: ; 1:
  2600 000051AE 30DB                <1> 	xor	bl, bl
  2601 000051B0 381D[8C6E0000]      <1> 	cmp	[imod], bl ; 0	
  2602                              <1> 		; tstb imod / has i-node of current file
  2603                              <1> 			  ; / been modified i.e., imod set
  2604 000051B6 7629                <1> 	jna	short iget_2
  2605                              <1> 		; beq 1f
  2606 000051B8 881D[8C6E0000]      <1> 	mov	[imod], bl ; 0
  2607                              <1> 		;  clrb	imod / if it has, 
  2608                              <1> 			   ; / we must write the new i-node out on disk
  2609                              <1> 	; 24/12/2021
  2610 000051BE 50                  <1> 	push	eax ; *
  2611                              <1> 	;push	ax
  2612                              <1> 		; mov r1,-(sp)
  2613                              <1> 	;mov	dl, [cdev]
  2614 000051BF 52                  <1> 	push	edx ; **
  2615                              <1> 	;push	dx
  2616                              <1> 		; mov cdev,-(sp)
  2617 000051C0 66A1[7C6E0000]      <1> 	mov	ax, [ii]
  2618                              <1> 		; mov ii,r1
  2619                              <1> 	;mov	dh, [idev]
  2620 000051C6 8835[7F6E0000]      <1> 	mov	[cdev], dh
  2621                              <1> 		; mov idev,cdev
  2622 000051CC FEC3                <1> 	inc	bl ; 1
  2623                              <1> 	; 31/07/2013
  2624 000051CE 881D[1C6F0000]      <1> 	mov     [rw], bl ; 1 == write 
  2625                              <1> 	;;28/07/2013 rw -> u.rw
  2626                              <1>         ;;mov   [u.rw], bl ; 1 == write
  2627 000051D4 E848000000          <1> 	call	icalc
  2628                              <1> 		; jsr r0,icalc; 1
  2629                              <1> 	;pop	dx
  2630                              <1> 	; 24/12/2021
  2631 000051D9 5A                  <1> 	pop	edx ; **
  2632 000051DA 8815[7F6E0000]      <1> 	mov	[cdev], dl
  2633                              <1> 		; mov (sp)+,cdev
  2634                              <1> 	; 24/12/2021
  2635 000051E0 58                  <1> 	pop	eax ; *
  2636                              <1> 	;pop	ax
  2637                              <1> 		; mov (sp)+,r1
  2638                              <1> iget_2: ; 1:
  2639 000051E1 6621C0              <1> 	and	ax, ax
  2640                              <1> 		; tst r1 / is new i-number non zero
  2641 000051E4 7434                <1> 	jz	short iget_4 ; 2f
  2642                              <1> 		; beq 2f / branch if r1=0
  2643                              <1> 
  2644                              <1> 	;mov 	dl, [cdev]
  2645 000051E6 08D2                <1> 	or	dl, dl
  2646                              <1> 		; tst cdev / is the current device number non zero
  2647                              <1> 			 ; / (i.e., device =/ drum)
  2648 000051E8 7517                <1> 	jnz	short iget_3 ;  1f
  2649                              <1> 		; bne 1f / branch 1f cdev =/ 0  ;; (cdev != 0)
  2650 000051EA 663B05[846E0000]    <1> 	cmp	ax, [mnti]			
  2651                              <1> 		; cmp r1,mnti / mnti is the i-number of the cross device
  2652                              <1> 			    ; / file (root directory of mounted device)
  2653 000051F1 750E                <1> 	jne	short iget_3 ; 1f
  2654                              <1> 		; bne 1f
  2655                              <1>         ;mov    bl, [mntd]
  2656 000051F3 FEC2                <1> 	inc	dl ; mov dl, 1 ; 17/07/2013
  2657 000051F5 8815[7F6E0000]      <1>         mov	[cdev], dl ; 17/07/2013 - 09/07/2013
  2658                              <1> 		; mov mntd,cdev / make mounted device the current device
  2659 000051FB 66A1[886E0000]      <1> 	mov	ax, [rootdir]
  2660                              <1> 		; mov rootdir,r1
  2661                              <1> iget_3: ; 1:
  2662 00005201 66A3[7C6E0000]      <1> 	mov	[ii], ax
  2663                              <1> 		; mov r1,ii
  2664 00005207 8815[7E6E0000]      <1> 	mov	[idev], dl ; cdev
  2665                              <1> 		; mov cdev,idev
  2666 0000520D 30DB                <1> 	xor	bl, bl
  2667                              <1>         ; 31/07/2013
  2668 0000520F 881D[1C6F0000]      <1> 	mov     [rw], bl ; 0 == read 
  2669                              <1> 	;;28/07/2013 rw -> u.rw       
  2670                              <1>         ;;mov   [u.rw], bl ; 0 = read
  2671 00005215 E807000000          <1> 	call	icalc
  2672                              <1> 		; jsr r0,icalc; 0 / read in i-node ii
  2673                              <1> iget_4: ; 2:
  2674 0000521A 66A1[7C6E0000]      <1> 	mov	ax, [ii]
  2675                              <1> 		; mov ii,r1
  2676                              <1> iget_5:
  2677 00005220 C3                  <1> 	retn
  2678                              <1> 		; rts r0
  2679                              <1> 
  2680                              <1> icalc:
  2681                              <1> 	; 09/01/2022
  2682                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2683                              <1> 	; 02/07/2015
  2684                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2685                              <1> 	; 07/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2686                              <1> 	;
  2687                              <1> 	; calculate physical block number from i-number then
  2688                              <1> 	; read or write that block
  2689                              <1> 	;
  2690                              <1> 	; 'icalc' is called from 'iget'
  2691                              <1> 	;
  2692                              <1> 	; for original unix v1:
  2693                              <1> 	; / i-node i is located in block (i+31.)/16. and begins 32.*
  2694                              <1>        	; / (i+31.) mod 16. bytes from its start
  2695                              <1> 	;
  2696                              <1> 	; for retro unix 8086 v1:
  2697                              <1> 	;  i-node is located in block (i+47)/16 and
  2698                              <1> 	;  begins 32*(i+47) mod 16 bytes from its start
  2699                              <1> 	;
  2700                              <1> 	; INPUTS ->
  2701                              <1> 	;    r1 - i-number of i-node
  2702                              <1> 	; 	 
  2703                              <1> 	; OUTPUTS ->
  2704                              <1> 	;    inode r/w
  2705                              <1> 	;
  2706                              <1> 	; ((AX = R1)) input
  2707                              <1> 	;
  2708                              <1> 	;  (Retro UNIX Prototype : 14/07/2012 - 18/11/2012, UNIXCOPY.ASM)
  2709                              <1>         ;  ((Modified registers: eAX, eDX, eCX, eBX, eSI, eDI, eBP))  
  2710                              <1> 	;
  2711 00005221 0FB7D0              <1> 	movzx	edx, ax	
  2712 00005224 6683C22F            <1> 	add	dx, 47
  2713 00005228 89D0                <1> 	mov	eax, edx
  2714                              <1> 	;add	ax, 47	; add 47 to inode number
  2715                              <1> 		; add $31.,r1 / add 31. to i-number
  2716 0000522A 50                  <1> 	push	eax
  2717                              <1> 		; mov r1,-(sp) / save i+31. on stack
  2718                              <1> 	; 09/01/2022
  2719 0000522B C1E804              <1> 	shr	eax, 4
  2720                              <1> 	;shr 	ax, 4
  2721                              <1> 		; asr r1 / divide by 16.
  2722                              <1> 		; asr r1
  2723                              <1> 		; asr r1
  2724                              <1> 		; asr r1 / r1 contains block number of block
  2725                              <1> 		       ; / in which i-node exists
  2726 0000522E E83E0A0000          <1> 	call	dskrd
  2727                              <1> 		; jsr r0,dskrd / read in block containing i-node i.
  2728                              <1> 	; 31/07/2013
  2729 00005233 803D[1C6F0000]00    <1>         cmp     byte [rw], 0 ; Retro Unix 8086 v1 feature !
  2730                              <1> 	;; 28/07/2013 rw -> u.rw
  2731                              <1>         ;;cmp	byte [u.rw], 0 ; Retro Unix 8086 v1 feature !
  2732                              <1> 		; tst (r0)
  2733 0000523A 7605                <1> 	jna	short icalc_1
  2734                              <1> 		; beq 1f / branch to wslot when argument
  2735                              <1> 		       ; / in icalc call = 1
  2736                              <1> 	; eAX = r1 = block number
  2737 0000523C E8A20A0000          <1> 	call	wslot
  2738                              <1> 		; jsr r0,wslot / set up data buffer for write
  2739                              <1> 			     ; / (will be same buffer as dskrd got)
  2740                              <1> 	; eBX = r5 points to first word in data area for this block
  2741                              <1> icalc_1: ; 1:
  2742 00005241 5A                  <1> 	pop	edx 
  2743 00005242 83E20F              <1> 	and 	edx, 0Fh ; (i+47) mod 16
  2744                              <1> 		; bic $!17,(sp) / zero all but last 4 bits; 
  2745                              <1> 			      ; / gives (i+31.) mod 16
  2746 00005245 C1E205              <1> 	shl 	edx, 5
  2747                              <1> 	; eDX = 32 * ((i+47) mod 16)
  2748 00005248 89DE                <1> 	mov	esi, ebx  ; ebx points 1st word of the buffer
  2749 0000524A 01D6                <1> 	add	esi, edx  ; edx is inode offset in the buffer
  2750                              <1>           	; eSI (r5) points to first word in i-node i.	
  2751                              <1> 		; mov (sp)+,mq / calculate offset in data buffer; 
  2752                              <1> 			     ; / 32.*(i+31.)mod16
  2753                              <1> 		; mov $5,lsh / for i-node i.
  2754                              <1> 		; add mq,r5 / r5 points to first word in i-node i.
  2755 0000524C BF[986B0000]        <1> 	mov	edi, inode
  2756                              <1> 		; mov $inode,r1 / inode is address of first word 
  2757                              <1> 			      ; / of current i-node
  2758                              <1> 	; 09/01/2022
  2759 00005251 29C9                <1> 	sub	ecx, ecx
  2760 00005253 B108                <1> 	mov	cl, 8 
  2761                              <1> 	;mov 	ecx, 8 ; 02/07/2015(32 bit modification)
  2762                              <1> 		; mov $16.,r3
  2763                              <1>        ; 31/07/2013
  2764 00005255 382D[1C6F0000]      <1>   	cmp     [rw], ch ; 0  ;; Retro Unix 8086 v1 feature !
  2765                              <1>        ;;28/07/2013 rw -> u.rw                 
  2766                              <1>        ;;cmp    [u.rw], ch ; 0  ;; Retro Unix 8086 v1 feature !
  2767                              <1> 		; tst (r0)+ / branch to 2f when argument in icalc call = 0
  2768 0000525B 7609                <1> 	jna	short icalc_3
  2769                              <1> 		; beq 2f / r0 now contains proper return address 
  2770                              <1> 		       ; / for rts r0
  2771                              <1> icalc_2: ; 1:
  2772 0000525D 87F7                <1> 	xchg 	esi, edi
  2773                              <1> 	; overwrite old i-node (in buffer to be written)
  2774 0000525F F3A5                <1> 	rep 	movsd
  2775                              <1> 		; mov (r1)+,(r5)+ / over write old i-node
  2776                              <1> 		; dec r3
  2777                              <1> 		; bgt 1b
  2778                              <1> 	;call	dskwr
  2779                              <1> 		; jsr r0,dskwr / write inode out on device
  2780                              <1> 	;retn
  2781                              <1> 		; rts r0
  2782                              <1> 	; 24/12/2021
  2783 00005261 E9990A0000          <1> 	jmp	dskwr
  2784                              <1> 
  2785                              <1> icalc_3: ; 2:
  2786                              <1> 	; copy new i-node into inode area of (core) memory
  2787 00005266 F3A5                <1> 	rep 	movsd
  2788                              <1> 		; mov (r5)+,(r1)+ / read new i-node into 
  2789                              <1> 		                ; / "inode" area of core
  2790                              <1> 		; dec r3
  2791                              <1> 		; bgt 2b
  2792 00005268 C3                  <1> 	retn
  2793                              <1> 		; rts r0
  2794                              <1> 
  2795                              <1> access:
  2796                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2797                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2798                              <1> 	; 24/04/2013 - 29/04/2013 (Retro UNIX 8086 v1)
  2799                              <1> 	;
  2800                              <1> 	; check whether user is owner of file or user has read or write
  2801                              <1> 	; permission (based on i.flgs).
  2802                              <1> 	;
  2803                              <1> 	; INPUTS ->
  2804                              <1> 	;    r1 - i-number of file
  2805                              <1> 	;    u.uid
  2806                              <1> 	; arg0 -> (owner flag mask)	 		
  2807                              <1> 	;     Retro UNIX 8086 v1 feature -> owner flag mask in DL (DX) 	 
  2808                              <1> 	; OUTPUTS ->
  2809                              <1> 	;    inode (or jump to error)
  2810                              <1> 	;
  2811                              <1> 	; ((AX = R1)) input/output
  2812                              <1> 	;
  2813                              <1>         ;  ((Modified registers: eCX, eBX, eDX, eSI, eDI, eBP))  
  2814                              <1> 	
  2815                              <1> 	;push	dx  ; save flags (DL)
  2816                              <1> 	; 24/12/2021
  2817 00005269 52                  <1> 	push	edx ; save flags (DL)
  2818 0000526A E826FFFFFF          <1> 	call	iget
  2819                              <1> 		; jsr r0,iget / read in i-node for current directory
  2820                              <1> 			    ; / (i-number passed in r1)
  2821 0000526F 8A0D[986B0000]      <1> 	mov	cl, [i.flgs]
  2822                              <1> 		; mov i.flgs,r2
  2823                              <1> 	; 24/12/2021
  2824 00005275 5A                  <1> 	pop	edx ; restore flags (DL)
  2825                              <1> 	;pop	dx  ; restore flags (DL)
  2826 00005276 8A35[E46E0000]      <1> 	mov	dh, [u.uid]
  2827 0000527C 3A35[9B6B0000]      <1> 	cmp	dh, [i.uid]
  2828                              <1> 		; cmpb i.uid,u.uid / is user same as owner of file
  2829 00005282 7503                <1> 	jne	short access_1
  2830                              <1> 		; bne 1f / no, then branch
  2831 00005284 C0E902              <1> 	shr	cl, 2
  2832                              <1> 		; asrb r2 / shift owner read write bits into non owner
  2833                              <1> 		        ; / read/write bits
  2834                              <1> 		; asrb r2
  2835                              <1> access_1: ; 1:
  2836 00005287 20D1                <1> 	and	cl, dl
  2837                              <1> 		; bit r2,(r0)+ / test read-write flags against argument
  2838                              <1> 			     ; / in access call
  2839 00005289 7513                <1> 	jnz	short access_2
  2840                              <1> 		; bne 1f
  2841 0000528B 08F6                <1> 	or	dh, dh	; super user (root) ?
  2842                              <1> 		; tstb u.uid
  2843 0000528D 740F                <1> 	jz	short access_2 ; yes, super user
  2844                              <1> 	;jnz	error
  2845                              <1> 		; beq 1f
  2846                              <1> 		; jmp error
  2847 0000528F C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS 
  2847 00005297 0000                <1>
  2848                              <1> 			; 'permission denied !' error
  2849 00005299 E934E8FFFF          <1> 	jmp	error
  2850                              <1> 
  2851                              <1> access_2: ; 1:
  2852                              <1> 	; DL = flags
  2853 0000529E C3                  <1> 	retn
  2854                              <1> 		; rts r0
  2855                              <1> 
  2856                              <1> setimod:
  2857                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2858                              <1> 	; 09/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2859                              <1> 	;
  2860                              <1> 	; 'setimod' sets byte at location 'imod' to 1; thus indicating that 
  2861                              <1> 	; the inode has been modified. Also puts the time of modification
  2862                              <1> 	; into the inode.
  2863                              <1> 	;
  2864                              <1> 	; (Retro UNIX Prototype : 14/07/2012 - 23/02/2013, UNIXCOPY.ASM)
  2865                              <1>         ; ((Modified registers: eDX, eCX, eBX)) 
  2866                              <1> 	;
  2867                              <1> 	
  2868                              <1> 	;push 	edx
  2869 0000529F 50                  <1> 	push	eax
  2870                              <1> 
  2871 000052A0 C605[8C6E0000]01    <1> 	mov 	byte [imod], 1
  2872                              <1> 		; movb $1,imod / set current i-node modified bytes
  2873                              <1> 	; Erdogan Tan 14-7-2012
  2874 000052A7 E869E3FFFF          <1> 	call 	epoch
  2875                              <1> 		 ; mov s.time,i.mtim 
  2876                              <1> 			    ; / put present time into file modified time
  2877                              <1> 		 ; mov s.time+2,i.mtim+2
  2878                              <1> 
  2879 000052AC A3[B26B0000]        <1> 	mov 	[i.mtim], eax
  2880                              <1> 	
  2881                              <1> 	; Retro UNIX 386 v1 modification ! (cmp)
  2882                              <1> 	; Retro UNIX 8086 v1 modification ! (test)
  2883 000052B1 833D[AE6B0000]00    <1> 	cmp	dword [i.ctim], 0
  2884 000052B8 7505                <1> 	jnz	short setimod_ok
  2885                              <1> 
  2886 000052BA A3[AE6B0000]        <1> 	mov 	[i.ctim], eax
  2887                              <1> 
  2888                              <1> setimod_ok: ; 31/07/2013
  2889 000052BF 58                  <1> 	pop	eax
  2890                              <1> 	;pop	edx
  2891                              <1> 	
  2892 000052C0 C3                  <1> 	retn
  2893                              <1> 		; rts r0
  2894                              <1> 
  2895                              <1> itrunc:
  2896                              <1> 	; 03/02/2022
  2897                              <1> 	; 09/01/2022
  2898                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1) 
  2899                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2900                              <1> 	; 23/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2901                              <1> 	;
  2902                              <1> 	; 'itrunc' truncates a file whose i-number is given in r1
  2903                              <1> 	;  to zero length.
  2904                              <1> 	;
  2905                              <1> 	; INPUTS ->
  2906                              <1> 	;    r1 - i-number of i-node
  2907                              <1> 	;    i.dskp - pointer to contents or indirect block in an i-node
  2908                              <1> 	;    i.flgs - large file flag		
  2909                              <1> 	;    i.size - size of file	
  2910                              <1> 	; 	 
  2911                              <1> 	; OUTPUTS ->
  2912                              <1> 	;    i.flgs - large file flag is cleared
  2913                              <1> 	;    i.size - set to 0	
  2914                              <1> 	;    i.dskp .. i.dskp+16 - entire list is cleared
  2915                              <1> 	;    setimod - set to indicate i-node has been modified
  2916                              <1> 	;    r1 - i-number of i-node  					
  2917                              <1> 	;
  2918                              <1> 	; ((AX = R1)) input/output
  2919                              <1> 	;
  2920                              <1> 	;  (Retro UNIX Prototype : 01/12/2012 - 10/03/2013, UNIXCOPY.ASM)
  2921                              <1>         ;  ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  2922                              <1> 
  2923 000052C1 E8CFFEFFFF          <1> 	call	iget
  2924                              <1> 		; jsr r0,iget
  2925 000052C6 BE[9E6B0000]        <1> 	mov	esi, i.dskp
  2926                              <1> 		; mov $i.dskp,r2 / address of block pointers in r2
  2927 000052CB 31C0                <1> 	xor	eax, eax
  2928                              <1> itrunc_1: ; 1:
  2929 000052CD 66AD                <1> 	lodsw
  2930                              <1> 		; mov (r2)+,r1 / move physical block number into r1
  2931                              <1> 	; 09/01/2022
  2932 000052CF 09C0                <1> 	or	eax, eax
  2933                              <1> 	;or 	ax, ax
  2934 000052D1 7433                <1> 	jz	short itrunc_5
  2935                              <1> 		; beq 5f
  2936 000052D3 56                  <1> 	push	esi
  2937                              <1> 		; mov r2,-(sp)
  2938                              <1> 	; 09/01/2022
  2939 000052D4 F605[996B0000]10    <1> 	test	byte [i.flgs+1], 10h
  2940                              <1> 	;test	word [i.flgs], 1000h
  2941                              <1> 		; bit $10000,i.flgs / test large file bit?
  2942 000052DB 7423                <1> 	jz	short itrunc_4
  2943                              <1> 		; beq 4f / if clear, branch
  2944 000052DD 50                  <1> 	push	eax
  2945                              <1> 		; mov r1,-(sp) / save block number of indirect block
  2946 000052DE E88E090000          <1> 	call	dskrd
  2947                              <1> 		; jsr r0,dskrd / read in block, 1st data word 
  2948                              <1> 			     ; / pointed to by r5
  2949                              <1> 	; eBX = r5 = Buffer data address (the 1st word)
  2950                              <1> 	; 09/01/2022
  2951 000052E3 31C9                <1> 	xor	ecx, ecx
  2952 000052E5 FEC5                <1> 	inc	ch ; mov ch, 1
  2953                              <1> 	; ecx = 256
  2954                              <1> 	;mov	ecx, 256
  2955                              <1> 		; mov $256.,r3 / move word count into r3
  2956 000052E7 89DE                <1> 	mov	esi, ebx
  2957                              <1> itrunc_2: ; 2:
  2958 000052E9 66AD                <1> 	lodsw
  2959                              <1> 		; mov (r5)+,r1 / put 1st data word in r1; 
  2960                              <1> 			     ; / physical block number
  2961                              <1> 	; 09/01/2022
  2962 000052EB 21C0                <1> 	and	eax, eax
  2963                              <1> 	;and	ax, ax
  2964 000052ED 7407                <1> 	jz	short itrunc_3
  2965                              <1> 		; beq 3f / branch if zero
  2966                              <1> 	; 24/12/2021
  2967 000052EF 51                  <1> 	push	ecx
  2968                              <1> 	;push	cx
  2969                              <1> 		; mov r3,-(sp) / save r3, r5 on stack
  2970                              <1> 	;push	esi
  2971                              <1> 		; mov r5,-(sp)
  2972 000052F0 E855FEFFFF          <1> 	call	free
  2973                              <1> 		; jsr r0,free / free block in free storage map
  2974                              <1> 	;pop	esi
  2975                              <1> 		; mov(sp)+,r5
  2976                              <1> 	;pop	cx
  2977 000052F5 59                  <1> 	pop	ecx
  2978                              <1> 		; mov (sp)+,r3
  2979                              <1> itrunc_3: ; 3:
  2980 000052F6 E2F1                <1> 	loop	itrunc_2
  2981                              <1> 		; dec r3 / decrement word count
  2982                              <1> 		; bgt 2b / branch if positive
  2983 000052F8 58                  <1> 	pop	eax
  2984                              <1> 		; mov (sp)+,r1 / put physical block number of 
  2985                              <1> 			     ; / indirect block
  2986                              <1> 	; 01/08/2013
  2987                              <1> 	;and	word [i.flgs], 0EFFFh ; 1110111111111111b
  2988                              <1> 	; 03/02/2022
  2989 000052F9 8025[996B0000]EF    <1> 	and	byte [i.flgs+1], 0EFh
  2990                              <1> itrunc_4: ; 4:
  2991 00005300 E845FEFFFF          <1> 	call	free
  2992                              <1> 		; jsr r0,free / free indirect block
  2993 00005305 5E                  <1> 	pop	esi
  2994                              <1> 		; mov (sp)+,r2
  2995                              <1> itrunc_5: ; 5:
  2996 00005306 81FE[AE6B0000]      <1> 	cmp	esi, i.dskp+16
  2997                              <1> 		; cmp r2,$i.dskp+16.
  2998 0000530C 72BF                <1> 	jb	short itrunc_1	
  2999                              <1> 		; bne 1b / branch until all i.dskp entries check
  3000                              <1> 	; 03/02/2022
  3001                              <1> 	;and	byte [i.flgs+1], 0EFh
  3002                              <1> 	; 01/08/2013
  3003                              <1> 	;and	word [i.flgs], 0EFFFh ; 1110111111111111b
  3004                              <1> 		; bic $10000,i.flgs / clear large file bit
  3005 0000530E BF[9E6B0000]        <1> 	mov	edi, i.dskp
  3006                              <1> 	;mov	cx, 8
  3007                              <1> 	;xor 	ax, ax
  3008                              <1> 	; 09/01/2022
  3009 00005313 29C9                <1> 	sub	ecx, ecx
  3010 00005315 B108                <1> 	mov	cl, 8
  3011 00005317 29C0                <1> 	sub	eax, eax
  3012 00005319 66A3[9C6B0000]      <1> 	mov	[i.size], ax ; 0
  3013                              <1> 		; clr i.size / zero file size
  3014 0000531F F366AB              <1> 	rep	stosw
  3015                              <1> 		; jsr r0,copyz; i.dskp; i.dskp+16. 
  3016                              <1> 			   ; / zero block pointers
  3017 00005322 E878FFFFFF          <1> 	call	setimod
  3018                              <1> 		; jsr r0,setimod / set i-node modified flag
  3019 00005327 66A1[7C6E0000]      <1> 	mov	ax, [ii]
  3020                              <1> 		; mov ii,r1
  3021 0000532D C3                  <1> 	retn
  3022                              <1> 		; rts r0
  3023                              <1> 
  3024                              <1> imap:
  3025                              <1> 	; 11/02/2022
  3026                              <1> 	; 03/02/2022
  3027                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3028                              <1> 	; 26/04/2013 (Retro UNIX 8086 v1)
  3029                              <1> 	;
  3030                              <1> 	; 'imap' finds the byte in core (superblock) containing
  3031                              <1> 	; allocation bit for an i-node whose number in r1.
  3032                              <1> 	;
  3033                              <1> 	; INPUTS ->
  3034                              <1> 	;    r1 - contains an i-number
  3035                              <1> 	;    fsp - start of table containing open files
  3036                              <1> 	;
  3037                              <1> 	; OUTPUTS ->
  3038                              <1> 	;    r2 - byte address of byte with the allocation bit
  3039                              <1> 	;    mq - a mask to locate the bit position.	
  3040                              <1> 	;	  (a 1 is in calculated bit posisiton)
  3041                              <1> 	;
  3042                              <1> 	; ((AX = R1)) input/output
  3043                              <1> 	; ((DL/DX = MQ)) output
  3044                              <1> 	; ((BX = R2)) output
  3045                              <1> 	;
  3046                              <1> 	;    (Retro UNIX Prototype : 02/12/2012, UNIXCOPY.ASM)
  3047                              <1>         ;    ((Modified registers: eDX, eCX, eBX, eSI))  
  3048                              <1> 	;
  3049                              <1> 		; / get the byte that has the allocation bit for 
  3050                              <1> 		; / the i-number contained in r1
  3051                              <1> 	;mov	dx, 1
  3052 0000532E B201                <1> 	mov	dl, 1
  3053                              <1> 		; mov $1,mq / put 1 in the mq
  3054 00005330 0FB7D8              <1> 	movzx	ebx, ax
  3055                              <1> 		; mov r1,r2 / r2 now has i-number whose byte
  3056                              <1>  		          ; / in the map we must find
  3057 00005333 6683EB29            <1> 	sub	bx, 41
  3058                              <1> 		; sub $41.,r2 / r2 has i-41
  3059 00005337 88D9                <1> 	mov	cl, bl
  3060                              <1> 		; mov r2,r3 / r3 has i-41
  3061 00005339 80E107              <1> 	and	cl, 7
  3062                              <1> 		; bic $!7,r3 / r3 has (i-41) mod 8 to get 
  3063                              <1> 			   ; / the bit position
  3064 0000533C 7402                <1> 	jz	short imap1
  3065                              <1> 	;shl	dx, cl
  3066 0000533E D2E2                <1> 	shl	dl, cl
  3067                              <1> 		; mov r3,lsh / move the 1 over (i-41) mod 8 positions
  3068                              <1> imap1:			   ; / to the left to mask the correct bit
  3069                              <1> 	; 03/02/2022
  3070 00005340 C1EB03              <1> 	shr	ebx, 3
  3071                              <1> 	;shr	bx, 3
  3072                              <1> 		; asr r2
  3073                              <1> 		; asr r2
  3074                              <1> 		; asr r2 / r2 has (i-41) base 8 of the byte number
  3075                              <1> 		       ; / from the start of the map
  3076                              <1> 		; mov r2,-(sp) / put (i-41) base 8 on the stack
  3077 00005343 BE[587B0000]        <1> 	mov	esi, systm
  3078                              <1> 		; mov $systm,r2 / r2 points to the in-core image of
  3079                              <1> 				; / the super block for drum
  3080                              <1> 	;cmp	word [cdev], 0
  3081 00005348 803D[7F6E0000]00    <1> 	cmp	byte [cdev], 0
  3082                              <1> 		; tst cdev / is the device the disk
  3083 0000534F 7606                <1> 	jna	short imap2
  3084                              <1> 		; beq 1f / yes
  3085 00005351 81C608020000        <1> 	add	esi, mount - systm
  3086                              <1> 		; add $mount-systm,r2 / for mounted device,
  3087                              <1> 			; / r2 points to 1st word of its super block
  3088                              <1> imap2: ; 1:
  3089 00005357 66031E              <1> 	add	bx, [esi] ;; add free map size to si
  3090                              <1> 		; add (r2)+,(sp) / get byte address of allocation bit
  3091 0000535A 6683C304            <1> 	add	bx, 4
  3092 0000535E 01F3                <1> 	add	ebx, esi
  3093                              <1>         	; add (sp)+,r2 / ?
  3094                              <1> 	;add	ebx, 4 ;; inode map offset in superblock
  3095                              <1> 		      ;; (2 + free map size + 2)
  3096                              <1> 		; add $2,r2 / ?
  3097                              <1> 
  3098                              <1> 	; 11/02/2022
  3099 00005360 81C68B010000        <1> 	add	esi, eofitab-1 ; last byte of the inode table in sb
  3100 00005366 39DE                <1> 	cmp	esi, ebx  ; cf will be 1
  3101                              <1> 			  ; if inode num overs inode count
  3102                              <1> 
  3103                              <1>  	; DL/DX (MQ) has a 1 in the calculated bit position
  3104                              <1>         ; BX (R2) has byte address of the byte with allocation bit
  3105                              <1> 
  3106                              <1> 	; 11/02/2022
  3107                              <1> 	; if ebx > last byte of the inode table --> cf = 1
  3108                              <1> 	;	(number of requested inode > inode count)
  3109                              <1> 
  3110 00005368 C3                  <1> 	retn
  3111                              <1> 		; rts r0
  2097                                  %include 'u6.s'        ; 31/05/2015
  2098                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS6.INC
  2099                              <1> ; Last Modification: 03/02/2022
  2100                              <1> ; ----------------------------------------------------------------------------
  2101                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2102                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2103                              <1> ;
  2104                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2105                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2106                              <1> ; <Bell Laboratories (17/3/1972)>
  2107                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2108                              <1> ;
  2109                              <1> ; Retro UNIX 8086 v1 - U6.ASM (23/07/2014) //// UNIX v1 -> u6.s
  2110                              <1> ;
  2111                              <1> ; ****************************************************************************
  2112                              <1> 
  2113                              <1> readi:
  2114                              <1> 	; 11/01/2022
  2115                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2116                              <1> 	; 20/05/2015
  2117                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2118                              <1> 	; 11/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2119                              <1> 	;
  2120                              <1> 	; Reads from an inode whose number in R1
  2121                              <1> 	; 
  2122                              <1> 	; INPUTS ->
  2123                              <1> 	;    r1 - inode number
  2124                              <1> 	;    u.count - byte count user desires
  2125                              <1> 	;    u.base - points to user buffer
  2126                              <1> 	;    u.fofp - points to word with current file offset
  2127                              <1> 	; OUTPUTS ->
  2128                              <1> 	;    u.count - cleared
  2129                              <1> 	;    u.nread - accumulates total bytes passed back
  2130                              <1> 	;
  2131                              <1> 	; ((AX = R1)) input/output
  2132                              <1> 	;    (Retro UNIX Prototype : 01/03/2013 - 14/12/2012, UNIXCOPY.ASM)
  2133                              <1>         ;    ((Modified registers: edx, ebx, ecx, esi, esi, ebp))  
  2134                              <1> 
  2135 00005369 31D2                <1> 	xor	edx, edx ; 0
  2136 0000536B 8915[C06E0000]      <1> 	mov 	[u.nread], edx ; 0
  2137                              <1> 		 ; clr u.nread / accumulates number of bytes transmitted
  2138 00005371 668915[FD6E0000]    <1> 	mov	[u.pcount], dx ; 19/05/2015
  2139 00005378 3915[BC6E0000]      <1> 	cmp 	[u.count], edx ; 0
  2140                              <1> 	         ; tst u.count / is number of bytes to be read greater than 0
  2141 0000537E 7701                <1> 	ja 	short readi_1 ; 1f
  2142                              <1> 		 ; bgt 1f / yes, branch
  2143 00005380 C3                  <1> 	retn
  2144                              <1> 		 ; rts r0 / no, nothing to read; return to caller
  2145                              <1> readi_1: ; 1:
  2146                              <1> 	         ; mov r1,-(sp) / save i-number on stack
  2147 00005381 6683F828            <1> 	cmp	ax, 40
  2148                              <1> 		 ; cmp r1,$40. / want to read a special file 
  2149                              <1> 		 ;             / (i-nodes 1,...,40 are for special files)
  2150                              <1>         ;ja	dskr 
  2151                              <1> 		 ; ble 1f / yes, branch
  2152                              <1> 		 ; jmp dskr / no, jmp to dskr; 
  2153                              <1> 		 ;         / read file with i-node number (r1)
  2154                              <1> 		 ;    / starting at byte ((u.fofp)), read in u.count bytes
  2155                              <1> 	; 24/12/2021
  2156 00005385 7605                <1> 	jna	short readi_3
  2157 00005387 E9CF000000          <1> 	jmp	dskr
  2158                              <1> readi_3:
  2159                              <1> 	; (20/05/2015)
  2160 0000538C 50                  <1> 	push	eax ; because subroutines will jump to 'ret_'
  2161                              <1> 	; 1:
  2162 0000538D 0FB6D8              <1> 	movzx	ebx, al
  2163                              <1> 	; 11/01/2022
  2164 00005390 C1E302              <1> 	shl	ebx, 2
  2165                              <1> 	;shl	bx, 2
  2166                              <1> 		 ; asl r1 / multiply inode number by 2
  2167 00005393 81C3[97530000]      <1> 	add	ebx, readi_2 - 4
  2168 00005399 FF23                <1> 	jmp	dword [ebx]	
  2169                              <1> 		 ; jmp *1f-2(r1)
  2170                              <1> readi_2: ; 1:
  2171 0000539B [E7530000]          <1> 	dd	rtty ; tty, AX = 1 (runix)
  2172                              <1> 		 ;rtty / tty; r1=2
  2173                              <1> 		 ;rppt / ppt; r1=4
  2174 0000539F [37540000]          <1> 	dd	rmem ; mem, AX = 2 (runix)
  2175                              <1> 		 ;rmem / mem; r1=6
  2176                              <1> 		 ;rrf0 / rf0
  2177                              <1> 		 ;rrk0 / rk0
  2178                              <1> 		 ;rtap / tap0
  2179                              <1> 		 ;rtap / tap1
  2180                              <1> 		 ;rtap / tap2
  2181                              <1> 		 ;rtap / tap3
  2182                              <1> 		 ;rtap / tap4
  2183                              <1> 		 ;rtap / tap5
  2184                              <1> 		 ;rtap / tap6
  2185                              <1> 		 ;rtap / tap7
  2186 000053A3 [225B0000]          <1> 	dd	rfd ; fd0, AX = 3 (runix only)
  2187 000053A7 [225B0000]          <1> 	dd	rfd ; fd1, AX = 4 (runix only)
  2188 000053AB [225B0000]          <1> 	dd	rhd ; hd0, AX = 5 (runix only)
  2189 000053AF [225B0000]          <1> 	dd	rhd ; hd1, AX = 6 (runix only)	
  2190 000053B3 [225B0000]          <1> 	dd	rhd ; hd2, AX = 7 (runix only)
  2191 000053B7 [225B0000]          <1> 	dd	rhd ; hd3, AX = 8 (runix only)	
  2192 000053BB [4C540000]          <1> 	dd	rlpr ; lpr, AX = 9 (invalid, write only device !?)
  2193 000053BF [33540000]          <1> 	dd	rcvt ; tty0, AX = 10 (runix)	  
  2194                              <1> 		 ;rcvt / tty0
  2195 000053C3 [33540000]          <1> 	dd	rcvt ; tty1, AX = 11 (runix)	  
  2196                              <1> 		 ;rcvt / tty1
  2197 000053C7 [33540000]          <1> 	dd	rcvt ; tty2, AX = 12 (runix)	  
  2198                              <1> 		 ;rcvt / tty2
  2199 000053CB [33540000]          <1> 	dd	rcvt ; tty3, AX = 13 (runix)	  
  2200                              <1> 		 ;rcvt / tty3
  2201 000053CF [33540000]          <1> 	dd	rcvt ; tty4, AX = 14 (runix)	  
  2202                              <1> 		 ;rcvt / tty4
  2203 000053D3 [33540000]          <1> 	dd	rcvt ; tty5, AX = 15 (runix)	  
  2204                              <1> 		 ;rcvt / tty5
  2205 000053D7 [33540000]          <1> 	dd	rcvt ; tty6, AX = 16 (runix)	  
  2206                              <1> 		 ;rcvt / tty6
  2207 000053DB [33540000]          <1> 	dd	rcvt ; tty7, AX = 17 (runix)	  
  2208                              <1> 		 ;rcvt / tty7
  2209 000053DF [33540000]          <1> 	dd	rcvt ; COM1, AX = 18 (runix only)	  
  2210                              <1> 		 ;rcrd / crd
  2211 000053E3 [33540000]          <1> 	dd	rcvt ; COM2, AX = 19 (runix only)
  2212                              <1> 
  2213                              <1> rtty: ; / read from console tty
  2214                              <1> 	; 11/01/2022
  2215                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2216                              <1> 	; 17/10/2015 - 16/07/2015 (Retro UNIX 8086 v1)
  2217                              <1> 	; 	     (Only 1 byte is read, by ignoring byte count!)
  2218                              <1> 	;  	     WHAT FOR: Every character from Keyboard input 
  2219                              <1> 	;	     must be written immediate on video page (screen)
  2220                              <1> 	;	     when it is required.	
  2221                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2222                              <1> 	; 11/03/2013 - 19/06/2014 (Retro UNIX 8086 v1)
  2223                              <1> 	;
  2224                              <1> 	; Console tty buffer is PC keyboard buffer
  2225                              <1> 	; and keyboard-keystroke handling is different than original
  2226                              <1> 	; unix (PDP-11) here. TTY/Keyboard procedures here are changed
  2227                              <1> 	; according to IBM PC compatible ROM BIOS keyboard functions. 
  2228                              <1> 	;
  2229                              <1> 	; 06/12/2013
  2230 000053E7 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2231 000053EE 8A83[F76B0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2232                              <1> rttys:
  2233                              <1> 		; mov tty+[8*ntty]-8+6,r5 / r5 is the address of the 4th word of
  2234                              <1> 	               ; / of the control and status block
  2235                              <1> 		; tst 2(r5) / for the console tty; this word points to the console
  2236                              <1> 		       ; / tty buffer
  2237                              <1> 	; 28/07/2013
  2238 000053F4 A2[EC6E0000]        <1> 	mov 	[u.ttyn], al
  2239                              <1> 	; 13/01/2014
  2240 000053F9 FEC0                <1> 	inc	al
  2241 000053FB A2[C86E0000]        <1> 	mov	[u.ttyp], al ; tty number + 1
  2242                              <1> rtty_nc: ; 01/02/2014
  2243                              <1> 	; 29/09/2013
  2244                              <1> 	;mov	ecx, 10
  2245                              <1> 	; 11/01/2022
  2246 00005400 29C9                <1> 	sub	ecx, ecx
  2247 00005402 B10A                <1> 	mov	cl, 10
  2248                              <1> rtty_1: 	; 01/02/2014
  2249                              <1> 	;push 	cx ; 29/09/2013
  2250                              <1> 	; 24/12/2021
  2251 00005404 51                  <1> 	push	ecx
  2252                              <1> 	; byte [u.ttyn] = tty number (0 to 9) 
  2253 00005405 B001                <1> 	mov 	al, 1
  2254 00005407 E8660B0000          <1> 	call 	getc
  2255                              <1> 	; 24/12/2021
  2256 0000540C 59                  <1> 	pop	ecx
  2257                              <1> 	;pop 	cx ; 29/09/2013	
  2258 0000540D 7516                <1> 	jnz	short rtty_2
  2259                              <1> 		; bne 1f / 2nd word of console tty buffer contains number
  2260                              <1> 	               ; / of chars. Is this number non-zero?
  2261 0000540F E20D                <1> 	loop	rtty_idle ; 01/02/2014
  2262                              <1> 	; 05/10/2013
  2263 00005411 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn]
  2264                              <1> 	; 29/09/2013
  2265 00005417 E89AFBFFFF          <1> 	call	sleep
  2266                              <1> 		; jsr r0,canon; ttych / if 0, call 'canon' to get a line
  2267                              <1>                 ;           / (120 chars.)
  2268                              <1> 	;byte [u.ttyn] = tty number (0 to 9) 
  2269 0000541C EBE2                <1> 	jmp	short rtty_nc ; 01/02/2014
  2270                              <1> 
  2271                              <1> rtty_idle:
  2272                              <1> 	; 29/07/2013
  2273 0000541E E806FBFFFF          <1> 	call 	idle
  2274 00005423 EBDF                <1> 	jmp	short rtty_1 ; 01/02/2014
  2275                              <1> 	;1:
  2276                              <1> 		; tst 2(r5) / is the number of characters zero
  2277                              <1> 		; beq ret1 / yes, return to caller via 'ret1'
  2278                              <1> 		; movb *4(r5),r1 / no, put character in r1
  2279                              <1> 		; inc 4(r5) / 3rd word of console tty buffer points to byte which
  2280                              <1> 		          ; / contains the next char.
  2281                              <1> 		; dec 2(r5) / decrement the character count
  2282                              <1> rtty_2:
  2283 00005425 30C0                <1> 	xor 	al, al
  2284 00005427 E8460B0000          <1> 	call 	getc
  2285 0000542C E892000000          <1> 	call	passc
  2286                              <1> 		; jsr r0,passc / move the character to core (user)
  2287                              <1> 	;; 17/10/2015 - 16/07/2015
  2288                              <1> 	; 19/06/2014
  2289                              <1> 	;;jnz	short rtty_nc
  2290 00005431 58                  <1> 	pop	eax  ; (20/05/2015)
  2291 00005432 C3                  <1> 	retn 
  2292                              <1> ;ret1:
  2293                              <1> 		; jmp ret / return to caller via 'ret'
  2294                              <1> 
  2295                              <1> rcvt:   ; < receive/read character from tty >
  2296                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2297                              <1> 	; 15/05/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2298                              <1> 	;
  2299                              <1> 	; Retro UNIX 8086 v1 modification !
  2300                              <1> 	; 
  2301                              <1> 	; In original UNIX v1, 'rcvt' routine 
  2302                              <1> 	;		(exactly different than this one)
  2303                              <1> 	;	was in 'u9.s' file.
  2304                              <1> 	;
  2305 00005433 2C0A                <1> 	sub 	al, 10
  2306                              <1> 	; AL = tty number (0 to 9), (COM1=8, COM2=9)
  2307                              <1> 	; 16/07/2013
  2308                              <1> 	; 21/05/2013
  2309 00005435 EBBD                <1>         jmp     short rttys
  2310                              <1>       
  2311                              <1> ;rppt: / read paper tape
  2312                              <1> ;	jsr	r0,pptic / gets next character in clist for ppt input and
  2313                              <1> ;			 / places
  2314                              <1> ;		br ret / it in r1; if there 1s no problem with reader, it
  2315                              <1> ;		       / also enables read bit in prs
  2316                              <1> ;	jsr	r0,passc / place character in users buffer area
  2317                              <1> ;	br	rppt
  2318                              <1> 
  2319                              <1> rmem: ; / transfer characters from memory to a user area of core
  2320                              <1> 	; 17/10/2015
  2321                              <1> 	; 11/06/2015
  2322                              <1> 	; 24/05/2015
  2323                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2324                              <1> 	;
  2325 00005437 8B35[A86E0000]      <1> 	mov     esi, [u.fofp]
  2326                              <1> rmem_1:
  2327 0000543D 8B1E                <1>         mov     ebx, [esi]        
  2328                              <1> 	        ; mov *u.fofp,r1 / save file offset which points to the char
  2329                              <1> 		               ; / to be transferred to user
  2330 0000543F FF06                <1>         inc     dword [esi] ; 17/10/2015
  2331                              <1> 		; inc *u.fofp / increment file offset to point to 'next' 
  2332                              <1> 			    ; / char in memory file
  2333 00005441 8A03                <1> 	mov	al, [ebx]
  2334                              <1> 		; movb (r1),r1 / get character from memory file, 
  2335                              <1> 		             ; / put it in r1
  2336 00005443 E87B000000          <1> 	call	passc        ; jsr r0,passc / move this character to 
  2337                              <1> 			     ;  / the next byte of the users core area
  2338                              <1> 		; br rmem / continue
  2339 00005448 75F3                <1> 	jnz	short rmem_1
  2340                              <1> ret_:
  2341 0000544A 58                  <1> 	pop	eax ; 09/06/2015
  2342 0000544B C3                  <1> 	retn
  2343                              <1> 
  2344                              <1> rlpr:
  2345                              <1> ;1:
  2346                              <1> ;rcrd:
  2347 0000544C C705[ED6E0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY ; 19/05/2015
  2347 00005454 0000                <1>
  2348 00005456 E977E6FFFF          <1> 	jmp	error
  2349                              <1> 		;jmp	error / see 'error' routine
  2350                              <1> 
  2351                              <1> dskr:
  2352                              <1> 	; 12/10/2015
  2353                              <1> 	; 21/08/2015
  2354                              <1> 	; 25/07/2015
  2355                              <1> 	; 10/07/2015
  2356                              <1> 	; 16/06/2015
  2357                              <1> 	; 31/05/2015
  2358                              <1> 	; 24/05/2015 (Retro UNIX 386 v1 - Beginning)
  2359                              <1> 	; 26/04/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2360                              <1> dskr_0:
  2361 0000545B 50                  <1> 	push	eax
  2362                              <1> 		; mov (sp),r1 / i-number in r1
  2363                              <1> 	; AX = i-number
  2364 0000545C E834FDFFFF          <1> 	call	iget
  2365                              <1> 		; jsr r0,iget / get i-node (r1) into i-node section of core
  2366 00005461 0FB715[9C6B0000]    <1>         movzx   edx, word [i.size] ; 16/06/2015
  2367                              <1> 		; mov i.size,r2 / file size in bytes in r2
  2368 00005468 8B1D[A86E0000]      <1> 	mov	ebx, [u.fofp]
  2369 0000546E 2B13                <1> 	sub	edx, [ebx]
  2370                              <1> 		; sub *u.fofp,r2 / subtract file offset
  2371                              <1>         ; 12/10/2015
  2372                              <1> 	; jna     short ret_ 
  2373                              <1> 		; blos ret
  2374 00005470 7709                <1> 	ja	short dskr_1
  2375                              <1> 	;
  2376                              <1> dskr_retn: ; 12/10/2015
  2377 00005472 58                  <1> 	pop	eax
  2378 00005473 C605[FF6E0000]00    <1> 	mov	byte [u.kcall], 0
  2379 0000547A C3                  <1> 	retn	
  2380                              <1> dskr_1: 
  2381 0000547B 3B15[BC6E0000]      <1> 	cmp     edx, [u.count] 
  2382                              <1> 		; cmp r2,u.count / are enough bytes left in file 
  2383                              <1> 			       ; / to carry out read
  2384 00005481 7306                <1> 	jnb	short dskr_2
  2385                              <1> 		; bhis 1f
  2386 00005483 8915[BC6E0000]      <1> 	mov	[u.count], edx
  2387                              <1> 		; mov r2,u.count / no, just read to end of file
  2388                              <1> dskr_2: ; 1:
  2389                              <1> 	; AX = i-number
  2390 00005489 E8A0FBFFFF          <1> 	call	mget
  2391                              <1> 		; jsr r0,mget / returns physical block number of block 
  2392                              <1> 			    ; / in file where offset points
  2393                              <1> 	; eAX = physical block number
  2394 0000548E E8DE070000          <1> 	call	dskrd
  2395                              <1> 		; jsr r0,dskrd / read in block, r5 points to 
  2396                              <1> 			     ; / 1st word of data in buffer
  2397                              <1> 	; 09/06/2015
  2398 00005493 803D[FF6E0000]00    <1> 	cmp	byte [u.kcall], 0 ; the caller is 'namei' sign (=1)
  2399 0000549A 770F                <1> 	ja	short dskr_4	  ; zf=0 -> the caller is 'namei'
  2400 0000549C 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0
  2401 000054A4 7705                <1> 	ja	short dskr_4
  2402                              <1> dskr_3:
  2403                              <1> 	; [u.base] = virtual address to transfer (as destination address)
  2404 000054A6 E853000000          <1> 	call	trans_addr_w ; translate virtual address to physical (w)
  2405                              <1> dskr_4:
  2406                              <1> 	; eBX (r5) = system (I/O) buffer address -physical-
  2407 000054AB E8BC020000          <1> 	call	sioreg
  2408                              <1> 		; jsr r0,sioreg
  2409 000054B0 87F7                <1> 	xchg	esi, edi
  2410                              <1> 	; eDI = file (user data) offset
  2411                              <1> 	; eSI = sector (I/O) buffer offset
  2412                              <1> 	; eCX = byte count
  2413 000054B2 F3A4                <1> 	rep	movsb
  2414                              <1> 		; movb (r2)+,(r1)+ / move data from buffer into working core
  2415                              <1> 		                 ; / starting at u.base
  2416                              <1> 		; dec r3
  2417                              <1> 		; bne 2b / branch until proper number of bytes are transferred
  2418                              <1> 	; 25/07/2015
  2419                              <1> 	; eax = remain bytes in buffer
  2420                              <1>         ;       (check if remain bytes in the buffer > [u.pcount])
  2421 000054B4 09C0                <1> 	or	eax, eax
  2422 000054B6 75EE                <1> 	jnz	short dskr_3 ; (page end before system buffer end!)		
  2423                              <1> 	; 03/08/2013
  2424                              <1> 	;pop	eax
  2425 000054B8 390D[BC6E0000]      <1> 	cmp	[u.count], ecx ; 0
  2426                              <1> 		; tst u.count / all bytes read off disk
  2427                              <1> 		; bne dskr
  2428                              <1> 		; br ret
  2429                              <1>         ;ja	short dskr_0
  2430                              <1> 	;mov	[u.kcall], cl ; 0 ; 09/06/2015
  2431                              <1> 	;retn
  2432                              <1> 	; 12/10/2015
  2433 000054BE 76B2                <1> 	jna	short dskr_retn
  2434 000054C0 58                  <1> 	pop	eax  ; (i-node number)
  2435 000054C1 EB98                <1> 	jmp	short dskr_0
  2436                              <1> 	
  2437                              <1> passc:
  2438                              <1> 	; 18/10/2015
  2439                              <1> 	; 10/07/2015
  2440                              <1> 	; 01/07/2015
  2441                              <1> 	; 08/06/2015
  2442                              <1> 	; 04/06/2015
  2443                              <1> 	; 20/05/2015
  2444                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2445                              <1> 	;
  2446                              <1>    	;(Retro UNIX 386 v1 - translation from user's virtual address
  2447                              <1> 	;		      to physical address
  2448 000054C3 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0 ; byte count in page = 0 (initial value)
  2449                              <1> 			     ; 1-4095 --> use previous physical base address
  2450                              <1> 			     ; in [u.pbase]
  2451 000054CB 7705                <1> 	ja	short passc_3
  2452                              <1> 	; 08/06/2015 - 10/07/2015
  2453 000054CD E82C000000          <1> 	call	trans_addr_w
  2454                              <1> passc_3:
  2455                              <1> 	; 19/05/2015
  2456 000054D2 66FF0D[FD6E0000]    <1> 	dec	word [u.pcount]
  2457                              <1> 	;
  2458 000054D9 8B1D[F96E0000]      <1> 	mov	ebx, [u.pbase]
  2459 000054DF 8803                <1> 	mov	[ebx], al
  2460                              <1> 		; movb r1,*u.base / move a character to the next byte of the
  2461                              <1> 		               ; / users buffer
  2462 000054E1 FF05[B86E0000]      <1> 	inc	dword [u.base]
  2463                              <1> 		; inc u.base / increment the pointer to point to 
  2464                              <1> 			  ; / the next byte in users buffer
  2465 000054E7 FF05[F96E0000]      <1> 	inc	dword [u.pbase] ; 04/06/2015
  2466 000054ED FF05[C06E0000]      <1> 	inc	dword [u.nread]
  2467                              <1> 		; inc u.nread / increment the number of bytes read
  2468 000054F3 FF0D[BC6E0000]      <1> 	dec	dword [u.count]
  2469                              <1> 		; dec u.count / decrement the number of bytes to be read
  2470                              <1> 		; bne 1f / any more bytes to read?; yes, branch
  2471 000054F9 C3                  <1> 	retn
  2472                              <1> 		; mov (sp)+,r0 / no, do a non-local return to the caller of
  2473                              <1> 		             ; / 'readi' by:
  2474                              <1> 		;/ (1) pop the return address off the stack into r0
  2475                              <1> 		; mov (sp)+,r1 / (2) pop the i-number off the stack into r1
  2476                              <1> 	;1:
  2477                              <1> 		; clr	*$ps / clear processor status
  2478                              <1> 		; rts r0 / return to address currently on top of stack
  2479                              <1> 
  2480                              <1> trans_addr_r:
  2481                              <1> 	; Translate virtual address to physical address 
  2482                              <1> 	; for reading from user's memory space
  2483                              <1> 	; (Retro UNIX 386 v1 feature only !)
  2484                              <1> 	; 18/10/2015
  2485                              <1> 	; 10/07/2015
  2486                              <1> 	; 09/06/2015
  2487                              <1> 	; 08/06/2015 
  2488                              <1> 	; 04/06/2015
  2489                              <1> 	;
  2490                              <1> 	; 18/10/2015
  2491 000054FA 31D2                <1> 	xor	edx, edx ; 0 (read access sign)
  2492 000054FC EB04                <1> 	jmp 	short trans_addr_rw
  2493                              <1> 
  2494                              <1> 	;push	eax
  2495                              <1> 	;push	ebx
  2496                              <1> 	;mov	ebx, [u.base]
  2497                              <1> 	;call	get_physical_addr ; get physical address
  2498                              <1> 	;;jnc	short cpass_0
  2499                              <1> 	;jnc	short passc_1
  2500                              <1> 	;mov	[u.error], eax
  2501                              <1> 	;;pop	ebx
  2502                              <1> 	;;pop	eax
  2503                              <1> 	;jmp	error
  2504                              <1> ;cpass_0:
  2505                              <1> 	; 18/10/2015
  2506                              <1> 	; 20/05/2015
  2507                              <1> 	;mov 	[u.pbase], eax ; physical address	
  2508                              <1> 	;mov	[u.pcount], cx ; remain byte count in page (1-4096)
  2509                              <1> 	;pop	ebx
  2510                              <1> 	;pop	eax
  2511                              <1> 	;retn	; 08/06/2015
  2512                              <1> 
  2513                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2514                              <1> trans_addr_w:
  2515                              <1> 	; 31/12/2021
  2516                              <1> 	; Translate virtual address to physical address 
  2517                              <1> 	; for writing to user's memory space
  2518                              <1> 	; (Retro UNIX 386 v1 feature only !)
  2519                              <1> 	; 18/10/2015
  2520                              <1> 	; 29/07/2015
  2521                              <1> 	; 10/07/2015
  2522                              <1> 	; 09/06/2015
  2523                              <1> 	; 08/06/2015
  2524                              <1> 	; 04/06/2015 (passc)
  2525                              <1> 	;
  2526                              <1> 	; 18/10/2015
  2527 000054FE 29D2                <1> 	sub	edx, edx
  2528 00005500 FEC2                <1> 	inc	dl ; 1 (write access sign)
  2529                              <1> trans_addr_rw:
  2530 00005502 50                  <1> 	push	eax
  2531 00005503 53                  <1> 	push	ebx
  2532                              <1> 	; 18/10/2015
  2533 00005504 52                  <1> 	push 	edx ; r/w sign (in DL)
  2534                              <1> 	;
  2535 00005505 8B1D[B86E0000]      <1> 	mov	ebx, [u.base]
  2536 0000550B E892DCFFFF          <1> 	call	get_physical_addr ; get physical address
  2537 00005510 730A                <1> 	jnc	short passc_0
  2538 00005512 A3[ED6E0000]        <1> 	mov	[u.error], eax
  2539                              <1> 	;pop	edx
  2540                              <1> 	;pop 	ebx
  2541                              <1> 	;pop	eax
  2542 00005517 E9B6E5FFFF          <1> 	jmp	error
  2543                              <1> passc_0:
  2544 0000551C F6C202              <1> 	test	dl, PTE_A_WRITE ; writable page ; 18/10/2015
  2545 0000551F 5A                  <1> 	pop	edx ; 18/10/2015
  2546 00005520 7517                <1> 	jnz	short passc_1
  2547                              <1> 	; 18/10/2015
  2548 00005522 20D2                <1> 	and 	dl, dl
  2549 00005524 7413                <1> 	jz	short passc_1
  2550                              <1> 	; 20/05/2015
  2551                              <1> 	; read only (duplicated) page -must be copied to a new page-
  2552                              <1> 	; EBX = linear address
  2553 00005526 51                  <1> 	push 	ecx
  2554 00005527 53                  <1> 	push	ebx ; * ; 31/12/2021 (BugFix)
  2555 00005528 E8E4DBFFFF          <1> 	call 	copy_page
  2556 0000552D 5B                  <1> 	pop	ebx ; * ; 31/12/2021 (BugFix)
  2557 0000552E 59                  <1> 	pop	ecx
  2558 0000552F 7217                <1> 	jc	short passc_2
  2559                              <1> 	; 24/12/2021
  2560                              <1> 	;push	eax ; physical address of the new/allocated page
  2561                              <1> 	;call	add_to_swap_queue
  2562                              <1> 	;pop	eax
  2563                              <1> 	; 18/10/2015
  2564 00005531 81E3FF0F0000        <1> 	and 	ebx, PAGE_OFF ; 0FFFh
  2565                              <1> 	;mov 	ecx, PAGE_SIZE
  2566                              <1> 	;sub	ecx, ebx 
  2567 00005537 01D8                <1> 	add	eax, ebx  
  2568                              <1> passc_1: 
  2569                              <1> 	; 18/10/2015
  2570                              <1> 	; 20/05/2015
  2571 00005539 A3[F96E0000]        <1> 	mov 	[u.pbase], eax ; physical address	
  2572 0000553E 66890D[FD6E0000]    <1> 	mov	[u.pcount], cx ; remain byte count in page (1-4096)
  2573 00005545 5B                  <1> 	pop	ebx
  2574 00005546 58                  <1> 	pop	eax
  2575 00005547 C3                  <1> 	retn	; 08/06/2015
  2576                              <1> passc_2:
  2577 00005548 C705[ED6E0000]0400- <1> 	mov	dword [u.error], ERR_MINOR_IM ; "Insufficient memory !" error
  2577 00005550 0000                <1>
  2578                              <1> 	;pop 	ebx
  2579                              <1> 	;pop	eax
  2580 00005552 E97BE5FFFF          <1> 	jmp	error
  2581                              <1> 
  2582                              <1> writei:
  2583                              <1> 	; 03/02/2022
  2584                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2585                              <1> 	; 20/05/2015
  2586                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2587                              <1> 	; 12/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2588                              <1> 	;
  2589                              <1> 	; Write data to file with inode number in R1
  2590                              <1> 	; 
  2591                              <1> 	; INPUTS ->
  2592                              <1> 	;    r1 - inode number
  2593                              <1> 	;    u.count - byte count to be written
  2594                              <1> 	;    u.base - points to user buffer
  2595                              <1> 	;    u.fofp - points to word with current file offset
  2596                              <1> 	; OUTPUTS ->
  2597                              <1> 	;    u.count - cleared
  2598                              <1> 	;    u.nread - accumulates total bytes passed back	
  2599                              <1> 	; ((AX = R1))
  2600                              <1> 	;    (Retro UNIX Prototype : 18/11/2012 - 11/11/2012, UNIXCOPY.ASM)
  2601                              <1> 	;    ((Modified registers: DX, BX, CX, SI, DI, BP)) 	
  2602                              <1> 
  2603 00005557 31C9                <1> 	xor	ecx, ecx
  2604 00005559 890D[C06E0000]      <1> 	mov 	[u.nread], ecx  ; 0
  2605                              <1> 		; clr u.nread / clear the number of bytes transmitted during
  2606                              <1> 		            ; / read or write calls
  2607 0000555F 66890D[FD6E0000]    <1> 	mov	[u.pcount], cx ; 19/05/2015
  2608 00005566 390D[BC6E0000]      <1> 	cmp 	[u.count], ecx
  2609                              <1> 	;	; tst u.count / test the byte count specified by the user
  2610 0000556C 7701                <1> 	ja 	short writei_1 ; 1f
  2611                              <1> 		; bgt 1f / any bytes to output; yes, branch
  2612 0000556E C3                  <1> 	retn
  2613                              <1> 	;	; rts r0 / no, return - no writing to do
  2614                              <1> writei_1: ;1:
  2615                              <1> 		; mov r1 ,-(sp) / save the i-node number on the stack
  2616 0000556F 6683F828            <1> 	cmp 	ax, 40
  2617                              <1> 		; cmp r1,$40.
  2618                              <1> 		; / does the i-node number indicate a special file?
  2619                              <1> 	;ja	dskw 
  2620                              <1> 		; bgt dskw / no, branch to standard file output
  2621                              <1> 	; 24/12/2021
  2622 00005573 7605                <1> 	jna	short writei_3
  2623 00005575 E9ED000000          <1> 	jmp	dskw
  2624                              <1> writei_3:
  2625                              <1> 	; (20/05/2015)
  2626 0000557A 50                  <1> 	push	eax ; because subroutines will jump to 'wret'
  2627 0000557B 0FB6D8              <1> 	movzx	ebx, al
  2628                              <1> 	; 03/02/2022
  2629 0000557E C1E302              <1> 	shl	ebx, 2
  2630                              <1> 	;shl	bx, 2
  2631                              <1> 		; asl r1 / yes, calculate the index into the special file
  2632 00005581 81C3[85550000]      <1> 	add	ebx, writei_2 - 4
  2633 00005587 FF23                <1> 	jmp	dword [ebx]	
  2634                              <1> 		; jmp *1f-2(r1)
  2635                              <1> 		; / jump table and jump to the appropriate routine
  2636                              <1> writei_2: ;1:
  2637 00005589 [D5550000]          <1> 	dd	wtty ; tty, AX = 1 (runix)
  2638                              <1> 		 ;wtty / tty; r1=2
  2639                              <1> 		 ;wppt / ppt; r1=4
  2640 0000558D [37560000]          <1> 	dd	wmem ; mem, AX = 2 (runix)
  2641                              <1> 		 ;wmem / mem; r1=6
  2642                              <1> 		 ;wrf0 / rf0
  2643                              <1> 		 ;wrk0 / rk0
  2644                              <1> 		 ;wtap / tap0
  2645                              <1> 		 ;wtap / tap1
  2646                              <1> 		 ;wtap / tap2
  2647                              <1> 		 ;wtap / tap3
  2648                              <1> 		 ;wtap / tap4
  2649                              <1> 		 ;wtap / tap5
  2650                              <1> 		 ;wtap / tap6
  2651                              <1> 		 ;wtap / tap7
  2652 00005591 [AB5B0000]          <1> 	dd	wfd ; fd0, AX = 3 (runix only)
  2653 00005595 [AB5B0000]          <1> 	dd	wfd ; fd1, AX = 4 (runix only)
  2654 00005599 [AB5B0000]          <1> 	dd	whd ; hd0, AX = 5 (runix only)
  2655 0000559D [AB5B0000]          <1> 	dd	whd ; hd1, AX = 6 (runix only)	
  2656 000055A1 [AB5B0000]          <1> 	dd	whd ; hd2, AX = 7 (runix only)
  2657 000055A5 [AB5B0000]          <1> 	dd	whd ; hd3, AX = 8 (runix only)	
  2658 000055A9 [28560000]          <1> 	dd	wlpr ; lpr, AX = 9   (runix)
  2659 000055AD [22560000]          <1> 	dd	xmtt ; tty0, AX = 10 (runix)	  
  2660                              <1> 		 ;xmtt / tty0
  2661 000055B1 [22560000]          <1> 	dd	xmtt ; tty1, AX = 11 (runix)	  
  2662                              <1> 		 ;xmtt / tty1
  2663 000055B5 [22560000]          <1> 	dd	xmtt ; tty2, AX = 12 (runix)	  
  2664                              <1> 		 ;xmtt / tty2
  2665 000055B9 [22560000]          <1> 	dd	xmtt ; tty3, AX = 13 (runix)	  
  2666                              <1> 		 ;xmtt / tty3
  2667 000055BD [22560000]          <1> 	dd	xmtt ; tty4, AX = 14 (runix)	  
  2668                              <1> 		 ;xmtt / tty4
  2669 000055C1 [22560000]          <1> 	dd	xmtt ; tty5, AX = 15 (runix)	  
  2670                              <1> 		 ;xmtt / tty5
  2671 000055C5 [22560000]          <1> 	dd	xmtt ; tty6, AX = 16 (runix)	  
  2672                              <1> 		 ;xmtt / tty6
  2673 000055C9 [22560000]          <1> 	dd	xmtt ; tty7, AX = 17 (runix)	  
  2674                              <1> 		 ;xmtt / tty7
  2675 000055CD [22560000]          <1> 	dd	xmtt ; COM1, AX = 18 (runix only)	  
  2676                              <1> 		; / wlpr / lpr
  2677 000055D1 [22560000]          <1> 	dd	xmtt ; COM2, AX = 19 (runix only)	
  2678                              <1> 
  2679                              <1> wtty: ; write to console tty (write to screen)
  2680                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2681                              <1> 	; 18/11/2015
  2682                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2683                              <1> 	; 12/03/2013 - 07/07/2014 (Retro UNIX 8086 v1)
  2684                              <1> 	;
  2685                              <1> 	; Console tty output is on current video page
  2686                              <1> 	; Console tty character output procedure is changed here
  2687                              <1> 	; acconding to IBM PC compatible ROM BIOS video (text mode) functions.
  2688                              <1> 	;
  2689 000055D5 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2690 000055DC 8AA3[F76B0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; current/console tty
  2691 000055E2 88E0                <1> 	mov	al, ah ; 07/07/2014
  2692                              <1> wttys:	
  2693                              <1> 	; 10/10/2013
  2694 000055E4 8825[EC6E0000]      <1> 	mov 	[u.ttyn], ah
  2695                              <1> 	; 13/01/2014
  2696 000055EA FEC0                <1> 	inc	al
  2697 000055EC A2[C96E0000]        <1> 	mov	[u.ttyp+1], al ; tty number + 1
  2698                              <1> wtty_nc: ; 15/05/2013
  2699                              <1> 	; AH = [u.ttyn] = tty number ; 28/07/2013
  2700 000055F1 E816010000          <1> 	call	cpass
  2701                              <1> 		; jsr r0,cpass / get next character from user buffer area; if
  2702                              <1> 		             ; / none go to return address in syswrite
  2703                              <1> 		; tst r1 / is character = null
  2704                              <1> 		; beq wtty / yes, get next character
  2705                              <1> 	; 10/10/2013
  2706 000055F6 7428                <1> 	jz	short wret
  2707                              <1> 	;1 : 
  2708                              <1> 		;mov 	$240,*$ps / no, set processor priority to five
  2709                              <1> 		;cmpb	cc+1,$20. / is character count for console tty greater
  2710                              <1> 		;	          / than 20
  2711                              <1> 		;bhis	2f / yes; branch to put process to sleep
  2712                              <1> 	; 27/06/2014
  2713                              <1> wtty_1:
  2714                              <1> 	; AH = tty number
  2715                              <1> 	; AL = ASCII code of the character
  2716                              <1> 	; 15/04/2014
  2717                              <1> 	;push	ax
  2718                              <1> 	; 24/12/2021
  2719 000055F8 50                  <1> 	push	eax
  2720 000055F9 E8E2090000          <1> 	call	putc ; 14/05/2013
  2721 000055FE 731D                <1> 	jnc	short wtty_2
  2722                              <1> 	; 18/11/2015
  2723 00005600 E824F9FFFF          <1> 	call	idle
  2724                              <1> 	;mov	ax, [esp]
  2725                              <1> 	; 24/12/2021
  2726 00005605 8B0424              <1> 	mov	eax, [esp]
  2727 00005608 E8D3090000          <1> 	call	putc
  2728 0000560D 730E                <1> 	jnc	short wtty_2 
  2729                              <1> 	; 02/06/2014
  2730 0000560F 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn]
  2731 00005615 E89CF9FFFF          <1> 	call	sleep
  2732                              <1> 	;pop	ax
  2733                              <1> 	; 24/12/2021
  2734 0000561A 58                  <1> 	pop	eax
  2735 0000561B EBDB                <1> 	jmp 	short wtty_1
  2736                              <1> 		; jc 	error ; 15/05/2013 (COM1 or COM2 serial port error)
  2737                              <1> 		; jsr 	r0,putc; 1 / find place in freelist to assign to 
  2738                              <1> 			      ; / console tty and
  2739                              <1> 		; br 	2f / place character in list; if none available
  2740                              <1> 		   	  ; / branch to put process to sleep
  2741                              <1> 		; jsr	r0,startty / attempt to output character on tty
  2742                              <1> wtty_2:
  2743                              <1> 	; 15/04/2014
  2744                              <1> 	;pop	ax
  2745                              <1> 	; 24/12/2021
  2746 0000561D 58                  <1> 	pop	eax
  2747 0000561E EBD1                <1> 	jmp	short wtty_nc
  2748                              <1> 		; br wtty
  2749                              <1> wret:	; 10/10/2013 (20/05/2015)
  2750 00005620 58                  <1> 	pop	eax
  2751 00005621 C3                  <1> 	retn
  2752                              <1> 	;2:
  2753                              <1> 		;mov	r1,-(sp) / place character on stack
  2754                              <1> 		;jsr	r0,sleep; 1 / put process to sleep
  2755                              <1> 		;mov	(sp)+,r1 / remove character from stack
  2756                              <1> 		;br	1b / try again to place character in clist and output
  2757                              <1> 
  2758                              <1> xmtt:   ; < send/write character to tty >
  2759                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2760                              <1> 	; 15/05/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2761                              <1> 	;
  2762                              <1> 	; Retro UNIX 8086 v1 modification !
  2763                              <1> 	; 
  2764                              <1> 	; In original UNIX v1, 'xmtt' routine 
  2765                              <1> 	;		(exactly different than this one)
  2766                              <1> 	;	was in 'u9.s' file.
  2767                              <1> 	;
  2768 00005622 2C0A                <1> 	sub 	al, 10
  2769                              <1> 	; AL = tty number (0 to 9), (COM1=8, COM2=9)
  2770                              <1> 	; 10/10/2013
  2771 00005624 88C4                <1> 	mov	ah, al
  2772                              <1> 	; 28/07/2013
  2773 00005626 EBBC                <1> 	jmp	short wttys
  2774                              <1> 
  2775                              <1> ;wppt:
  2776                              <1> ;	jsr	r0,cpass / get next character from user buffer area,
  2777                              <1> ;		         / if none return to writei's calling routine
  2778                              <1> ;	jsr	r0,pptoc / output character on ppt
  2779                              <1> ;	br	wppt
  2780                              <1> wlpr:
  2781 00005628 C705[ED6E0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY ; 19/05/2015
  2781 00005630 0000                <1>
  2782 00005632 E99BE4FFFF          <1> 	jmp 	error   ; ... Printing procedure will be located here ...
  2783                              <1> 		;/	jsr	r0,cpass
  2784                              <1> 		;/	cmp	r0,$'a
  2785                              <1> 		;/	blo	1f
  2786                              <1> 		;/	cmp	r1,$'z
  2787                              <1> 		;/	bhi	1f
  2788                              <1> 		;/	sub	$40,r1
  2789                              <1> 		;/1:
  2790                              <1> 		;/	jsr	r0,lptoc
  2791                              <1> 		;/	br	wlpr
  2792                              <1> 		; br rmem / continue
  2793                              <1> 
  2794                              <1> wmem: ; / transfer characters from a user area of core to memory file
  2795                              <1> 	; 17/10/2015
  2796                              <1> 	; 11/06/2015
  2797                              <1> 	; 24/05/2015
  2798                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2799                              <1> 	;
  2800 00005637 813D[11070000]-     <1> 	cmp	dword [x_timer], clock ; multi tasking clock/timer
  2800 0000563D [4C4F0000]          <1>
  2801 00005641 7415                <1>         je      short wmem_acc_err
  2802                              <1> 	;
  2803 00005643 8B35[A86E0000]      <1>         mov     esi, [u.fofp] 
  2804                              <1> wmem_1:
  2805 00005649 E8BE000000          <1> 	call	cpass
  2806                              <1> 		; jsr r0,cpass / get next character from users area of
  2807                              <1> 			     ; / core and put it in r1
  2808                              <1>         	; mov r1,-(sp) / put character on the stack
  2809                              <1> 	; 20/09/2013
  2810 0000564E 74D0                <1> 	jz	short wret ; wmem_2  
  2811 00005650 8B1E                <1>         mov     ebx, [esi]
  2812                              <1> 		; mov *u.fofp,r1 / save file offset in r1
  2813 00005652 FF06                <1>         inc     dword [esi] ; 17/10/2015
  2814                              <1> 		; inc *u.fofp / increment file offset to point to next
  2815                              <1> 			    ; / available location in file
  2816 00005654 8803                <1> 	mov	[ebx], al	
  2817                              <1> 		; movb (sp)+,(r1) / pop char off stack, put in memory loc 
  2818                              <1> 			        ; / assigned to it
  2819 00005656 EBF1                <1> 	jmp	short wmem_1
  2820                              <1> 		; br wmem / continue
  2821                              <1> 	;1:
  2822                              <1> 	;jmp	error / ?
  2823                              <1> ;wmem_2:	
  2824                              <1> ;	; 20/09/2013
  2825                              <1> ;	pop	ax
  2826                              <1> ;	retn
  2827                              <1> 
  2828                              <1> wmem_acc_err:
  2829 00005658 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  2829 00005660 0000                <1>
  2830 00005662 E96BE4FFFF          <1> 	jmp	error
  2831                              <1> 
  2832                              <1> 
  2833                              <1> dskw: ; / write routine for non-special files
  2834                              <1> 	;
  2835                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2836                              <1> 	; 25/07/2015
  2837                              <1> 	; 16/06/2015
  2838                              <1> 	; 09/06/2015
  2839                              <1> 	; 31/05/2015 (Retro UNIX 386 v1 - Beginning)
  2840                              <1> 	; 26/04/2013 - 20/09/2013 (Retro UNIX 8086 v1)
  2841                              <1> 	;
  2842                              <1> 	; 01/08/2013 (mkdir_w check)
  2843                              <1> 
  2844                              <1> 	;push	ax ; 26/04/2013
  2845                              <1> 		; mov (sp),r1 / get an i-node number from the stack into r1
  2846                              <1> 	; 24/12/2021
  2847 00005667 50                  <1> 	push	eax
  2848                              <1> 	; AX = inode number
  2849 00005668 E828FBFFFF          <1> 	call	iget
  2850                              <1> 		; jsr r0,iget / write i-node out (if modified), 
  2851                              <1> 		            ; / read i-node 'r1' into i-node area of core
  2852 0000566D 8B1D[A86E0000]      <1>         mov     ebx, [u.fofp] 
  2853 00005673 8B13                <1> 	mov 	edx, [ebx]
  2854                              <1> 		; mov *u.fofp,r2 / put the file offset [(u.off) or the offset
  2855                              <1> 			       ; / in the fsp entry for this file] in r2
  2856 00005675 0315[BC6E0000]      <1> 	add 	edx, [u.count]	
  2857                              <1> 		; add u.count,r2 / no. of bytes to be written
  2858                              <1> 			       ; / + file offset is put in r2
  2859                              <1> 	; 16/06/2015        
  2860 0000567B 81FAFFFF0000        <1> 	cmp	edx, 65535 ; file size limit (for UNIX v1 file system)
  2861 00005681 760F                <1> 	jna	short dskw_0
  2862 00005683 C705[ED6E0000]1400- <1> 	mov	dword [u.error], ERR_FILE_SIZE ; 'file size error !'
  2862 0000568B 0000                <1>
  2863 0000568D E940E4FFFF          <1> 	jmp	error
  2864                              <1> dskw_0:	
  2865 00005692 663B15[9C6B0000]    <1> 	cmp     dx, [i.size]
  2866                              <1> 		; cmp r2,i.size / is this greater than the present size of
  2867                              <1> 		              ; / the file?
  2868 00005699 760C                <1> 	jna	short dskw_1
  2869                              <1> 		; blos 1f / no, branch
  2870 0000569B 668915[9C6B0000]    <1>         mov     [i.size], dx
  2871                              <1> 	 	; mov r2,i.size / yes, increase the file size to 
  2872                              <1> 			      ; / file offset + no. of data bytes
  2873 000056A2 E8F8FBFFFF          <1> 	call	setimod
  2874                              <1> 	 	; jsr r0,setimod / set imod=1 (i.e., core inode has been
  2875                              <1> 		          ; / modified), stuff time of modification into
  2876                              <1> 	          	  ; / core image of i-node
  2877                              <1> dskw_1: ; 1:	
  2878 000056A7 E882F9FFFF          <1> 	call	mget
  2879                              <1> 	; eAX = Block number
  2880                              <1> 		; jsr r0,mget / get the block no. in which to write 
  2881                              <1> 			    ; /	the next data byte
  2882                              <1> 	; eax = block number
  2883 000056AC 8B1D[A86E0000]      <1> 	mov     ebx, [u.fofp]
  2884 000056B2 8B13                <1> 	mov	edx, [ebx]
  2885 000056B4 81E2FF010000        <1> 	and	edx, 1FFh  
  2886                              <1> 		; bit *u.fofp,$777 / test the lower 9 bits of the file offset
  2887 000056BA 750C                <1> 	jnz	short dskw_2
  2888                              <1> 		; bne 2f / if its non-zero, branch; if zero, file offset = 0,
  2889                              <1> 		       ; / 512, 1024,...(i.e., start of new block)
  2890 000056BC 813D[BC6E0000]0002- <1> 	cmp	dword [u.count], 512
  2890 000056C4 0000                <1>
  2891                              <1> 		; cmp u.count,$512. / if zero, is there enough data to fill
  2892                              <1> 				  ; / an entire block? (i.e., no. of
  2893 000056C6 7305                <1> 	jnb	short dskw_3
  2894                              <1> 		; bhis 3f / bytes to be written greater than 512.? 
  2895                              <1> 			; / Yes, branch. Don't have to read block
  2896                              <1> dskw_2: ; 2: / in as no past info. is to be saved (the entire block will be
  2897                              <1>    		; / overwritten).
  2898 000056C8 E8A4050000          <1> 	call	dskrd
  2899                              <1> 		; jsr r0,dskrd / no, must retain old info.. 
  2900                              <1> 			     ; / Hence, read block 'r1' into an I/O buffer
  2901                              <1> dskw_3: ; 3:
  2902                              <1> 	; eAX (r1) = block/sector number
  2903 000056CD E811060000          <1> 	call	wslot
  2904                              <1> 		; jsr r0,wslot / set write and inhibit bits in I/O queue, 
  2905                              <1> 			   ; / proc. status=0, r5 points to 1st word of data
  2906 000056D2 803D[FF6E0000]00    <1> 	cmp	byte [u.kcall], 0
  2907 000056D9 770F                <1> 	ja	short dskw_5 ; zf=0 -> the caller is 'mkdir'
  2908                              <1> 	;
  2909 000056DB 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0
  2910 000056E3 7705                <1> 	ja	short dskw_5
  2911                              <1> dskw_4:
  2912                              <1> 	; [u.base] = virtual address to transfer (as source address)
  2913 000056E5 E810FEFFFF          <1> 	call	trans_addr_r ; translate virtual address to physical (r)
  2914                              <1> dskw_5:
  2915                              <1> 	; eBX (r5) = system (I/O) buffer address
  2916 000056EA E87D000000          <1> 	call	sioreg
  2917                              <1> 		; jsr r0,sioreg / r3 = no. of bytes of data, 
  2918                              <1> 			     ; / r1 = address of data, r2 points to location
  2919                              <1> 			     ; / in buffer in which to start writing data
  2920                              <1> 	; eSI = file (user data) offset
  2921                              <1> 	; eDI = sector (I/O) buffer offset
  2922                              <1> 	; eCX = byte count
  2923                              <1> 	;
  2924 000056EF F3A4                <1>   	rep	movsb
  2925                              <1> 		; movb (r1 )+,(r2)+ 
  2926                              <1> 		         ; / transfer a byte of data to the I/O buffer
  2927                              <1> 		; dec r3 / decrement no. of bytes to be written
  2928                              <1> 		; bne 2b / have all bytes been transferred? No, branch
  2929                              <1> 	; 25/07/2015
  2930                              <1> 	; eax = remain bytes in buffer
  2931                              <1>         ;       (check if remain bytes in the buffer > [u.pcount])
  2932 000056F1 09C0                <1> 	or	eax, eax
  2933 000056F3 75F0                <1> 	jnz	short dskw_4 ; (page end before system buffer end!)	
  2934                              <1> dskw_6:
  2935 000056F5 E805060000          <1> 	call	dskwr
  2936                              <1> 		; jsr r0,dskwr / yes, write the block and the i-node
  2937 000056FA 833D[BC6E0000]00    <1>         cmp     dword [u.count], 0
  2938                              <1> 		; tst u.count / any more data to write?
  2939 00005701 77A4                <1> 	ja	short dskw_1
  2940                              <1> 		; bne 1b / yes, branch
  2941                              <1> 	; 03/08/2013
  2942 00005703 C605[FF6E0000]00    <1> 	mov	byte [u.kcall], 0
  2943                              <1> 	; 20/09/2013 (;;)
  2944                              <1> 	;pop	ax
  2945                              <1> 	; 24/12/2021
  2946 0000570A 58                  <1> 	pop	eax
  2947 0000570B C3                  <1> 	retn
  2948                              <1> 	;;jmp 	short dskw_ret 
  2949                              <1> 	        ; jmp ret / no, return to the caller via 'ret'
  2950                              <1> 
  2951                              <1> cpass: ; / get next character from user area of core and put it in r1
  2952                              <1> 	; 18/10/2015
  2953                              <1> 	; 10/10/2015
  2954                              <1> 	; 10/07/2015
  2955                              <1> 	; 02/07/2015
  2956                              <1> 	; 01/07/2015
  2957                              <1> 	; 24/06/2015
  2958                              <1> 	; 08/06/2015
  2959                              <1> 	; 04/06/2015
  2960                              <1> 	; 20/05/2015
  2961                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2962                              <1> 	;
  2963                              <1> 	; INPUTS -> 
  2964                              <1> 	;     [u.base] = virtual address in user area
  2965                              <1> 	;     [u.count] = byte count (max.)
  2966                              <1> 	;     [u.pcount] = byte count in page (0 = reset)		
  2967                              <1> 	; OUTPUTS -> 
  2968                              <1> 	;     AL = the character which is pointed by [u.base]
  2969                              <1> 	;     zf = 1 -> transfer count has been completed	
  2970                              <1>         ;
  2971                              <1> 	; ((Modified registers:  EAX, EDX, ECX))
  2972                              <1> 	;
  2973                              <1> 	;
  2974 0000570C 833D[BC6E0000]00    <1> 	cmp 	dword [u.count], 0  ; 14/08/2013
  2975                              <1> 		; tst u.count / have all the characters been transferred
  2976                              <1> 			    ; / (i.e., u.count, # of chars. left
  2977 00005713 763F                <1> 	jna	short cpass_3
  2978                              <1> 		; beq 1f / to be transferred = 0?) yes, branch
  2979 00005715 FF0D[BC6E0000]      <1> 	dec	dword [u.count]
  2980                              <1> 		; dec u.count / no, decrement u.count
  2981                              <1>         ; 19/05/2015 
  2982                              <1> 	;(Retro UNIX 386 v1 - translation from user's virtual address
  2983                              <1> 	;		      to physical address
  2984 0000571B 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0 ; byte count in page = 0 (initial value)
  2985                              <1> 			     ; 1-4095 --> use previous physical base address
  2986                              <1> 			     ; in [u.pbase]
  2987 00005723 770E                <1> 	ja	short cpass_1
  2988                              <1> 	; 02/07/2015
  2989 00005725 833D[F56E0000]00    <1>         cmp     dword [u.ppgdir], 0  ; is the caller os kernel
  2990 0000572C 7427                <1>         je      short cpass_k       ; (sysexec, '/etc/init') ? 
  2991                              <1> 	; 08/06/2015 - 10/07/2015
  2992 0000572E E8C7FDFFFF          <1> 	call	trans_addr_r
  2993                              <1> cpass_1:
  2994                              <1> 	; 02/07/2015
  2995                              <1> 	; 24/06/2015
  2996 00005733 66FF0D[FD6E0000]    <1> 	dec	word [u.pcount]
  2997                              <1> cpass_2: 
  2998                              <1> 	; 10/10/2015
  2999                              <1> 	; 02/07/2015
  3000 0000573A 8B15[F96E0000]      <1> 	mov	edx, [u.pbase]
  3001 00005740 8A02                <1> 	mov	al, [edx] ; 10/10/2015
  3002                              <1> 		; movb *u.base,r1 / take the character pointed to 
  3003                              <1> 				; / by u.base and put it in r1
  3004 00005742 FF05[C06E0000]      <1> 	inc	dword [u.nread]
  3005                              <1> 		; inc u.nread / increment no. of bytes transferred
  3006 00005748 FF05[B86E0000]      <1> 	inc	dword [u.base]
  3007                              <1> 		; inc u.base / increment the buffer address to point to the
  3008                              <1> 			   ; / next byte
  3009 0000574E FF05[F96E0000]      <1> 	inc	dword [u.pbase] ; 04/06/2015
  3010                              <1> cpass_3:
  3011 00005754 C3                  <1> 	retn
  3012                              <1> 		; rts	r0 / next byte
  3013                              <1> 	; 1: 
  3014                              <1> 		; mov (sp)+,r0 
  3015                              <1> 		         ; / put return address of calling routine into r0
  3016                              <1> 		; mov (sp)+,r1 / i-number in r1
  3017                              <1> 		; rts r0 / non-local return
  3018                              <1> cpass_k:
  3019                              <1> 	; 02/07/2015
  3020                              <1> 	; The caller is os kernel 
  3021                              <1> 	; (get sysexec arguments from kernel's memory space)
  3022                              <1> 	;
  3023 00005755 8B1D[B86E0000]      <1> 	mov	ebx, [u.base]
  3024 0000575B 66C705[FD6E0000]00- <1>         mov     word [u.pcount], PAGE_SIZE ; 4096
  3024 00005763 10                  <1>
  3025 00005764 891D[F96E0000]      <1> 	mov	[u.pbase], ebx
  3026 0000576A EBCE                <1> 	jmp	short cpass_2
  3027                              <1> 	
  3028                              <1> sioreg: 
  3029                              <1> 	; 25/07/2015
  3030                              <1> 	; 18/07/2015
  3031                              <1> 	; 02/07/2015
  3032                              <1> 	; 17/06/2015
  3033                              <1> 	; 09/06/2015
  3034                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  3035                              <1> 	; 12/03/2013 - 22/07/2013 (Retro UNIX 8086 v1)
  3036                              <1> 	;
  3037                              <1> 	; INPUTS -> 
  3038                              <1> 	;     eBX = system buffer (data) address (r5)
  3039                              <1> 	;     [u.fofp] = pointer to file offset pointer
  3040                              <1> 	;     [u.base] = virtual address of the user buffer
  3041                              <1> 	;     [u.pbase] = physical address of the user buffer
  3042                              <1> 	;     [u.count] = byte count
  3043                              <1> 	;     [u.pcount] = byte count within page frame 			
  3044                              <1> 	; OUTPUTS -> 
  3045                              <1> 	;     eSI = user data offset (r1)
  3046                              <1> 	;     eDI = system (I/O) buffer offset (r2)
  3047                              <1> 	;     eCX = byte count (r3)
  3048                              <1> 	;     EAX = remain bytes after byte count within page frame
  3049                              <1> 	;	(If EAX > 0, transfer will continue from the next page)
  3050                              <1>         ;
  3051                              <1> 	; ((Modified registers:  EDX))
  3052                              <1>  
  3053 0000576C 8B35[A86E0000]      <1>         mov     esi, [u.fofp]
  3054 00005772 8B3E                <1>         mov     edi, [esi]
  3055                              <1> 		; mov *u.fofp,r2 / file offset (in bytes) is moved to r2
  3056 00005774 89F9                <1> 	mov	ecx, edi
  3057                              <1> 		; mov r2,r3 / and also to r3
  3058 00005776 81C900FEFFFF        <1> 	or	ecx, 0FFFFFE00h
  3059                              <1> 		; bis $177000,r3 / set bits 9,...,15 of file offset in r3
  3060 0000577C 81E7FF010000        <1> 	and	edi, 1FFh
  3061                              <1> 		; bic $!777,r2 / calculate file offset mod 512.
  3062 00005782 01DF                <1> 	add	edi, ebx ; EBX = system buffer (data) address
  3063                              <1> 		; add r5,r2 / r2 now points to 1st byte in system buffer
  3064                              <1> 			  ; / where data is to be placed
  3065                              <1>                 ; mov u.base,r1 / address of data is in r1
  3066 00005784 F7D9                <1> 	neg	ecx
  3067                              <1> 		; neg r3 / 512 - file offset (mod512.) in r3 
  3068                              <1> 		       ; / (i.e., the no. of free bytes in the file block)
  3069 00005786 3B0D[BC6E0000]      <1> 	cmp	ecx, [u.count]
  3070                              <1> 		; cmp r3,u.count / compare this with the no. of data bytes
  3071                              <1> 			       ; / to be written to the file
  3072 0000578C 7606                <1> 	jna	short sioreg_0
  3073                              <1> 		; blos	2f / if less than branch. Use the no. of free bytes
  3074                              <1> 			 ; / in the file block as the number to be written
  3075 0000578E 8B0D[BC6E0000]      <1> 	mov	ecx, [u.count]
  3076                              <1> 		; mov u.count,r3 / if greater than, use the no. of data 
  3077                              <1> 			       ; / bytes as the number to be written
  3078                              <1> sioreg_0:
  3079                              <1> 	; 17/06/2015
  3080 00005794 803D[FF6E0000]00    <1> 	cmp	byte [u.kcall], 0 
  3081 0000579B 7613                <1> 	jna	short sioreg_1
  3082                              <1> 	; 25/07/2015
  3083                              <1> 	; the caller is 'mkdir' or 'namei'
  3084 0000579D A1[B86E0000]        <1> 	mov	eax, [u.base] ; 25/07/2015
  3085 000057A2 A3[F96E0000]        <1> 	mov 	[u.pbase], eax ; physical address = virtual address
  3086 000057A7 66890D[FD6E0000]    <1> 	mov	word [u.pcount], cx ; remain bytes in buffer (1 sector)
  3087 000057AE EB0B                <1> 	jmp	short sioreg_2
  3088                              <1> sioreg_1:
  3089                              <1> 	; 25/07/2015
  3090                              <1> 	; 18/07/2015
  3091                              <1> 	; 09/06/2015 
  3092 000057B0 0FB715[FD6E0000]    <1> 	movzx	edx, word [u.pcount]
  3093                              <1> 		; ecx and [u.pcount] are always > 0, here
  3094 000057B7 39D1                <1> 	cmp	ecx, edx	
  3095 000057B9 772A                <1> 	ja	short sioreg_4 ; transfer count > [u.pcount]
  3096                              <1> sioreg_2: ; 2:
  3097 000057BB 31C0                <1> 	xor 	eax, eax ; 25/07/2015
  3098                              <1> sioreg_3:
  3099 000057BD 010D[C06E0000]      <1> 	add 	[u.nread], ecx
  3100                              <1> 		; add r3,u.nread / r3 + number of bytes xmitted 
  3101                              <1> 			         ; / during write is put into u.nread
  3102 000057C3 290D[BC6E0000]      <1> 	sub 	[u.count], ecx
  3103                              <1> 		; sub r3,u.count / u.count = no. of bytes that still 
  3104                              <1> 			       ; / must be written or read
  3105 000057C9 010D[B86E0000]      <1> 	add 	[u.base], ecx
  3106                              <1> 		; add r3,u.base / u.base points to the 1st of the remaining
  3107                              <1> 			      ; / data bytes
  3108 000057CF 010E                <1>         add 	[esi], ecx 
  3109                              <1> 		; add r3,*u.fofp / new file offset = number of bytes done
  3110                              <1> 			       ; / + old file offset
  3111                              <1> 	; 25/07/2015
  3112 000057D1 8B35[F96E0000]      <1> 	mov	esi, [u.pbase]
  3113 000057D7 66290D[FD6E0000]    <1> 	sub	[u.pcount], cx
  3114 000057DE 010D[F96E0000]      <1> 	add	[u.pbase], ecx
  3115 000057E4 C3                  <1>         retn
  3116                              <1> 		; rts r0
  3117                              <1> 		; transfer count > [u.pcount]
  3118                              <1> sioreg_4:
  3119                              <1> 	; 25/07/2015
  3120                              <1> 	; transfer count > [u.pcount] 
  3121                              <1> 	; (ecx > edx)
  3122 000057E5 89C8                <1> 	mov	eax, ecx
  3123 000057E7 29D0                <1> 	sub	eax, edx ; remain bytes for 1 sector (block) transfer 
  3124 000057E9 89D1                <1> 	mov	ecx, edx ; current transfer count = [u.pcount]
  3125 000057EB EBD0                <1> 	jmp	short sioreg_3
  2098                                  %include 'u7.s'        ; 18/04/2015
  2099                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS7.INC
  2100                              <1> ; Last Modification: 03/03/2022
  2101                              <1> ; ----------------------------------------------------------------------------
  2102                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2103                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2104                              <1> ;
  2105                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2106                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2107                              <1> ; <Bell Laboratories (17/3/1972)>
  2108                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2109                              <1> ;
  2110                              <1> ; Retro UNIX 8086 v1 - U7.ASM (13/07/2014) //// UNIX v1 -> u7.s
  2111                              <1> ;
  2112                              <1> ; ****************************************************************************
  2113                              <1> 
  2114                              <1> sysmount: ; / mount file system; args special; name
  2115                              <1> 	; 09/02/2022
  2116                              <1> 	; 08/02/2022
  2117                              <1> 	; 07/02/2022
  2118                              <1> 	; 11/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2119                              <1> 	; 14/11/2015
  2120                              <1> 	; 24/10/2015
  2121                              <1> 	; 13/10/2015
  2122                              <1> 	; 10/07/2015
  2123                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  2124                              <1> 	; 09/07/2013 - 04/11/2013 (Retro UNIX 8086 v1)
  2125                              <1> 	;
  2126                              <1> 	; 'sysmount' anounces to the system that a removable 
  2127                              <1> 	; file system has been mounted on a special file.
  2128                              <1> 	; The device number of the special file is obtained via
  2129                              <1> 	; a call to 'getspl'. It is put in the I/O queue entry for
  2130                              <1> 	; dismountable file system (sb1) and the I/O queue entry is
  2131                              <1> 	; set up to read (bit 10 is set). 'ppoke' is then called to
  2132                              <1> 	; to read file system into core, i.e. the first block on the
  2133                              <1> 	; mountable file system is read in. This block is super block
  2134                              <1> 	; for the file system. This call is super user restricted.	
  2135                              <1> 	;
  2136                              <1> 	; Calling sequence:
  2137                              <1> 	;	sysmount; special; name
  2138                              <1> 	; Arguments:
  2139                              <1> 	;	special - pointer to name of special file (device)
  2140                              <1> 	;	name -  pointer to name of the root directory of the
  2141                              <1> 	;		newly mounted file system. 'name' should 
  2142                              <1> 	;		always be a directory.
  2143                              <1> 	; Inputs: - 
  2144                              <1> 	; Outputs: -
  2145                              <1> 	; ...............................................................
  2146                              <1> 	;				
  2147                              <1> 	; Retro UNIX 8086 v1 modification: 
  2148                              <1> 	;       'sysmount' system call has two arguments; so,
  2149                              <1> 	;	* 1st argument, special is pointed to by BX register
  2150                              <1> 	;	* 2nd argument, name is in CX register
  2151                              <1> 	;
  2152                              <1> 	;	NOTE: Device numbers, names and related procedures are 
  2153                              <1> 	;	       already modified for IBM PC compatibility and 
  2154                              <1> 	;	       Retro UNIX 8086 v1 device configuration.	
  2155                              <1> 	
  2156                              <1> 	;call	arg2
  2157                              <1> 		; jsr r0,arg2 / get arguments special and name
  2158 000057ED 891D[B06E0000]      <1> 	mov	[u.namep], ebx
  2159                              <1> 	; 09/02/2022
  2160                              <1> 	;push	ecx ; directory name
  2161 000057F3 66833D[846E0000]00  <1> 	cmp	word [mnti], 0
  2162                              <1> 		; tst mnti / is the i-number of the cross device file
  2163                              <1> 			 ; / zero?
  2164                              <1> 	;;ja	error
  2165                              <1>         	; bne errora / no, error
  2166                              <1> 	;ja	sysmnt_err0
  2167                              <1> 	; 11/01/2022
  2168 000057FB 7605                <1> 	jna	short sysmnt_0
  2169 000057FD E907010000          <1> 	jmp	sysmnt_err0
  2170                              <1> sysmnt_0:
  2171                              <1> 	; 09/02/2022
  2172 00005802 51                  <1> 	push	ecx ; directory name
  2173 00005803 E8E9000000          <1> 	call	getspl
  2174                              <1> 		; jsr r0,getspl / get special files device number in r1
  2175                              <1> 	; 09/02/2022
  2176 00005808 8F05[B06E0000]      <1> 	pop	dword [u.namep] ; directory name
  2177                              <1> 	; 13/10/2015
  2178                              <1> 	;movzx	ebx, ax ; Retro UNIX 8086 v1 device number (0 to 5)
  2179                              <1> 	; 11/01/2022
  2180 0000580E 29DB                <1> 	sub	ebx, ebx
  2181 00005810 88C3                <1> 	mov	bl, al
  2182 00005812 F683[1A660000]80    <1> 	test    byte [ebx+drv.status], 80h ; 24/10/2015 
  2183 00005819 750F                <1> 	jnz	short sysmnt_1
  2184                              <1> sysmnt_err1:
  2185 0000581B C705[ED6E0000]0F00- <1>         mov     dword [u.error], ERR_DRV_NOT_RDY ; drive not ready !
  2185 00005823 0000                <1>
  2186 00005825 E9A8E2FFFF          <1> 	jmp	error
  2187                              <1> sysmnt_1:
  2188                              <1> 	; 09/02/2022
  2189                              <1> 	;pop	dword [u.namep]
  2190                              <1>         	; mov (sp)+,u.namep / put the name of file to be placed
  2191                              <1> 				  ; / on the device
  2192                              <1> 	; 14/11/2015
  2193 0000582A 53                  <1> 	push	ebx ; 13/10/2015
  2194                              <1> 		; mov r1,-(sp) / save the device number
  2195                              <1>         ;
  2196 0000582B E8A0F1FFFF          <1> 	call	namei
  2197                              <1> 	;or	ax, ax ; Retro UNIX 8086 v1 modification !
  2198                              <1> 		       ; ax = 0 -> file not found 	
  2199                              <1> 	;jz	error
  2200                              <1> 	;jc	error
  2201                              <1> 		; jsr r0,namei / get the i-number of the file
  2202                              <1>                	; br errora
  2203 00005830 730F                <1> 	jnc	short sysmnt_2
  2204                              <1> sysmnt_err2:
  2205 00005832 C705[ED6E0000]0C00- <1>         mov     dword [u.error], ERR_FILE_NOT_FOUND ; drive not ready !
  2205 0000583A 0000                <1>
  2206 0000583C E991E2FFFF          <1> 	jmp	error
  2207                              <1> sysmnt_2:	
  2208 00005841 66A3[846E0000]      <1> 	mov	[mnti], ax
  2209                              <1>         	; mov r1,mnti / put it in mnti
  2210                              <1> 	; 11/01/2022
  2211 00005847 BB[587D0000]        <1> 	mov	ebx, sb1 ; super block buffer header (of mounted disk)
  2212                              <1> sysmnt_3: ;1:
  2213                              <1>         ;cmp	byte [ebx+1], 0
  2214                              <1> 		; tstb sb1+1 / is 15th bit of I/O queue entry for
  2215                              <1> 			   ; / dismountable device set?
  2216                              <1>         ;jna	short sysmnt_4		
  2217                              <1> 		; bne 1b / (inhibit bit) yes, skip writing
  2218                              <1> 	;call	idle 	; (wait for hardware interrupt)
  2219                              <1> 	;jmp	short sysmnt_3
  2220                              <1> sysmnt_4:   
  2221 0000584C 58                  <1> 	pop	eax ; Retro UNIX 8086 v1 device number/ID (0 to 5)     
  2222 0000584D A2[816E0000]        <1> 	mov	[mdev], al
  2223                              <1> 		; mov (sp),mntd / no, put the device number in mntd
  2224 00005852 8803                <1> 	mov	[ebx], al
  2225                              <1>         	; movb (sp),sb1 / put the device number in the lower byte
  2226                              <1> 			      ; / of the I/O queue entry
  2227                              <1> 	;mov	byte [cdev], 1 ; mounted device/drive
  2228                              <1>         	; mov (sp)+,cdev / put device number in cdev
  2229 00005854 66810B0004          <1>         or	word [ebx], 400h ; Bit 10, 'read' flag/bit
  2230                              <1> 		; bis $2000,sb1 / set the read bit
  2231                              <1> 	; Retro UNIX 386 v1 modification : 
  2232                              <1> 	;	32 bit block number at buffer header offset 4
  2233 00005859 C7430401000000      <1> 	mov	dword [ebx+4], 1 ; physical block number = 1
  2234 00005860 E8E5050000          <1> 	call 	diskio
  2235 00005865 7345                <1> 	jnc	short sysmnt_5
  2236 00005867 31C0                <1> 	xor 	eax, eax
  2237 00005869 66A3[846E0000]      <1> 	mov	[mnti], ax ; 0
  2238 0000586F A2[816E0000]        <1> 	mov	[mdev], al ; 0
  2239                              <1> 	;mov	[cdev], al ; 0
  2240                              <1> 	; 08/02/2022
  2241 00005874 803D[006F0000]FF    <1> 	cmp	byte [u.brwdev], 0FFh ; is error code set in [u.error] ?
  2242 0000587B 7508                <1> 	jne	short sysmnt_err3
  2243                              <1> 	; yes, clear [u.brwdev] for next check
  2244                              <1> 	; ([u.error] = DRV_NOT_RDY or OUT_OF_VOLUME error) 
  2245 0000587D FE05[006F0000]      <1> 	inc	byte [u.brwdev] ; 0, reset
  2246 00005883 EB0A                <1> 	jmp	short sysmnt_err4
  2247                              <1> sysmnt_err3:	; 08/02/2022
  2248                              <1> 	; no, set [u.error] to disk read error
  2249 00005885 C705[ED6E0000]1100- <1> 	mov	dword [u.error], ERR_DRV_READ ; 'disk read error !'
  2249 0000588D 0000                <1>
  2250                              <1> sysmnt_err4:
  2251                              <1> 	; 08/02/2022
  2252                              <1> 	; 14/11/2015
  2253 0000588F FEC8                <1> 	dec 	al
  2254 00005891 8903                <1> 	mov	[ebx], eax ; 000000FFh
  2255 00005893 FEC0                <1> 	inc	al
  2256 00005895 48                  <1> 	dec	eax
  2257 00005896 894304              <1> 	mov	[ebx+4], eax ; 0FFFFFFFFh
  2258 00005899 E934E2FFFF          <1> 	jmp	error
  2259                              <1> sysmnt_invd:
  2260                              <1> 	; 08/02/2022
  2261 0000589E C705[ED6E0000]1C00- <1> 	mov	 dword [u.error], ERR_INV_FS ; 28
  2261 000058A6 0000                <1>
  2262                              <1> 				 ;'invalid fs/superblock !' error
  2263 000058A8 30C0                <1> 	xor	al, al
  2264 000058AA EBE3                <1> 	jmp	short sysmnt_err4	
  2265                              <1> 
  2266                              <1> sysmnt_5:
  2267                              <1> 	; 08/02/2022
  2268                              <1> 	; 11/01/2022 (BugFix)
  2269                              <1> 	; 14/11/2015 (Retro UNIX 386 v1 modification)
  2270                              <1> 	; (Following check is needed to prevent mounting an
  2271                              <1> 	; invalid file system (invalid super block).
  2272                              <1> 	; 
  2273 000058AC 0FB603              <1> 	movzx	eax, byte [ebx] ; device number
  2274 000058AF C0E002              <1> 	shl	al, 2 ; 4*index
  2275 000058B2 8B88[FE650000]      <1> 	mov	ecx, [eax+drv.size] ; volume (fs) size
  2276 000058B8 C1E903              <1> 	shr 	ecx, 3 ; 11/01/2021 (8 sectors per 1 fbm byte)
  2277                              <1> 	; ecx = number of free map bytes (required)
  2278                              <1> 	;movzx	edx, word [sb1+8] ; the 1st data word ('mount:')
  2279 000058BB 0FB75308            <1> 	movzx	edx, word [ebx+8] ; the 1st data word (of the buffer)	
  2280                              <1> 	; edx = number of free blocks map bytes
  2281                              <1> 	;shl	edx, 3 ; convert free map bytes to free map bits
  2282                              <1> 	; 07/02/2022
  2283                              <1> 	;xor	al, al ; 08/02/2022
  2284 000058BF 39D1                <1> 	cmp	ecx, edx ; compare free map bits and volume size
  2285                              <1> 			 ; (in sectors), if they are not equal
  2286                              <1> 			 ; the disk to be mounted is an...	
  2287 000058C1 75DB                <1> 	jne	short sysmnt_invd ; invalid disk !
  2288                              <1> 			 ; (which has not got a valid super block)
  2289                              <1> 	;
  2290 000058C3 C6430100            <1> 	mov	byte [ebx+1], 0
  2291                              <1> 	       	; jsr r0,ppoke / read in entire file system
  2292                              <1> ;sysmnt_6: ;1:
  2293                              <1> 	;;cmp	byte [sb1+1], 0
  2294                              <1> 		; tstb sb1+1 / done reading?
  2295                              <1>    	;;jna	sysret
  2296                              <1> 	;;call	idle ; (wait for hardware interrupt)
  2297                              <1> 	;;jmp	short sysmnt_6
  2298                              <1> 		; bne 1b / no, wait
  2299                              <1>         	; br sysreta / yes
  2300 000058C7 E926E2FFFF          <1> 	jmp	sysret
  2301                              <1> 
  2302                              <1> sysumount: ; / special dismount file system
  2303                              <1> 	; 11/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2304                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  2305                              <1> 	; 09/07/2013 - 04/11/2013 (Retro UNIX 8086 v1)
  2306                              <1> 	;
  2307                              <1> 	; 04/11/2013
  2308                              <1> 	; 09/07/2013
  2309                              <1> 	; 'sysumount' anounces to the system that the special file, 
  2310                              <1> 	; indicated as an argument is no longer contain a removable
  2311                              <1> 	; file system. 'getspl' gets the device number of the special
  2312                              <1> 	; file. If no file system was mounted on that device an error
  2313                              <1> 	; occurs. 'mntd' and 'mnti' are cleared and control is passed
  2314                              <1> 	; to 'sysret'.
  2315                              <1> 	;
  2316                              <1> 	; Calling sequence:
  2317                              <1> 	;	sysmount; special
  2318                              <1> 	; Arguments:
  2319                              <1> 	;	special - special file to dismount (device)
  2320                              <1> 	;
  2321                              <1> 	; Inputs: - 
  2322                              <1> 	; Outputs: -
  2323                              <1> 	; ...............................................................
  2324                              <1> 	;				
  2325                              <1> 	; Retro UNIX 8086 v1 modification: 
  2326                              <1> 	;       'sysumount' system call has one argument; so,
  2327                              <1> 	;	* Single argument, special is pointed to by BX register
  2328                              <1> 	;
  2329                              <1> 	
  2330                              <1> 	;mov 	ax, 1 ; one/single argument, put argument in BX	
  2331                              <1> 	;call	arg
  2332                              <1> 		; jsr r0,arg; u.namep / point u.namep to special
  2333 000058CC 891D[B06E0000]      <1>         mov	[u.namep], ebx
  2334 000058D2 E81A000000          <1> 	call	getspl
  2335                              <1> 		; jsr r0,getspl / get the device number in r1
  2336 000058D7 3A05[816E0000]      <1> 	cmp	al, [mdev]
  2337                              <1> 		; cmp r1,mntd / is it equal to the last device mounted?
  2338 000058DD 752A                <1> 	jne	short sysmnt_err0 ; 'permission denied !' error
  2339                              <1> 	;jne	error
  2340                              <1>         	; bne errora / no error
  2341 000058DF 30C0                <1> 	xor	al, al ; ah = 0
  2342                              <1> sysumnt_0: ;1:
  2343                              <1>      	; 11/01/2022
  2344                              <1> 	;cmp 	[sb1+1], al ; 0
  2345                              <1> 	;	; tstb sb1+1 / yes, is the device still doing I/O 
  2346                              <1> 	;		   ; / (inhibit bit set)?
  2347                              <1> 	;jna	short sysumnt_1		
  2348                              <1> 	;	; bne 1b / yes, wait
  2349                              <1> 	;call	idle ; (wait for hardware interrupt)
  2350                              <1> 	;jmp	short sysumnt_0
  2351                              <1> sysumnt_1:        
  2352 000058E1 A2[816E0000]        <1> 	mov	[mdev], al ; 0
  2353                              <1> 	     	; clr mntd / no, clear these
  2354 000058E6 66A3[846E0000]      <1>    	mov	[mnti], ax ; 0
  2355                              <1>         	; clr mnti
  2356 000058EC E901E2FFFF          <1>         jmp	sysret
  2357                              <1> 		; br sysreta / return
  2358                              <1> 
  2359                              <1> getspl: ; / get device number from a special file name
  2360 000058F1 E8DAF0FFFF          <1> 	call	namei
  2361                              <1> 	;or	ax, ax ; Retro UNIX 8086 v1 modification !
  2362                              <1> 		       ; ax = 0 -> file not found 	
  2363                              <1> 	;jc	sysmnt_err2 ; 'file not found !' error
  2364                              <1> 	; 11/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2365 000058F6 7305                <1> 	jnc	short getspl_0
  2366 000058F8 E935FFFFFF          <1> 	jmp	sysmnt_err2 ; 'file not found !' error
  2367                              <1> getspl_0:
  2368                              <1> 	;jz	error
  2369                              <1> 	;jc	error
  2370                              <1> 		; jsr r0,namei / get the i-number of the special file
  2371                              <1>                 ; br errora / no such file
  2372 000058FD 6683E803            <1>         sub	ax, 3 ; Retro UNIX 8086 v1 modification !
  2373                              <1> 		      ;	i-number-3, 0 = fd0, 5 = hd3 
  2374                              <1> 		; sub $4,r1 / i-number-4 rk=1,tap=2+n
  2375 00005901 7206                <1>         jc	short sysmnt_err0 ; 'permission denied !' error
  2376                              <1> 	;jc	error
  2377                              <1> 		; ble errora / less than 0?  yes, error
  2378 00005903 6683F805            <1>         cmp	ax, 5 ;
  2379                              <1> 		; cmp r1,$9. / greater than 9  tap 7
  2380                              <1> 	;ja	short sysmnt_err0 ; 'permission denied !' error
  2381                              <1> 	;;ja	error
  2382                              <1> 		; bgt errora / yes, error
  2383                              <1> 	; 11/01/2022
  2384 00005907 760F                <1> 	jna	short getspl_retn
  2385                              <1> 	; AX = Retro UNIX 8086 v1 Device Number (0 to 5)
  2386                              <1> ;iopen_retn:
  2387                              <1> ;	retn
  2388                              <1> 		; rts r0 / return with device number in r1
  2389                              <1> sysmnt_err0:
  2390 00005909 C705[ED6E0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  2390 00005911 0000                <1>
  2391 00005913 E9BAE1FFFF          <1> 	jmp	error
  2392                              <1> 
  2393                              <1> getspl_retn:
  2394                              <1> 	; AX = Retro UNIX 8086 v1 Device Number (0 to 5)
  2395                              <1> 	; 11/01/2022
  2396                              <1> iopen_retn:
  2397 00005918 C3                  <1> 	retn
  2398                              <1> 
  2399                              <1> iopen:
  2400                              <1> 	; 11/01/2022
  2401                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2402                              <1> 	; 19/05/2015
  2403                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2404                              <1> 	; 21/05/2013 - 27/08/2013 (Retro UNIX 8086 v1)
  2405                              <1> 	;
  2406                              <1> 	; open file whose i-number is in r1
  2407                              <1> 	; 
  2408                              <1> 	; INPUTS ->
  2409                              <1> 	;    r1 - inode number
  2410                              <1> 	; OUTPUTS ->
  2411                              <1> 	;    file's inode in core	
  2412                              <1> 	;    r1 - inode number (positive)
  2413                              <1> 	;
  2414                              <1> 	; ((AX = R1))
  2415                              <1>         ; ((Modified registers: edx, ebx, ecx, esi, edi, ebp)) 
  2416                              <1> 	;        
  2417                              <1> ; / open file whose i-number is in r1
  2418 00005919 F6C480              <1> 	test	ah, 80h ; Bit 15 of AX
  2419                              <1> 		; tst r1 / write or read access?
  2420 0000591C 7568                <1>         jnz	short iopen_2
  2421                              <1> 		; blt 2f / write, go to 2f
  2422 0000591E B202                <1> 	mov	dl, 2 ; read access
  2423 00005920 E844F9FFFF          <1> 	call	access
  2424                              <1>         	; jsr r0,access; 2 
  2425                              <1> 	; / get inode into core with read access
  2426                              <1> 	; DL=2
  2427                              <1> iopen_0:
  2428 00005925 6683F828            <1>         cmp	ax, 40
  2429                              <1> 		; cmp r1,$40. / is it a special file
  2430 00005929 77ED                <1>         ja	short iopen_retn
  2431                              <1> 		; bgt  3f / no. 3f
  2432 0000592B 50                  <1> 	push	eax ; 08/01/2022
  2433                              <1> 	;push	ax
  2434                              <1> 		; mov r1,-(sp) / yes, figure out
  2435 0000592C 0FB6D8              <1> 	movzx	ebx, al
  2436 0000592F C0E302              <1> 	shl	bl, 2 ; * 4 ; 08/01/2022
  2437                              <1> 	;shl	bx, 2
  2438                              <1> 		; asl r1
  2439 00005932 81C3[36590000]      <1>         add     ebx, iopen_1 - 4
  2440 00005938 FF23                <1> 	jmp	dword [ebx]
  2441                              <1>         	; jmp *1f-2(r1) / which one and transfer to it
  2442                              <1> iopen_1: ; 1:
  2443 0000593A [9E590000]          <1> 	dd	otty ; tty, AX = 1 (runix)
  2444                              <1>  		 ;otty / tty ; r1=2
  2445                              <1>         	 ;oppt / ppt ; r1=4
  2446 0000593E [565A0000]          <1> 	dd	sret ; mem, AX = 2 (runix)
  2447                              <1> 		 ;sret / mem ; r1=6
  2448                              <1> 		 ;sret / rf0
  2449                              <1>         	 ;sret / rk0
  2450                              <1>         	 ;sret / tap0
  2451                              <1>         	 ;sret / tap1
  2452                              <1>         	 ;sret / tap2
  2453                              <1>         	 ;sret / tap3
  2454                              <1>         	 ;sret / tap4
  2455                              <1>         	 ;sret / tap5
  2456                              <1>         	 ;sret / tap6
  2457                              <1>         	 ;sret / tap7
  2458 00005942 [565A0000]          <1>         dd	sret ; fd0, AX = 3 (runix only)
  2459 00005946 [565A0000]          <1>         dd	sret ; fd1, AX = 4 (runix only)
  2460 0000594A [565A0000]          <1>         dd	sret ; hd0, AX = 5 (runix only)
  2461 0000594E [565A0000]          <1>         dd	sret ; hd1, AX = 6 (runix only) 
  2462 00005952 [565A0000]          <1>         dd	sret ; hd2, AX = 7 (runix only)
  2463 00005956 [565A0000]          <1>         dd	sret ; hd3, AX = 8 (runix only) 
  2464                              <1> 	;dd	error ; lpr, AX = 9 (error !)
  2465 0000595A [565A0000]          <1>         dd      sret ; lpr, AX = 9 (runix)
  2466 0000595E [AF590000]          <1> 	dd	ocvt ; tty0, AX = 10 (runix)	  
  2467                              <1> 		 ;ocvt / tty0
  2468 00005962 [AF590000]          <1> 	dd	ocvt ; tty1, AX = 11 (runix)	  
  2469                              <1> 		 ;ocvt / tty1
  2470 00005966 [AF590000]          <1> 	dd	ocvt ; tty2, AX = 12 (runix)	  
  2471                              <1> 		 ;ocvt / tty2
  2472 0000596A [AF590000]          <1> 	dd	ocvt ; tty3, AX = 13 (runix)	  
  2473                              <1> 		 ;ocvt / tty3
  2474 0000596E [AF590000]          <1> 	dd	ocvt ; tty4, AX = 14 (runix)	  
  2475                              <1> 		 ;ocvt / tty4
  2476 00005972 [AF590000]          <1> 	dd	ocvt ; tty5, AX = 15 (runix)	  
  2477                              <1> 		 ;ocvt / tty5
  2478 00005976 [AF590000]          <1> 	dd	ocvt ; tty6, AX = 16 (runix)	  
  2479                              <1> 		 ;ocvt / tty6
  2480 0000597A [AF590000]          <1> 	dd	ocvt ; tty7, AX = 17 (runix)	  
  2481                              <1> 		 ;ocvt / tty7
  2482 0000597E [AF590000]          <1> 	dd	ocvt ; COM1, AX = 18 (runix only)	  
  2483                              <1> 		 ;error / crd
  2484 00005982 [AF590000]          <1> 	dd	ocvt ; COM2, AX = 19 (runix only)
  2485                              <1> 
  2486                              <1> iopen_2: ; 2: / check open write access
  2487 00005986 66F7D8              <1> 	neg	ax
  2488                              <1> 		;neg r1 / make inode number positive
  2489 00005989 B201                <1> 	mov	dl, 1 ; write access
  2490 0000598B E8D9F8FFFF          <1> 	call	access
  2491                              <1> 		;jsr r0,access; 1 / get inode in core
  2492                              <1> 	; DL=1
  2493                              <1> 	; 11/01/2022
  2494 00005990 F605[996B0000]40    <1> 	test	byte [i.flgs+1], 40h
  2495                              <1> 	;test	word [i.flgs], 4000h ; Bit 14 : Directory flag
  2496                              <1>  		; bit $40000,i.flgs / is it a directory?
  2497 00005997 748C                <1> 	jz	short iopen_0
  2498                              <1> 	;mov	[u.error], ERR_DIR_ACCESS
  2499                              <1> 	;jmp	error ; permission denied !
  2500 00005999 E96BFFFFFF          <1> 	jmp	sysmnt_err0
  2501                              <1> 	;;jnz	error		
  2502                              <1>        		; bne 2f / yes, transfer (error)
  2503                              <1>         ;;jmp	short iopen_0
  2504                              <1> 	;cmp	ax, 40
  2505                              <1> 		; cmp r1,$40. / no, is it a special file?
  2506                              <1>         ;ja	short iopen_2
  2507                              <1> 		; bgt 3f / no, return
  2508                              <1> 	;push	ax
  2509                              <1> 		; mov r1,-(sp) / yes
  2510                              <1> 	;movzx	ebx, al
  2511                              <1> 	;shl	bx, 1
  2512                              <1> 		; asl r1
  2513                              <1> 	;add	ebx, ipen_3 - 2
  2514                              <1> 	;jmp	dword [ebx]
  2515                              <1> 		; jmp *1f-2(r1) / figure out 
  2516                              <1> 			; / which special file it is and transfer
  2517                              <1> ;iopen_3: ; 1:
  2518                              <1> ;	dd 	otty ; tty, AX = 1 (runix)
  2519                              <1>  		 ;otty / tty ; r1=2
  2520                              <1>         	 ;leadr / ppt ; r1=4
  2521                              <1> ;	dd	sret ; mem, AX = 2 (runix)
  2522                              <1> 		 ;sret / mem ; r1=6
  2523                              <1> 		 ;sret / rf0
  2524                              <1>         	 ;sret / rk0
  2525                              <1>         	 ;sret / tap0
  2526                              <1>         	 ;sret / tap1
  2527                              <1>         	 ;sret / tap2
  2528                              <1>         	 ;sret / tap3
  2529                              <1>         	 ;sret / tap4
  2530                              <1>         	 ;sret / tap5
  2531                              <1>         	 ;sret / tap6
  2532                              <1>         	 ;sret / tap7
  2533                              <1> ;	dd 	sret ; fd0, AX = 3 (runix only)
  2534                              <1> ;	dd 	sret ; fd1, AX = 4 (runix only)
  2535                              <1> ;	dd 	sret ; hd0, AX = 5 (runix only)
  2536                              <1> ;	dd 	sret ; hd1, AX = 6 (runix only)	
  2537                              <1> ;	dd 	sret ; hd2, AX = 7 (runix only)
  2538                              <1> ;	dd 	sret ; hd3, AX = 8 (runix only)	
  2539                              <1> ;	dd	sret ; lpr, AX = 9  (runix)
  2540                              <1> 	;dd	ejec ; lpr, AX = 9  (runix)
  2541                              <1> ;	dd	sret ; tty0, AX = 10 (runix)	  
  2542                              <1> 		 ;ocvt / tty0
  2543                              <1> ;	dd	sret ; tty1, AX = 11 (runix)	  
  2544                              <1> 		 ;ocvt / tty1
  2545                              <1> ;	dd	sret ; tty2, AX = 12 (runix)	  
  2546                              <1> 		 ;ocvt / tty2
  2547                              <1> ;	dd	sret ; tty3, AX = 13 (runix)	  
  2548                              <1> 		 ;ocvt / tty3
  2549                              <1> ;	dd	sret ; tty4, AX = 14 (runix)	  
  2550                              <1> 		 ;ocvt / tty4
  2551                              <1> ;	dd	sret ; tty5, AX = 15 (runix)	  
  2552                              <1> 		 ;ocvt / tty5
  2553                              <1> ;	dd	sret ; tty6, AX = 16 (runix)	  
  2554                              <1> 		 ;ocvt / tty6
  2555                              <1> ;	dd	sret ; tty7, AX = 17 (runix)	  
  2556                              <1> 		 ;ocvt / tty7
  2557                              <1> ;	dd	ocvt ; COM1, AX = 18 (runix only)	  
  2558                              <1> 		 ;/ ejec / lpr
  2559                              <1> ;	dd	ocvt ; COM2, AX = 19 (runix only)
  2560                              <1> 
  2561                              <1> otty: ;/ open console tty for reading or writing
  2562                              <1> 	; 03/03/2022
  2563                              <1> 	; 02/03/2022
  2564                              <1> 	; 26/02/2022
  2565                              <1> 	; 09/02/2022
  2566                              <1> 	; 06/02/2022
  2567                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2568                              <1> 	; 16/11/2015
  2569                              <1> 	; 12/11/2015
  2570                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2571                              <1> 	; 21/05/2013 - 13/07/2014 (Retro UNIX 8086 v1)
  2572                              <1> 	; 16/07/2013
  2573                              <1> 	; Retro UNIX 8086 v1 modification:
  2574                              <1> 	;  If a tty is open for read or write by
  2575                              <1> 	;     a process (u.uno), only same process can open
  2576                              <1> 	;     same tty to write or read (R->R&W or W->W&R).	
  2577                              <1> 	;
  2578                              <1> 	; (INPUT: DL=2 for Read, DL=1 for Write, DL=0 for sysstty)
  2579                              <1> 	;
  2580 0000599E 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2581 000059A5 8A83[F76B0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2582                              <1> 	; 13/01/2014
  2583                              <1> 	;jmp	short ottyp
  2584                              <1> 	; 26/02/2022
  2585 000059AB 88C4                <1> 	mov	ah, al
  2586 000059AD EB06                <1> 	jmp	short ottypc ; ah = al = console tty number
  2587                              <1> ocvt:
  2588 000059AF 2C0A                <1> 	sub	al, 10
  2589                              <1> ;ottyp:	; (call from sysstty)
  2590                              <1> 	; 08/01/2022
  2591 000059B1 31DB                <1> 	xor	ebx, ebx
  2592                              <1> ottyp:	; (ebx < 256) ; 06/02/2022
  2593                              <1> 	; 26/02/2022
  2594 000059B3 B4FF                <1> 	mov	ah, 0FFh
  2595                              <1> ottypc:
  2596                              <1> 	; 03/03/2022
  2597                              <1> 	; 26/02/2022
  2598                              <1> 	; 09/02/2022
  2599                              <1> 	; 08/01/2022
  2600                              <1> 	; 16/11/2015
  2601                              <1> 	; 12/11/2015
  2602                              <1> 	; 18/05/2015 (32 bit modifications)
  2603                              <1> 	; 06/12/2013 - 13/07/2014
  2604 000059B5 88C6                <1> 	mov	dh, al ; tty number
  2605                              <1> 	;movzx 	ebx, al ; AL = tty number (0 to 9), AH = 0
  2606                              <1> 	; 08/01/2022
  2607 000059B7 88C3                <1> 	mov	bl, al
  2608 000059B9 D0E3                <1> 	shl 	bl, 1  ; aligned to word
  2609                              <1> 	; 26/01/2014	
  2610 000059BB 81C3[246B0000]      <1> 	add 	ebx, ttyl
  2611 000059C1 668B0B              <1> 	mov 	cx, [ebx]
  2612                              <1> 		   ; CL = lock value (0 or process number)
  2613                              <1> 		   ; CH = open count 
  2614 000059C4 20C9                <1> 	and 	cl, cl
  2615                              <1> 	; 13/01/2014
  2616                              <1> 	;jz 	short otty_ret
  2617                              <1> 	; 08/01/2022
  2618 000059C6 7447                <1> 	jz 	short ottys_0
  2619                              <1> 	;
  2620                              <1> 	; 16/11/2015
  2621 000059C8 3A0D[E76E0000]      <1> 	cmp 	cl, [u.uno]
  2622 000059CE 746E                <1> 	je	short ottys_3
  2623                              <1> 	;
  2624                              <1> 	;
  2625                              <1> 	; 26/02/2022
  2626                              <1> 	; (is it the console tty of the current process?)
  2627                              <1> 	; ((fast check/permit for console tty open function))
  2628 000059D0 38E0                <1> 	cmp	al, ah ; cmp dh, ah
  2629 000059D2 746A                <1> 	je	short ottys_3 ; bypass parent process check
  2630                              <1> 	;
  2631                              <1> 	; 26/02/2022
  2632                              <1> 	;movzx 	ebx, cl ; the process which has locked the tty
  2633                              <1> 	;shl 	bl, 1
  2634                              <1> 	;mov 	ax, [ebx+p.pid-2]
  2635                              <1> 	;;movzx ebx, byte [u.uno]
  2636                              <1> 	;mov	bl, [u.uno]
  2637                              <1> 	;shl 	bl, 1
  2638                              <1> 	;cmp 	ax, [ebx+p.ppid-2]
  2639                              <1> 	;je 	short ottys_3  ; 16/11/2015
  2640                              <1> 	; 26/02/2022 (BugFix) ; *
  2641 000059D4 0FB6F1              <1> 	movzx 	esi, cl ; the process which has locked the tty
  2642 000059D7 D1E6                <1> 	shl 	esi, 1
  2643 000059D9 668B86[B66B0000]    <1> 	mov 	ax, [esi+p.pid-2]
  2644 000059E0 96                  <1> 	xchg	esi, eax
  2645 000059E1 A0[E76E0000]        <1> 	mov	al, [u.uno]
  2646 000059E6 D0E0                <1> 	shl 	al, 1
  2647 000059E8 663BB0[D66B0000]    <1> 	cmp 	si, [eax+p.ppid-2]
  2648 000059EF 744D                <1> 	je 	short ottys_3 ; *
  2649                              <1> 	; 26/02/2022
  2650                              <1> 	; check console tty of the process
  2651                              <1> 	; (open permission must be given if the -requested- tty is
  2652                              <1> 	;  console tty of current process)
  2653 000059F1 D0E8                <1> 	shr	al, 1
  2654 000059F3 38B0[F76B0000]      <1> 	cmp	[eax+p.ttyc-1], dh ; console tty ?
  2655 000059F9 7443                <1> 	je 	short ottys_3
  2656                              <1> 	;
  2657                              <1> 	; the tty is locked by another process
  2658                              <1> 	; except the parent process (p.ppid)
  2659                              <1>         ;
  2660                              <1> 	; 09/02/2022
  2661                              <1> 	;mov	dword [u.error], ERR_DEV_ACCESS
  2662                              <1> 	;		; permission denied ! error
  2663                              <1> otty_err: ; 13/01/2014
  2664                              <1> 	;or 	dl, dl	; DL = 0 -> called by sysstty
  2665                              <1> 	;;jnz	error
  2666                              <1> 	; 05/12/2021
  2667                              <1> 	;jz	short otty_stc_retn
  2668                              <1> 	;jmp	error
  2669                              <1> 	; 09/02/2022
  2670 000059FB 80FA01              <1> 	cmp	dl, 1 ; dl = 0 ?
  2671 000059FE 7257                <1> 	jb	short otty_retn ; yes, cf=1, called by sysstty
  2672                              <1> 	; iopen (dl=1 or dl=2)
  2673 00005A00 C705[ED6E0000]0B00- <1> 	mov     dword [u.error], ERR_DEV_ACCESS
  2673 00005A08 0000                <1>
  2674                              <1> 			; permission denied ! error
  2675 00005A0A E9C3E0FFFF          <1> 	jmp	error
  2676                              <1> ;otty_stc_retn:
  2677                              <1> 	;stc
  2678                              <1> 	;retn
  2679                              <1> ottys_0:
  2680                              <1> 	; 08/01/2022
  2681                              <1> otty_ret: 
  2682                              <1> 	; 13/01/2014
  2683 00005A0F 80FE07              <1> 	cmp 	dh, 7
  2684 00005A12 7624                <1> 	jna	short ottys_2
  2685                              <1> 	; 16/11/2015
  2686                              <1> com_port_check:
  2687 00005A14 BE[426B0000]        <1> 	mov	esi, com1p
  2688 00005A19 80FE08              <1> 	cmp	dh, 8	; COM1 (tty8) ?
  2689 00005A1C 7601                <1> 	jna	short ottys_1 ; yes, it is COM1
  2690 00005A1E 46                  <1> 	inc	esi	; no, it is COM2 (tty9)
  2691                              <1> ottys_1:
  2692                              <1> 	; 12/11/2015
  2693 00005A1F 803E00              <1> 	cmp	byte [esi], 0 ; E3h (or 23h)
  2694 00005A22 7714                <1> 	ja	short com_port_ready
  2695                              <1> 	;
  2696                              <1> 	; 09/02/2022
  2697 00005A24 80FA01              <1> 	cmp	dl, 1 ; dl = 0 ?
  2698 00005A27 722E                <1> 	jb	short otty_retn ; yes, cf=1, called by sysstty
  2699 00005A29 C705[ED6E0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY
  2699 00005A31 0000                <1>
  2700                              <1> 			   ; device not ready ! error
  2701                              <1> 	;jmp	short otty_err
  2702 00005A33 E99AE0FFFF          <1> 	jmp	error
  2703                              <1> com_port_ready:
  2704                              <1> ottys_2:
  2705                              <1> 	; 02/03/2022
  2706                              <1> 	;or	cl, cl  ; cl = lock/owner, ch = open count
  2707                              <1> 	;jnz	short ottys_3
  2708 00005A38 8A0D[E76E0000]      <1> 	mov	cl, [u.uno]
  2709                              <1> ottys_3:
  2710 00005A3E FEC5                <1> 	inc 	ch
  2711 00005A40 66890B              <1> 	mov 	[ebx], cx ; set tty lock again
  2712                              <1> 	; 06/12/2013
  2713 00005A43 FEC6                <1> 	inc	dh ; tty number + 1
  2714 00005A45 BB[C86E0000]        <1> 	mov	ebx, u.ttyp
  2715                              <1> 	; 13/01/2014
  2716 00005A4A F6C202              <1> 	test	dl, 2 ; open for read sign
  2717 00005A4D 7501                <1> 	jnz	short ottys_4
  2718 00005A4F 43                  <1> 	inc	ebx
  2719                              <1> ottys_4:
  2720                              <1> 	; Set 'u.ttyp' ('the recent TTY') value
  2721 00005A50 8833                <1> 	mov 	[ebx], dh ; tty number + 1
  2722                              <1> 	; 09/02/2022
  2723 00005A52 08D2                <1> 	or	dl, dl ; sysstty system call check (DL=0)
  2724 00005A54 7401                <1> 	jz	short otty_retn ; 03/03/2022
  2725                              <1> sret:
  2726                              <1> 	;pop 	ax
  2727 00005A56 58                  <1> 	pop	eax ; 08/01/2022
  2728                              <1> otty_retn:	; 09/02/2022
  2729                              <1> iclose_retn:	
  2730 00005A57 C3                  <1> 	retn
  2731                              <1> 
  2732                              <1> 	;
  2733                              <1> 	; Original UNIX v1 'otty' routine:
  2734                              <1> 	;	
  2735                              <1> 	;mov    $100,*$tks / set interrupt enable bit (zero others) in
  2736                              <1>         ;                 / reader status reg
  2737                              <1>         ;mov    $100,*$tps / set interrupt enable bit (zero others) in
  2738                              <1>         ;                 / punch status reg
  2739                              <1>         ;mov    tty+[ntty*8]-8+6,r5 / r5 points to the header of the
  2740                              <1>         ;                          / console tty buffer
  2741                              <1>         ;incb   (r5) / increment the count of processes that opened the
  2742                              <1>         ;            / console tty
  2743                              <1>         ;tst    u.ttyp / is there a process control tty (i.e., has a tty
  2744                              <1>         ;             / buffer header
  2745                              <1>         ;bne    sret / address been loaded into u.ttyp yet)?  yes, branch
  2746                              <1>         ;mov    r5,u.ttyp / no, make the console tty the process control
  2747                              <1>         ;                 / tty
  2748                              <1>         ;br     sret / ?
  2749                              <1> ;sret:
  2750                              <1> 		;clr *$ps / set processor priority to zero
  2751                              <1> ;	pop	ax
  2752                              <1>         	;mov (sp)+,r1 / pop stack to r1
  2753                              <1> ;3:
  2754                              <1> ;	retn
  2755                              <1>         	;rts r0
  2756                              <1> 	
  2757                              <1> ;ocvt:	; < open tty >
  2758                              <1> 	; 13/01/2014
  2759                              <1> 	; 06/12/2013 (major modification: p.ttyc, u.ttyp)
  2760                              <1> 	; 24/09/2013 consistency check -> ok
  2761                              <1> 	; 16/09/2013
  2762                              <1> 	; 03/09/2013
  2763                              <1> 	; 27/08/2013
  2764                              <1> 	; 16/08/2013
  2765                              <1> 	; 16/07/2013
  2766                              <1> 	; 27/05/2013
  2767                              <1> 	; 21/05/2013
  2768                              <1> 	;
  2769                              <1> 	; Retro UNIX 8086 v1 modification !
  2770                              <1> 	; 
  2771                              <1> 	; In original UNIX v1, 'ocvt' routine 
  2772                              <1> 	;	(exactly different than this one)
  2773                              <1> 	;	was in 'u9.s' file.
  2774                              <1> 	;
  2775                              <1> 	; 16/07/2013
  2776                              <1> 	; Retro UNIX 8086 v1 modification:
  2777                              <1> 	;  If a tty is open for read or write by
  2778                              <1> 	;     a process (u.uno), only same process can open
  2779                              <1> 	;     same tty to write or read (R->R&W or W->W&R).	
  2780                              <1> 	;
  2781                              <1> 	; INPUT: DL=2 for Read DL=1 for Write
  2782                              <1> 
  2783                              <1> 	; 16/09/2013
  2784                              <1> 	; sub 	al, 10
  2785                              <1> 	
  2786                              <1> 	; 06/12/2013
  2787                              <1> 	;cmp	al, 7
  2788                              <1>         ;jna     short ottyp
  2789                              <1> 	; 13/01/2014
  2790                              <1> 	;jmp	short ottyp
  2791                              <1> 
  2792                              <1> ;oppt: / open paper tape for reading or writing
  2793                              <1> ;        mov    $100,*$prs / set reader interrupt enable bit
  2794                              <1> ;        tstb   pptiflg / is file already open
  2795                              <1> ;        bne    2f / yes, branch
  2796                              <1> ;1:
  2797                              <1> ;        mov    $240,*$ps / no, set processor priority to 5
  2798                              <1> ;        jsr    r0,getc; 2 / remove all entries in clist
  2799                              <1> ;               br .+4 / for paper tape input and place in free list
  2800                              <1> ;        br     1b
  2801                              <1> ;        movb   $2,pptiflg / set pptiflg to indicate file just open
  2802                              <1> ;        movb   $10.,toutt+1 / place 10 in paper tape input tout entry
  2803                              <1> ;        br     sret
  2804                              <1> ;2:
  2805                              <1> ;        jmp    error / file already open
  2806                              <1> 
  2807                              <1> iclose:
  2808                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2809                              <1> 	; 19/05/2015
  2810                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2811                              <1> 	; 21/05/2013 - 13/01/2014 (Retro UNIX 8086 v1)
  2812                              <1> 	;
  2813                              <1> 	; close file whose i-number is in r1
  2814                              <1> 	; 
  2815                              <1> 	; INPUTS ->
  2816                              <1> 	;    r1 - inode number
  2817                              <1> 	; OUTPUTS ->
  2818                              <1> 	;    file's inode in core	
  2819                              <1> 	;    r1 - inode number (positive)
  2820                              <1> 	;
  2821                              <1> 	; ((AX = R1))
  2822                              <1>         ;    ((Modified registers: -ebx-, edx)) 
  2823                              <1> 	;        
  2824                              <1> ;/ close file whose i-number is in r1
  2825 00005A58 B202                <1> 	mov	dl, 2 ; 12/01/2014
  2826 00005A5A F6C480              <1> 	test	ah, 80h ; Bit 15 of AX
  2827                              <1> 		; tst r1 / test i-number
  2828                              <1>         ;jnz	short iclose_2
  2829                              <1> 		; blt 2f / if neg., branch
  2830 00005A5D 7405                <1> 	jz	short iclose_0 ; 30/07/2013
  2831                              <1> 	; 16/07/2013 
  2832 00005A5F 66F7D8              <1> 	neg	ax ; make it positive
  2833                              <1> 	; 12/01/2014
  2834 00005A62 FECA                <1> 	dec	dl ; dl = 1 (open for write)
  2835                              <1> iclose_0:
  2836 00005A64 6683F828            <1> 	cmp	ax, 40
  2837                              <1> 		; cmp r1,$40. / is it a special file
  2838 00005A68 77ED                <1>         ja	short iclose_retn  ; 13/01/2014
  2839                              <1> 		; bgt 3b / no, return
  2840                              <1> 	; 12/01/2014
  2841                              <1> 	; DL=2 -> special file was opened for reading
  2842                              <1> 	; DL=1 -> special file was opened for writing
  2843 00005A6A 50                  <1> 	push	eax ; 08/01/2022
  2844                              <1> 	;push	ax
  2845                              <1> 		; mov r1,-(sp) / yes, save r1 on stack
  2846 00005A6B 0FB6D8              <1> 	movzx	ebx, al
  2847                              <1> 	; 08/01/2022
  2848 00005A6E C0E302              <1> 	shl	bl, 2
  2849                              <1> 	;shl	bx, 2
  2850                              <1> 		; asl r1
  2851 00005A71 81C3[755A0000]      <1> 	add	ebx, iclose_1 - 4
  2852 00005A77 FF23                <1> 	jmp	dword [ebx]
  2853                              <1> 		; jmp *1f-2(r1) / compute jump address and transfer
  2854                              <1> iclose_1 :
  2855 00005A79 [C55A0000]          <1> 	dd	ctty ; tty, AX = 1 (runix)
  2856 00005A7D [205B0000]          <1> 	dd	cret ; mem, AX = 2 (runix)
  2857 00005A81 [205B0000]          <1> 	dd	cret ; fd0, AX = 3 (runix only)
  2858 00005A85 [205B0000]          <1> 	dd	cret ; fd1, AX = 4 (runix only)
  2859 00005A89 [205B0000]          <1> 	dd	cret ; hd0, AX = 5 (runix only)
  2860 00005A8D [205B0000]          <1> 	dd	cret ; hd1, AX = 6 (runix only)	
  2861 00005A91 [205B0000]          <1> 	dd	cret ; hd2, AX = 7 (runix only)
  2862 00005A95 [205B0000]          <1> 	dd	cret ; hd3, AX = 8 (runix only)	
  2863 00005A99 [205B0000]          <1> 	dd	cret ; lpr, AX = 9 (runix)
  2864                              <1> 	;dd	error; lpr, AX = 9 (error !)
  2865                              <1> 	;;dd	offset ejec ;;lpr, AX = 9  
  2866 00005A9D [D45A0000]          <1> 	dd	ccvt ; tty0, AX = 10 (runix)	  
  2867 00005AA1 [D45A0000]          <1> 	dd	ccvt ; tty1, AX = 11 (runix)	  
  2868 00005AA5 [D45A0000]          <1> 	dd	ccvt ; tty2, AX = 12 (runix)	  
  2869 00005AA9 [D45A0000]          <1> 	dd	ccvt ; tty3, AX = 13 (runix)	  
  2870 00005AAD [D45A0000]          <1> 	dd	ccvt ; tty4, AX = 14 (runix)	  
  2871 00005AB1 [D45A0000]          <1> 	dd	ccvt ; tty5, AX = 15 (runix)	  
  2872 00005AB5 [D45A0000]          <1> 	dd	ccvt ; tty6, AX = 16 (runix)	  
  2873 00005AB9 [D45A0000]          <1> 	dd	ccvt ; tty7, AX = 17 (runix)	  
  2874 00005ABD [D45A0000]          <1> 	dd	ccvt ; COM1, AX = 18 (runix only)	  
  2875 00005AC1 [D45A0000]          <1> 	dd	ccvt ; COM2, AX = 19 (runix only)
  2876                              <1> 
  2877                              <1> 	; 1:
  2878                              <1> 	;        ctty   / tty
  2879                              <1> 	;        cppt   / ppt
  2880                              <1> 	;        sret   / mem
  2881                              <1> 	;        sret   / rf0
  2882                              <1> 	;        sret   / rk0
  2883                              <1> 	;        sret   / tap0
  2884                              <1> 	;        sret   / tap1
  2885                              <1> 	;        sret   / tap2
  2886                              <1> 	;        sret   / tap3
  2887                              <1> 	;        sret   / tap4
  2888                              <1> 	;        sret   / tap5
  2889                              <1> 	;        sret   / tap6
  2890                              <1> 	;        sret   / tap7
  2891                              <1> 	;        ccvt   / tty0
  2892                              <1> 	;        ccvt   / tty1
  2893                              <1> 	;        ccvt   / tty2
  2894                              <1> 	;        ccvt   / tty3
  2895                              <1> 	;        ccvt   / tty4
  2896                              <1> 	;        ccvt   / tty5
  2897                              <1> 	;        ccvt   / tty6
  2898                              <1> 	;        ccvt   / tty7
  2899                              <1> 	;        error / crd
  2900                              <1> 
  2901                              <1> ;iclose_2: ; 2: / negative i-number
  2902                              <1> 	;neg	ax
  2903                              <1> 		;neg r1 / make it positive
  2904                              <1> 	;cmp	ax, 40
  2905                              <1> 		;cmp r1,$40. / is it a special file?
  2906                              <1>         ;ja	short @b
  2907                              <1> 		;bgt    3b / no. return
  2908                              <1> 	;push	ax
  2909                              <1> 		;mov r1,-(sp)
  2910                              <1> 	;movzx	ebx, al
  2911                              <1> 	;shl	bx, 1
  2912                              <1> 		;asl r1 / yes. compute jump address and transfer
  2913                              <1> 	;add	ebx, iclose_3 - 2
  2914                              <1> 	;jmp	dword [ebx]
  2915                              <1> 		;jmp *1f-2(r1) / figure out 
  2916                              <1> ;iclose_3:
  2917                              <1> 	;dd	ctty ; tty, AX = 1 (runix)
  2918                              <1> 	;dd	sret ; mem, AX = 2 (runix)
  2919                              <1> 	;dd	sret ; fd0, AX = 3 (runix only)
  2920                              <1> 	;dd	sret ; fd1, AX = 4 (runix only)
  2921                              <1> 	;dd	sret ; hd0, AX = 5 (runix only)
  2922                              <1> 	;dd	sret ; hd1, AX = 6 (runix only)	
  2923                              <1> 	;dd	sret ; hd2, AX = 7 (runix only)
  2924                              <1> 	;dd	sret ; hd3, AX = 8 (runix only)
  2925                              <1> 	 ;dd	sret ; lpr, AX = 9	
  2926                              <1> 	;dd	ejec ; lpr, AX = 9  (runix)
  2927                              <1> 	;dd	ccvt ; tty0, AX = 10 (runix)	  
  2928                              <1> 	;dd	ccvt ; tty1, AX = 11 (runix)	  
  2929                              <1> 	;dd	ccvt ; tty2, AX = 12 (runix)	  
  2930                              <1> 	;dd	ccvt ; tty3, AX = 13 (runix)	  
  2931                              <1> 	;dd	ccvt ; tty4, AX = 14 (runix)	  
  2932                              <1> 	;dd	ccvt ; tty5, AX = 15 (runix)	  
  2933                              <1> 	;dd	ccvt ; tty6, AX = 16 (runix)	  
  2934                              <1> 	;dd	ccvt ; tty7, AX = 17 (runix)	  
  2935                              <1> 	;dd	ccvt ; COM1, AX = 18 (runix only)	  
  2936                              <1> 	;dd	ccvt ; COM2, AX = 19 (runix only) 
  2937                              <1> 	
  2938                              <1> 	;1:
  2939                              <1> 	;      	ctty   / tty
  2940                              <1> 	;       leadr  / ppt
  2941                              <1> 	;       sret   / mem
  2942                              <1> 	;       sret   / rf0
  2943                              <1> 	;       sret   / rk0
  2944                              <1> 	;       sret   / tap0
  2945                              <1> 	;       sret   / tap1
  2946                              <1> 	;       sret   / tap2
  2947                              <1> 	;       sret   / tap3
  2948                              <1> 	;       sret   / tap4
  2949                              <1> 	;       sret   / tap5
  2950                              <1> 	;       sret   / tap6
  2951                              <1> 	;       sret   / tap7
  2952                              <1> 	;       ccvt   / tty0
  2953                              <1> 	;       ccvt   / tty1
  2954                              <1> 	;       ccvt   / tty2
  2955                              <1> 	;       ccvt   / tty3
  2956                              <1> 	;       ccvt   / tty4
  2957                              <1> 	;       ccvt   / tty5
  2958                              <1> 	;       ccvt   / tty6
  2959                              <1> 	;       ccvt   / tty7
  2960                              <1> 	;/      ejec   / lpr
  2961                              <1> 
  2962                              <1> ctty: ; / close console tty
  2963                              <1> 	; 26/02/2022
  2964                              <1> 	; 09/02/2022
  2965                              <1> 	; 06/02/2022
  2966                              <1> 	; 08/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2967                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2968                              <1> 	; 21/05/2013 - 26/01/2014 (Retro UNIX 8086 v1)
  2969                              <1> 	;
  2970                              <1> 	; Retro UNIX 8086 v1 modification !
  2971                              <1> 	; (DL = 2 -> it is open for reading)
  2972                              <1> 	; (DL = 1 -> it is open for writing)
  2973                              <1> 	; (DL = 0 -> it is open for sysstty system call)
  2974                              <1> 	;
  2975                              <1> 	; 06/12/2013
  2976 00005AC5 0FB61D[E76E0000]    <1>         movzx   ebx, byte [u.uno] ; process number
  2977 00005ACC 8A83[F76B0000]      <1>         mov     al, [ebx+p.ttyc-1]
  2978                              <1> 	; 13/01/2014
  2979                              <1> 	;jmp	short cttyp
  2980                              <1> 	; 06/02/2022
  2981 00005AD2 EB04                <1> 	jmp	short ctty_0
  2982                              <1> ccvt:
  2983 00005AD4 2C0A                <1> 	sub 	al, 10
  2984                              <1> cttyp:	; (call from sysstty)
  2985                              <1> 	; 08/01/2022
  2986 00005AD6 31DB                <1> 	xor	ebx, ebx
  2987                              <1> ctty_0: ; (ebx < 256)  ; 06/02/2022
  2988                              <1> 	; 08/01/2022
  2989                              <1> 	; 18/05/2015 (32 bit modifications)
  2990                              <1> 	; 16/08/2013 - 26/01/2014
  2991                              <1> 	;movzx 	ebx, al ; tty number (0 to 9)
  2992                              <1> 	; 08/01/2022
  2993 00005AD8 88C3                <1> 	mov	bl, al
  2994 00005ADA D0E3                <1> 	shl 	bl, 1  ; aligned to word	
  2995                              <1> 	; 26/01/2014
  2996 00005ADC 81C3[246B0000]      <1> 	add 	ebx, ttyl
  2997 00005AE2 88C6                <1> 	mov 	dh, al ; tty number
  2998 00005AE4 668B03              <1> 	mov 	ax, [ebx]
  2999                              <1> 		   ; AL = lock value (0 or process number)
  3000                              <1> 		   ; AH = open count 
  3001 00005AE7 20E4                <1> 	and 	ah, ah
  3002 00005AE9 7514                <1> 	jnz	short ctty_ret
  3003                              <1>   	; 09/02/2022
  3004 00005AEB 80FA01              <1> 	cmp	dl, 1	; DL = 0 -> called by sysstty
  3005 00005AEE 7231                <1> 	jb	short ctty_stc_retn ; cf=1
  3006                              <1> 	; iclose (dl=1 or dl=2)
  3007 00005AF0 C705[ED6E0000]0A00- <1>         mov     dword [u.error], ERR_DEV_NOT_OPEN
  3007 00005AF8 0000                <1>
  3008                              <1> 			; device not open ! error
  3009                              <1> 	;jmp 	short ctty_err ; open count = 0, it is not open !
  3010 00005AFA E9D3DFFFFF          <1> 	jmp	error
  3011                              <1> 	; 26/01/2014
  3012                              <1> ctty_ret:
  3013 00005AFF FECC                <1> 	dec 	ah ; decrease open count
  3014 00005B01 7502                <1> 	jnz	short ctty_1
  3015 00005B03 30C0                <1> 	xor	al, al ; unlock/free tty
  3016                              <1> ctty_1:
  3017 00005B05 668903              <1> 	mov 	[ebx], ax ; close tty instance
  3018                              <1> 	;
  3019 00005B08 BB[C86E0000]        <1> 	mov	ebx, u.ttyp
  3020                              <1> 	;test	dl, 1 ; open for write sign
  3021                              <1> 	;jz	short ctty_2
  3022                              <1> 	; 26/02/2022
  3023 00005B0D F6C202              <1> 	test	dl, 2 ; open for read sign
  3024 00005B10 7501                <1> 	jnz	short ctty_2
  3025 00005B12 43                  <1> 	inc	ebx
  3026                              <1> ctty_2:
  3027 00005B13 FEC6                <1> 	inc	dh ; tty number + 1
  3028 00005B15 3A33                <1> 	cmp	dh, [ebx]
  3029                              <1> 	;jne	short cret
  3030 00005B17 7503                <1> 	jne	short ctty_3 ; 09/02/2022
  3031                              <1> 	; Reset/Clear 'u.ttyp' ('the recent TTY') value
  3032 00005B19 C60300              <1> 	mov	byte [ebx], 0
  3033                              <1> ctty_3:
  3034                              <1> 	; 09/02/2022
  3035 00005B1C 08D2                <1> 	or	dl, dl ; sysstty system call check (DL=0)
  3036 00005B1E 7401                <1> 	jz	short ctty_4
  3037                              <1> cret:
  3038                              <1> 	;pop	ax
  3039                              <1> 	; 08/01/2022
  3040 00005B20 58                  <1> 	pop	eax
  3041                              <1> ctty_stc_retn:	; 09/02/2022
  3042                              <1> ctty_4:
  3043 00005B21 C3                  <1> 	retn
  3044                              <1> 
  3045                              <1> ;ctty_err: ; 13/01/2014
  3046                              <1> ;	or 	dl, dl ; DL = 0 -> called by sysstty
  3047                              <1> ;	jnz	error
  3048                              <1> ;	stc
  3049                              <1> ;	retn
  3050                              <1> 
  3051                              <1> 	; Original UNIX v1 'ctty' routine:
  3052                              <1> 	;	
  3053                              <1>         ;mov    tty+[ntty*8]-8+6,r5 
  3054                              <1> 	;		;/ point r5 to the console tty buffer
  3055                              <1>         ;decb   (r5) / dec number of processes using console tty
  3056                              <1>         ;br     sret / return via sret
  3057                              <1> 
  3058                              <1> ;ccvt:	; < close tty >
  3059                              <1> 	; 21/05/2013 - 13/01/2014 (Retro UNIX 8086 v1)
  3060                              <1> 	;
  3061                              <1> 	; Retro UNIX 8086 v1 modification !
  3062                              <1> 	; 
  3063                              <1> 	; In original UNIX v1, 'ccvt' routine 
  3064                              <1> 	;		(exactly different than this one)
  3065                              <1> 	;	was in 'u9.s' file.
  3066                              <1> 	;
  3067                              <1> 	; DL = 2 -> it is open for reading
  3068                              <1> 	; DL = 1 -> it is open for writing
  3069                              <1> 	;
  3070                              <1> 	; 17/09/2013
  3071                              <1> 	;sub 	al, 10
  3072                              <1> 	;cmp	al, 7
  3073                              <1> 	;jna	short cttyp
  3074                              <1> 	; 13/01/2014
  3075                              <1> 	;jmp	short cttyp
  3076                              <1> 
  3077                              <1> ;cppt: / close paper tape
  3078                              <1> ;        clrb   pptiflg / set pptiflg to indicate file not open
  3079                              <1> ;1:
  3080                              <1> ;        mov    $240,*$ps /set process or priority to 5
  3081                              <1> ;        jsr    r0,getc; 2 / remove all ppt input entries from clist
  3082                              <1> ;                          / and assign to free list
  3083                              <1> ;               br sret
  3084                              <1> ;        br     1b
  3085                              <1> 
  3086                              <1> ;ejec:	
  3087                              <1> ;	jmp	error
  3088                              <1> ;/ejec:
  3089                              <1> ;/       mov    $100,*$lps / set line printer interrupt enable bit
  3090                              <1> ;/       mov    $14,r1 / 'form feed' character in r1 (new page).
  3091                              <1> ;/       jsr    r0,lptoc / space the printer to a new page
  3092                              <1> ;/       br     sret / return to caller via 'sret'
  2099                                  %include 'u8.s'        ; 11/06/2015
  2100                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS8.INC
  2101                              <1> ; Last Modification: 12/02/2022
  2102                              <1> ; ----------------------------------------------------------------------------
  2103                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2104                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2105                              <1> ;
  2106                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2107                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2108                              <1> ; <Bell Laboratories (17/3/1972)>
  2109                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2110                              <1> ;
  2111                              <1> ; Retro UNIX 8086 v1 - U8.ASM (18/01/2014) //// UNIX v1 -> u8.s
  2112                              <1> ;
  2113                              <1> ; ****************************************************************************
  2114                              <1> 
  2115                              <1> ;; I/O Buffer - Retro UNIX 386 v1 modification
  2116                              <1> ;;     (8+512 bytes, 8 bytes header, 512 bytes data)
  2117                              <1> ;; Word 1, byte 0 = device id
  2118                              <1> ;; Word 1, byte 1 = status bits (bits 8 to 15)
  2119                              <1> ;;          bit 9 = write bit
  2120                              <1> ;;	    bit 10 = read bit	  
  2121                              <1> ;;	    bit 12 = waiting to write bit	
  2122                              <1> ;;	    bit 13 = waiting to read bit
  2123                              <1> ;;	    bit 15 = inhibit bit
  2124                              <1> ;; Word 2 (byte 2 & byte 3) = reserved (for now - 07/06/2015)
  2125                              <1> ;; Word 3 + Word 4 (byte 4,5,6,7) = physical block number 
  2126                              <1> ;;		   (In fact, it is 32 bit LBA for Retro UNIX 386 v1)
  2127                              <1> ;;
  2128                              <1> ;; I/O Buffer ((8+512 bytes in original Unix v1))
  2129                              <1> ;;	      ((4+512 bytes in Retro UNIX 8086 v1))
  2130                              <1> ;;
  2131                              <1> ;; I/O Queue Entry (of original UNIX operating system v1)
  2132                              <1> ;; Word 1, Byte 0 = device id
  2133                              <1> ;; Word 1, Byte 1 = (bits 8 to 15)
  2134                              <1> ;;          bit 9 = write bit
  2135                              <1> ;;	    bit 10 = read bit	  
  2136                              <1> ;;	    bit 12 = waiting to write bit	
  2137                              <1> ;;	    bit 13 = waiting to read bit
  2138                              <1> ;;	    bit 15 = inhibit bit
  2139                              <1> ;; Word 2 = physical block number (In fact, it is LBA for Retro UNIX 8086 v1)
  2140                              <1> ;;
  2141                              <1> ;; Original UNIX v1 ->
  2142                              <1> ;;		Word 3 = number of words in buffer (=256) 		
  2143                              <1> ;; Original UNIX v1 -> 
  2144                              <1> ;;		Word 4 = bus address (addr of first word of data buffer)
  2145                              <1> ;;
  2146                              <1> ;; Retro UNIX 8086 v1 -> Buffer Header (I/O Queue Entry) size is 4 bytes !
  2147                              <1> ;;
  2148                              <1> ;; Device IDs (of Retro Unix 8086 v1)
  2149                              <1> ;;          0 = fd0
  2150                              <1> ;;	    1 = fd1
  2151                              <1> ;;	    2 = hd0
  2152                              <1> ;;	    3 = hd1
  2153                              <1> ;;	    4 = hd2
  2154                              <1> ;;	    5 = hd3
  2155                              <1> 
  2156                              <1> ; Retro UNIX 386 v1 - 32 bit modifications (rfd, wfd, rhd, whd) - 09/06/2015
  2157                              <1> 
  2158                              <1> 	; 08/02/2022
  2159                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2160                              <1> rfd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2161                              <1> 	; 26/04/2013
  2162                              <1>    	; 13/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2163                              <1>    	;sub 	ax, 3 ; zero based device number (Floppy disk)
  2164                              <1>       	;jmp 	short bread ; **** returns to routine that called readi			
  2165                              <1> 
  2166                              <1> 	; 08/02/2022
  2167                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2168                              <1> rhd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2169                              <1> 	; 26/04/2013
  2170                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2171                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2172                              <1>    	;jmp	short bread ; **** returns to routine that called readi	
  2173                              <1> 
  2174                              <1> bread: 
  2175                              <1> 	; 08/02/2022
  2176                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2177                              <1> 	; 14/07/2015
  2178                              <1> 	; 10/07/2015
  2179                              <1> 	; 09/06/2015
  2180                              <1> 	; 07/06/2015 (Retro UNIX 386 v1 - Beginning)
  2181                              <1> 	; 13/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2182                              <1> 	;	
  2183                              <1> 	; / read a block from a block structured device
  2184                              <1> 	;
  2185                              <1> 	; INPUTS ->
  2186                              <1> 	;    [u.fofp] points to the block number
  2187                              <1> 	;    CX = maximum block number allowed on device
  2188                              <1> 	;	 ; that was an arg to bread, in original Unix v1, but
  2189                              <1> 	;	 ; CX register is used instead of arg in Retro Unix 8086 v1 		
  2190                              <1> 	;    [u.count]	number of bytes to read in
  2191                              <1> 	; OUTPUTS ->
  2192                              <1> 	;    [u.base] starting address of data block or blocks in user area  	
  2193                              <1> 	;    [u.fofp] points to next consecutive block to be read
  2194                              <1> 	;
  2195                              <1> 	; ((Modified registers: eAX, eDX, eCX, eBX, eSI, eDI, eBP))
  2196                              <1> 	;
  2197                              <1> 	; NOTE: Original UNIX v1 has/had a defect/bug here, even if read
  2198                              <1> 	;       byte count is less than 512, block number in *u.fofp (u.off)
  2199                              <1> 	;	is increased by 1. For example: If user/program request 
  2200                              <1> 	;       to read 16 bytes in current block, 'sys read' increases
  2201                              <1> 	;  	the next block number just as 512 byte reading is done.
  2202                              <1> 	;       This wrong is done in 'bread'. So, in Retro UNIX 8086 v1, 
  2203                              <1> 	;       for user (u) structure compatibility (because 16 bit is not
  2204                              <1> 	;       enough to keep byte position/offset of the disk), this
  2205                              <1> 	;	defect will not be corrected, user/program must request
  2206                              <1> 	;	512 byte read per every 'sys read' call to block devices
  2207                              <1> 	;       for achieving correct result. In future version(s), 
  2208                              <1> 	;	this defect will be corrected by using different 
  2209                              <1> 	;       user (u) structure. 26/07/2013 - Erdogan Tan 	
  2210                              <1> 
  2211                              <1> 	   	; jsr r0,tstdeve / error on special file I/O 
  2212                              <1> 			       ; / (only works on tape)
  2213                              <1> 		; mov *u.fofp,r1 / move block number to r1
  2214                              <1> 		; mov $2.-cold,-(sp) / "2-cold" to stack
  2215                              <1> ;1:
  2216                              <1> 		; cmp r1,(r0) / is this block # greater than or equal to
  2217                              <1> 			    ; / maximum block # allowed on device
  2218                              <1> 		; jnb short @f
  2219                              <1> 		; bhis	1f / yes, 1f (error)
  2220                              <1> 		; mov r1,-(sp) / no, put block # on stack
  2221                              <1> 		; jsr r0,preread / read in the block into an I/O buffer
  2222                              <1> 		; mov (sp)+,r1 / return block # to r1
  2223                              <1> 		; inc r1 / bump block # to next consecutive block
  2224                              <1> 		; dec (sp) / "2-1-cold" on stack
  2225                              <1> 		; bgt 1b / 2-1-cold = 0?  No, go back and read in next block
  2226                              <1> ;1:
  2227                              <1> 		; tst (sp)+ / yes, pop stack to clear off cold calculation
  2228                              <1> 	;push	ecx ; **
  2229                              <1> 	; 26/04/2013
  2230                              <1> 	;sub	ax, 3 ; 3 to 8 -> 0 to 5
  2231 00005B22 2C03                <1> 	sub	al, 3
  2232                              <1> 		; AL = Retro Unix 8086 v1 disk (block device) number
  2233 00005B24 A2[006F0000]        <1> 	mov	[u.brwdev], al
  2234                              <1> 	; 09/06/2015
  2235                              <1> 	;movzx	ebx, al
  2236                              <1> 	;mov	ecx, [ebx+drv.size] ; disk size (in sectors)
  2237                              <1> 	; 12/01/2022 (BugFix)
  2238 00005B29 C0E002              <1> 	shl	al, 2 ; * 4
  2239 00005B2C 8B88[FE650000]      <1> 	mov	ecx, [eax+drv.size] ; disk size (in sectors)
  2240                              <1> bread_0:
  2241 00005B32 51                  <1> 	push	ecx ; ** ; 09/06/2015 
  2242                              <1> 	; 10/07/2015 (Retro UNIX 386 v1 modification!)
  2243                              <1> 	; [u.fofp] points to byte position in disk, not sector/block !
  2244 00005B33 8B1D[A86E0000]      <1> 	mov	ebx, [u.fofp]
  2245 00005B39 8B03                <1> 	mov	eax, [ebx]
  2246 00005B3B C1E809              <1> 	shr	eax, 9 ; convert byte position to block/sector number
  2247                              <1> 		; mov *u.fofp,r1 / restore r1 to initial value of the
  2248                              <1> 			       ; / block #
  2249 00005B3E 39C8                <1> 	cmp	eax, ecx
  2250                              <1> 		; cmp r1,(r0)+ / block # greater than or equal to maximum
  2251                              <1>        	                     ; / block number allowed
  2252                              <1> 	;jnb	error 	     ; 18/04/2013
  2253                              <1> 		; bhis error10 / yes, error
  2254                              <1> 	; 08/02/2022
  2255                              <1> 	;jb	short bread_1
  2256                              <1> 	;mov 	dword [u.error], ERR_DEV_VOL_SIZE  ; 'out of volume' error
  2257                              <1> 	;jmp	error
  2258 00005B40 735A                <1> 	jnb	short brw_oov_err ; 'out of volume' error
  2259                              <1> bread_1:
  2260                              <1> 	;inc 	dword [ebx] ; 10/07/2015 (Retro UNIX 386 v1 - modification!)
  2261                              <1> 		; inc *u.fofp / no, *u.fofp has next block number
  2262                              <1> 	; eAX = Block number (zero based)
  2263                              <1> 		;;jsr r0,preread / read in the block whose number is in r1
  2264                              <1> preread: ;; call preread
  2265 00005B42 BF[006F0000]        <1> 	mov	edi, u.brwdev ; block device number for direct I/O
  2266 00005B47 E888020000          <1> 	call	bufaloc_0 ; 26/04/2013
  2267                              <1> 	;; jc 	error
  2268                              <1> 	; eBX = Buffer (Header) Address -Physical-
  2269                              <1>         ; eAX = Block/Sector number (r1)
  2270                              <1> 	       ; jsr r0,bufaloc / get a free I/O buffer (r1 has block number)
  2271                              <1> 	; 14/03/2013
  2272 00005B4C 7411                <1>         jz	short bread_2 ; Retro UNIX 8086 v1 modification
  2273                              <1>        		; br 1f / branch if block already in a I/O buffer
  2274 00005B4E 66810B0004          <1> 	or	word [ebx], 400h ; set read bit (10) in I/O Buffer
  2275                              <1>         	; bis $2000,(r5) / set read bit (bit 10 in I/O buffer)
  2276 00005B53 E8DA010000          <1> 	call	poke
  2277                              <1>         	; jsr r0,poke / perform the read
  2278                              <1> 	;;jc	error ;2 0/07/2013
  2279                              <1> ; 1:
  2280                              <1>  		; clr *$ps / ps = 0
  2281                              <1>         	; rts r0
  2282                              <1> 	; 08/02/2022
  2283 00005B58 7305                <1> 	jnc	short bread_2
  2284 00005B5A E937010000          <1> 	jmp	dskrd_err
  2285                              <1> 	;
  2286                              <1> ;; return from preread
  2287                              <1> bread_2:
  2288 00005B5F 66810B0040          <1> 	or	word [ebx], 4000h 
  2289                              <1> 		; bis $40000,(r5) 
  2290                              <1> 			; / set bit 14 of the 1st word of the I/O buffer
  2291                              <1> bread_3: ; 1:
  2292 00005B64 66F7030024          <1> 	test	word [ebx], 2400h
  2293                              <1> 		; bit $22000,(r5) / are 10th and 13th bits set (read bits)
  2294 00005B69 7407                <1> 	jz	short bread_4
  2295                              <1> 		; beq 1f / no
  2296                              <1> 		; cmp cdev,$1 / disk or drum?
  2297                              <1> 		; ble 2f / yes
  2298                              <1> 		; tstb uquant / is the time quantum = 0?
  2299                              <1> 		; bne 2f / no, 2f
  2300                              <1> 		; mov r5,-(sp) / yes, save r5 (buffer address)
  2301                              <1> 		; jsr r0,sleep; 31. 
  2302                              <1> 			; / put process to sleep in channel 31 (tape)
  2303                              <1> 		; mov (sp)+,r5 / restore r5
  2304                              <1> 		; br 1b / go back
  2305                              <1> ; 2: / drum or disk
  2306                              <1>         ;; mov	cx, [s.wait_]+2 ;; 29/07/2013
  2307 00005B6B E8B9F3FFFF          <1> 	call	idle
  2308                              <1> 		; jsr r0,idle; s.wait+2 / wait
  2309 00005B70 EBF2                <1> 	jmp	short bread_3
  2310                              <1>        		; br 1b
  2311                              <1> bread_4: ; 1: / 10th and 13th bits not set
  2312 00005B72 668123FFBF          <1> 	and	word [ebx], 0BFFFh ; 1011111111111111b
  2313                              <1> 		; bic $40000,(r5) / clear bit 14
  2314                              <1>        		; jsr r0,tstdeve / test device for error (tape)
  2315 00005B77 83C308              <1> 	add	ebx, 8
  2316                              <1> 		; add $8,r5 / r5 points to data in I/O buffer
  2317                              <1> 	; 09/06/2015
  2318 00005B7A 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0
  2319 00005B82 7705                <1> 	ja	short bread_5
  2320 00005B84 E875F9FFFF          <1> 	call	trans_addr_w ; translate virtual address to physical (w)
  2321                              <1> bread_5:
  2322                              <1> 	; eBX = system (I/O) buffer address
  2323 00005B89 E870000000          <1> 	call	dioreg
  2324                              <1>        		; jsr r0,dioreg / do bookkeeping on u.count etc.
  2325                              <1> 	; esi = start address of the transfer (in the buffer)
  2326                              <1> 	; edi = [u.pbase], destination address in user's memory space
  2327                              <1> 	; ecx = transfer count (in bytes)
  2328                              <1> 	;
  2329                              <1> ;1: / r5 points to beginning of data in I/O buffer, r2 points to beginning
  2330                              <1> ;   / of users data
  2331 00005B8E F3A4                <1> 	rep	movsb
  2332                              <1> 		; movb (r5)+,(r2)+ / move data from the I/O buffer
  2333                              <1>        		; dec r3 / to the user's area in core starting at u.base
  2334                              <1>        		; bne 1b
  2335 00005B90 59                  <1> 	pop	ecx ; **
  2336 00005B91 833D[BC6E0000]00    <1> 	cmp	dword [u.count], 0
  2337                              <1> 		; tst u.count / done
  2338 00005B98 7798                <1> 	ja	short bread_0 ; 09/06/2015
  2339                              <1>        		; beq 1f / yes, return
  2340                              <1> 		; tst -(r0) / no, point r0 to the argument again
  2341                              <1>        		; br bread / read some more
  2342                              <1> ; 1:
  2343 00005B9A 58                  <1> 	pop	eax ; ****
  2344                              <1>        		; mov (sp)+,r0
  2345 00005B9B C3                  <1>         retn		; 09/06/2015
  2346                              <1> 	;jmp	ret_ 
  2347                              <1> 		;jmp ret  / jump to routine that called readi
  2348                              <1> 
  2349                              <1> 	; 08/02/2022
  2350                              <1> brw_oov_err:
  2351 00005B9C C705[ED6E0000]1000- <1> 	mov 	dword [u.error], ERR_DEV_VOL_SIZE  ; 'out of volume' error
  2351 00005BA4 0000                <1>
  2352 00005BA6 E927DFFFFF          <1> 	jmp	error
  2353                              <1> 
  2354                              <1> 	; 08/02/2022
  2355                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2356                              <1> wfd:    ; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2357                              <1> 	; 26/04/2013
  2358                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2359                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2360                              <1>    	;jmp	short bwrite ; **** returns to routine that called writei
  2361                              <1> 
  2362                              <1> 
  2363                              <1> 	; 08/02/2022
  2364                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)				
  2365                              <1> whd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2366                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2367                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2368                              <1>    	;jmp 	short bwrite ; **** returns to routine that called writei ('jmp ret')
  2369                              <1> 
  2370                              <1> bwrite:
  2371                              <1> 	; 08/02/2022
  2372                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2373                              <1> 	; 14/07/2015
  2374                              <1> 	; 10/07/2015
  2375                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2376                              <1> 	; 14/03/2013 - 20/07/2013 (Retro UNIX 8086 v1)
  2377                              <1> 	;	
  2378                              <1> 	;; / write on block structured device
  2379                              <1> 	;
  2380                              <1> 	; INPUTS ->
  2381                              <1> 	;    [u.fofp] points to the block number
  2382                              <1> 	;    CX = maximum block number allowed on device
  2383                              <1> 	;	 ; that was an arg to bwrite, in original Unix v1, but
  2384                              <1> 	;	 ; CX register is used instead of arg in Retro Unix 8086 v1 		
  2385                              <1> 	;    [u.count]	number of bytes to user desires to write
  2386                              <1> 	; OUTPUTS ->
  2387                              <1> 	;    [u.fofp] points to next consecutive block to be written into
  2388                              <1> 	;
  2389                              <1> 	; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))
  2390                              <1> 	;
  2391                              <1> 	; NOTE: Original UNIX v1 has/had a defect/bug here, even if write
  2392                              <1> 	;       byte count is less than 512, block number in *u.fofp (u.off)
  2393                              <1> 	;	is increased by 1. For example: If user/program request 
  2394                              <1> 	;       to write 16 bytes in current block, 'sys write' increases
  2395                              <1> 	;  	the next block number just as 512 byte writing is done.
  2396                              <1> 	;       This wrong is done in 'bwrite'. So, in Retro UNIX 8086 v1, 
  2397                              <1> 	;       for user (u) structure compatibility (because 16 bit is not
  2398                              <1> 	;       enough to keep byte position/offset of the disk), this
  2399                              <1> 	;	defect will not be corrected, user/program must request
  2400                              <1> 	;	512 byte write per every 'sys write' call to block devices
  2401                              <1> 	;       for achieving correct result. In future version(s), 
  2402                              <1> 	;	this defect will be corrected by using different 
  2403                              <1> 	;       user (u) structure. 26/07/2013 - Erdogan Tan 	
  2404                              <1> 
  2405                              <1>        		; jsr r0,tstdeve / test the device for an error
  2406                              <1> 	;push	ecx ; **
  2407                              <1> 	; 26/04/2013
  2408                              <1> 	;sub	ax, 3 ; 3 to 8 -> 0 to 5
  2409 00005BAB 2C03                <1> 	sub	al, 3
  2410                              <1> 		; AL = Retro Unix 8086 v1 disk (block device) number
  2411 00005BAD A2[006F0000]        <1> 	mov	[u.brwdev], al
  2412                              <1> 	; 09/06/2015
  2413                              <1> 	;movzx	ebx, al
  2414                              <1> 	;mov	ecx, [ebx+drv.size] ; disk size (in sectors)
  2415                              <1> 	; 12/01/2022 (BugFix)
  2416 00005BB2 C0E002              <1> 	shl	al, 2 ; * 4
  2417 00005BB5 8B88[FE650000]      <1> 	mov	ecx, [eax+drv.size] ; disk size (in sectors)
  2418                              <1> bwrite_0:
  2419 00005BBB 51                  <1> 	push	ecx ; ** ; 09/06/2015
  2420                              <1> 	; 10/07/2015 (Retro UNIX 386 v1 modification!)
  2421                              <1> 	; [u.fofp] points to byte position in disk, not sector/block !
  2422 00005BBC 8B1D[A86E0000]      <1> 	mov	ebx, [u.fofp]
  2423 00005BC2 8B03                <1> 	mov	eax, [ebx]       
  2424 00005BC4 C1E809              <1> 	shr	eax, 9 ; convert byte position to block/sector number
  2425                              <1> 		; mov *u.fofp,r1 / put the block number in r1
  2426 00005BC7 39C8                <1> 	cmp	eax, ecx
  2427                              <1> 		; cmp r1,(r0)+ / does block number exceed maximum allowable #
  2428                              <1>        	                     ; / block number allowed
  2429                              <1> 	;jnb	error	     ; 18/04/2013
  2430                              <1> 		; bhis error10 / yes, error
  2431                              <1>      	; 08/02/2022
  2432                              <1> 	;jb	short bwrite_1
  2433                              <1> 	;mov 	dword [u.error], ERR_DEV_VOL_SIZE  ; 'out of volume' error
  2434                              <1> 	;jmp	error
  2435 00005BC9 73D1                <1> 	jnb	short brw_oov_err ; 'out of volume' error
  2436                              <1> bwrite_1:
  2437                              <1> 	;inc 	dword [ebx] ; 10/07/2015 (Retro UNIX 386 v1 - modification!)
  2438                              <1> 		; inc *u.fofp / no, increment block number
  2439                              <1> 	; 09/06/2015 - 10/07/2015
  2440 00005BCB 66833D[FD6E0000]00  <1> 	cmp	word [u.pcount], 0
  2441 00005BD3 7705                <1> 	ja	short bwrite_2
  2442 00005BD5 E820F9FFFF          <1> 	call	trans_addr_r ; translate virtual address to physical (r)
  2443                              <1> bwrite_2:
  2444 00005BDA BF[006F0000]        <1> 	mov	edi, u.brwdev  ; block device number for direct I/O
  2445 00005BDF E8D3000000          <1>        	call	bwslot ; 26/04/2013 (wslot -> bwslot)	 				
  2446                              <1> 		; jsr r0,wslot / get an I/O buffer to write into
  2447                              <1> 		; add $8,r5 / r5 points to data in I/O buffer
  2448 00005BE4 E815000000          <1>         call	dioreg
  2449                              <1> 		; jsr r0,dioreg / do the necessary bookkeeping
  2450                              <1> 	; esi = destination address (in the buffer)
  2451                              <1> 	; edi = [u.pbase], start address of transfer in user's memory space
  2452                              <1> 	; ecx = transfer count (in bytes)
  2453                              <1> ; 1: / r2 points to the users data; r5 points to the I/O buffers data area
  2454 00005BE9 87F7                <1> 	xchg 	esi, edi ; 14/07/2015
  2455 00005BEB F3A4                <1> 	rep	movsb
  2456                              <1> 		; movb (r2)+,(r5)+ / ; r3, has the byte count
  2457                              <1>        		; dec r3 / area to the I/O buffer
  2458                              <1>        		; bne 1b
  2459 00005BED E80D010000          <1> 	call	dskwr
  2460                              <1> 		; jsr r0,dskwr / write it out on the device
  2461 00005BF2 59                  <1> 	pop	ecx ; **
  2462 00005BF3 833D[BC6E0000]00    <1>         cmp     dword [u.count], 0
  2463                              <1> 		; tst u.count / done
  2464 00005BFA 77BF                <1> 	ja	short bwrite_0 ; 09/06/2015
  2465                              <1> 		; beq 1f / yes, 1f
  2466                              <1> 		; tst -(r0) / no, point r0 to the argument of the call
  2467                              <1>        		; br bwrite / go back and write next block
  2468                              <1> ; 1:
  2469 00005BFC 58                  <1> 	pop	eax ; ****
  2470                              <1>        		; mov (sp)+,r0
  2471 00005BFD C3                  <1> 	retn		; 09/06/2015
  2472                              <1>         ;jmp	ret_ 
  2473                              <1> 		; jmp ret / return to routine that called writei
  2474                              <1> ;error10:
  2475                              <1> ;       jmp     error  ; / see 'error' routine
  2476                              <1> 
  2477                              <1> dioreg:
  2478                              <1> 	; 04/02/2022
  2479                              <1> 	; 14/07/2015
  2480                              <1> 	; 10/07/2015 (UNIX v1 bugfix - [u.fofp]: byte pos., not block)
  2481                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2482                              <1> 	; 14/03/2013 (Retro UNIX 8086 v1)
  2483                              <1> 	;	
  2484                              <1> 	; bookkeeping on block transfers of data
  2485                              <1> 	;
  2486                              <1> 	; * returns value of u.pbase before it gets updated, in EDI
  2487                              <1> 	; * returns byte count (to transfer) in ECX (<=512)
  2488                              <1> 	; 10/07/2015
  2489                              <1> 	; * returns byte offset from beginning of current sector buffer
  2490                              <1> 	; (beginning of data) in ESI
  2491                              <1> 	;
  2492 00005BFE 8B0D[BC6E0000]      <1> 	mov	ecx, [u.count]
  2493                              <1> 		; mov u.count,r3 / move char count to r3
  2494                              <1> 	; 04/02/2022
  2495 00005C04 31D2                <1> 	xor	edx, edx
  2496 00005C06 B602                <1> 	mov	dh, 2
  2497                              <1> 	; edx = 512
  2498 00005C08 39D1                <1> 	cmp	ecx, edx ; 512
  2499                              <1> 	;cmp 	ecx, 512
  2500                              <1> 		; cmp r3,$512. / more than 512. char?
  2501 00005C0A 7602                <1> 	jna	short dioreg_0
  2502                              <1> 		; blos 1f / no, branch
  2503 00005C0C 89D1                <1> 	mov	ecx, edx ; 512
  2504                              <1> 	;mov	ecx, 512
  2505                              <1> 		; mov $512.,r3 / yes, just take 512.
  2506                              <1> dioreg_0:
  2507                              <1> 	; 09/06/2015
  2508 00005C0E 663B0D[FD6E0000]    <1> 	cmp	cx, [u.pcount]
  2509 00005C15 7607                <1> 	jna	short dioreg_1
  2510 00005C17 668B0D[FD6E0000]    <1> 	mov	cx, [u.pcount]
  2511                              <1> dioreg_1:
  2512                              <1> ; 1:
  2513 00005C1E 8B15[B86E0000]      <1> 	mov	edx, [u.base] ; 09/06/2015 (eax -> edx)
  2514                              <1> 	        ; mov u.base,r2 / put users base in r2
  2515 00005C24 010D[C06E0000]      <1> 	add	[u.nread], ecx
  2516                              <1> 		; add r3,u.nread / add the number to be read to u.nread
  2517 00005C2A 290D[BC6E0000]      <1> 	sub	[u.count], ecx
  2518                              <1> 		; sub r3,u.count / update count
  2519 00005C30 010D[B86E0000]      <1> 	add	[u.base], ecx
  2520                              <1> 		; add r3,u.base / update base
  2521                              <1> 	; 10/07/2015
  2522                              <1> 	; Retro UNIX 386 v1 - modification !
  2523                              <1> 	; (File pointer points to byte position, not block/sector no.)
  2524                              <1> 	; (It will point to next byte position instead of next block no.)
  2525 00005C36 8B35[A86E0000]      <1> 	mov	esi, [u.fofp] ; u.fopf points to byte position pointer  
  2526 00005C3C 8B06                <1> 	mov	eax, [esi] ; esi points to current byte pos. on the disk
  2527 00005C3E 010E                <1> 	add	[esi], ecx ; ecx is added to set the next byte position
  2528 00005C40 25FF010000          <1> 	and	eax, 1FFh  ; get offset from beginning of current block	
  2529 00005C45 89DE                <1> 	mov	esi, ebx   ; beginning of data in sector/block buffer
  2530 00005C47 01C6                <1> 	add	esi, eax   ; esi contains start address of the transfer
  2531                              <1> 	; 09/06/2015 - 10/07/2015
  2532 00005C49 66290D[FD6E0000]    <1> 	sub	[u.pcount], cx
  2533 00005C50 81E2FF0F0000        <1> 	and	edx, PAGE_OFF ; 0FFFh
  2534 00005C56 8B3D[F96E0000]      <1> 	mov	edi, [u.pbase]
  2535 00005C5C 81E700F0FFFF        <1> 	and	edi, ~PAGE_OFF
  2536 00005C62 01D7                <1> 	add	edi, edx
  2537 00005C64 893D[F96E0000]      <1> 	mov	[u.pbase], edi
  2538 00005C6A 010D[F96E0000]      <1> 	add	[u.pbase], ecx ; 14/07/2015
  2539 00005C70 C3                  <1> 	retn
  2540                              <1> 		; rts r0 / return
  2541                              <1> 
  2542                              <1> dskrd:
  2543                              <1> 	; 08/02/2022 (Retro UNIX 386 v1.1)
  2544                              <1> 	; 18/08/2015
  2545                              <1> 	; 02/07/2015
  2546                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2547                              <1> 	; 14/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2548                              <1> 	;
  2549                              <1> 	; 'dskrd' acquires an I/O buffer, puts in the proper
  2550                              <1> 	; I/O queue entries (via bufaloc) then reads a block
  2551                              <1> 	; (number specified in r1) in the acquired buffer.)
  2552                              <1> 	; If the device is busy at the time dskrd is called,	
  2553                              <1> 	; dskrd calls idle.
  2554                              <1> 	; 
  2555                              <1> 	; INPUTS ->
  2556                              <1> 	;    r1 - block number
  2557                              <1> 	;    cdev - current device number 
  2558                              <1> 	; OUTPUTS ->
  2559                              <1> 	;    r5 - points to first data word in I/O buffer
  2560                              <1> 	;
  2561                              <1> 	; ((AX = R1)) input/output
  2562                              <1> 	; ((BX = R5)) output 
  2563                              <1> 	;
  2564                              <1>         ; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  2565                              <1> 	;
  2566 00005C71 E851010000          <1> 	call 	bufaloc
  2567                              <1> 		; jsr r0,bufaloc / shuffle off to bufaloc; 
  2568                              <1> 			       ; / get a free I/O buffer
  2569                              <1> 	;;jc	error ; 20/07/2013
  2570 00005C76 740C                <1> 	jz	short dskrd_1 ; Retro UNIX 8086 v1 modification
  2571                              <1>        		; br 1f / branch if block already in a I/O buffer
  2572                              <1> dskrd_0: ; 10/07/2015 (wslot)
  2573 00005C78 66810B0004          <1> 	or	word [ebx], 400h ; set read bit (10) in I/O Buffer
  2574                              <1>         	; bis $2000,(r5) / set bit 10 of word 1 of 
  2575                              <1> 		               ; / I/O queue entry for buffer
  2576 00005C7D E8B0000000          <1> 	call	poke
  2577                              <1> 		; jsr r0,poke / just assigned in bufaloc, 
  2578                              <1> 			    ; /	bit 10=1 says read
  2579                              <1> 	; 09/06/2015
  2580                              <1> 	;jnc	short dskrd_1
  2581                              <1> 	;mov	dword [u.error], ERR_DRV_READ ; disk read error !
  2582                              <1> 	;jmp	error
  2583                              <1> 	; 08/02/2022
  2584 00005C82 7212                <1> 	jc	short dskrd_3
  2585                              <1> dskrd_1: ; 1:
  2586                              <1>        		;clr *$ps
  2587 00005C84 66F7030024          <1>        	test	word [ebx], 2400h
  2588                              <1> 		; bit $22000,(r5) / if either bits 10, or 13 are 1; 
  2589                              <1> 				; / jump to idle
  2590 00005C89 7407                <1>        	jz	short dskrd_2
  2591                              <1> 		; beq 1f
  2592                              <1>         ;;mov   ecx, [s.wait_]
  2593 00005C8B E899F2FFFF          <1>        	call	idle
  2594                              <1> 		; jsr r0,idle; s.wait+2
  2595 00005C90 EBF2                <1> 	jmp 	short dskrd_1
  2596                              <1>        		; br 1b
  2597                              <1> dskrd_2: ; 1:
  2598 00005C92 83C308              <1>         add	ebx, 8
  2599                              <1> 		; add $8,r5 / r5 points to first word of data in block 
  2600                              <1> 			  ; / just read in
  2601 00005C95 C3                  <1>        	retn
  2602                              <1> 		; rts r0
  2603                              <1> dskrd_err: 
  2604                              <1> 	; 08/02/2022
  2605                              <1> 	; (jump from 'bread' error)	
  2606                              <1> dskrd_3:	
  2607                              <1> 	; 08/02/2022
  2608 00005C96 803D[006F0000]FF    <1> 	cmp	byte [u.brwdev], 0FFh ; is error code set in [u.error] ?
  2609 00005C9D 7509                <1> 	jne	short dskrd_4 ; no
  2610                              <1> 	; yes, clear [u.brwdev] for next check and jump to 'error'
  2611 00005C9F C605[006F0000]00    <1> 	mov	byte [u.brwdev], 0
  2612 00005CA6 EB0A                <1> 	jmp	short dskrd_5
  2613                              <1> dskrd_4:
  2614 00005CA8 C705[ED6E0000]1100- <1> 	mov	dword [u.error], ERR_DRV_READ ; disk read error !
  2614 00005CB0 0000                <1>
  2615                              <1> dskrd_5:
  2616 00005CB2 E91BDEFFFF          <1> 	jmp	error
  2617                              <1> 
  2618                              <1> bwslot:
  2619                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2620                              <1> 	; 10/07/2015
  2621                              <1> 	;	If the block/sector is not placed in a buffer
  2622                              <1> 	;	before 'wslot', it must be read before
  2623                              <1> 	;	it is written! (Otherwise transfer counts less
  2624                              <1> 	;	than 512 bytes will be able to destroy existing 
  2625                              <1> 	;	data on disk.)
  2626                              <1> 	;
  2627                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2628                              <1> 	; 26/04/2013(Retro UNIX 8086 v1)
  2629                              <1> 	; Retro UNIX 8086 v1 modification !
  2630                              <1> 	; ('bwslot' will be called from 'bwrite' only!)
  2631                              <1> 	; INPUT -> eDI - points to device id (in u.brwdev)	
  2632                              <1> 	;	-> eAX = block number
  2633                              <1> 	;
  2634 00005CB7 E818010000          <1> 	call	bufaloc_0
  2635 00005CBC 742A                <1> 	jz	short wslot_0 ; block/sector already is in the buffer
  2636                              <1> 	; 12/01/2022
  2637                              <1> 	; ebx = buffer header address
  2638                              <1> bwslot_0:
  2639                              <1> 	; 10/07/2015
  2640 00005CBE 8B35[A86E0000]      <1> 	mov	esi, [u.fofp]
  2641 00005CC4 8B06                <1> 	mov	eax, [esi]
  2642 00005CC6 25FF010000          <1> 	and	eax, 1FFh ; offset from beginning of the sector/block
  2643 00005CCB 750C                <1> 	jnz 	short bwslot_1 ; it is not a full sector write
  2644                              <1> 		       ; recent disk data must be placed in the buffer
  2645 00005CCD 813D[BC6E0000]0002- <1> 	cmp	dword [u.count], 512
  2645 00005CD5 0000                <1>
  2646 00005CD7 730F                <1> 	jnb	short wslot_0	
  2647                              <1> bwslot_1:
  2648 00005CD9 E89AFFFFFF          <1> 	call	dskrd_0
  2649                              <1> 	; 12/01/2022
  2650                              <1> 	; ebx = buffer data address = buffer header address + 8
  2651 00005CDE 83EB08              <1> 	sub	ebx, 8 ; set ebx to the buffer header address again
  2652 00005CE1 EB05                <1> 	jmp 	short wslot_0
  2653                              <1> 
  2654                              <1> wslot:
  2655                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2656                              <1> 	; 		(32 bit modifications)
  2657                              <1> 	; 14/03/2013 - 29/07/2013(Retro UNIX 8086 v1)
  2658                              <1> 	;
  2659                              <1> 	; 'wslot' calls 'bufaloc' and obtains as a result, a pointer
  2660                              <1> 	; to the I/O queue of an I/O buffer for a block structured
  2661                              <1> 	; device. It then checks the first word of I/O queue entry.	
  2662                              <1> 	; If bits 10 and/or 13 (read bit, waiting to read bit) are set,
  2663                              <1> 	; wslot calls 'idle'. When 'idle' returns, or if bits 10 
  2664                              <1> 	; and/or 13 are not set, 'wslot' sets bits 9 and 15 of the first
  2665                              <1> 	; word of the I/O queue entry (write bit, inhibit bit).
  2666                              <1> 	;
  2667                              <1> 	; INPUTS ->
  2668                              <1>  	;    r1 - block number
  2669                              <1> 	;    cdev - current (block/disk) device number
  2670                              <1>  	;
  2671                              <1> 	; OUTPUTS ->
  2672                              <1> 	;    bufp - bits 9 and 15 are set, 
  2673                              <1> 	;           the remainder of the word left unchanged
  2674                              <1> 	;    r5 - points to first data word in I/O buffer
  2675                              <1> 	;
  2676                              <1> 	; ((AX = R1)) input/output
  2677                              <1> 	; ((BX = R5)) output 
  2678                              <1> 	;
  2679                              <1>         ; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP)) 
  2680                              <1> 
  2681 00005CE3 E8DF000000          <1> 	call	bufaloc
  2682                              <1> 	; 10/07/2015
  2683                              <1> 		; jsr r0,bufaloc / get a free I/O buffer; pointer to first
  2684                              <1>         	; br 1f / word in buffer in r5
  2685                              <1> 	; eBX = Buffer (Header) Address (r5) (ES=CS=DS, system/kernel segment)
  2686                              <1>         ; eAX = Block/Sector number (r1)
  2687                              <1> wslot_0: ;1:
  2688 00005CE8 66F7030024          <1>      	test	word [ebx], 2400h
  2689                              <1> 		; bit $22000,(r5) / check bits 10, 13 (read, waiting to read)
  2690                              <1> 				; / of I/O queue entry
  2691 00005CED 7407                <1> 	jz	short wslot_1
  2692                              <1>                 ; beq 1f  / branch if 10, 13 zero (i.e., not reading, 
  2693                              <1> 		     ; / or not waiting to read)
  2694                              <1> 
  2695                              <1>         ;; mov     ecx, [s.wait_] ; 29/07/2013
  2696 00005CEF E835F2FFFF          <1> 	call	idle
  2697                              <1> 		; jsr r0,idle; / if buffer is reading or writing to read,
  2698                              <1>        	                     ; / idle
  2699 00005CF4 EBF2                <1> 	jmp	short wslot_0
  2700                              <1> 		; br 1b / till finished
  2701                              <1> wslot_1: ;1:
  2702 00005CF6 66810B0082          <1>         or      word [ebx], 8200h
  2703                              <1>        		; bis $101000,(r5) / set bits 9, 15 in 1st word of I/O queue
  2704                              <1>                             	 ; / (write, inhibit bits)
  2705                              <1>        		; clr     *$ps / clear processor status
  2706 00005CFB 83C308              <1>         add	ebx, 8 ; 11/06/2015
  2707                              <1> 		; add $8,r5 / r5 points to first word in data area 
  2708                              <1> 			  ; / for this block
  2709                              <1> dskwr_1:	; 08/02/2022
  2710 00005CFE C3                  <1>        	retn
  2711                              <1> 		; rts r0
  2712                              <1> dskwr:
  2713                              <1> 	; 08/02/2022 (Retro UNIX 386 v1.1)
  2714                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2715                              <1> 	; 14/03/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2716                              <1> 	;
  2717                              <1> 	; 'dskwr' writes a block out on disk, via ppoke. The only
  2718                              <1> 	; thing dskwr does is clear bit 15 in the first word of I/O queue
  2719                              <1> 	; entry pointed by 'bufp'. 'wslot' which must have been called
  2720                              <1> 	; previously has supplied all the information required in the
  2721                              <1> 	; I/O queue entry.
  2722                              <1> 	;
  2723                              <1> 	; (Modified registers: eCX, eDX, eBX, eSI, eDI)
  2724                              <1> 	;
  2725                              <1> 	;
  2726 00005CFF 8B1D[5C6E0000]      <1> 	mov	ebx, [bufp]
  2727 00005D05 668123FF7F          <1> 	and	word [ebx], 7FFFh ; 0111111111111111b
  2728                              <1> 		; bic $100000,*bufp / clear bit 15 of I/O queue entry at
  2729                              <1>                                   ; / bottom of queue
  2730 00005D0A E823000000          <1> 	call	poke
  2731                              <1> 	; 09/06/2015
  2732 00005D0F 73ED                <1> 	jnc	short dskwr_1
  2733                              <1> 	; 08/02/2022
  2734 00005D11 803D[006F0000]FF    <1> 	cmp	byte [u.brwdev], 0FFh ; is error code set in [u.error] ?
  2735 00005D18 7509                <1> 	jne	short dskwr_0 ; no
  2736                              <1> 	; yes, clear [u.brwdev] for next check and jump to 'error'
  2737 00005D1A C605[006F0000]00    <1> 	mov	byte [u.brwdev], 0
  2738 00005D21 EB0A                <1> 	jmp	short dskwr_2
  2739                              <1> dskwr_0:
  2740 00005D23 C705[ED6E0000]1200- <1> 	mov	dword [u.error], ERR_DRV_WRITE ; disk write error !
  2740 00005D2B 0000                <1>
  2741                              <1> dskwr_2:
  2742 00005D2D E9A0DDFFFF          <1> 	jmp	error
  2743                              <1> ;dskwr_1:
  2744                              <1> ;	retn
  2745                              <1> 
  2746                              <1> ;ppoke:
  2747                              <1>        		; mov $340,*$ps
  2748                              <1>        		; jsr r0,poke
  2749                              <1>        		; clr *$ps
  2750                              <1> 		; rts r0
  2751                              <1> poke:
  2752                              <1> 	; 24/12/2021 (32 bit reg push-pop)
  2753                              <1> 	; 24/10/2015
  2754                              <1> 	; 20/08/2015
  2755                              <1> 	; 18/08/2015
  2756                              <1> 	; 02/07/2015
  2757                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2758                              <1> 	; 15/03/2013 - 18/01/2014 (Retro UNIX 8086 v1)
  2759                              <1> 	;
  2760                              <1> 	; (NOTE: There are some disk I/O code modifications & extensions
  2761                              <1> 	; & exclusions on original 'poke' & other device I/O procedures of 
  2762                              <1> 	; UNIX v1 OS for performing disk I/O functions by using IBM PC 
  2763                              <1> 	; compatible rombios calls in Retro UNIX 8086 v1 kernel.)
  2764                              <1> 	;
  2765                              <1> 	; Basic I/O functions for all block structured devices
  2766                              <1> 	;
  2767                              <1>         ; (Modified registers: eCX, eDX, eSI, eDI)
  2768                              <1> 	;
  2769                              <1> 	; 20/07/2013 modifications
  2770                              <1> 	;            (Retro UNIX 8086 v1 features only !)
  2771                              <1> 	; INPUTS -> 
  2772                              <1> 	;        (EBX = buffer header address)
  2773                              <1> 	; OUTPUTS ->
  2774                              <1> 	;	 cf=0 -> successed r/w (at least, for the caller's buffer) 
  2775                              <1> 	;	 cf=1 -> error, word [eBX] = 0FFFFh
  2776                              <1> 	;		(drive not ready or r/w error!)
  2777                              <1> 	;	 (dword [EBX+4] <> 0FFFFFFFFh indicates r/w success)	
  2778                              <1> 	;	 (dword [EBx+4] = 0FFFFFFFFh means RW/IO error)
  2779                              <1> 	;        (also it indicates invalid buffer data)
  2780                              <1> 	;
  2781 00005D32 53                  <1> 	push	ebx
  2782                              <1>        		; mov r1,-(sp)
  2783                              <1>        		; mov r2,-(sp)
  2784                              <1>        		; mov r3,-(sp)
  2785 00005D33 50                  <1> 	push 	eax ; Physical Block Number (r1) (mget)
  2786                              <1> 	;
  2787                              <1> 	; 09/06/2015
  2788                              <1> 	; (permit read/write after a disk  R/W error)
  2789 00005D34 8A0B                <1> 	mov	cl, [ebx] ; device id (0 to 5)
  2790 00005D36 B001                <1> 	mov	al, 1
  2791 00005D38 D2E0                <1> 	shl	al, cl
  2792 00005D3A 8405[826E0000]      <1> 	test 	al, [active] ; busy ? (error)
  2793 00005D40 7408                <1> 	jz	short poke_0
  2794 00005D42 F6D0                <1> 	not	al
  2795 00005D44 2005[826E0000]      <1> 	and	[active], al ; reset busy bit for this device only
  2796                              <1> poke_0:
  2797 00005D4A BE[7C6E0000]        <1>         mov     esi, bufp + (4*(nbuf+2)) 
  2798                              <1> 		; mov $bufp+nbuf+nbuf+6,r2 / r2 points to highest priority
  2799                              <1> 					 ; / I/O queue pointer
  2800                              <1> poke_1: ; 1:
  2801 00005D4F 83EE04              <1>         sub	esi, 4
  2802 00005D52 8B1E                <1> 	mov	ebx, [esi]
  2803                              <1> 		; mov -(r2),r1 / r1 points to an I/O queue entry
  2804 00005D54 668B03              <1> 	mov	ax, [ebx] ; 17/07/2013
  2805 00005D57 F6C406              <1>        	test	ah, 06h
  2806                              <1> 	;test	word [ebx], 600h ; 0000011000000000b
  2807                              <1> 		; bit $3000,(r1) / test bits 9 and 10 of word 1 of I/O 
  2808                              <1> 			       ; / queue entry
  2809 00005D5A 745C                <1>         jz      short poke_5
  2810                              <1> 		; beq 2f / branch to 2f if both are clear
  2811                              <1> 	; 31/07/2013
  2812                              <1> 	;test	ah, 0B0h ; (*)
  2813                              <1> 	;;test	word [ebx], 0B000h ; 1011000000000000b
  2814                              <1> 		; bit $130000,(r1) / test bits 12, 13, and 15
  2815                              <1>         ;jnz	short poke_5 ; 31/07/2013 (*)
  2816                              <1> 		; bne 2f / branch if any are set
  2817                              <1> 	;movzx	ecx, byte [ebx] ; 09/06/2015 ; Device Id
  2818                              <1>     		; movb (r1),r3 / get device id
  2819 00005D5C 0FB6C8              <1> 	movzx	ecx, al ; 18/08/2015
  2820                              <1> 	;mov	edi, ecx ; 26/04/2013
  2821 00005D5F 31C0                <1> 	xor 	eax, eax ; 0
  2822                              <1> 	;cmp 	[edi+drv.error], al ; 0
  2823                              <1> 		; tstb deverr(r3) / test for errors on this device
  2824                              <1>        	;jna	short poke_2 
  2825                              <1> 		; beq 3f / branch if no errors
  2826                              <1> 	; 02/07/2015
  2827                              <1> 	;dec	eax
  2828                              <1> 	;mov	[ebx+4], ax ; 0FFFFFFFFh ; -1 
  2829                              <1>        		; mov $-1,2(r1) / destroy associativity
  2830                              <1> 	;shr	eax, 24
  2831                              <1> 	;mov	[ebx], eax ; 000000FFh, reset
  2832                              <1> 		; clrb 1(r1) / do not do I/O
  2833                              <1> 	;jmp	short poke_5
  2834                              <1>         ;       ; br 2f
  2835                              <1>                 ; rts r0
  2836                              <1> poke_2: ; 3:
  2837                              <1> 	; 02/07/2015
  2838 00005D61 FEC1                <1> 	inc	cl ; 0FFh -> 0
  2839 00005D63 7453                <1> 	jz	short poke_5
  2840 00005D65 FEC0                <1> 	inc	al ; mov ax, 1
  2841 00005D67 FEC9                <1> 	dec	cl
  2842 00005D69 7402                <1> 	jz	short poke_3
  2843                              <1> 	; 26/04/2013 Modification
  2844                              <1> 	;inc	al ; mov ax, 1
  2845                              <1> 	;or	cl, cl ; Retro UNIX 8086 v1 device id.
  2846                              <1> 	;jz	short poke_3 ; cl = 0
  2847 00005D6B D2E0                <1> 	shl	al, cl ; shl ax, cl
  2848                              <1> poke_3:
  2849                              <1> 	;test	[active], ax
  2850 00005D6D 8405[826E0000]      <1> 	test	[active], al
  2851                              <1> 		; bit $2,active / test disk busy bit
  2852 00005D73 7543                <1> 	jnz     short poke_5
  2853                              <1> 		; bne 2f / branch if bit is set
  2854                              <1> 	;or	[active], ax
  2855 00005D75 0805[826E0000]      <1> 	or	[active], al
  2856                              <1> 		; bis $2,active / set disk busy bit
  2857                              <1> 	;push	ax
  2858                              <1> 	; 24/12/2021
  2859 00005D7B 50                  <1> 	push	eax
  2860 00005D7C E8C9000000          <1> 	call	diskio ; Retro UNIX 8086 v1 Only !
  2861                              <1> 	;mov    [edi+drv.error], ah
  2862                              <1> 	; 24/12/2021
  2863 00005D81 58                  <1> 	pop	eax
  2864                              <1> 	;pop	ax
  2865 00005D82 730E                <1> 	jnc	short poke_4 ; 20/07/2013
  2866                              <1> 	;cmp 	[edi+drv.error], al ; 0	
  2867                              <1> 	;jna	short poke_4
  2868                              <1> 		; tstb deverr(r3) / test for errors on this device
  2869                              <1>        		; beq 3f / branch if no errors
  2870                              <1> 	; 02/07/2015 (32 bit modification)
  2871                              <1> 	; 20/07/2013
  2872 00005D84 C74304FFFFFFFF      <1> 	mov	dword [ebx+4], 0FFFFFFFFh ; -1 
  2873                              <1>        		; mov $-1,2(r1) / destroy associativity
  2874 00005D8B 66C703FF00          <1> 	mov	word [ebx], 0FFh ; 20/08/2015 
  2875                              <1> 		; clrb 1(r1) / do not do I/O
  2876 00005D90 EB26                <1> 	jmp     short poke_5
  2877                              <1> poke_4:	; 20/07/2013
  2878                              <1> 	; 17/07/2013
  2879 00005D92 F6D0                <1> 	not 	al 
  2880 00005D94 2005[826E0000]      <1> 	and	[active], al ; reset, not busy
  2881                              <1> 	; eBX = system I/O buffer header (queue entry) address
  2882                              <1> seta: ; / I/O queue bookkeeping; set read/write waiting bits.
  2883 00005D9A 668B03              <1> 	mov	ax, [ebx]
  2884                              <1>        		; mov (r1),r3 / move word 1 of I/O queue entry into r3
  2885 00005D9D 66250006            <1>         and	ax, 600h
  2886                              <1> 		; bic $!3000,r3 / clear all bits except 9 and 10
  2887 00005DA1 668123FFF9          <1> 	and 	word [ebx], 0F9FFh
  2888                              <1>        		; bic $3000,(r1) / clear only bits 9 and 10
  2889 00005DA6 C0E403              <1> 	shl	ah, 3
  2890                              <1>        		; rol r3
  2891                              <1>                 ; rol r3
  2892                              <1>                 ; rol r3	
  2893 00005DA9 660903              <1> 	or	[ebx], ax
  2894                              <1> 		; bis r3,(r1) / or old value of bits 9 and 10 with 
  2895                              <1> 			   ; bits 12 and 13
  2896 00005DAC E878F1FFFF          <1> 	call	idle ; 18/01/2014
  2897                              <1> 	;; sti
  2898                              <1> 	;hlt 	; wait for a hardware interrupt
  2899                              <1> 	;; cli
  2900                              <1> 	; NOTE: In fact, disk controller's 'disk I/O completed' 
  2901                              <1>         ; interrupt would be used to reset busy bits, but INT 13h
  2902                              <1> 	; returns when disk I/O is completed. So, here, as temporary
  2903                              <1> 	; method, this procedure will wait for a time according to
  2904                              <1> 	; multi tasking and time sharing concept.
  2905                              <1> 	;
  2906                              <1> 	; 24/10/2015
  2907                              <1> 	;not	ax 
  2908 00005DB1 66B8FF00            <1> 	mov 	ax, 0FFh ; 24/10/2015 (temporary)
  2909 00005DB5 662103              <1> 	and	[ebx], ax ; clear bits 12 and 13
  2910                              <1> poke_5: ;2:
  2911 00005DB8 81FE[5C6E0000]      <1>         cmp     esi, bufp
  2912                              <1>                ; cmp r2,$bufp / test to see if entire I/O queue 
  2913                              <1>                             ; / has been scanned
  2914 00005DBE 778F                <1> 	ja      short poke_1
  2915                              <1>                ; bhi 1b
  2916                              <1> 	; 24/03/2013
  2917                              <1>        		; mov (sp)+,r3
  2918                              <1>        		; mov (sp)+,r2
  2919                              <1>        		; mov (sp)+,r1
  2920 00005DC0 58                  <1>         pop 	eax  ; Physical Block Number (r1) (mget)
  2921 00005DC1 5B                  <1> 	pop 	ebx
  2922                              <1> 	; 02/07/2015 (32 bit modification)
  2923                              <1> 	; 20/07/2013
  2924                              <1> 	;cmp 	dword [ebx+4], 0FFFFFFFFh
  2925 00005DC2 803BFF              <1> 	cmp	byte [ebx], 0FFh ; 20/08/2015
  2926                              <1> 	;	
  2927                              <1> 	; 'poke' returns with cf=0 if the requested buffer is read 
  2928                              <1> 	; or written successfully; even if an error occurs while
  2929                              <1> 	; reading to or writing from other buffers. 20/07/2013
  2930                              <1> 	;
  2931                              <1> 	; 09/06/2015
  2932 00005DC5 F5                  <1> 	cmc
  2933 00005DC6 C3                  <1> 	retn
  2934                              <1>                 ; rts r0
  2935                              <1> 
  2936                              <1> bufaloc:
  2937                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2938                              <1> 	; 20/08/2015
  2939                              <1> 	; 19/08/2015
  2940                              <1> 	; 02/07/2015
  2941                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2942                              <1> 	;	     (32 bit modifications)	
  2943                              <1> 	; 13/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2944                              <1> 	;
  2945                              <1> 	; bufaloc - Block device I/O buffer allocation
  2946                              <1> 	; 
  2947                              <1> 	; INPUTS ->
  2948                              <1> 	;    r1 - block number
  2949                              <1> 	;    cdev - current (block/disk) device number
  2950                              <1> 	;    bufp+(2*n)-2 --- n = 1 ... nbuff
  2951                              <1> 	; OUTPUTS ->
  2952                              <1> 	;    r5 - pointer to buffer allocated
  2953                              <1> 	;    bufp ... bufp+12 --- (bufp), (bufp)+2
  2954                              <1> 	;
  2955                              <1> 	; ((AX = R1)) input/output
  2956                              <1> 	; ((BX = R5)) output
  2957                              <1>         ;    ((Modified registers: DX, CX, BX, SI, DI, BP))
  2958                              <1> 	;    zf=1 -> block already in a I/O buffer
  2959                              <1> 	;    zf=0 -> a new I/O buffer has been allocated
  2960                              <1> 	;    ((DL = Device ID))
  2961                              <1> 	;    (((DH = 0 or 1)))
  2962                              <1> 	;    (((CX = previous value of word ptr [bufp])))
  2963                              <1> 	;    ((CX and DH will not be used after return)))
  2964                              <1> 
  2965                              <1> 	;;push 	esi ; ***
  2966                              <1> 		; mov r2,-(sp) / save r2 on stack
  2967                              <1>        		; mov $340,*$ps / set processor priority to 7
  2968                              <1> 	; 20/07/2013
  2969                              <1> 	; 26/04/2013
  2970                              <1> 	;movzx	ebx, byte [cdev] ; 0 or 1
  2971                              <1> 	;mov	edi, rdev ; offset mdev = offset rdev + 1
  2972                              <1> 	;add	edi, ebx
  2973                              <1> 	; 09/01/2022
  2974 00005DC7 0FB63D[7F6E0000]    <1> 	movzx	edi, byte [cdev] ; 0 or 1
  2975 00005DCE 81C7[806E0000]      <1> 	add	edi, rdev
  2976                              <1> bufaloc_0: ; 26/04/2013 !! here is called from bread or bwrite !!
  2977                              <1> 			;; eDI points to device id.
  2978 00005DD4 0FB61F              <1> 	movzx	ebx, byte [edi] ; [EDI] -> rdev/mdev or brwdev
  2979                              <1> 	; 11/06/2015
  2980 00005DD7 80BB[1A660000]F0    <1> 	cmp 	byte [ebx+drv.status], 0F0h ; Drive not ready !
  2981 00005DDE 720F                <1> 	jb	short bufaloc_9
  2982 00005DE0 C705[ED6E0000]0F00- <1> 	mov	dword [u.error], ERR_DRV_NOT_RDY
  2982 00005DE8 0000                <1>
  2983 00005DEA E9E3DCFFFF          <1> 	jmp	error
  2984                              <1> bufaloc_9:
  2985 00005DEF 89DA                <1> 	mov	edx, ebx ; dh = 0, dl = device number (0 to 5)
  2986                              <1> bufaloc_10: ; 02/07/2015
  2987 00005DF1 31ED                <1> 	xor 	ebp, ebp ; 0
  2988 00005DF3 55                  <1> 	push	ebp ; 0
  2989 00005DF4 89E5                <1>         mov     ebp, esp	
  2990                              <1> 	;
  2991                              <1> bufaloc_1: ;1:
  2992                              <1> 		; clr -(sp) / vacant buffer
  2993 00005DF6 BE[5C6E0000]        <1>         mov 	esi, bufp
  2994                              <1> 		; mov $bufp,r2 / bufp contains pointers to I/O queue 
  2995                              <1> 			     ; / entrys in buffer area
  2996                              <1> bufaloc_2: ;2:
  2997 00005DFB 8B1E                <1> 	mov	ebx, [esi]
  2998                              <1>        		; mov (r2)+,r5 / move pointer to word 1 of an I/O 
  2999                              <1> 			    ; queue entry into r5
  3000 00005DFD 66F70300F6          <1> 	test	word [ebx], 0F600h
  3001                              <1> 		; bit $173000,(r5) / lock+keep+active+outstanding
  3002 00005E02 7503                <1>         jnz	short bufaloc_3
  3003                              <1> 		; bne 3f / branch when 
  3004                              <1> 		       ; / any of bits 9,10,12,13,14,15 are set
  3005                              <1>                        ; / (i.e., buffer busy)
  3006 00005E04 897500              <1>         mov     [ebp], esi ; pointer to I/0 queue entry
  3007                              <1>                 ; mov  r2,(sp) ;/ save pointer to last non-busy buffer
  3008                              <1> 			; / found points to word 2 of I/O queue entry)
  3009                              <1> bufaloc_3: ;3:
  3010                              <1> 	;mov	dl, [edi] ; 26/04/2013
  3011                              <1> 	;
  3012 00005E07 3813                <1> 	cmp	[ebx], dl	
  3013                              <1> 		; cmpb (r5),cdev / is device in I/O queue entry same 
  3014                              <1> 			       ; / as current device
  3015 00005E09 7508                <1> 	jne	short bufaloc_4
  3016                              <1>        		; bne 3f
  3017 00005E0B 394304              <1> 	cmp	[ebx+4], eax
  3018                              <1>        		; cmp 2(r5),r1 / is block number in I/O queue entry, 
  3019                              <1> 			     ; / same as current block number
  3020 00005E0E 7503                <1>        	jne	short bufaloc_4
  3021                              <1> 		; bne 3f
  3022                              <1> 	;add	esp, 4
  3023 00005E10 59                  <1> 	pop	ecx
  3024                              <1>        		; tst (sp)+ / bump stack pointer
  3025 00005E11 EB20                <1> 	jmp	short bufaloc_7 ; Retro Unix 8086 v1 modification
  3026                              <1> 				; jump to bufaloc_6 in original Unix v1
  3027                              <1>        		; br 1f / use this buffer
  3028                              <1> bufaloc_4: ;3:
  3029 00005E13 83C604              <1> 	add	esi, 4 ; 20/08/2015
  3030                              <1> 	;
  3031 00005E16 81FE[746E0000]      <1> 	cmp	esi, bufp + (nbuf*4)
  3032                              <1> 		; cmp r2,$bufp+nbuf+nbuf
  3033 00005E1C 72DD                <1> 	jb	short bufaloc_2
  3034                              <1> 		; blo 2b / go to 2b if r2 less than bufp+nbuf+nbuf (all
  3035                              <1>                        ; / buffers not checked)
  3036 00005E1E 5E                  <1>         pop	esi
  3037                              <1> 		; mov (sp)+,r2 / once all bufs are examined move pointer
  3038                              <1> 			     ; / to last free block
  3039 00005E1F 09F6                <1>        	or	esi, esi 
  3040 00005E21 7507                <1> 	jnz	short bufaloc_5
  3041                              <1> 		; bne 2f / if (sp) is non zero, i.e., 
  3042                              <1> 	        ; / if a free buffer is found branch to 2f
  3043                              <1>         ;; mov  ecx, [s.wait_]
  3044 00005E23 E801F1FFFF          <1> 	call	idle
  3045                              <1> 		; jsr r0,idle; s.wait+2 / idle if no free buffers
  3046 00005E28 EBC7                <1> 	jmp 	short bufaloc_10 ; 02/07/2015
  3047                              <1>        		; br 1b
  3048                              <1> bufaloc_5: ;2:
  3049                              <1> 		; tst (r0)+ / skip if warmed over buffer
  3050 00005E2A FEC6                <1> 	inc	dh ; Retro UNIX 8086 v1 modification
  3051                              <1> bufaloc_6: ;1:
  3052 00005E2C 8B1E                <1>         mov    	ebx, [esi] 
  3053                              <1> 		; mov -(r2),r5 / put pointer to word 1 of I/O queue 
  3054                              <1> 			     ; / entry in r5
  3055                              <1> 	;; 26/04/2013
  3056                              <1>         ;mov	dl, [edi] ; byte [rdev] or byte [mdev]
  3057 00005E2E 8813                <1> 	mov 	[ebx], dl
  3058                              <1> 		; movb cdev,(r5) / put current device number 
  3059                              <1> 				 ; / in I/O queue entry
  3060 00005E30 894304              <1> 	mov 	[ebx+4], eax
  3061                              <1> 		; mov r1,2(r5) / move block number into word 2 
  3062                              <1> 			     ; / of I/O queue entry
  3063                              <1> bufaloc_7: ;1:
  3064 00005E33 81FE[5C6E0000]      <1>         cmp	esi, bufp
  3065                              <1> 		; cmp r2,$bufp / bump all entrys in bufp 
  3066                              <1> 			     ; / and put latest assigned
  3067 00005E39 760A                <1> 	jna	short bufaloc_8	
  3068                              <1>        		; blos 1f / buffer on the top 
  3069                              <1> 			; / (this makes if the lowest priority)
  3070 00005E3B 83EE04              <1> 	sub	esi, 4
  3071 00005E3E 8B0E                <1> 	mov	ecx, [esi]
  3072 00005E40 894E04              <1> 	mov	[esi+4], ecx
  3073                              <1> 		; mov -(r2),2(r2) / job for a particular device
  3074 00005E43 EBEE                <1> 	jmp 	short bufaloc_7        
  3075                              <1> 		; br 1b
  3076                              <1> bufaloc_8: ;1:
  3077 00005E45 891E                <1>         mov	[esi], ebx
  3078                              <1> 		; mov r5,(r2)
  3079                              <1> 	;;pop	esi ; ***
  3080                              <1>        		; mov (sp)+,r2 / restore r2
  3081 00005E47 08F6                <1>        	or 	dh, dh ; 0 or 1 ?
  3082                              <1> 		; Retro UNIX 8086 v1 modification
  3083                              <1> 		; zf=1 --> block already is in an I/O buffer
  3084                              <1> 		; zf=0 --> a new I/O buffer has been allocated
  3085 00005E49 C3                  <1> 	retn
  3086                              <1> 		; rts r0
  3087                              <1> 
  3088                              <1> diskio:
  3089                              <1> 	; 12/02/2022
  3090                              <1> 	; 10/02/2022
  3091                              <1> 	; 08/02/2022
  3092                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1 2022, Kernel v0.2.1.2)
  3093                              <1> 	; 10/07/2015
  3094                              <1> 	; 02/07/2015
  3095                              <1> 	; 16/06/2015
  3096                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  3097                              <1> 	;	     (80386 protected mode modifications)	
  3098                              <1> 	; 15/03/2013 - 29/04/2013 (Retro UNIX 8086 v1)
  3099                              <1> 	;
  3100                              <1> 	; Retro UNIX 8086 v1 feature only !
  3101                              <1> 	;
  3102                              <1> 	; Derived from proc_chs_read procedure of TRDOS DISKIO.ASM (2011)
  3103                              <1> 	; 04/07/2009 - 20/07/2011
  3104                              <1> 	;
  3105                              <1> 	; NOTE: Reads only 1 block/sector (sector/block size is 512 bytes)
  3106                              <1> 	;
  3107                              <1>         ; INPUTS ->
  3108                              <1> 	; 	   eBX = System I/O Buffer header address
  3109                              <1> 	;
  3110                              <1>         ; OUTPUTS -> cf=0 --> done 
  3111                              <1> 	; 	     cf=1 --> error code in AH
  3112                              <1> 	;	     ; 08/02/2022
  3113                              <1> 	;	     cf=1 & [u.brwdev] = 0FFh -->
  3114                              <1> 	;		error code in [u.error]
  3115                              <1> 	;		
  3116                              <1> 	; (Modified registers: eAX, eCX, eDX)
  3117                              <1> 	
  3118                              <1> ;rw_disk_sector:
  3119                              <1> 	; 12/02/2022
  3120                              <1> 	; 10/02/2022
  3121                              <1> 	; 08/02/2022
  3122                              <1> 	; 10/07/2015
  3123                              <1> 	; 02/07/2015
  3124                              <1> 	; 11/06/2015 - Retro UNIX 386 v1 - 'u8.s' 
  3125                              <1> 	; 21/02/2015 ('dsectpm.s', 'read_disk_sector')
  3126                              <1> 	; 16/02/2015 (Retro UNIX 386 v1 test - 'unix386.s')
  3127                              <1> 	; 01/12/2014 - 18/01/2015 ('dsectrm2.s')
  3128                              <1> 	;
  3129                              <1> 	;mov	dx, 0201h ; Read 1 sector/block
  3130 00005E4A B602                <1> 	mov	dh, 2
  3131 00005E4C 668B03              <1> 	mov	ax, [ebx] 
  3132                              <1> 	;
  3133 00005E4F 56                  <1> 	push	esi ; ****
  3134 00005E50 53                  <1> 	push	ebx ; ***
  3135                              <1> 	;
  3136 00005E51 0FB6C8              <1> 	movzx	ecx, al
  3137 00005E54 89CE                <1> 	mov	esi, ecx
  3138                              <1> 	;
  3139 00005E56 38F1                <1> 	cmp	cl, dh ; 2
  3140 00005E58 7202                <1> 	jb	short rwdsk0
  3141 00005E5A 047E                <1> 	add	al, 7Eh  ; 80h, 81h, 82h, 83h
  3142                              <1> rwdsk0:
  3143 00005E5C A2[CB650000]        <1> 	mov	[drv], al
  3144 00005E61 81C6[1A660000]      <1> 	add	esi, drv.status
  3145                              <1> 	; 11/06/2015
  3146 00005E67 803EF0              <1> 	cmp	byte [esi], 0F0h 
  3147 00005E6A 7204                <1> 	jb      short rwdsk1
  3148                              <1> 	; 'drive not ready' error
  3149                              <1> 	; 10/02/2022
  3150                              <1> 	; 08/02/2022
  3151                              <1> 	;mov	byte [u.brwdev], 0FFh ; error code in [u.error]
  3152                              <1> 	;mov	dword [u.error], ERR_DRV_NOT_RDY
  3153                              <1> 	;;jmp	error
  3154                              <1> 	;stc	; cf = 1
  3155                              <1> 	;retn
  3156                              <1> 	; 10/02/2022
  3157 00005E6C B10F                <1> 	mov	cl, ERR_DRV_NOT_RDY
  3158 00005E6E EB20                <1> 	jmp	short rwdsk_err1
  3159                              <1> rwdsk1:
  3160 00005E70 F6C402              <1> 	test	ah, 2
  3161                              <1> 	;test	ax, 200h ; Bit 9 of word 0 (status word)
  3162                              <1> 			 ; write bit
  3163 00005E73 7402                <1> 	jz	short rwdsk2
  3164                              <1> 	;test	ah, 4
  3165                              <1> 	;;test	ax, 400h ; Bit 10 of word 0 (status word)
  3166                              <1> 	;		 ; read bit
  3167                              <1> 	;jz	short diskio_ret
  3168 00005E75 FEC6                <1> 	inc	dh ; 03h = write
  3169                              <1> rwdsk2:
  3170 00005E77 88C2                <1> 	mov	dl, al
  3171 00005E79 83C304              <1> 	add	ebx, 4 ; sector/block address/number pointer
  3172 00005E7C 8B03                <1> 	mov	eax, [ebx] ; sector/block number (LBA)
  3173 00005E7E C0E102              <1> 	shl	cl, 2
  3174 00005E81 81C1[FE650000]      <1> 	add	ecx, drv.size ; disk size
  3175 00005E87 3B01                <1> 	cmp	eax, [ecx] ; Last sector + 1 (number of secs.)
  3176 00005E89 7214                <1> 	jb      short rwdsk3
  3177                              <1>  	; 'out of volume' error
  3178                              <1> 	; 10/02/2022
  3179                              <1> 	; 08/02/2022
  3180                              <1> 	;mov	byte [u.brwdev], 0FFh ; error code in [u.error]
  3181                              <1> 	;mov 	dword [u.error], ERR_DEV_VOL_SIZE
  3182                              <1> 	;;jmp	error
  3183                              <1> 	;stc	; cf = 1
  3184                              <1> 	;retn
  3185                              <1> 	; 10/02/2022
  3186 00005E8B B910000000          <1> 	mov	ecx, ERR_DEV_VOL_SIZE
  3187                              <1> rwdsk_err1:
  3188 00005E90 C605[006F0000]FF    <1> 	mov	byte [u.brwdev], 0FFh
  3189 00005E97 890D[ED6E0000]      <1> 	mov 	[u.error], ecx ; 12/02/2022
  3190 00005E9D EB30                <1> 	jmp	short rwdsk_err2
  3191                              <1> rwdsk3:
  3192                              <1> 	; 11/06/2015
  3193 00005E9F 83C304              <1> 	add	ebx, 4 ; buffer address
  3194 00005EA2 C605[1E6F0000]04    <1> 	mov	byte [retry_count], 4
  3195 00005EA9 F60601              <1> 	test	byte [esi], 1 ; LBA ready ?
  3196 00005EAC 7432                <1>         jz      short rwdsk_chs
  3197                              <1> rwdsk_lba:
  3198                              <1> 	; LBA read/write (with private LBA function) 
  3199                              <1> 	;((Retro UNIX 386 v1 - DISK I/O code by Erdogan Tan))
  3200 00005EAE 83C607              <1>         add     esi, drv.error - drv.status ; 10/07/2015
  3201 00005EB1 89C1                <1> 	mov	ecx, eax ; sector number
  3202                              <1> 	; ebx = buffer (data) address
  3203                              <1> 	; dl = physical drive number (0,1, 80h, 81h, 82h, 83h)
  3204                              <1> rwdsk_lba_retry:
  3205                              <1> 	;mov	dl, [drv]
  3206                              <1> 		; Function 1Bh = LBA read, 1Ch = LBA write
  3207 00005EB3 B419                <1> 	mov	ah, 1Ch - 3h ; LBA write function number - 3
  3208 00005EB5 00F4                <1> 	add	ah, dh		
  3209 00005EB7 B001                <1> 	mov	al, 1
  3210                              <1> 	;int	13h
  3211 00005EB9 E8DEC6FFFF          <1> 	call	int13h
  3212 00005EBE 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3213 00005EC0 730E                <1> 	jnc	short rwdsk_lba_ok
  3214 00005EC2 80FC80              <1> 	cmp	ah, 80h ; time out ?
  3215 00005EC5 7408                <1>         je      short rwdsk_lba_fails
  3216 00005EC7 FE0D[1E6F0000]      <1> 	dec	byte [retry_count]
  3217 00005ECD 7504                <1>         jnz     short rwdsk_lba_reset ; 10/07/2015
  3218                              <1> rwdsk_err2:	; 10/02/2022
  3219                              <1> rwdsk_lba_fails:
  3220 00005ECF F9                  <1> 	stc
  3221                              <1> rwdsk_lba_ok:
  3222 00005ED0 5B                  <1> 	pop	ebx ; ***
  3223 00005ED1 5E                  <1> 	pop	esi ; ****
  3224 00005ED2 C3                  <1> 	retn
  3225                              <1> rwdsk_lba_reset:
  3226 00005ED3 B40D                <1> 	mov	ah, 0Dh ; Alternate reset
  3227                              <1> 	;int	13h
  3228 00005ED5 E8C2C6FFFF          <1>         call	int13h
  3229 00005EDA 73D7                <1> 	jnc     short rwdsk_lba_retry
  3230 00005EDC 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3231 00005EDE EBF0                <1> 	jmp	short rwdsk_lba_ok
  3232                              <1> 	;
  3233                              <1> 	; CHS read (convert LBA address to CHS values)	
  3234                              <1> rwdsk_chs:
  3235                              <1> 	; 10/07/2015
  3236 00005EE0 81EE[1A660000]      <1> 	sub	esi, drv.status
  3237 00005EE6 89F1                <1> 	mov	ecx, esi
  3238 00005EE8 81C6[21660000]      <1> 	add 	esi, drv.error
  3239                              <1> 	; 02/07/2015
  3240                              <1> 	; 16/06/2015
  3241                              <1>  	; 11/06/2015 
  3242 00005EEE 53                  <1> 	push	ebx ; ** ; buffer
  3243 00005EEF D1E1                <1> 	shl	ecx, 1
  3244 00005EF1 51                  <1> 	push	ecx ; * 
  3245                              <1> 	;
  3246 00005EF2 89CB                <1> 	mov	ebx, ecx
  3247 00005EF4 8835[1D6F0000]      <1> 	mov	[rwdsk], dh ; 02/07/2015
  3248 00005EFA 31D2                <1> 	xor	edx, edx ; 0
  3249                              <1> 	; 09/01/2022
  3250                              <1> 	;sub	ecx, ecx 
  3251 00005EFC 81C3[F0650000]      <1>         add     ebx, drv.spt
  3252 00005F02 668B0B              <1> 	mov	cx, [ebx] ; sector per track
  3253                              <1> 		; EDX:EAX = LBA
  3254 00005F05 F7F1                <1> 	div	ecx
  3255 00005F07 88D1                <1> 	mov	cl, dl	; sector number - 1
  3256 00005F09 FEC1                <1> 	inc	cl	; sector number (1 based)
  3257 00005F0B 5B                  <1> 	pop	ebx ; * ; 11/06/2015
  3258                              <1> 	;push	cx
  3259                              <1>         ; 09/01/2022
  3260 00005F0C 51                  <1> 	push	ecx
  3261 00005F0D 81C3[E2650000]      <1> 	add     ebx, drv.heads
  3262 00005F13 668B0B              <1> 	mov	cx, [ebx] ; heads
  3263 00005F16 31D2                <1> 	xor	edx, edx
  3264                              <1> 		; EAX = cylinders * heads + head
  3265 00005F18 F7F1                <1> 	div	ecx
  3266                              <1> 	;pop	cx     ; sector number
  3267                              <1> 	; 09/01/2022
  3268 00005F1A 59                  <1> 	pop	ecx
  3269 00005F1B 88D6                <1> 	mov	dh, dl ; head number
  3270 00005F1D 8A15[CB650000]      <1> 	mov	dl, [drv]
  3271 00005F23 88C5                <1> 	mov	ch, al ; cylinder (bits 0-7)
  3272 00005F25 C0E406              <1> 	shl	ah, 6
  3273 00005F28 08E1                <1> 	or	cl, ah ; cylinder (bits 8-9)
  3274                              <1> 		       ; sector (bits 0-7)
  3275 00005F2A 5B                  <1> 	pop	ebx ; ** ; buffer ; 11/06/2015
  3276                              <1> 		; CL = sector (bits 0-5)
  3277                              <1> 		;      cylinder (bits 8-9 -> bits 6-7)
  3278                              <1> 		; CH = cylinder (bits 0-7)
  3279                              <1> 		; DH = head
  3280                              <1> 		; DL = drive
  3281                              <1> 	;
  3282 00005F2B C605[1E6F0000]04    <1> 	mov	byte [retry_count], 4
  3283                              <1> rwdsk_retry:	
  3284 00005F32 8A25[1D6F0000]      <1> 	mov	ah, [rwdsk] ; 02h = read, 03h = write
  3285 00005F38 B001                <1> 	mov	al, 1 ; sector count	
  3286                              <1> 	;int	13h
  3287 00005F3A E85DC6FFFF          <1> 	call	int13h
  3288 00005F3F 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3289 00005F41 730E                <1> 	jnc	short rwdsk_ok ; ah = 0
  3290 00005F43 80FC80              <1> 	cmp	ah, 80h ; time out ?
  3291 00005F46 7408                <1> 	je	short rwdsk_fails
  3292 00005F48 FE0D[1E6F0000]      <1> 	dec	byte [retry_count]
  3293 00005F4E 7504                <1> 	jnz	short rwdsk_reset
  3294                              <1> rwdsk_fails:
  3295 00005F50 F9                  <1> 	stc
  3296                              <1> rwdsk_ok:
  3297 00005F51 5B                  <1> 	pop	ebx ; ***
  3298 00005F52 5E                  <1> 	pop	esi ; ****
  3299 00005F53 C3                  <1> 	retn
  3300                              <1> rwdsk_reset:
  3301                              <1> 	; 02/02/2015
  3302 00005F54 28E4                <1> 	sub	ah, ah
  3303 00005F56 80FA80              <1> 	cmp	dl, 80h
  3304 00005F59 7202                <1> 	jb	short rwdsk_fd_reset
  3305 00005F5B B40D                <1> 	mov	ah, 0Dh ; Alternate reset
  3306                              <1> rwdsk_fd_reset:
  3307                              <1> 	;int	13h
  3308 00005F5D E83AC6FFFF          <1>         call	int13h
  3309 00005F62 73CE                <1> 	jnc	short rwdsk_retry
  3310 00005F64 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3311 00005F66 EBE9                <1> 	jmp 	short rwdsk_ok
  3312                              <1> 
  3313                              <1> ; Original UNIX v1 - drum (& disk) interrupt routine
  3314                              <1> ;	(Equivalent to IRQ 14 & IRQ 15 disk/hardware interrupts)
  3315                              <1> ;
  3316                              <1> ; This feature is not used in Retro UNIX 386 (& 8086) for now.
  3317                              <1> ; Because, current Retro UNIX 386 disk I/O -INT13H- routine is 
  3318                              <1> ; derived from IBM PC AT -infact: XT286- BIOS source code, int 13h
  3319                              <1> ; that uses hardware -transfer has been completed-  interrupt inside it. 
  3320                              <1> ; In a next Retro UNIX 386 version, these interrupts
  3321                              <1> ; (fdc_int, hdc1_int, hdc2_int) will be handled by a separate routine
  3322                              <1> ; as in original unix v1.
  3323                              <1> ; I am not removing IBM BIOS source code derivatives -compatible code-
  3324                              <1> ; for now, regarding the new/next 32 bit TRDOS project by me
  3325                              <1> ; (to keep source code files easy adaptable to 32 bit TRDOS.)
  3326                              <1> ;
  3327                              <1> ; Erdogan tan (10/07/2015) 
  3328                              <1> 
  3329                              <1> ;drum: / interrupt handler
  3330                              <1> ;       jsr     r0,setisp / save r1,r2,r3, and clockp on the stack
  3331                              <1> ;       jsr     r0,trapt; dcs; rfap; 1 / check for stray interrupt or
  3332                              <1> ;                                      / error
  3333                              <1> ;               br 3f / no, error
  3334                              <1> ;       br      2f / error
  3335                              <1> ;
  3336                              <1> ;disk:
  3337                              <1> ;       jsr     r0,setisp / save r1,r2,r3, and clockp on the stack
  3338                              <1> ;       jmp     *$0f
  3339                              <1> ;0:
  3340                              <1> ;       jsr     r0,trapt; rkcs; rkap; 2
  3341                              <1> ;      	        br 3f / no, errors
  3342                              <1> ;       mov     $115,(r2) / drive reset, errbit was set
  3343                              <1> ;       mov     $1f,0b-2 / next time jmp *$0f is executed jmp will be
  3344                              <1> ;                        / to 1f
  3345                              <1> ;       br      4f
  3346                              <1> ;1:
  3347                              <1> ;       bit     $20000,rkcs
  3348                              <1> ;       beq     4f / wait for seek complete
  3349                              <1> ;       mov     $0b,0b-2
  3350                              <1> ;       mov     rkap,r1
  3351                              <1> ;2:
  3352                              <1> ;       bit     $3000,(r1) / are bits 9 or 10 set in the 1st word of
  3353                              <1> ;                          / the disk buffer
  3354                              <1> ;       bne     3f / no, branch ignore error if outstanding
  3355                              <1> ;       inc     r1
  3356                              <1> ;       asr     (r1)
  3357                              <1> ;       asr     (r1)
  3358                              <1> ;       asr     (r1) / reissue request
  3359                              <1> ;       dec     r1
  3360                              <1> ;3:
  3361                              <1> ;       bic     $30000,(r1) / clear bits 12 and 13 in 1st word of buffer
  3362                              <1> ;       mov     ac,-(sp)
  3363                              <1> ;       mov     mq,-(sp) / put these on the stack
  3364                              <1> ;       mov     sc,-(sp)
  3365                              <1> ;       jsr     r0,poke
  3366                              <1> ;       mov     (sp)+,sc
  3367                              <1> ;       mov     (sp)+,mq / pop them off stack
  3368                              <1> ;       mov     (sp)+,ac
  3369                              <1> ;4:
  3370                              <1> ;       jmp     retisp / u4-3
  3371                              <1> ;
  3372                              <1> ;trapt:                  / r2 points to the
  3373                              <1> ;       mov     (r0)+,r2 / device control register
  3374                              <1> ;       mov     *(r0)+,r1 / transaction pointer points to buffer
  3375                              <1> ;       tst     (sp)+
  3376                              <1> ;       tstb    (r2) / is ready bit of dcs set?
  3377                              <1> ;       bge     4b / device still active so branch
  3378                              <1> ;       bit     (r0),active / was device busy?
  3379                              <1> ;       beq     4b / no, stray interrupt
  3380                              <1> ;       bic     (r0)+,active / yes, set active to zero
  3381                              <1> ;       tst     (r2) / test the err(bit is) of dcs
  3382                              <1> ;       bge     2f / if no error jump to 2f
  3383                              <1> ;       tst     (r0)+ / skip on error
  3384                              <1> ; 2:
  3385                              <1> ;       jmp     (r0)
  2100                                  %include 'u9.s'        ; 29/06/2015
  2101                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYS9.INC
  2102                              <1> ; Last Modification: 27/02/2022
  2103                              <1> ; ----------------------------------------------------------------------------
  2104                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2105                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2106                              <1> ;
  2107                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2108                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2109                              <1> ; <Bell Laboratories (17/3/1972)>
  2110                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2111                              <1> ;
  2112                              <1> ; Retro UNIX 8086 v1 - U9.ASM (01/09/2014) //// UNIX v1 -> u9.s
  2113                              <1> ;
  2114                              <1> ; ****************************************************************************
  2115                              <1> 
  2116                              <1> getch:
  2117                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2118                              <1> 	; 30/06/2015
  2119                              <1> 	; 18/02/2015 - Retro UNIX 386 v1 - feature only!
  2120 00005F68 28C0                <1> 	sub	al, al ; 0
  2121                              <1> getch_q: ; 06/08/2015
  2122 00005F6A 8A25[066B0000]      <1> 	mov 	ah, [ptty] ; active (current) video page
  2123 00005F70 EB06                <1>         jmp     short getc_n
  2124                              <1> 
  2125                              <1> getc: 
  2126                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2127                              <1> 	; 12/11/2015
  2128                              <1> 	; 15/09/2015
  2129                              <1> 	; 01/07/2015
  2130                              <1> 	; 30/06/2015
  2131                              <1> 	; 18/02/2015 (Retro UNIX 386 v1 - Beginning)
  2132                              <1> 	; 13/05/2013 - 04/07/2014 (Retro UNIX 8086 v1)
  2133                              <1> 	;
  2134                              <1> 	; Retro UNIX 8086 v1 modification !
  2135                              <1> 	; 
  2136                              <1> 	; 'getc' gets (next) character 
  2137                              <1> 	;	 from requested TTY (keyboard) buffer 
  2138                              <1> 	; INPUTS ->
  2139                              <1> 	;     [u.ttyn] = tty number (0 to 7) (8 is COM1, 9 is COM2)	
  2140                              <1> 	;     AL=0 -> Get (next) character from requested TTY buffer
  2141                              <1> 	;	(Keyboard buffer will point to 
  2142                              <1> 	;			next character at next call)
  2143                              <1> 	;     AL=1 -> Test a key is available in requested TTY buffer
  2144                              <1> 	;	(Keyboard buffer will point to 
  2145                              <1> 	;			current character at next call)
  2146                              <1> 	; OUTPUTS ->
  2147                              <1> 	;     (If AL input is 1) ZF=1 -> 'empty buffer' (no chars)
  2148                              <1> 	;     			 ZF=0 -> AX has (current) character
  2149                              <1> 	;      AL = ascii code
  2150                              <1> 	;      AH = scan code	(AH = line status for COM1 or COM2)	 			
  2151                              <1> 	; 		        (cf=1 -> error code/flags in AH)
  2152                              <1> 	; Original UNIX V1 'getc': 
  2153                              <1> 	;		get a character off character list
  2154                              <1> 	;
  2155                              <1> 	; ((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))	
  2156                              <1> 	;
  2157                              <1> 	; 30/06/2015 (32 bit modifications)
  2158                              <1> 	; 16/07/2013
  2159                              <1> 	; mov 	[getctty], ah
  2160                              <1> 	;
  2161                              <1> 
  2162 00005F72 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn] 	; 28/07/2013
  2163                              <1> getc_n:
  2164                              <1> 	; 30/06/2015
  2165 00005F78 08E4                <1> 	or	ah, ah
  2166 00005F7A 740D                <1> 	jz	short getc0 
  2167 00005F7C D0E4                <1> 	shl	ah, 1
  2168 00005F7E 0FB6DC              <1> 	movzx	ebx, ah
  2169 00005F81 81C3[086B0000]      <1> 	add	ebx, ttychr
  2170 00005F87 EB05                <1> 	jmp	short getc1
  2171                              <1> getc0:
  2172 00005F89 BB[086B0000]        <1> 	mov	ebx, ttychr
  2173                              <1> getc1:
  2174 00005F8E 668B0B              <1> 	mov	cx, [ebx] 	; ascii & scan code
  2175                              <1> 				; (by kb_int)	
  2176 00005F91 6609C9              <1> 	or	cx, cx
  2177 00005F94 7507                <1> 	jnz	short getc2
  2178 00005F96 20C0                <1> 	and 	al, al
  2179 00005F98 7415                <1> 	jz	short getc_s
  2180                              <1> 	;xor	ax, ax
  2181                              <1> 	; 24/12/2021
  2182 00005F9A 31C0                <1> 	xor	eax, eax
  2183 00005F9C C3                  <1> 	retn
  2184                              <1> getc2:	
  2185 00005F9D 20C0                <1> 	and	al, al
  2186 00005F9F 6689C8              <1> 	mov	ax, cx
  2187 00005FA2 66B90000            <1> 	mov	cx, 0
  2188 00005FA6 7506                <1> 	jnz	short getc3
  2189                              <1> getc_sn:
  2190 00005FA8 66890B              <1> 	mov	[ebx], cx ; 0, reset
  2191 00005FAB 6639C8              <1> 	cmp	ax, cx  ; zf = 0
  2192                              <1> getc3:
  2193 00005FAE C3                  <1> 	retn
  2194                              <1> getc_s:
  2195                              <1> 	; 12/11/2015
  2196                              <1> 	; 15/09/2015
  2197                              <1> 	; 01/07/2015
  2198                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2199                              <1> 	; 16/07/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2200                              <1> 	;
  2201                              <1> 	; tty  of the current process is not 
  2202                              <1> 	; current tty (ptty); so, current process only 
  2203                              <1> 	; can use keyboard input when its tty becomes 
  2204                              <1> 	; current tty (ptty).
  2205                              <1> 	; 'sleep' is for preventing an endless lock
  2206                              <1> 	; during this tty input request.
  2207                              <1> 	; (Because, the user is not looking at the video page
  2208                              <1> 	; of the process to undersand there is a keyboard
  2209                              <1> 	; input request.)
  2210                              <1> 	;
  2211                              <1> 	;((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))
  2212                              <1> 	;
  2213                              <1> 	; 05/10/2013
  2214                              <1> 	; ah = byte ptr [u.ttyn] ; (tty number)
  2215                              <1> 	;
  2216                              <1> 	; 10/10/2013
  2217                              <1> gcw0:
  2218 00005FAF B10A                <1> 	mov	cl, 10 ; ch = 0
  2219                              <1> gcw1:	
  2220                              <1> 	; 12/11/2015
  2221 00005FB1 E829DCFFFF          <1> 	call intract ; jumps to 'sysexit' if [u.quit] = FFFFh
  2222                              <1> 	; 10/10/2013
  2223 00005FB6 E86EEFFFFF          <1> 	call	idle
  2224 00005FBB 668B03              <1> 	mov	ax, [ebx] 	; ascii & scan code
  2225                              <1> 				; (by kb_int)
  2226 00005FBE 6609C0              <1> 	or	ax, ax
  2227                              <1> ;	jnz	short gcw3
  2228 00005FC1 7519                <1> 	jnz	short gcw2 ; 15/09/2015
  2229                              <1> 	; 30/06/2015
  2230 00005FC3 FEC9                <1> 	dec	cl
  2231 00005FC5 75EA                <1> 	jnz	short gcw1
  2232                              <1> 	;
  2233 00005FC7 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn] 	; 20/10/2013
  2234                              <1> ;	; 10/12/2013
  2235                              <1> ;	cmp 	ah, [ptty]
  2236                              <1> ;	jne	short gcw2
  2237                              <1> ;	; 14/02/2014
  2238                              <1> ;	cmp	byte [u.uno], 1
  2239                              <1> ;	jna	short gcw0		
  2240                              <1> ;gcw2:
  2241 00005FCD E8E4EFFFFF          <1> 	call	sleep
  2242                              <1> 	;
  2243                              <1> 	; 20/09/2013
  2244 00005FD2 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn]
  2245 00005FD8 30C0                <1> 	xor 	al, al
  2246 00005FDA EB9C                <1> 	jmp	short getc_n
  2247                              <1> ;gcw3:
  2248                              <1> gcw2: 	; 15/09/2015
  2249                              <1> 	; 10/10/2013
  2250 00005FDC 30C9                <1> 	xor	cl, cl
  2251 00005FDE EBC8                <1> 	jmp	short getc_sn
  2252                              <1> 
  2253                              <1> putc:	
  2254                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2255                              <1> 	; 13/08/2015
  2256                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2257                              <1> 	; 15/05/2013 - 27/07/2014 (Retro UNIX 8086 v1)
  2258                              <1> 	;
  2259                              <1> 	; Retro UNIX 8086 v1 modification !
  2260                              <1> 	; 
  2261                              <1> 	; 'putc' puts a character 
  2262                              <1> 	;	 onto requested (tty) video page or
  2263                              <1> 	;	 serial port
  2264                              <1> 	; INPUTS ->
  2265                              <1> 	;     AL = ascii code of the character
  2266                              <1> 	;     AH = video page (tty) number (0 to 7)
  2267                              <1> 	;			  (8 is COM1, 9 is COM2)	
  2268                              <1> 	; OUTPUTS ->
  2269                              <1> 	;    (If AL input is 1) ZF=1 -> 'empty buffer' (no chars)
  2270                              <1> 	;      			ZF=0 -> AX has (current) character
  2271                              <1> 	;     cf=0 and AH = 0 -> no error
  2272                              <1> 	;     cf=1 and AH > 0 -> error (only for COM1 and COM2)		 			
  2273                              <1> 	; 
  2274                              <1> 	; Original UNIX V1 'putc': 
  2275                              <1> 	;     put a character at the end of character list
  2276                              <1> 	;
  2277                              <1> 	; ((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))
  2278                              <1> 	;
  2279 00005FE0 80FC07              <1> 	cmp	ah, 7
  2280                              <1>         ;ja	sndc
  2281 00005FE3 770A                <1>         ja      short sndc ; 24/12/2024
  2282                              <1> 	; 30/06/2015
  2283 00005FE5 0FB6DC              <1> 	movzx	ebx, ah
  2284                              <1> 	; 13/08/2015
  2285 00005FE8 B407                <1> 	mov	ah, 07h ; black background, light gray character color
  2286 00005FEA E9D7B3FFFF          <1> 	jmp	write_tty ; 'video.inc'
  2287                              <1> 
  2288                              <1> sndc:   ; <Send character>
  2289                              <1> 	;
  2290                              <1> 	; 12/01/2022
  2291                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2292                              <1> 	; 17/11/2015
  2293                              <1> 	; 16/11/2015
  2294                              <1> 	; 11/11/2015
  2295                              <1> 	; 10/11/2015
  2296                              <1> 	; 09/11/2015
  2297                              <1> 	; 08/11/2015
  2298                              <1> 	; 07/11/2015
  2299                              <1> 	; 06/11/2015 (serial4.asm, 'sendchr')	
  2300                              <1> 	; 29/10/2015
  2301                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2302                              <1> 	; 14/05/2013 - 28/07/2014 (Retro UNIX 8086 v1)
  2303                              <1> 	;
  2304                              <1> 	; Retro UNIX 8086 v1 feature only !
  2305                              <1> 	;
  2306                              <1> 	; ah = [u.ttyn]
  2307                              <1> 	;
  2308                              <1> 	; 30/06/2015
  2309 00005FEF 80EC08              <1> 	sub	ah, 8 ; ; 0 = tty8 or 1 = tty9
  2310                              <1> 	; 07/11/2015
  2311 00005FF2 0FB6DC              <1> 	movzx	ebx, ah ; serial port index (0 or 1)
  2312                              <1> sndc0:
  2313                              <1> 	; 07/11/2015
  2314 00005FF5 E80AF0FFFF          <1> 	call	isintr ; quit (ctrl+break) check
  2315 00005FFA 7405                <1> 	jz	short sndc1
  2316 00005FFC E8DEDBFFFF          <1> 	call	intract ; quit (ctrl+break) check
  2317                              <1> 	; CPU will jump to 'sysexit' if 'u.quit' = 0FFFFh (yes)
  2318                              <1> sndc1:
  2319                              <1> 	; 16/11/2015
  2320                              <1> 	;mov	cx, ax	; *** al = character (to be sent)
  2321                              <1> 	; 24/12/2021
  2322 00006001 89C1                <1> 	mov	ecx, eax ; *** al = character (to be sent)
  2323                              <1> sndcx:
  2324 00006003 8A83[4A6B0000]      <1> 	mov	al, [ebx+schar] ; last sent character
  2325 00006009 8AA3[486B0000]      <1> 	mov	ah, [ebx+rchar] ; last received character
  2326                              <1> 	;
  2327                              <1> 	; 17/11/2015
  2328                              <1> 	; check 'request for response' status
  2329 0000600F 80BB[446B0000]00    <1> 	cmp	byte [ebx+req_resp], 0
  2330 00006016 740A                <1> 	jz	short query
  2331                              <1> response:
  2332 00006018 FE05[476B0000]      <1> 	inc 	byte [comqr] ; query or response status
  2333 0000601E B0FF                <1> 	mov	al, 0FFh	 
  2334 00006020 EB14                <1> 	jmp	short sndc3
  2335                              <1> query:
  2336 00006022 08C0                <1> 	or 	al, al  ; 0 = query (also end of text)
  2337 00006024 750E                <1> 	jnz 	short sndc2 ; normal character
  2338                              <1> 	;cmp 	ah, 0FFh     ; is it responded by terminal ?
  2339                              <1> 	;je	short sndc2  ; yes, already responded
  2340                              <1> 	; 16/11/2015
  2341                              <1> 	; query: request for response (again)
  2342 00006026 8883[486B0000]      <1> 	mov	[ebx+rchar], al ; 0 ; reset
  2343 0000602C FE05[476B0000]      <1> 	inc 	byte [comqr] ; query or response status
  2344 00006032 EB02                <1> 	jmp	short sndc3
  2345                              <1> sndc2:
  2346 00006034 88C8                <1> 	mov	al, cl 	; *** character (to be sent)
  2347                              <1> sndc3:
  2348 00006036 8883[4A6B0000]      <1> 	mov	[ebx+schar], al ; current character (to be sent)
  2349 0000603C 88D8                <1> 	mov	al, bl ; 0 or 1 (serial port index)
  2350                              <1> 	; 30/06/2015
  2351 0000603E E837D5FFFF          <1> 	call	sp_status ; get serial port status
  2352                              <1> 	; AL = Line status, AH = Modem status
  2353                              <1> 	; 07/11/2015
  2354 00006043 A880                <1> 	test	al, 80h
  2355 00006045 7504                <1> 	jnz	short sndc4
  2356 00006047 A820                <1> 	test	al, 20h	; Transmitter holding register empty ?
  2357 00006049 751A                <1> 	jnz	short sndc5
  2358                              <1> sndc4: 	; Check line status again
  2359                              <1> 	; 16/11/2015
  2360                              <1> 	;push	cx
  2361                              <1> 	; 24/12/2021
  2362 0000604B 51                  <1> 	push	ecx
  2363                              <1> 	;mov	ecx, 6 ; 6*30 micro seconds (~5556 chars/second)
  2364                              <1> 	; 12/01/2022
  2365 0000604C 31C9                <1> 	xor	ecx, ecx
  2366 0000604E B106                <1> 	mov	cl, 6
  2367 00006050 E868B4FFFF          <1> 	call	WAITF
  2368                              <1> 	;pop	cx
  2369                              <1> 	; 24/12/1021
  2370 00006055 59                  <1> 	pop	ecx
  2371                              <1> 	;
  2372 00006056 88D8                <1> 	mov	al, bl ; 0 or 1 (serial port index)
  2373 00006058 E81DD5FFFF          <1> 	call	sp_status ; get serial port status
  2374                              <1> 	; 16/11/2015
  2375                              <1> 	; 09/11/2015
  2376                              <1> 	; 08/11/2015
  2377 0000605D A880                <1> 	test	al, 80h	; time out error
  2378 0000605F 7565                <1>         jnz     short sndc7
  2379 00006061 A820                <1> 	test	al, 20h	; Transmitter holding register empty ?
  2380 00006063 7461                <1>         jz	short sndc7
  2381                              <1> sndc5:  
  2382 00006065 8A83[4A6B0000]      <1> 	mov	al, [ebx+schar] ; character (to be sent)
  2383 0000606B 66BAF803            <1> 	mov	dx, 3F8h   ; data port (COM2)
  2384 0000606F 28DE                <1> 	sub	dh, bl
  2385 00006071 EE                  <1> 	out	dx, al	   ; send on serial port
  2386                              <1> 	; 10/11/2015
  2387                              <1> 	; delay for 3*30 (3*(15..80)) micro seconds
  2388                              <1> 	; (to improve text flow to the terminal)
  2389                              <1> 	; ('diskette.inc': 'WAITF')
  2390                              <1> 	; Uses port 61h, bit 4 to have CPU speed independent waiting.
  2391                              <1> 	; (refresh periods = 1 per 30 microseconds on most machines)
  2392                              <1> 	;push	cx
  2393                              <1> 	; 24/12/2021
  2394 00006072 51                  <1> 	push	ecx
  2395                              <1> 	;mov	ecx, 6 ; 6*30 micro seconds (~5556 chars/second)
  2396                              <1> 	; 12/01/2022
  2397 00006073 29C9                <1> 	sub	ecx, ecx
  2398 00006075 B106                <1> 	mov	cl, 6
  2399 00006077 E841B4FFFF          <1> 	call	WAITF
  2400                              <1> 	;pop	cx
  2401                              <1> 	; 24/12/1021
  2402 0000607C 59                  <1> 	pop	ecx
  2403                              <1>     	;
  2404                              <1> 	; 07/11/2015
  2405 0000607D 88D8                <1> 	mov	al, bl ; al = 0 (tty8) or 1 (tty9)
  2406                              <1> 	;
  2407 0000607F E8F6D4FFFF          <1> 	call	sp_status ; get serial port status
  2408                              <1> 	; AL = Line status, AH = Modem status
  2409                              <1> 	;
  2410 00006084 E87BEFFFFF          <1> 	call	isintr ; quit (ctrl+break) check
  2411 00006089 7405                <1> 	jz	short sndc6
  2412 0000608B E84FDBFFFF          <1> 	call	intract ; quit (ctrl+break) check
  2413                              <1> 	; CPU will jump to 'sysexit' if 'u.quit' = 0FFFFh (yes)
  2414                              <1> sndc6:
  2415 00006090 3C80                <1> 	cmp	al, 80h
  2416 00006092 7332                <1> 	jnb	short sndc7		
  2417                              <1> 	;
  2418 00006094 803D[476B0000]01    <1> 	cmp	byte [comqr], 1 ; 'query or response' ?
  2419 0000609B 7244                <1> 	jb	short sndc8 	; no, normal character
  2420 0000609D 883D[476B0000]      <1> 	mov 	byte [comqr], bh ; 0 ; reset
  2421                              <1> 	; 17/11/2015
  2422 000060A3 E881EEFFFF          <1> 	call	idle
  2423                              <1> 	;
  2424 000060A8 38BB[4A6B0000]      <1> 	cmp	[ebx+schar], bh ; 0 ; query ?
  2425                              <1>         ;ja	sndc2       ; response (will be followed by
  2426                              <1> 			    ; a normal character)
  2427                              <1> 	; 24/12/2021
  2428 000060AE 7602                <1> 	jna	short sndc_10
  2429 000060B0 EB82                <1> 	jmp	sndc2
  2430                              <1> sndc_10:
  2431                              <1> 	; Query request must be responded by the terminal
  2432                              <1> 	; before sending a normal character !
  2433 000060B2 53                  <1> 	push	ebx
  2434                              <1> 	;push	cx ; *** cl = character (to be sent)
  2435                              <1> 	; 24/12/2021
  2436 000060B3 51                  <1> 	push	ecx ; *** cl = character (to be sent)
  2437 000060B4 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn]
  2438 000060BA E8F7EEFFFF          <1> 	call	sleep ; this process will be awakened by
  2439                              <1> 		      ; received data available interrupt
  2440                              <1> 	;pop	cx ; *** cl = character (to be sent)
  2441                              <1> 	; 24/12/2021
  2442 000060BF 59                  <1> 	pop	ecx ; *** cl = character (to be sent) 
  2443 000060C0 5B                  <1> 	pop	ebx
  2444 000060C1 E93DFFFFFF          <1>         jmp	sndcx
  2445                              <1> sndc7:
  2446                              <1> 	 ; 16/11/2015
  2447 000060C6 803D[476B0000]01    <1> 	cmp	byte [comqr], 1 ; 'query or response' ?
  2448 000060CD 7213                <1> 	jb	short sndc9 	; no
  2449                              <1> 	;
  2450 000060CF 88BB[486B0000]      <1> 	mov	[ebx+rchar], bh ; 0 ; reset
  2451 000060D5 88BB[4A6B0000]      <1> 	mov	[ebx+schar], bh ; 0 ; reset
  2452                              <1> 	;
  2453 000060DB 883D[476B0000]      <1> 	mov	byte [comqr], bh ; 0 ; reset  
  2454                              <1> sndc8:
  2455 000060E1 F5                  <1> 	cmc  ; jnc -> jc, jb -> jnb
  2456                              <1> sndc9:
  2457                              <1> 	; AL = Line status, AH = Modem status
  2458 000060E2 C3                  <1> 	retn
  2459                              <1> 
  2460                              <1> get_cpos:
  2461                              <1> 	; 29/06/2015 (Retro UNIX 386 v1)
  2462                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - 'sysgtty')
  2463                              <1> 	;
  2464                              <1> 	; INPUT -> bl = video page number
  2465                              <1> 	; RETURN -> dx = cursor position
  2466                              <1> 
  2467 000060E3 53                  <1> 	push	ebx
  2468 000060E4 83E30F              <1> 	and	ebx, 0Fh ; 07h ; tty0 to tty7
  2469 000060E7 D0E3                <1> 	shl	bl, 1
  2470 000060E9 81C3[F66A0000]      <1> 	add	ebx, cursor_posn
  2471 000060EF 668B13              <1> 	mov	dx, [ebx]
  2472 000060F2 5B                  <1> 	pop	ebx
  2473 000060F3 C3                  <1> 	retn
  2474                              <1> 
  2475                              <1> read_ac_current:
  2476                              <1> 	; 29/06/2015 (Retro UNIX 386 v1)
  2477                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - 'sysgtty')
  2478                              <1> 	;
  2479                              <1> 	; INPUT -> bl = video page number
  2480                              <1> 	; RETURN -> ax = character (al) and attribute (ah)
  2481                              <1> 
  2482 000060F4 E837B4FFFF          <1> 	call 	find_position ; 'video.inc'
  2483                              <1> 	; dx = status port
  2484                              <1> 	; esi = cursor location/address
  2485 000060F9 81C600800B00        <1> 	add	esi, 0B8000h	; 30/08/2014 (Retro UNIX 386 v1)
  2486 000060FF 668B06              <1> 	mov 	ax, [esi]	; get the character and attribute
  2487 00006102 C3                  <1> 	retn
  2488                              <1> 
  2489                              <1> syssleep:
  2490                              <1> 	; 29/06/2015 - (Retro UNIX 386 v1)
  2491                              <1> 	; 11/06/2014 - (Retro UNIX 8086 v1)
  2492                              <1> 	;
  2493                              <1> 	; Retro UNIX 8086 v1 feature only
  2494                              <1> 	; (INPUT -> none)
  2495                              <1> 	;
  2496 00006103 0FB61D[E76E0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2497 0000610A 8AA3[F76B0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; current/console tty
  2498 00006110 E8A1EEFFFF          <1> 	call	sleep
  2499 00006115 E9D8D9FFFF          <1> 	jmp	sysret
  2500                              <1> 
  2501                              <1> 	; 27/02/2022
  2502                              <1> 	; (u1.s, 'wttyc' & 'wpc_clr')
  2503                              <1> %if 0
  2504                              <1> 
  2505                              <1> vp_clr:
  2506                              <1> 	; Reset/Clear Video Page
  2507                              <1> 	;
  2508                              <1> 	; 24/12/2021 - (Retro UNIX 386 v1.1)
  2509                              <1> 	; 30/06/2015 - (Retro UNIX 386 v1)
  2510                              <1> 	; 21/05/2013 - 30/10/2013(Retro UNIX 8086 v1) (U0.ASM)
  2511                              <1> 	;
  2512                              <1> 	; Retro UNIX 8086 v1 feature only !
  2513                              <1> 	;
  2514                              <1> 	; INPUTS -> 
  2515                              <1> 	;   BL = video page number	 
  2516                              <1> 	;
  2517                              <1> 	; OUTPUT ->
  2518                              <1> 	;   none
  2519                              <1> 	; ((Modified registers: eAX, BH, eCX, eDX, eSI, eDI))
  2520                              <1> 	;
  2521                              <1> 	; 04/12/2013
  2522                              <1> 	sub	al, al
  2523                              <1> 	; al = 0 (clear video page)
  2524                              <1> 	; bl = video page
  2525                              <1> 	mov	ah, 07h
  2526                              <1> 	; ah = 7 (attribute/color)
  2527                              <1> 	;xor 	cx, cx ; 0, left upper column (cl) & row (cl)
  2528                              <1> 	; 24/12/2021
  2529                              <1> 	xor	ecx, ecx
  2530                              <1> 	mov	dx, 184Fh ; right lower column & row (dl=24, dh=79)
  2531                              <1> 	call	scroll_up
  2532                              <1> 	; bl = video page
  2533                              <1> 	;xor	dx, dx ; 0 (cursor position) 
  2534                              <1> 	; 24/12/2021
  2535                              <1> 	xor	edx, edx 
  2536                              <1> 	jmp 	set_cpos
  2537                              <1> 
  2538                              <1> %endif
  2539                              <1> 
  2540                              <1> sysmsg:
  2541                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2542                              <1> 	; 11/11/2015
  2543                              <1> 	; 01/07/2015 - (Retro UNIX 386 v1 feature only!)
  2544                              <1> 	; Print user-application message on user's console tty
  2545                              <1> 	;
  2546                              <1> 	; Input -> EBX = Message address
  2547                              <1> 	;	   ECX = Message length (max. 255)
  2548                              <1> 	;	   DL = Color (IBM PC Rombios color attributes)
  2549                              <1> 	;
  2550 0000611A 81F9FF000000        <1> 	cmp	ecx, MAX_MSG_LEN ; 255
  2551                              <1> 	;ja	sysret ; nothing to do with big message size
  2552 00006120 7779                <1> 	ja	short sysmsg8 ; 24/12/2021
  2553 00006122 08C9                <1> 	or	cl, cl
  2554                              <1> 	;jz	sysret
  2555 00006124 7475                <1> 	jz	short sysmsg8 ; 24/12/2021
  2556 00006126 20D2                <1> 	and	dl, dl
  2557 00006128 7502                <1> 	jnz	short sysmsg0
  2558 0000612A B207                <1> 	mov	dl, 07h ; default color
  2559                              <1> 		; (black background, light gray character)
  2560                              <1> sysmsg0:
  2561 0000612C 891D[B86E0000]      <1> 	mov	[u.base], ebx
  2562 00006132 8815[076B0000]      <1> 	mov	[ccolor], dl ; color attributes
  2563 00006138 89E5                <1> 	mov	ebp, esp
  2564 0000613A 31DB                <1> 	xor	ebx, ebx ; 0
  2565 0000613C 891D[C06E0000]      <1> 	mov	[u.nread], ebx ; 0
  2566                              <1> 	;
  2567 00006142 381D[FF6E0000]      <1> 	cmp	[u.kcall], bl ; 0
  2568 00006148 7772                <1> 	ja	short sysmsgk ; Temporary (01/07/2015)
  2569                              <1> 	;
  2570 0000614A 890D[BC6E0000]      <1> 	mov	[u.count], ecx
  2571 00006150 41                  <1> 	inc	ecx ; + 00h ; ASCIIZ
  2572                              <1> 	; 24/12/2021
  2573                              <1> 	; (dword alignment for esp)
  2574 00006151 F6C103              <1> 	test	cl, 3
  2575 00006154 7404                <1> 	jz	short sysmsg_7
  2576 00006156 80C903              <1> 	or	cl, 3
  2577 00006159 41                  <1> 	inc	ecx
  2578                              <1> sysmsg_7:
  2579 0000615A 29CC                <1> 	sub	esp, ecx
  2580 0000615C 89E7                <1> 	mov	edi, esp
  2581 0000615E 89E6                <1> 	mov	esi, esp
  2582 00006160 66891D[FD6E0000]    <1> 	mov	[u.pcount], bx ; reset page (phy. addr.) counter
  2583                              <1> 	; 11/11/2015
  2584 00006167 8A25[C86E0000]      <1> 	mov 	ah, [u.ttyp] ; recent open tty
  2585                              <1> 	; 0 = none
  2586 0000616D FECC                <1> 	dec	ah
  2587 0000616F 790C                <1> 	jns	short sysmsg1 
  2588 00006171 8A1D[E76E0000]      <1> 	mov	bl, [u.uno] ; process number	
  2589 00006177 8AA3[F76B0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; user's (process's) console tty
  2590                              <1> sysmsg1:
  2591 0000617D 8825[EC6E0000]      <1> 	mov	[u.ttyn], ah
  2592                              <1> sysmsg2:
  2593 00006183 E884F5FFFF          <1> 	call	cpass
  2594 00006188 7416                <1> 	jz	short sysmsg5
  2595 0000618A AA                  <1> 	stosb
  2596 0000618B 20C0                <1> 	and	al, al
  2597 0000618D 75F4                <1> 	jnz	short sysmsg2
  2598                              <1> sysmsg3:
  2599 0000618F 80FC07              <1> 	cmp	ah, 7 ; tty number
  2600 00006192 7711                <1> 	ja	short sysmsg6 ; serial port
  2601 00006194 E83E000000          <1> 	call	print_cmsg
  2602                              <1> sysmsg4:
  2603 00006199 89EC                <1> 	mov	esp, ebp	
  2604                              <1> sysmsg8: ; 24/12/2021	
  2605 0000619B E952D9FFFF          <1> 	jmp	sysret
  2606                              <1> sysmsg5:
  2607 000061A0 C60700              <1> 	mov	byte [edi], 0
  2608 000061A3 EBEA                <1> 	jmp	short sysmsg3
  2609                              <1> sysmsg6:
  2610 000061A5 8A06                <1> 	mov	al, [esi]
  2611 000061A7 E843FEFFFF          <1> 	call	sndc
  2612 000061AC 72EB                <1> 	jc	short sysmsg4
  2613 000061AE 803E00              <1> 	cmp	byte [esi], 0  ; 0 is stop character
  2614 000061B1 76E6                <1> 	jna	short sysmsg4
  2615 000061B3 46                  <1> 	inc 	esi
  2616 000061B4 8A25[EC6E0000]      <1> 	mov	ah, [u.ttyn]
  2617 000061BA EBE9                <1> 	jmp	short sysmsg6
  2618                              <1> 
  2619                              <1> sysmsgk: ; Temporary (01/07/2015)
  2620                              <1> 	; The message has been sent by Kernel (ASCIIZ string)
  2621                              <1> 	; (ECX -character count- will not be considered)
  2622 000061BC 8B35[B86E0000]      <1> 	mov	esi, [u.base]
  2623 000061C2 8A25[066B0000]      <1> 	mov	ah, [ptty] ; present/current screen (video page)
  2624 000061C8 8825[EC6E0000]      <1> 	mov	[u.ttyn], ah
  2625 000061CE C605[FF6E0000]00    <1> 	mov	byte [u.kcall], 0
  2626 000061D5 EBB8                <1> 	jmp	short sysmsg3
  2627                              <1> 	
  2628                              <1> print_cmsg: 
  2629                              <1> 	; 01/07/2015 (retro UNIX 386 v1 feature only !)
  2630                              <1> 	;
  2631                              <1> 	; print message (on user's console tty) 
  2632                              <1> 	;	with requested color
  2633                              <1> 	;
  2634                              <1> 	; INPUTS:
  2635                              <1> 	;	esi = message address
  2636                              <1> 	;	[u.ttyn] = tty number (0 to 7)
  2637                              <1> 	;	[ccolor] = color attributes (IBM PC BIOS colors)
  2638                              <1> 	;
  2639 000061D7 AC                  <1> 	lodsb
  2640                              <1> pcmsg1:
  2641 000061D8 56                  <1> 	push 	esi
  2642 000061D9 0FB61D[EC6E0000]    <1>         movzx   ebx, byte [u.ttyn]
  2643 000061E0 8A25[076B0000]      <1> 	mov	ah, [ccolor]
  2644 000061E6 E8DBB1FFFF          <1> 	call 	write_tty
  2645 000061EB 5E                  <1> 	pop	esi
  2646 000061EC AC                  <1> 	lodsb
  2647 000061ED 20C0                <1> 	and 	al, al  ; 0
  2648 000061EF 75E7                <1> 	jnz 	short pcmsg1
  2649 000061F1 C3                  <1> 	retn
  2650                              <1> 
  2651                              <1> sysgeterr:
  2652                              <1> 	; 16/02/2022 - Retro UNIX 386 v1.1
  2653                              <1> 	; 09/12/2015
  2654                              <1> 	; 21/09/2015 - (Retro UNIX 386 v1 feature only!)
  2655                              <1> 	; Get last error number or page fault count
  2656                              <1> 	; (for debugging)
  2657                              <1> 	;
  2658                              <1> 	; Input -> EBX = return type
  2659                              <1> 	;	   0 = last error code (which is in 'u.error')	
  2660                              <1> 	;	   FFFFFFFFh = page fault count for running process
  2661                              <1> 	;	   FFFFFFFEh = total page fault count
  2662                              <1> 	;	   1 .. FFFFFFFDh = undefined 
  2663                              <1> 	;
  2664                              <1> 	; Output -> EAX = last error number or page fault count
  2665                              <1> 	;	   (depending on EBX input)
  2666                              <1> 	; 	
  2667 000061F2 21DB                <1> 	and 	ebx, ebx
  2668 000061F4 750F                <1> 	jnz	short glerr_2
  2669                              <1> glerr_0:
  2670 000061F6 A1[ED6E0000]        <1> 	mov	eax, [u.error]
  2671                              <1> glerr_1:
  2672 000061FB A3[986E0000]        <1> 	mov	[u.r0], eax
  2673                              <1>  	;retn
  2674                              <1> 	; 16/02/2022 (BugFix)
  2675 00006200 E9EDD8FFFF          <1> 	jmp	sysret
  2676                              <1> glerr_2:
  2677 00006205 43                  <1> 	inc	ebx ; FFFFFFFFh -> 0, FFFFFFFEh -> FFFFFFFFh
  2678 00006206 74FD                <1> 	jz	short glerr_2 ; page fault count for process
  2679 00006208 43                  <1> 	inc	ebx ; FFFFFFFFh -> 0	
  2680 00006209 75EB                <1> 	jnz	short glerr_0
  2681 0000620B A1[906B0000]        <1> 	mov	eax, [PF_Count] ; total page fault count
  2682 00006210 EBE9                <1>         jmp     short glerr_1
  2683                              <1> glerr_3:
  2684 00006212 A1[016F0000]        <1> 	mov 	eax, [u.pfcount]
  2685 00006217 EBE2                <1> 	jmp	short glerr_1
  2101                                  
  2102                                  ; 07/03/2015
  2103                                  ; Temporary Code
  2104                                  display_disks:
  2105 00006219 803D[CE650000]00        	cmp 	byte [fd0_type], 0
  2106 00006220 7605                    	jna 	short ddsks1
  2107 00006222 E87D000000              	call	pdskm
  2108                                  ddsks1:
  2109 00006227 803D[CF650000]00        	cmp	byte [fd1_type], 0
  2110 0000622E 760C                    	jna	short ddsks2
  2111 00006230 C605[BF670000]31        	mov	byte [dskx], '1'
  2112 00006237 E868000000              	call	pdskm
  2113                                  ddsks2:
  2114 0000623C 803D[D0650000]00        	cmp	byte [hd0_type], 0
  2115 00006243 7654                    	jna	short ddsk6
  2116 00006245 66C705[BD670000]68-     	mov	word [dsktype], 'hd'
  2116 0000624D 64                 
  2117 0000624E C605[BF670000]30        	mov	byte [dskx], '0'
  2118 00006255 E84A000000              	call	pdskm
  2119                                  ddsks3:
  2120 0000625A 803D[D1650000]00        	cmp	byte [hd1_type], 0
  2121 00006261 7636                    	jna	short ddsk6
  2122 00006263 C605[BF670000]31        	mov	byte [dskx], '1'
  2123 0000626A E835000000              	call	pdskm
  2124                                  ddsks4:
  2125 0000626F 803D[D2650000]00        	cmp	byte [hd2_type], 0
  2126 00006276 7621                    	jna	short ddsk6
  2127 00006278 C605[BF670000]32        	mov	byte [dskx], '2'
  2128 0000627F E820000000              	call	pdskm
  2129                                  ddsks5:
  2130 00006284 803D[D3650000]00        	cmp	byte [hd3_type], 0
  2131 0000628B 760C                    	jna	short ddsk6
  2132 0000628D C605[BF670000]33        	mov	byte [dskx], '3'
  2133 00006294 E80B000000              	call	pdskm
  2134                                  ddsk6:
  2135 00006299 BE[CE670000]            	mov	esi, nextline
  2136 0000629E E806000000              	call	pdskml
  2137                                  pdskm_ok:
  2138 000062A3 C3                      	retn
  2139                                  pdskm:
  2140 000062A4 BE[BB670000]            	mov	esi, dsk_ready_msg
  2141                                  pdskml:	
  2142 000062A9 AC                      	lodsb
  2143 000062AA 08C0                    	or	al, al
  2144 000062AC 74F5                    	jz	short pdskm_ok
  2145 000062AE 56                      	push	esi
  2146 000062AF 31DB                    	xor	ebx, ebx ; 0
  2147                                  			; Video page 0 (bl=0)
  2148 000062B1 B407                    	mov	ah, 07h ; Black background, 
  2149                                  			; light gray forecolor
  2150 000062B3 E80EB1FFFF              	call	write_tty
  2151 000062B8 5E                      	pop	esi
  2152 000062B9 EBEE                    	jmp	short pdskml
  2153                                  
  2154 000062BB 90<rep 5h>              align 16
  2155                                  
  2156                                  gdt:	; Global Descriptor Table
  2157                                  	; (30/07/2015, conforming cs)
  2158                                  	; (26/03/2015)
  2159                                  	; (24/03/2015, tss)
  2160                                  	; (19/03/2015)
  2161                                  	; (29/12/2013)
  2162                                  	;
  2163 000062C0 0000000000000000        	dw 0, 0, 0, 0		; NULL descriptor
  2164                                  	; 18/08/2014
  2165                                  			; 8h kernel code segment, base = 00000000h		
  2166 000062C8 FFFF0000009ACF00        	dw 0FFFFh, 0, 9A00h, 00CFh	; KCODE
  2167                                  			; 10h kernel data segment, base = 00000000h	
  2168 000062D0 FFFF00000092CF00        	dw 0FFFFh, 0, 9200h, 00CFh	; KDATA
  2169                                  			; 1Bh user code segment, base address = 400000h ; CORE
  2170 000062D8 FFFB000040FACF00        	dw 0FBFFh, 0, 0FA40h, 00CFh	; UCODE 
  2171                                  			; 23h user data segment, base address = 400000h ; CORE
  2172 000062E0 FFFB000040F2CF00        	dw 0FBFFh, 0, 0F240h, 00CFh	; UDATA
  2173                                  			; Task State Segment
  2174 000062E8 6700                    	dw 0067h ; Limit = 103 ; (104-1, tss size = 104 byte, 
  2175                                  			       ;  no IO permission in ring 3)
  2176                                  gdt_tss0:
  2177 000062EA 0000                    	dw 0  ; TSS base address, bits 0-15 
  2178                                  gdt_tss1:
  2179 000062EC 00                      	db 0  ; TSS base address, bits 16-23 
  2180                                  	      		; 49h	
  2181 000062ED E9                      	db 11101001b ; E9h => P=1/DPL=11/0/1/0/B/1 --> B = Task is busy (1)
  2182 000062EE 00                      	db 0 ; G/0/0/AVL/LIMIT=0000 ; (Limit bits 16-19 = 0000) (G=0, 1 byte)
  2183                                  gdt_tss2:
  2184 000062EF 00                      	db 0  ; TSS base address, bits 24-31 
  2185                                  
  2186                                  gdt_end:
  2187                                  	;; 9Ah = 1001 1010b (GDT byte 5) P=1/DPL=00/1/TYPE=1010, 
  2188                                  					;; Type= 1 (code)/C=0/R=1/A=0
  2189                                  		; P= Present, DPL=0=ring 0,  1= user (0= system)
  2190                                  		; 1= Code C= non-Conforming, R= Readable, A = Accessed
  2191                                  
  2192                                  	;; 92h = 1001 0010b (GDT byte 5) P=1/DPL=00/1/TYPE=1010, 
  2193                                  					;; Type= 0 (data)/E=0/W=1/A=0
  2194                                  		; P= Present, DPL=0=ring 0,  1= user (0= system)
  2195                                  		; 0= Data E= Expansion direction (1= down, 0= up)
  2196                                  		; W= Writeable, A= Accessed
  2197                                  	
  2198                                  	;; FAh = 1111 1010b (GDT byte 5) P=1/DPL=11/1/TYPE=1010, 
  2199                                  					;; Type= 1 (code)/C=0/R=1/A=0
  2200                                  		; P= Present, DPL=3=ring 3,  1= user (0= system)
  2201                                  		; 1= Code C= non-Conforming, R= Readable, A = Accessed
  2202                                  
  2203                                  	;; F2h = 1111 0010b (GDT byte 5) P=1/DPL=11/1/TYPE=0010, 
  2204                                  					;; Type= 0 (data)/E=0/W=1/A=0
  2205                                  		; P= Present, DPL=3=ring 3,  1= user (0= system)
  2206                                  		; 0= Data E= Expansion direction (1= down, 0= up)
  2207                                  	
  2208                                  	;; CFh = 1100 1111b (GDT byte 6) G=1/B=1/0/AVL=0, Limit=1111b (3)
  2209                                  
  2210                                  		;; Limit = FFFFFh (=> FFFFFh+1= 100000h) // bits 0-15, 48-51 //
  2211                                  		;	 = 100000h * 1000h (G=1) = 4GB
  2212                                  		;; Limit = FFBFFh (=> FFBFFh+1= FFC00h) // bits 0-15, 48-51 //
  2213                                  		;	 = FFC00h * 1000h (G=1) = 4GB - 4MB
  2214                                  		; G= Granularity (1= 4KB), B= Big (32 bit), 
  2215                                  		; AVL= Available to programmers	
  2216                                  
  2217                                  gdtd:
  2218 000062F0 2F00                            dw gdt_end - gdt - 1    ; Limit (size)
  2219 000062F2 [C0620000]                      dd gdt			; Address of the GDT
  2220                                  
  2221                                  	; 20/08/2014
  2222                                  idtd:
  2223 000062F6 FF01                            dw idt_end - idt - 1    ; Limit (size)
  2224 000062F8 [70680000]                      dd idt			; Address of the IDT
  2225                                  
  2226                                  Align 4
  2227                                  
  2228                                  	; 21/08/2014
  2229                                  ilist:
  2230                                  	;times 	32 dd cpu_except ; INT 0 to INT 1Fh
  2231                                  	;
  2232                                  	; Exception list
  2233                                  	; 25/08/2014	
  2234 000062FC [25080000]              	dd	exc0	; 0h,  Divide-by-zero Error
  2235 00006300 [2C080000]              	dd	exc1	
  2236 00006304 [33080000]              	dd 	exc2	
  2237 00006308 [3A080000]              	dd	exc3	
  2238 0000630C [3E080000]              	dd	exc4	
  2239 00006310 [42080000]              	dd	exc5	
  2240 00006314 [46080000]              	dd 	exc6	; 06h,  Invalid Opcode
  2241 00006318 [4A080000]              	dd	exc7	
  2242 0000631C [4E080000]              	dd	exc8	
  2243 00006320 [52080000]              	dd	exc9	
  2244 00006324 [56080000]              	dd 	exc10	
  2245 00006328 [5A080000]              	dd	exc11
  2246 0000632C [5E080000]              	dd	exc12
  2247 00006330 [62080000]              	dd	exc13	; 0Dh, General Protection Fault
  2248 00006334 [66080000]              	dd 	exc14	; 0Eh, Page Fault
  2249 00006338 [6A080000]              	dd	exc15
  2250 0000633C [6E080000]              	dd	exc16
  2251 00006340 [72080000]              	dd	exc17
  2252 00006344 [76080000]              	dd 	exc18
  2253 00006348 [7A080000]              	dd	exc19
  2254 0000634C [7E080000]              	dd 	exc20
  2255 00006350 [82080000]              	dd	exc21
  2256 00006354 [86080000]              	dd	exc22
  2257 00006358 [8A080000]              	dd	exc23
  2258 0000635C [8E080000]              	dd 	exc24
  2259 00006360 [92080000]              	dd	exc25
  2260 00006364 [96080000]              	dd	exc26
  2261 00006368 [9A080000]              	dd	exc27
  2262 0000636C [9E080000]              	dd 	exc28
  2263 00006370 [A2080000]              	dd	exc29
  2264 00006374 [A6080000]              	dd 	exc30
  2265 00006378 [AA080000]              	dd	exc31
  2266                                  	; Interrupt list
  2267 0000637C [60060000]              	dd	timer_int	; INT 20h
  2268                                  		;dd	irq0	
  2269 00006380 [640B0000]              	dd	keyb_int	; 27/08/2014
  2270                                  		;dd	irq1
  2271 00006384 [7F070000]              	dd	irq2
  2272                                  		; COM2 int
  2273 00006388 [83070000]              	dd	irq3
  2274                                  		; COM1 int
  2275 0000638C [8E070000]              	dd	irq4
  2276 00006390 [99070000]              	dd	irq5
  2277                                  ;DISKETTE_INT: ;06/02/2015
  2278 00006394 [49250000]              	dd	fdc_int		; 16/02/2015, IRQ 6 handler	
  2279                                  		;dd	irq6
  2280                                  ; Default IRQ 7 handler against spurious IRQs (from master PIC)
  2281                                  ; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  2282 00006398 [150B0000]              	dd	default_irq7	; 25/02/2015
  2283                                  		;dd	irq7
  2284                                  ; Real Time Clock Interrupt
  2285 0000639C [B3090000]              	dd	rtc_int		; 23/02/2015, IRQ 8 handler
  2286                                  		;dd	irq8	; INT 28h
  2287 000063A0 [A9070000]              	dd	irq9
  2288 000063A4 [AD070000]              	dd	irq10
  2289 000063A8 [B1070000]              	dd	irq11
  2290 000063AC [B5070000]              	dd	irq12
  2291 000063B0 [B9070000]              	dd	irq13
  2292                                  ;HDISK_INT1:  ;06/02/2015 	
  2293 000063B4 [6F2D0000]              	dd	hdc1_int 	; 21/02/2015, IRQ 14 handler		
  2294                                  		;dd	irq14
  2295                                  ;HDISK_INT2:  ;06/02/2015
  2296 000063B8 [922D0000]              	dd	hdc2_int 	; 21/02/2015, IRQ 15 handler		
  2297                                  		;dd	irq15	; INT 2Fh
  2298                                  		; 14/08/2015
  2299 000063BC [DA390000]              	dd	sysent		; INT 30h (system calls)
  2300                                  	
  2301                                  	;dd	ignore_int
  2302 000063C0 00000000                	dd	0
  2303                                  
  2304                                  ;;;
  2305                                  ;;; 11/03/2015
  2306                                  %include 'kybdata.inc'	; KEYBOARD (BIOS) DATA
  2307                              <1> ; Retro UNIX 386 v1 Kernel - KYBDATA.INC
  2308                              <1> ; Last Modification: 11/03/2015
  2309                              <1> ;		 (Data Section for 'KEYBOARD.INC')	
  2310                              <1> ;
  2311                              <1> ; ///////// KEYBOARD DATA ///////////////
  2312                              <1> 
  2313                              <1> ; 05/12/2014
  2314                              <1> ; 04/12/2014 (derived from pc-xt-286 bios source code -1986-) 
  2315                              <1> ; 03/06/86  KEYBOARD BIOS
  2316                              <1> 
  2317                              <1> ;---------------------------------------------------------------------------------
  2318                              <1> ;	KEY IDENTIFICATION SCAN TABLES
  2319                              <1> ;---------------------------------------------------------------------------------
  2320                              <1> 
  2321                              <1> ;-----	TABLES FOR ALT CASE ------------
  2322                              <1> ;-----	ALT-INPUT-TABLE 
  2323 000063C4 524F50514B          <1> K30:	db	82,79,80,81,75
  2324 000063C9 4C4D474849          <1> 	db	76,77,71,72,73		; 10 NUMBER ON KEYPAD
  2325                              <1> ;-----	SUPER-SHIFT-TABLE 
  2326 000063CE 101112131415        <1> 	db	16,17,18,19,20,21	; A-Z TYPEWRITER CHARS
  2327 000063D4 161718191E1F        <1> 	db	22,23,24,25,30,31
  2328 000063DA 202122232425        <1> 	db	32,33,34,35,36,37
  2329 000063E0 262C2D2E2F30        <1> 	db	38,44,45,46,47,48
  2330 000063E6 3132                <1> 	db	49,50
  2331                              <1> 
  2332                              <1> ;-----	TABLE OF SHIFT KEYS AND MASK VALUES
  2333                              <1> ;-----	KEY_TABLE 
  2334 000063E8 52                  <1> _K6:    db      INS_KEY                 ; INSERT KEY
  2335 000063E9 3A4546381D          <1> 	db	CAPS_KEY,NUM_KEY,SCROLL_KEY,ALT_KEY,CTL_KEY
  2336 000063EE 2A36                <1>         db      LEFT_KEY,RIGHT_KEY
  2337                              <1> _K6L    equ     $-_K6
  2338                              <1> 
  2339                              <1> ;-----	MASK_TABLE
  2340 000063F0 80                  <1> _K7:    db      INS_SHIFT               ; INSERT MODE SHIFT
  2341 000063F1 4020100804          <1> 	db	CAPS_SHIFT,NUM_SHIFT,SCROLL_SHIFT,ALT_SHIFT,CTL_SHIFT
  2342 000063F6 0201                <1> 	db	LEFT_SHIFT,RIGHT_SHIFT
  2343                              <1> 
  2344                              <1> ;-----	TABLES FOR CTRL CASE		;---- CHARACTERS ------
  2345 000063F8 1BFF00FFFFFF        <1> _K8:	db	27,-1,0,-1,-1,-1	; Esc, 1, 2, 3, 4, 5
  2346 000063FE 1EFFFFFFFF1F        <1> 	db 	30,-1,-1,-1,-1,31	; 6, 7, 8, 9, 0, -
  2347 00006404 FF7FFF111705        <1> 	db	-1,127,-1,17,23,5	; =, Bksp, Tab, Q, W, E
  2348 0000640A 12141915090F        <1> 	db	18,20,25,21,9,15	; R, T, Y, U, I, O
  2349 00006410 101B1D0AFF01        <1> 	db	16,27,29,10,-1,1	; P, [, ], Enter, Ctrl, A
  2350 00006416 13040607080A        <1> 	db	19,4,6,7,8,10		; S, D, F, G, H, J
  2351 0000641C 0B0CFFFFFFFF        <1> 	db	11,12,-1,-1,-1,-1	; K, L, :, ', `, LShift
  2352 00006422 1C1A18031602        <1> 	db	28,26,24,3,22,2		; Bkslash, Z, X, C, V, B
  2353 00006428 0E0DFFFFFFFF        <1> 	db	14,13,-1,-1,-1,-1	; N, M, ,, ., /, RShift
  2354 0000642E 96FF20FF            <1> 	db	150,-1,' ',-1		; *, ALT, Spc, CL
  2355                              <1> 	;				;----- FUNCTIONS ------		
  2356 00006432 5E5F60616263        <1> 	db 	94,95,96,97,98,99	; F1 - F6
  2357 00006438 64656667FFFF        <1> 	db	100,101,102,103,-1,-1	; F7 - F10, NL, SL
  2358 0000643E 778D848E738F        <1> 	db	119,141,132,142,115,143	; Home, Up, PgUp, -, Left, Pad5
  2359 00006444 749075917692        <1> 	db 	116,144,117,145,118,146 ; Right, +, End, Down, PgDn, Ins
  2360 0000644A 93FFFFFF898A        <1> 	db	147,-1,-1,-1,137,138	; Del, SysReq, Undef, WT, F11, F12
  2361                              <1> 
  2362                              <1> ;-----	TABLES FOR LOWER CASE ----------
  2363 00006450 1B3132333435363738- <1> K10:	db 	27,'1234567890-=',8,9
  2363 00006459 39302D3D0809        <1>
  2364 0000645F 71776572747975696F- <1> 	db 	'qwertyuiop[]',13,-1,'asdfghjkl;',39
  2364 00006468 705B5D0DFF61736466- <1>
  2364 00006471 67686A6B6C3B27      <1>
  2365 00006478 60FF5C7A786376626E- <1> 	db	96,-1,92,'zxcvbnm,./',-1,'*',-1,' ',-1
  2365 00006481 6D2C2E2FFF2AFF20FF  <1>
  2366                              <1> ;-----	LC TABLE SCAN
  2367 0000648A 3B3C3D3E3F          <1> 	db	59,60,61,62,63		; BASE STATE OF F1 - F10
  2368 0000648F 4041424344          <1> 	db	64,65,66,67,68
  2369 00006494 FFFF                <1> 	db	-1,-1			; NL, SL
  2370                              <1> 
  2371                              <1> ;-----	KEYPAD TABLE
  2372 00006496 474849FF4BFF        <1> K15:	db	71,72,73,-1,75,-1	; BASE STATE OF KEYPAD KEYS
  2373 0000649C 4DFF4F50515253      <1> 	db	77,-1,79,80,81,82,83
  2374 000064A3 FFFF5C8586          <1> 	db	-1,-1,92,133,134	; SysRq, Undef, WT, F11, F12
  2375                              <1> 
  2376                              <1> ;-----	TABLES FOR UPPER CASE ----------
  2377 000064A8 1B21402324255E262A- <1> K11:	db 	27,'!@#$%',94,'&*()_+',8,0
  2377 000064B1 28295F2B0800        <1>
  2378 000064B7 51574552545955494F- <1> 	db 	'QWERTYUIOP{}',13,-1,'ASDFGHJKL:"'
  2378 000064C0 507B7D0DFF41534446- <1>
  2378 000064C9 47484A4B4C3A22      <1>
  2379 000064D0 7EFF7C5A584356424E- <1> 	db	126,-1,'|ZXCVBNM<>?',-1,'*',-1,' ',-1
  2379 000064D9 4D3C3E3FFF2AFF20FF  <1>
  2380                              <1> ;-----	UC TABLE SCAN
  2381 000064E2 5455565758          <1> K12:	db	84,85,86,87,88		; SHIFTED STATE OF F1 - F10
  2382 000064E7 595A5B5C5D          <1> 	db	89,90,91,92,93
  2383 000064EC FFFF                <1> 	db	-1,-1			; NL, SL
  2384                              <1> 
  2385                              <1> ;-----	NUM STATE TABLE
  2386 000064EE 3738392D3435362B31- <1> K14:	db 	'789-456+1230.'		; NUMLOCK STATE OF KEYPAD KEYS
  2386 000064F7 3233302E            <1>
  2387                              <1> 	;
  2388 000064FB FFFF7C8788          <1> 	db	-1,-1,124,135,136	; SysRq, Undef, WT, F11, F12
  2389                              <1> 
  2390                              <1> Align	4
  2391                              <1> ;----------------------------------------
  2392                              <1> ;	VIDEO DISPLAY DATA AREA		;
  2393                              <1> ;----------------------------------------
  2394 00006500 03                  <1> CRT_MODE	db	3	; CURRENT DISPLAY MODE (TYPE)
  2395 00006501 29                  <1> CRT_MODE_SET	db	29h	; CURRENT SETTING OF THE 3X8 REGISTER
  2396                              <1> 				; (29h default setting for video mode 3)
  2397                              <1> 				; Mode Select register Bits
  2398                              <1> 				;   BIT 0 - 80x25 (1), 40x25 (0)
  2399                              <1> 				;   BIT 1 - ALPHA (0), 320x200 GRAPHICS (1)
  2400                              <1> 				;   BIT 2 - COLOR (0), BW (1)
  2401                              <1> 				;   BIT 3 - Video Sig. ENABLE (1), DISABLE (0)
  2402                              <1> 				;   BIT 4 - 640x200 B&W Graphics Mode (1)
  2403                              <1> 				;   BIT 5 - ALPHA mode BLINKING (1)
  2404                              <1> 				;   BIT 6, 7 - Not Used
  2405                              <1> 
  2406                              <1> ; Mode 0 - 2Ch = 101100b	; 40x25 text, 16 gray colors
  2407                              <1> ; Mode 1 - 28h = 101000b	; 40x25 text, 16 fore colors, 8 back colors
  2408                              <1> ; Mode 2 - 2Dh = 101101b	; 80x25 text, 16 gray colors	
  2409                              <1> ; MODE 3 - 29h = 101001b	; 80x25 text, 16 fore color, 8 back color
  2410                              <1> ; Mode 4 - 2Ah = 101010b	; 320x200 graphics, 4 colors
  2411                              <1> ; Mode 5 - 2Eh = 101110b	; 320x200 graphics, 4 gray colors
  2412                              <1> ; Mode 6 - 1Eh = 011110b	; 640x200 graphics, 2 colors
  2413                              <1> ; Mode 7 - 29h = 101001b	; 80x25 text, black & white colors
  2414                              <1> ; Mode & 37h = Video signal OFF
  2415                              <1> 			
  2416                              <1> 
  2417                              <1> ; 26/08/2014
  2418                              <1> ; Retro UNIX 8086 v1 - UNIX.ASM (03/03/2014)
  2419                              <1> ; Derived from IBM "pc-at" 
  2420                              <1> ; rombios source code (06/10/1985)
  2421                              <1> ; 'dseg.inc'
  2422                              <1> 
  2423                              <1> ;---------------------------------------;
  2424                              <1> ;	SYSTEM DATA AREA		;
  2425                              <1> ;----------------------------------------
  2426 00006502 00                  <1> BIOS_BREAK	db	0		; BIT 7=1 IF BREAK KEY HAS BEEN PRESSED
  2427                              <1> 
  2428                              <1> ;----------------------------------------
  2429                              <1> ;	KEYBOARD DATA AREAS		;
  2430                              <1> ;----------------------------------------
  2431                              <1> 
  2432 00006503 00                  <1> KB_FLAG		db	0		; KEYBOARD SHIFT STATE AND STATUS FLAGS
  2433 00006504 00                  <1> KB_FLAG_1	db	0		; SECOND BYTE OF KEYBOARD STATUS
  2434 00006505 00                  <1> KB_FLAG_2	db	0		; KEYBOARD LED FLAGS
  2435 00006506 00                  <1> KB_FLAG_3	db	0		; KEYBOARD MODE STATE AND TYPE FLAGS
  2436 00006507 00                  <1> ALT_INPUT	db	0		; STORAGE FOR ALTERNATE KEY PAD ENTRY
  2437 00006508 [18650000]          <1> BUFFER_START	dd	KB_BUFFER 	; OFFSET OF KEYBOARD BUFFER START
  2438 0000650C [38650000]          <1> BUFFER_END	dd	KB_BUFFER + 32	; OFFSET OF END OF BUFFER
  2439 00006510 [18650000]          <1> BUFFER_HEAD	dd	KB_BUFFER 	; POINTER TO HEAD OF KEYBOARD BUFFER
  2440 00006514 [18650000]          <1> BUFFER_TAIL	dd	KB_BUFFER 	; POINTER TO TAIL OF KEYBOARD BUFFER
  2441                              <1> ; ------	HEAD = TAIL	INDICATES THAT THE BUFFER IS EMPTY
  2442 00006518 0000<rep 10h>       <1> KB_BUFFER	times	16 dw 0		; ROOM FOR 16 SCAN CODE ENTRIES
  2443                              <1> 
  2444                              <1> ; /// End Of KEYBOARD DATA ///
  2307                                  %include 'vidata.inc'	; VIDEO (BIOS) DATA
  2308                              <1> ; Retro UNIX 386 v1 Kernel - VIDATA.INC
  2309                              <1> ; Last Modification: 11/03/2015
  2310                              <1> ;		    (Data section for 'VIDEO.INC')	
  2311                              <1> ;
  2312                              <1> ; ///////// VIDEO DATA ///////////////
  2313                              <1> 
  2314                              <1> video_params:
  2315                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2316                              <1> 	;ORGS.ASM ----- 06/10/85   COMPATIBILITY MODULE
  2317                              <1> 	; VIDEO MODE 3
  2318 00006538 71505A0A1F0619      <1> 	db	71h,50h,5Ah,0Ah,1Fh,6,19h	; SET UP FOR 80X25
  2319 0000653F 1C02070607          <1> 	db	1Ch,2,7,6,7	; cursor start = 6, cursor stop = 7
  2320 00006544 00000000            <1> 	db	0,0,0,0
  2321                              <1> 
  2322                              <1> ; /// End Of VIDEO DATA ///
  2308                                  %include 'diskdata.inc'	; DISK (BIOS) DATA (initialized)
  2309                              <1> ; Retro UNIX 386 v1 Kernel - DISKDATA.INC
  2310                              <1> ; Last Modification: 11/03/2015
  2311                              <1> ;	(Initialized Disk Parameters Data section for 'DISKIO.INC') 
  2312                              <1> ;
  2313                              <1> ; *****************************************************************************
  2314                              <1> 
  2315                              <1> ;----------------------------------------
  2316                              <1> ;	80286 INTERRUPT LOCATIONS	:
  2317                              <1> ;	REFERENCED BY POST & BIOS	:
  2318                              <1> ;----------------------------------------
  2319                              <1> 
  2320 00006548 [AB650000]          <1> DISK_POINTER:	dd	MD_TBL6		; Pointer to Diskette Parameter Table
  2321                              <1> 
  2322                              <1> ; IBM PC-XT Model 286 source code ORGS.ASM (06/10/85) - 14/12/2014
  2323                              <1> ;----------------------------------------------------------------
  2324                              <1> ; DISK_BASE							:
  2325                              <1> ;	THIS IS THE SET OF PARAMETERS REQUIRED FOR		:
  2326                              <1> ;	DISKETTE OPERATION. THEY ARE POINTED AT BY THE		:
  2327                              <1> ;	DATA VARIABLE @DISK_POINTER. TO MODIFY THE PARAMETERS,	:
  2328                              <1> ;	BUILD ANOTHER PARAMETER BLOCK AND POINT AT IT		:
  2329                              <1> ;----------------------------------------------------------------
  2330                              <1> 
  2331                              <1> ;DISK_BASE:	
  2332                              <1> ;	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2333                              <1> ;	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2334                              <1> ;	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2335                              <1> ;	DB	2		; 512 BYTES/SECTOR
  2336                              <1> ;	;DB	15		; EOT (LAST SECTOR ON TRACK)
  2337                              <1> ;	db	18		; (EOT for 1.44MB diskette)
  2338                              <1> ;	DB	01BH		; GAP LENGTH
  2339                              <1> ;	DB	0FFH		; DTL
  2340                              <1> ;	;DB	054H		; GAP LENGTH FOR FORMAT
  2341                              <1> ;	db	06ch		; (for 1.44MB dsikette)
  2342                              <1> ;	DB	0F6H		; FILL BYTE FOR FORMAT
  2343                              <1> ;	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2344                              <1> ;	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2345                              <1> 
  2346                              <1> ;----------------------------------------
  2347                              <1> ;	ROM BIOS DATA AREAS		:
  2348                              <1> ;----------------------------------------
  2349                              <1> 
  2350                              <1> ;DATA		SEGMENT AT 40H		; ADDRESS= 0040:0000
  2351                              <1> 
  2352                              <1> ;@EQUIP_FLAG	DW	?		; INSTALLED HARDWARE FLAGS
  2353                              <1> 
  2354                              <1> ;----------------------------------------
  2355                              <1> ;	DISKETTE DATA AREAS		:
  2356                              <1> ;----------------------------------------
  2357                              <1> 
  2358                              <1> ;@SEEK_STATUS	DB	?		; DRIVE RECALIBRATION STATUS
  2359                              <1> ;					; BIT 3-0 = DRIVE 3-0 RECALIBRATION
  2360                              <1> ;					; BEFORE NEXT SEEK IF BIT IS = 0
  2361                              <1> ;@MOTOR_STATUS	DB	?		; MOTOR STATUS
  2362                              <1> ;					; BIT 3-0 = DRIVE 3-0 CURRENTLY RUNNING
  2363                              <1> ;					; BIT 7 = CURRENT OPERATION IS A WRITE
  2364                              <1> ;@MOTOR_COUNT	DB	?		; TIME OUT COUNTER FOR MOTOR(S) TURN OFF
  2365                              <1> ;@DSKETTE_STATUS DB	?		; RETURN CODE STATUS BYTE
  2366                              <1> ;					; CMD_BLOCK  IN STACK FOR DISK OPERATION
  2367                              <1> ;@NEC_STATUS	DB	7 DUP(?)	; STATUS BYTES FROM DISKETTE OPERATION
  2368                              <1> 
  2369                              <1> ;----------------------------------------
  2370                              <1> ;	POST AND BIOS WORK DATA AREA	:
  2371                              <1> ;----------------------------------------
  2372                              <1> 
  2373                              <1> ;@INTR_FLAG	DB	?		; FLAG INDICATING AN INTERRUPT HAPPENED
  2374                              <1> 
  2375                              <1> ;----------------------------------------
  2376                              <1> ;	TIMER DATA AREA 		:
  2377                              <1> ;----------------------------------------
  2378                              <1> 
  2379                              <1> ; 17/12/2014  (IRQ 0 - INT 08H)
  2380                              <1> ;TIMER_LOW	equ	46Ch		; Timer ticks (counter)  @ 40h:006Ch
  2381                              <1> ;TIMER_HIGH	equ	46Eh		; (18.2 timer ticks per second)
  2382                              <1> ;TIMER_OFL	equ	470h		; Timer - 24 hours flag  @ 40h:0070h
  2383                              <1> 
  2384                              <1> ;----------------------------------------
  2385                              <1> ;	ADDITIONAL MEDIA DATA		:
  2386                              <1> ;----------------------------------------
  2387                              <1> 
  2388                              <1> ;@LASTRATE	DB	?		; LAST DISKETTE DATA RATE SELECTED
  2389                              <1> ;@DSK_STATE	DB	?		; DRIVE 0 MEDIA STATE
  2390                              <1> ;		DB	?		; DRIVE 1 MEDIA STATE
  2391                              <1> ;		DB	?		; DRIVE 0 OPERATION START STATE
  2392                              <1> ;		DB	?		; DRIVE 1 OPERATION START STATE
  2393                              <1> ;@DSK_TRK	DB	?		; DRIVE 0 PRESENT CYLINDER
  2394                              <1> ;		DB	?		; DRIVE 1 PRESENT CYLINDER
  2395                              <1> 
  2396                              <1> ;DATA		ENDS			; END OF BIOS DATA SEGMENT
  2397                              <1> 
  2398                              <1> ;--------------------------------------------------------
  2399                              <1> ;	DRIVE TYPE TABLE				:
  2400                              <1> ;--------------------------------------------------------
  2401                              <1> 		; 16/02/2015 (unix386.s, 32 bit modifications)
  2402                              <1> DR_TYPE:
  2403 0000654C 01                  <1> 		DB	01		;DRIVE TYPE, MEDIA TABLE
  2404                              <1>                 ;DW      MD_TBL1
  2405 0000654D [6A650000]          <1> 		dd	MD_TBL1
  2406 00006551 82                  <1> 		DB	02+BIT7ON
  2407                              <1> 		;DW      MD_TBL2
  2408 00006552 [77650000]          <1>                 dd      MD_TBL2
  2409 00006556 02                  <1> DR_DEFAULT:	DB	02
  2410                              <1>                 ;DW      MD_TBL3
  2411 00006557 [84650000]          <1> 		dd      MD_TBL3
  2412 0000655B 03                  <1> 		DB	03
  2413                              <1>                 ;DW      MD_TBL4
  2414 0000655C [91650000]          <1> 		dd      MD_TBL4
  2415 00006560 84                  <1> 		DB	04+BIT7ON
  2416                              <1>                 ;DW      MD_TBL5
  2417 00006561 [9E650000]          <1> 		dd      MD_TBL5
  2418 00006565 04                  <1> 		DB	04
  2419                              <1>                 ;DW      MD_TBL6
  2420 00006566 [AB650000]          <1> 		dd      MD_TBL6
  2421                              <1> DR_TYPE_E       equ $                   ; END OF TABLE
  2422                              <1> ;DR_CNT		EQU	(DR_TYPE_E-DR_TYPE)/3
  2423                              <1> DR_CNT		equ	(DR_TYPE_E-DR_TYPE)/5
  2424                              <1> ;--------------------------------------------------------
  2425                              <1> ;	MEDIA/DRIVE PARAMETER TABLES			:
  2426                              <1> ;--------------------------------------------------------
  2427                              <1> ;--------------------------------------------------------
  2428                              <1> ;	360 KB MEDIA IN 360 KB DRIVE			:
  2429                              <1> ;--------------------------------------------------------
  2430                              <1> MD_TBL1:        
  2431 0000656A DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2432 0000656B 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2433 0000656C 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2434 0000656D 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2435 0000656E 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2436 0000656F 2A                  <1> 	DB	02AH		; GAP LENGTH
  2437 00006570 FF                  <1> 	DB	0FFH		; DTL
  2438 00006571 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2439 00006572 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2440 00006573 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2441 00006574 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2442 00006575 27                  <1> 	DB	39		; MAX. TRACK NUMBER
  2443 00006576 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2444                              <1> ;--------------------------------------------------------
  2445                              <1> ;	360 KB MEDIA IN 1.2 MB DRIVE			:
  2446                              <1> ;--------------------------------------------------------
  2447                              <1> MD_TBL2:        
  2448 00006577 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2449 00006578 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2450 00006579 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2451 0000657A 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2452 0000657B 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2453 0000657C 2A                  <1> 	DB	02AH		; GAP LENGTH
  2454 0000657D FF                  <1> 	DB	0FFH		; DTL
  2455 0000657E 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2456 0000657F F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2457 00006580 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2458 00006581 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2459 00006582 27                  <1> 	DB	39		; MAX. TRACK NUMBER
  2460 00006583 40                  <1> 	DB	RATE_300	; DATA TRANSFER RATE
  2461                              <1> ;--------------------------------------------------------
  2462                              <1> ;	1.2 MB MEDIA IN 1.2 MB DRIVE			:
  2463                              <1> ;--------------------------------------------------------
  2464                              <1> MD_TBL3:
  2465 00006584 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2466 00006585 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2467 00006586 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2468 00006587 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2469 00006588 0F                  <1> 	DB	15		; EOT (LAST SECTOR ON TRACK)
  2470 00006589 1B                  <1> 	DB	01BH		; GAP LENGTH
  2471 0000658A FF                  <1> 	DB	0FFH		; DTL
  2472 0000658B 54                  <1> 	DB	054H		; GAP LENGTH FOR FORMAT
  2473 0000658C F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2474 0000658D 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2475 0000658E 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2476 0000658F 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2477 00006590 00                  <1> 	DB	RATE_500	; DATA TRANSFER RATE
  2478                              <1> ;--------------------------------------------------------
  2479                              <1> ;	720 KB MEDIA IN 720 KB DRIVE			:
  2480                              <1> ;--------------------------------------------------------
  2481                              <1> MD_TBL4:
  2482 00006591 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2483 00006592 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2484 00006593 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2485 00006594 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2486 00006595 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2487 00006596 2A                  <1> 	DB	02AH		; GAP LENGTH
  2488 00006597 FF                  <1> 	DB	0FFH		; DTL
  2489 00006598 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2490 00006599 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2491 0000659A 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2492 0000659B 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2493 0000659C 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2494 0000659D 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2495                              <1> ;--------------------------------------------------------
  2496                              <1> ;	720 KB MEDIA IN 1.44 MB DRIVE			:
  2497                              <1> ;--------------------------------------------------------
  2498                              <1> MD_TBL5:
  2499 0000659E DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2500 0000659F 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2501 000065A0 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2502 000065A1 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2503 000065A2 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2504 000065A3 2A                  <1> 	DB	02AH		; GAP LENGTH
  2505 000065A4 FF                  <1> 	DB	0FFH		; DTL
  2506 000065A5 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2507 000065A6 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2508 000065A7 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2509 000065A8 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2510 000065A9 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2511 000065AA 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2512                              <1> ;--------------------------------------------------------
  2513                              <1> ;	1.44 MB MEDIA IN 1.44 MB DRIVE			:
  2514                              <1> ;--------------------------------------------------------
  2515                              <1> MD_TBL6:
  2516 000065AB AF                  <1> 	DB	10101111B	; SRT=A, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2517 000065AC 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2518 000065AD 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2519 000065AE 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2520 000065AF 12                  <1> 	DB	18		; EOT (LAST SECTOR ON TRACK)
  2521 000065B0 1B                  <1> 	DB	01BH		; GAP LENGTH
  2522 000065B1 FF                  <1> 	DB	0FFH		; DTL
  2523 000065B2 6C                  <1> 	DB	06CH		; GAP LENGTH FOR FORMAT
  2524 000065B3 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2525 000065B4 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2526 000065B5 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2527 000065B6 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2528 000065B7 00                  <1> 	DB	RATE_500	; DATA TRANSFER RATE
  2529                              <1> 
  2530                              <1> 
  2531                              <1> ; << diskette.inc >>
  2532                              <1> ; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2533                              <1> ;
  2534                              <1> ;----------------------------------------
  2535                              <1> ;	ROM BIOS DATA AREAS		:
  2536                              <1> ;----------------------------------------
  2537                              <1> 
  2538                              <1> ;DATA		SEGMENT AT 40H		; ADDRESS= 0040:0000
  2539                              <1> 
  2540                              <1> ;----------------------------------------
  2541                              <1> ;	FIXED DISK DATA AREAS		:
  2542                              <1> ;----------------------------------------
  2543                              <1> 
  2544                              <1> ;DISK_STATUS1:	DB	0		; FIXED DISK STATUS
  2545                              <1> ;HF_NUM:		DB	0		; COUNT OF FIXED DISK DRIVES
  2546                              <1> ;CONTROL_BYTE:	DB	0		; HEAD CONTROL BYTE
  2547                              <1> ;@PORT_OFF	DB	?		;  RESERVED (PORT OFFSET)
  2548                              <1> 
  2549                              <1> ;----------------------------------------
  2550                              <1> ;	ADDITIONAL MEDIA DATA		:
  2551                              <1> ;----------------------------------------
  2552                              <1> 
  2553                              <1> ;@LASTRATE	DB	?		; LAST DISKETTE DATA RATE SELECTED
  2554                              <1> ;HF_STATUS	DB	0		; STATUS REGISTER
  2555                              <1> ;HF_ERROR	DB	0		; ERROR REGISTER
  2556                              <1> ;HF_INT_FLAG	DB	0		; FIXED DISK INTERRUPT FLAG
  2557                              <1> ;HF_CNTRL	DB	0		; COMBO FIXED DISK/DISKETTE CARD BIT 0=1
  2558                              <1> ;@DSK_STATE	DB	?		; DRIVE 0 MEDIA STATE
  2559                              <1> ;		DB	?		; DRIVE 1 MEDIA STATE
  2560                              <1> ;		DB	?		; DRIVE 0 OPERATION START STATE
  2561                              <1> ;		DB	?		; DRIVE 1 OPERATION START STATE
  2562                              <1> ;@DSK_TRK	DB	?		; DRIVE 0 PRESENT CYLINDER
  2563                              <1> ;		DB	?		; DRIVE 1 PRESENT CYLINDER
  2564                              <1> 
  2565                              <1> ;DATA		ENDS			; END OF BIOS DATA SEGMENT
  2566                              <1> ;
  2567                              <1> ; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2568                              <1> 
  2569                              <1> ERR_TBL:
  2570 000065B8 E0                  <1> 	db	NO_ERR
  2571 000065B9 024001BB            <1> 	db	BAD_ADDR_MARK,BAD_SEEK,BAD_CMD,UNDEF_ERR
  2572 000065BD 04BB100A            <1> 	db	RECORD_NOT_FND,UNDEF_ERR,BAD_ECC,BAD_SECTOR
  2573                              <1> 
  2574                              <1> ; 17/12/2014 (mov ax, [cfd])
  2575                              <1> ; 11/12/2014
  2576 000065C1 00                  <1> cfd:		db 0			; current floppy drive (for GET_PARM)
  2577                              <1> ; 17/12/2014				; instead of 'DISK_POINTER'
  2578 000065C2 01                  <1> pfd:		db 1			; previous floppy drive (for GET_PARM)
  2579                              <1> 					; (initial value of 'pfd 
  2580                              <1> 					; must be different then 'cfd' value
  2581                              <1> 					; to force updating/initializing
  2582                              <1> 					; current drive parameters) 
  2583 000065C3 90                  <1> align 2
  2584                              <1> 
  2585 000065C4 F001                <1> HF_PORT:	dw 	1F0h  ; Default = 1F0h
  2586                              <1> 			      ; (170h)
  2587 000065C6 F603                <1> HF_REG_PORT:	dw	3F6h  ; HF_PORT + 206h
  2588                              <1> 
  2589                              <1> ; 05/01/2015 
  2590 000065C8 00                  <1> hf_m_s:         db      0     ; (0 = Master, 1 = Slave)
  2591                              <1> 
  2592                              <1> ; *****************************************************************************
  2309                                  ;;;
  2310                                  
  2311 000065C9 90                      Align 2
  2312                                  
  2313                                  ; 12/11/2014 (Retro UNIX 386 v1)
  2314 000065CA 00                      boot_drv:    db 0 ; boot drive number (physical)
  2315                                  ; 24/11/2014
  2316 000065CB 00                      drv:	     db 0 
  2317 000065CC 00                      last_drv:    db 0 ; last hdd
  2318 000065CD 00                      hdc:         db 0  ; number of hard disk drives
  2319                                  		     ; (present/detected)
  2320                                  ;
  2321                                  ; 24/11/2014 (Retro UNIX 386 v1)
  2322                                  ; Physical drive type & flags
  2323 000065CE 00                      fd0_type:    db 0  ; floppy drive type
  2324 000065CF 00                      fd1_type:    db 0  ; 4 = 1.44 Mb, 80 track, 3.5" (18 spt)
  2325                                  		     ; 6 = 2.88 Mb, 80 track, 3.5" (36 spt)
  2326                                  		     ; 3 = 720 Kb, 80 track, 3.5" (9 spt)
  2327                                  		     ; 2 = 1.2 Mb, 80 track, 5.25" (15 spt)
  2328                                  		     ; 1 = 360 Kb, 40 track, 5.25" (9 spt)		
  2329 000065D0 00                      hd0_type:    db 0  ; EDD status for hd0 (bit 7 = present flag)
  2330 000065D1 00                      hd1_type:    db 0  ; EDD status for hd1 (bit 7 = present flag)
  2331 000065D2 00                      hd2_type:    db 0  ; EDD status for hd2 (bit 7 = present flag)
  2332 000065D3 00                      hd3_type:    db 0  ; EDD status for hd3 (bit 7 = present flag)
  2333                                  		     ; bit 0 - Fixed disk access subset supported
  2334                                  		     ; bit 1 - Drive locking and ejecting
  2335                                  		     ; bit 2 - Enhanced disk drive support
  2336                                  		     ; bit 3 = Reserved (64 bit EDD support)
  2337                                  		     ; (If bit 0 is '1' Retro UNIX 386 v1
  2338                                  		     ; will interpret it as 'LBA ready'!)		
  2339                                  
  2340                                  ; 11/03/2015 - 10/07/2015
  2341 000065D4 000000000000000000-     drv.cylinders: dw 0,0,0,0,0,0,0
  2341 000065DD 0000000000         
  2342 000065E2 000000000000000000-     drv.heads:     dw 0,0,0,0,0,0,0
  2342 000065EB 0000000000         
  2343 000065F0 000000000000000000-     drv.spt:       dw 0,0,0,0,0,0,0
  2343 000065F9 0000000000         
  2344 000065FE 000000000000000000-     drv.size:      dd 0,0,0,0,0,0,0
  2344 00006607 000000000000000000-
  2344 00006610 000000000000000000-
  2344 00006619 00                 
  2345 0000661A 00000000000000          drv.status:    db 0,0,0,0,0,0,0
  2346 00006621 00000000000000          drv.error:     db 0,0,0,0,0,0,0		
  2347                                  ;
  2348                                  
  2349                                  ; 27/08/2014
  2350                                  scr_row:
  2351 00006628 E0810B00                	dd 0B8000h + 0A0h + 0A0h + 0A0h ; Row 3
  2352                                  scr_col:
  2353 0000662C 00000000                	dd 0
  2354                                  
  2355                                  ;; 14/08/2015
  2356                                  ;;msgPM:
  2357                                  ;;      db "Protected mode and paging are ENABLED ... ", 0
  2358                                  msgKVER:
  2359 00006630 526574726F20554E49-     	db "Retro UNIX 386 v1.1 - Kernel v0.2.1.2 [03/03/2022]", 0
  2359 00006639 58203338362076312E-
  2359 00006642 31202D204B65726E65-
  2359 0000664B 6C2076302E322E312E-
  2359 00006654 32205B30332F30332F-
  2359 0000665D 323032325D00       
  2360                                  
  2361 00006663 90                      Align 2
  2362                                  
  2363                                  ; 20/08/2014
  2364                                    ; /* This is the default interrupt "handler" :-) */ 
  2365                                    ; Linux v0.12 (head.s)
  2366                                  int_msg:
  2367 00006664 556E6B6E6F776E2069-     	db "Unknown interrupt ! ", 0
  2367 0000666D 6E7465727275707420-
  2367 00006676 212000             
  2368                                  
  2369 00006679 90                      Align 2  
  2370                                  
  2371                                  ; 21/08/2014
  2372                                  timer_msg:
  2373 0000667A 49525120302028494E-     	db "IRQ 0 (INT 20h) ! Timer Interrupt : "
  2373 00006683 542032306829202120-
  2373 0000668C 54696D657220496E74-
  2373 00006695 657272757074203A20 
  2374                                  tcountstr:
  2375 0000669E 303030303020            	db "00000 "
  2376 000066A4 00                      	db 0
  2377                                  
  2378 000066A5 90                      Align 2
  2379                                  	; 21/08/2014
  2380                                  exc_msg:
  2381 000066A6 435055206578636570-     	db "CPU exception ! "
  2381 000066AF 74696F6E202120     
  2382                                  excnstr: 		; 25/08/2014
  2383 000066B6 3F3F68202045495020-     	db "??h", "  EIP : "
  2383 000066BF 3A20               
  2384                                  EIPstr: ; 29/08/2014
  2385 000066C1 00<rep Ch>              	times 12 db 0
  2386                                  rtc_msg:
  2387 000066CD 5265616C2054696D65-     	db "Real Time Clock - "
  2387 000066D6 20436C6F636B202D20 
  2388                                  datestr:
  2389 000066DF 30302F30302F303030-     	db "00/00/0000"
  2389 000066E8 30                 
  2390 000066E9 20                      	db " "
  2391                                  daystr:
  2392 000066EA 44415920                	db "DAY "
  2393                                  timestr:	
  2394 000066EE 30303A30303A3030                db "00:00:00"
  2395 000066F6 20                      	db " "
  2396 000066F7 00                      	db 0 
  2397                                  
  2398                                  daytmp:
  2399                                  	; 28/02/2015
  2400 000066F8 3F3F3F2053554E204D-     	db "??? SUN MON TUE WED THU FRI SAT "
  2400 00006701 4F4E20545545205745-
  2400 0000670A 442054485520465249-
  2400 00006713 2053415420         
  2401                                  
  2402 00006718 FF                      ptime_seconds: db 0FFh
  2403                                  
  2404                                  	; 23/02/2015
  2405                                  	; 25/08/2014
  2406                                  ;scounter:
  2407                                  ;	db 5
  2408                                  ;	db 19
  2409                                  
  2410                                  ; 02/01/2022
  2411                                  ; 05/11/2014
  2412                                  ;msg_out_of_memory:
  2413                                  ;	db 	07h, 0Dh, 0Ah
  2414                                  ;       db	'Insufficient memory ! (Minimum 2 MB memory is needed.)'
  2415                                  ; 	db	0Dh, 0Ah, 0
  2416                                  	;
  2417                                  setup_error_msg:
  2418 00006719 0D0A                    	db 0Dh, 0Ah
  2419 0000671B 4469736B2053657475-     	db 'Disk Setup Error!' 
  2419 00006724 70204572726F7221   
  2420 0000672C 0D0A00                  	db 0Dh, 0Ah,0
  2421                                  
  2422                                  ; 02/09/2014 (Retro UNIX 386 v1)
  2423                                  ;crt_ulc : db 0 ; upper left column (for scroll) 
  2424                                  ;	  db 0 ; upper left row (for scroll)	
  2425                                  
  2426                                  ;crt_lrc : db 79 ; lower right column (for scroll) 
  2427                                  ;	  db 24 ; lower right row (for scroll)
  2428                                  
  2429                                  
  2430                                  ; 06/11/2014 (Temporary Data)
  2431                                  ; Memory Information message
  2432                                  ; 14/08/2015
  2433                                  msg_memory_info:
  2434 0000672F 07                      	db	07h
  2435 00006730 0D0A                    	db	0Dh, 0Ah
  2436                                  	;db 	"MEMORY ALLOCATION INFO", 0Dh, 0Ah, 0Dh, 0Ah
  2437 00006732 546F74616C206D656D-     	db	"Total memory : "
  2437 0000673B 6F7279203A20       
  2438                                  mem_total_b_str: ; 10 digits
  2439 00006741 303030303030303030-     	db	"0000000000 bytes", 0Dh, 0Ah
  2439 0000674A 302062797465730D0A 
  2440 00006753 202020202020202020-     	db	"               ", 20h, 20h, 20h
  2440 0000675C 202020202020202020 
  2441                                  mem_total_p_str: ; 7 digits
  2442 00006765 303030303030302070-     	db	"0000000 pages", 0Dh, 0Ah
  2442 0000676E 616765730D0A       
  2443 00006774 0D0A                    	db 	0Dh, 0Ah
  2444 00006776 46726565206D656D6F-     	db	"Free memory  : "
  2444 0000677F 727920203A20       
  2445                                  free_mem_b_str:  ; 10 digits
  2446 00006785 3F3F3F3F3F3F3F3F3F-     	db	"?????????? bytes", 0Dh, 0Ah
  2446 0000678E 3F2062797465730D0A 
  2447 00006797 202020202020202020-     	db	"               ", 20h, 20h, 20h
  2447 000067A0 202020202020202020 
  2448                                  free_mem_p_str:  ; 7 digits
  2449 000067A9 3F3F3F3F3F3F3F2070-     	db	"??????? pages", 0Dh, 0Ah
  2449 000067B2 616765730D0A       
  2450 000067B8 0D0A00                  	db	0Dh, 0Ah, 0
  2451                                  
  2452                                  dsk_ready_msg:
  2453 000067BB 0D0A                    	db 	0Dh, 0Ah
  2454                                  dsktype:
  2455 000067BD 6664                    	db	'fd'
  2456                                  dskx:
  2457 000067BF 30                      	db	'0'
  2458 000067C0 20                      	db	20h
  2459 000067C1 697320524541445920-     	db 	'is READY ...'
  2459 000067CA 2E2E2E             
  2460 000067CD 00                      	db 	0
  2461                                  nextline:
  2462 000067CE 0D0A00                  	db 	0Dh, 0Ah, 0
  2463                                  
  2464                                  ; KERNEL - SYSINIT Messages
  2465                                  ; 24/08/2015
  2466                                  ; 13/04/2015 - (Retro UNIX 386 v1 Beginning)
  2467                                  ; 14/07/2013
  2468                                  ;kernel_init_err_msg:
  2469                                  ;	db 0Dh, 0Ah
  2470                                  ;	db 07h
  2471                                  ;	db 'Kernel initialization ERROR !'
  2472                                  ;	db 0Dh, 0Ah, 0 
  2473                                  ; 24/08/2015
  2474                                  ;;; (temporary kernel init message has been removed
  2475                                  ;;;  from 'sys_init' code)
  2476                                  ;kernel_init_ok_msg: 
  2477                                  ;	db 0Dh, 0Ah
  2478                                  ;	db 07h
  2479                                  ;	db 'Welcome to Retro UNIX 386 v1.1 Operating System !'
  2480                                  ;	db 0Dh, 0Ah
  2481                                  ;       db 'by Erdogan Tan - 04/02/2016 (v0.2.1.0)'
  2482                                  ;	db 0Dh, 0Ah, 0
  2483                                  panic_msg:
  2484 000067D1 0D0A07                  	db 0Dh, 0Ah, 07h
  2485 000067D4 4552524F523A204B65-     	db 'ERROR: Kernel Panic !'
  2485 000067DD 726E656C2050616E69-
  2485 000067E6 632021             
  2486 000067E9 0D0A00                  	db 0Dh, 0Ah, 0
  2487                                  etc_init_err_msg:
  2488 000067EC 0D0A                    	db 0Dh, 0Ah
  2489 000067EE 07                      	db 07h
  2490 000067EF 4552524F523A202F65-     	db 'ERROR: /etc/init !?'
  2490 000067F8 74632F696E69742021-
  2490 00006801 3F                 
  2491 00006802 0D0A00                  	db 0Dh, 0Ah, 0
  2492                                  
  2493                                  ; 10/05/2015
  2494                                  badsys_msg:
  2495 00006805 0D0A                    	db 0Dh, 0Ah
  2496 00006807 07                      	db 07h
  2497 00006808 496E76616C69642053-     	db 'Invalid System Call !'
  2497 00006811 797374656D2043616C-
  2497 0000681A 6C2021             
  2498 0000681D 0D0A                    	db 0Dh, 0Ah
  2499 0000681F 4541583A20              	db 'EAX: '
  2500                                  bsys_msg_eax:
  2501 00006824 303030303030303068      	db '00000000h'
  2502 0000682D 0D0A                    	db 0Dh, 0Ah
  2503 0000682F 4549503A20              	db 'EIP: '
  2504                                  bsys_msg_eip:
  2505 00006834 303030303030303068      	db '00000000h' 
  2506 0000683D 0D0A00                  	db 0Dh, 0Ah, 0
  2507                                  
  2508                                  BSYS_M_SIZE equ $ - badsys_msg
  2509                                  
  2510                                  
  2511                                  align 2
  2512                                  
  2513                                  ; EPOCH Variables
  2514                                  ; 13/04/2015 - Retro UNIX 386 v1 Beginning
  2515                                  ; 09/04/2013 epoch variables
  2516                                  ; Retro UNIX 8086 v1 Prototype: UNIXCOPY.ASM, 10/03/2013
  2517                                  ;
  2518 00006840 B207                    year: 	dw 1970
  2519 00006842 0100                    month: 	dw 1
  2520 00006844 0100                    day: 	dw 1
  2521 00006846 0000                    hour: 	dw 0
  2522 00006848 0000                    minute: dw 0
  2523 0000684A 0000                    second: dw 0
  2524                                  
  2525                                  DMonth:
  2526 0000684C 0000                    	dw 0
  2527 0000684E 1F00                    	dw 31
  2528 00006850 3B00                    	dw 59
  2529 00006852 5A00                    	dw 90
  2530 00006854 7800                    	dw 120
  2531 00006856 9700                    	dw 151
  2532 00006858 B500                    	dw 181
  2533 0000685A D400                    	dw 212
  2534 0000685C F300                    	dw 243
  2535 0000685E 1101                    	dw 273
  2536 00006860 3001                    	dw 304
  2537 00006862 4E01                    	dw 334
  2538                                  
  2539                                  ; 02/01/2022 (Retro UNIX 386 v1.1, Runix Kernel v0.2.1.2)
  2540                                  ; 04/11/2014 (Retro UNIX 386 v1)
  2541 00006864 0000                    mem_1m_1k:   dw 0  ; Number of contiguous KB between
  2542                                  		   ;   1 and 16 MB, max. 3C00h = 15 MB.
  2543 00006866 0000                    	     dw 0  ; 02/01/2022 (Retro UNIX 386 v1.2)
  2544 00006868 0000                    mem_16m_64k: dw 0  ; Number of contiguous 64 KB blocks
  2545                                  		   ;   between 16 MB and 4 GB.
  2546 0000686A 0000                    	     dw 0  ; 02/01/2022 (Retro UNIX 386 v1.2)
  2547                                  
  2548                                  ; 02/01/2022
  2549                                  KEND:
  2550                                  
  2551 0000686C 90<rep 4h>              align 16
  2552                                  
  2553                                  bss_start:
  2554                                  
  2555                                  ABSOLUTE bss_start
  2556                                  
  2557                                  	; 11/03/2015
  2558                                  	; Interrupt Descriptor Table (20/08/2014)
  2559                                  idt:
  2560 00006870 <res 200h>              	resb	64*8 ; INT 0 to INT 3Fh
  2561                                  idt_end:
  2562                                  
  2563                                  ;alignb 4
  2564                                  
  2565                                  task_state_segment:
  2566                                  	; 24/03/2015
  2567 00006A70 ????                    tss.link:   resw 1
  2568 00006A72 ????                    	    resw 1
  2569                                  ; tss offset 4	
  2570 00006A74 ????????                tss.esp0:   resd 1
  2571 00006A78 ????                    tss.ss0:    resw 1
  2572 00006A7A ????                    	    resw 1	
  2573 00006A7C ????????                tss.esp1:   resd 1
  2574 00006A80 ????                    tss.ss1:    resw 1
  2575 00006A82 ????                    	    resw 1 	
  2576 00006A84 ????????                tss.esp2:   resd 1
  2577 00006A88 ????                    tss.ss2:    resw 1
  2578 00006A8A ????                    	    resw 1
  2579                                  ; tss offset 28
  2580 00006A8C ????????                tss.CR3:    resd 1
  2581 00006A90 ????????                tss.eip:    resd 1
  2582 00006A94 ????????                tss.eflags: resd 1
  2583                                  ; tss offset 40
  2584 00006A98 ????????                tss.eax:    resd 1		 		
  2585 00006A9C ????????                tss.ecx:    resd 1
  2586 00006AA0 ????????                tss.edx:    resd 1
  2587 00006AA4 ????????                tss.ebx:    resd 1
  2588 00006AA8 ????????                tss.esp:    resd 1
  2589 00006AAC ????????                tss.ebp:    resd 1
  2590 00006AB0 ????????                tss.esi:    resd 1
  2591 00006AB4 ????????                tss.edi:    resd 1
  2592                                  ; tss offset 72
  2593 00006AB8 ????                    tss.ES:     resw 1
  2594 00006ABA ????                    	    resw 1	
  2595 00006ABC ????                    tss.CS:	    resw 1
  2596 00006ABE ????                    	    resw 1
  2597 00006AC0 ????                    tss.SS:	    resw 1
  2598 00006AC2 ????                    	    resw 1
  2599 00006AC4 ????                    tss.DS:	    resw 1
  2600 00006AC6 ????                    	    resw 1
  2601 00006AC8 ????                    tss.FS:	    resw 1
  2602 00006ACA ????                    	    resw 1
  2603 00006ACC ????                    tss.GS:	    resw 1
  2604 00006ACE ????                    	    resw 1		
  2605 00006AD0 ????                    tss.LDTR:   resw 1
  2606 00006AD2 ????                    	    resw 1
  2607                                  ; tss offset 100		
  2608 00006AD4 ????                    	    resw 1		
  2609 00006AD6 ????                    tss.IOPB:   resw 1
  2610                                  ; tss offset 104 
  2611                                  tss_end:
  2612                                  
  2613 00006AD8 ????????                k_page_dir:  resd 1 ; Kernel's (System) Page Directory address
  2614                                  		  ;   (Physical address = Virtual address)	 	
  2615 00006ADC ????????                memory_size: resd 1 ; memory size in pages
  2616 00006AE0 ????????                free_pages:  resd 1 ; number of free pages		
  2617 00006AE4 ????????                next_page:   resd 1 ; offset value in M.A.T. for
  2618                                  		  ;   first free page search
  2619 00006AE8 ????????                last_page:   resd 1 ; offset value in M.A.T. which
  2620                                  		  ;   next free page search will be
  2621                                  		  ; stopped after it. (end of M.A.T.)
  2622 00006AEC ????????                first_page:  resd 1 ;   offset value in M.A.T. which
  2623                                  		  ; first free page search
  2624                                  		  ;   will be started on it. (for user)
  2625 00006AF0 ????????                mat_size:    resd 1 ; Memory Allocation Table size in pages		
  2626                                  
  2627                                  ;;;
  2628                                  ; 02/09/2014 (Retro UNIX 386 v1)
  2629                                  ; 04/12/2013 (Retro UNIX 8086 v1)
  2630 00006AF4 ????                    CRT_START:   resw 1 	  ; starting address in regen buffer
  2631                                  			  ; NOTE: active page only
  2632 00006AF6 <res 10h>               cursor_posn: resw 8 	  ; cursor positions for video pages
  2633                                  active_page: 
  2634 00006B06 ??                      ptty: 	     resb 1 	  ; current tty
  2635                                  ; 01/07/2015
  2636 00006B07 ??                      ccolor:	     resb 1	  ; current color attributes ('sysmsg')	
  2637                                  ; 26/10/2015
  2638                                  ; 07/09/2014
  2639 00006B08 <res 14h>               ttychr:      resw ntty+2  ; Character buffer (multiscreen)
  2640                                  
  2641                                  ; 21/08/2014
  2642 00006B1C ????????                tcount:	     resd 1
  2643                                  
  2644                                  ; 18/05/2015 (03/06/2013 - Retro UNIX 8086 v1 feature only!)
  2645 00006B20 ????????                p_time:      resd 1     ; present time (for systime & sysmdate)
  2646                                  
  2647                                  ; 18/05/2015 (16/08/2013 - Retro UNIX 8086 v1 feature only !)
  2648                                  ; (open mode locks for pseudo TTYs)
  2649                                  ; [ major tty locks (return error in any conflicts) ]
  2650 00006B24 <res 14h>               ttyl:        resw ntty+2 ; opening locks for TTYs.
  2651                                  
  2652                                  ; 15/04/2015 (Retro UNIX 386 v1)
  2653                                  ; 22/09/2013 (Retro UNIX 8086 v1)
  2654 00006B38 <res Ah>                wlist:       resb ntty+2 ; wait channel list (0 to 9 for TTYs)
  2655                                  ; 15/04/2015 (Retro UNIX 386 v1)
  2656                                  ;; 12/07/2014 -> sp_init set comm. parameters as 0E3h
  2657                                  ;; 0 means serial port is not available 
  2658                                  ;;comprm: ; 25/06/2014
  2659 00006B42 ??                      com1p:       resb 1  ;;0E3h
  2660 00006B43 ??                      com2p:       resb 1  ;;0E3h
  2661                                  
  2662                                  ; 17/11/2015
  2663                                  ; request for response (from the terminal)	
  2664 00006B44 ????                    req_resp:     resw 1 			
  2665                                  ; 07/11/2015
  2666 00006B46 ??                      ccomport:    resb 1 ; current COM (serial) port
  2667                                  		    ; (0= COM1, 1= COM2)
  2668                                  ; 09/11/2015
  2669 00006B47 ??                      comqr:	     resb 1 ; 'query or response' sign (u9.s, 'sndc')
  2670                                  ; 07/11/2015
  2671 00006B48 ????                    rchar:	     resw 1 ; last received char for COM 1 and COM 2		
  2672 00006B4A ????                    schar:	     resw 1 ; last sent char for COM 1 and COM 2
  2673                                  
  2674                                  ; 23/10/2015
  2675                                  ; SERIAL PORTS - COMMUNICATION MODES
  2676                                  ; (Retro UNIX 386 v1 feature only!)
  2677                                  ; 0 - command mode (default/initial mode)
  2678                                  ; 1 - terminal mode (Retro UNIX 386 v1 terminal, ascii chars)
  2679                                  ;;; communication modes for futre versions:  
  2680                                  ; // 2 - keyboard mode (ascii+scancode input)
  2681                                  ; // 3 - mouse mode
  2682                                  ; // 4 - device control (output) mode
  2683                                  ; VALID COMMANDS for current version:
  2684                                  ; 	'LOGIN'
  2685                                  ;  Login request: db 0FFh, 'LOGIN', 0 
  2686                                  ;	 ("Retro UNIX 386 v1 terminal requests login")
  2687                                  ;  Login response: db 0FFh, 'login', 0
  2688                                  ;	 ("login request accepted, wait for login prompt") 
  2689                                  ; When a login requests is received and acknowledged (by
  2690                                  ; serial port interrupt handler (communication procedure),
  2691                                  ; Retro UNIX 386 v1 operating system will start terminal mode
  2692                                  ; (login procedure) by changing comm. mode to 1 (terminal mode)
  2693                                  ; and then running 'etc/getty' for tty8 (COM1) or tty9 (COM2)
  2694                                  ; 
  2695                                  ; 'sys connect' system call is used to change communication mode
  2696                                  ; except 'LOGIN' command which is used to start terminal mode
  2697                                  ; by using (COM port) terminal.
  2698                                  
  2699                                  ;com1own:     resb 1 ; COM1 owner (u.uno)
  2700                                  ;com2own:     resb 1 ; COM2 owner (u.uno)
  2701                                  ;com1mode:    resb 1 ; communication mode for COM1
  2702                                  ;com1com:     resb 1 ; communication command for COM1
  2703                                  ;com2mode:    resb 1 ; communication mode for COM1
  2704                                  ;com2com      resb 1 ; communication command for COM1
  2705                                  ;com1cbufp:   resb 8 ; COM1 command buffer char pointer	
  2706                                  ;com2cbufp:   resb 8 ; COM2 command buffer char pointer	
  2707                                  ;com1cbuf:    resb 8 ; COM2 command buffer
  2708                                  ;com2cbuf:    resb 8 ; COM2 command buffer
  2709                                  
  2710                                  ; 22/08/2014 (RTC)
  2711                                  ; (Packed BCD)
  2712 00006B4C ??                      time_seconds: resb 1
  2713 00006B4D ??                      time_minutes: resb 1
  2714 00006B4E ??                      time_hours:   resb 1
  2715 00006B4F ??                      date_wday:    resb 1
  2716 00006B50 ??                      date_day:     resb 1
  2717 00006B51 ??                      date_month:   resb 1			
  2718 00006B52 ??                      date_year:    resb 1
  2719 00006B53 ??                      date_century: resb 1
  2720                                  
  2721                                  %include 'diskbss.inc'	; UNINITIALIZED DISK (BIOS) DATA
  2722                              <1> ; Retro UNIX 386 v1 Kernel - DISKBSS.INC
  2723                              <1> ; Last Modification: 10/07/2015
  2724                              <1> ;	(Unnitialized Disk Parameters Data section for 'DISKIO.INC') 
  2725                              <1> ;
  2726                              <1> ; *****************************************************************************
  2727                              <1> 
  2728                              <1> alignb 2
  2729                              <1> 
  2730                              <1> ;----------------------------------------
  2731                              <1> ;	TIMER DATA AREA 		:
  2732                              <1> ;----------------------------------------
  2733                              <1> 
  2734                              <1> TIMER_LH:	; 16/02/205
  2735 00006B54 ????                <1> TIMER_LOW:      resw	1               ; LOW WORD OF TIMER COUNT
  2736 00006B56 ????                <1> TIMER_HIGH:     resw	1               ; HIGH WORD OF TIMER COUNT
  2737 00006B58 ??                  <1> TIMER_OFL:      resb 	1               ; TIMER HAS ROLLED OVER SINCE LAST READ
  2738                              <1> 
  2739                              <1> ;----------------------------------------
  2740                              <1> ;	DISKETTE DATA AREAS		:
  2741                              <1> ;----------------------------------------
  2742                              <1> 
  2743 00006B59 ??                  <1> SEEK_STATUS:	resb	1
  2744 00006B5A ??                  <1> MOTOR_STATUS:	resb	1
  2745 00006B5B ??                  <1> MOTOR_COUNT:	resb	1
  2746 00006B5C ??                  <1> DSKETTE_STATUS:	resb	1
  2747 00006B5D ??????????????      <1> NEC_STATUS:	resb	7
  2748                              <1> 
  2749                              <1> ;----------------------------------------
  2750                              <1> ;	ADDITIONAL MEDIA DATA		:
  2751                              <1> ;----------------------------------------
  2752                              <1> 
  2753 00006B64 ??                  <1> LASTRATE:	resb 	1
  2754 00006B65 ??                  <1> HF_STATUS:	resb 	1
  2755 00006B66 ??                  <1> HF_ERROR:	resb 	1
  2756 00006B67 ??                  <1> HF_INT_FLAG:	resb 	1
  2757 00006B68 ??                  <1> HF_CNTRL:	resb 	1
  2758 00006B69 ????????            <1> DSK_STATE:	resb 	4
  2759 00006B6D ????                <1> DSK_TRK:	resb 	2
  2760                              <1> 
  2761                              <1> ;----------------------------------------
  2762                              <1> ;	FIXED DISK DATA AREAS		:
  2763                              <1> ;----------------------------------------
  2764                              <1> 
  2765 00006B6F ??                  <1> DISK_STATUS1:	resb 	1		; FIXED DISK STATUS
  2766 00006B70 ??                  <1> HF_NUM:		resb 	1		; COUNT OF FIXED DISK DRIVES
  2767 00006B71 ??                  <1> CONTROL_BYTE:	resb 	1		; HEAD CONTROL BYTE
  2768                              <1> ;@PORT_OFF	resb	1		; RESERVED (PORT OFFSET)
  2769                              <1> ;port1_off	resb	1		; Hard disk controller 1 - port offset
  2770                              <1> ;port2_off	resb	1		; Hard idsk controller 2 - port offset
  2771                              <1> 
  2772 00006B72 ????                <1> alignb 4
  2773                              <1> 
  2774                              <1> ;HF_TBL_VEC:	resd	1 		; Primary master disk param. tbl. pointer
  2775                              <1> ;HF1_TBL_VEC:	resd	1		; Primary slave disk param. tbl. pointer
  2776                              <1> HF_TBL_VEC: ; 22/12/2014	
  2777 00006B74 ????????            <1> HDPM_TBL_VEC:	resd	1 		; Primary master disk param. tbl. pointer
  2778 00006B78 ????????            <1> HDPS_TBL_VEC:	resd	1		; Primary slave disk param. tbl. pointer
  2779 00006B7C ????????            <1> HDSM_TBL_VEC:	resd	1 		; Secondary master disk param. tbl. pointer
  2780 00006B80 ????????            <1> HDSS_TBL_VEC:	resd	1		; Secondary slave disk param. tbl. pointer
  2781                              <1> 
  2782                              <1> ; 03/01/2015
  2783 00006B84 ??                  <1> LBAMode:     	resb	1
  2784                              <1> 
  2785                              <1> ; *****************************************************************************
  2722                                  
  2723                                  ;;; Real Mode Data (10/07/2015 - BSS)
  2724                                  
  2725                                  ;alignb 2
  2726                                  
  2727                                  ; 02/01/2022
  2728                                  ;%include 'ux.s' ; 12/04/2015 (unix system/user/process data)
  2729                                  
  2730                                  ; 24/12/2021
  2731                                  ; (memory page swap parameters are disabled as temporary)
  2732                                  ;
  2733                                  ;; Memory (swap) Data (11/03/2015)
  2734                                  ; 09/03/2015
  2735                                  ;swpq_count: resw 1 ; count of pages on the swap que
  2736                                  ;swp_drv:    resd 1 ; logical drive description table address of the swap drive/disk
  2737                                  ;swpd_size:  resd 1 ; size of swap drive/disk (volume) in sectors (512 bytes).	
  2738                                  ;swpd_free:  resd 1 ; free page blocks (4096 bytes) on swap disk/drive (logical)
  2739                                  ;swpd_next:  resd 1 ; next free page block
  2740                                  ;swpd_last:  resd 1 ; last swap page block	
  2741                                  	
  2742 00006B85 ??????                  alignb 4
  2743                                  
  2744                                  ; 10/07/2015
  2745                                  ; 28/08/2014
  2746 00006B88 ????????                error_code:	resd 1
  2747                                  ; 29/08/2014
  2748 00006B8C ????????                FaultOffset: 	resd 1
  2749                                  ; 21/09/2015
  2750 00006B90 ????????                PF_Count:	resd 1	; total page fault count
  2751                                  		       	; (for debugging - page fault analyze)
  2752                                  		 	; 'page _fault_handler' (memory.inc)
  2753                                  			; 'sysgeterr' (u9.s)
  2754                                  ; 26/02/2022
  2755 00006B94 ????????                rtc_ticks:	resd 1  ; (temporary! this rtc counter value may be used 
  2756                                  			;  for a system call in next retro unix 386 version)
  2757                                  			; -2 ticks per second-
  2758                                  ;; 21/08/2015
  2759                                  ;;buffer: resb (nbuf*520) ;; sysdefs.inc, ux.s
  2760                                  
  2761                                  ; 02/01/2022
  2762                                  %include 'ux.s' ; 12/04/2015 (unix system/user/process data)
  2763                              <1> ; Retro UNIX 386 v1 Kernel (v0.2.1.2) - SYSX.INC (ux.s)
  2764                              <1> ; Last Modification: 26/02/2022
  2765                              <1> ; ----------------------------------------------------------------------------
  2766                              <1> ; Retro UNIX 386 v1 Kernel - ux.s
  2767                              <1> ; Last Modification: 04/12/2015
  2768                              <1> ;
  2769                              <1> ; ///////// RETRO UNIX 386 V1 SYSTEM DEFINITIONS ///////////////
  2770                              <1> ; (Modified from 
  2771                              <1> ;	Retro UNIX 8086 v1 system definitions in 'UNIX.ASM', 01/09/2014)
  2772                              <1> ; ((UNIX.ASM (RETRO UNIX 8086 V1 Kernel), 11/03/2013 - 01/09/2014))
  2773                              <1> ; ----------------------------------------------------------------------------
  2774                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2775                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2776                              <1> ; <Bell Laboratories (17/3/1972)>
  2777                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2778                              <1> ; (Section E10 (17/3/1972) - ux.s)
  2779                              <1> ; ****************************************************************************
  2780                              <1> 
  2781                              <1> alignb 2
  2782                              <1> 
  2783                              <1> inode:
  2784                              <1> 	; 11/03/2013. 
  2785                              <1> 	;Derived from UNIX v1 source code 'inode' structure (ux).
  2786                              <1> 	;i.
  2787                              <1> 
  2788 00006B98 ????                <1> 	i.flgs:	 resw 1
  2789 00006B9A ??                  <1> 	i.nlks:	 resb 1
  2790 00006B9B ??                  <1> 	i.uid:	 resb 1
  2791 00006B9C ????                <1>         i.size:  resw 1 ; size
  2792 00006B9E <res 10h>           <1> 	i.dskp:	 resw 8 ; 16 bytes
  2793 00006BAE ????????            <1> 	i.ctim:	 resd 1
  2794 00006BB2 ????????            <1> 	i.mtim:	 resd 1
  2795 00006BB6 ????                <1> 	i.rsvd:  resw 1 ; Reserved (ZERO/Undefined word for UNIX v1.)
  2796                              <1> 
  2797                              <1> I_SIZE	equ $ - inode 
  2798                              <1> 
  2799                              <1> process:
  2800                              <1> 	; 26/02/2022
  2801                              <1> 	; 12/01/2022 (Retro UNIX 386 v1.1) 
  2802                              <1> 	; 06/05/2015
  2803                              <1> 	; 11/03/2013 - 05/02/2014
  2804                              <1> 	;Derived from UNIX v1 source code 'proc' structure (ux).
  2805                              <1> 	;p.
  2806                              <1> 	
  2807 00006BB8 <res 20h>           <1>         p.pid:   resw nproc
  2808 00006BD8 <res 20h>           <1>         p.ppid:  resw nproc
  2809                              <1> 	;p.break: resw nproc ; 12/01/2022 (p.break is not used)
  2810 00006BF8 <res 10h>           <1>         p.ttyc:  resb nproc ; console tty in Retro UNIX 8086 v1.
  2811                              <1> 	; 26/02/2022 (p.waitc is not used)
  2812                              <1> 	;p.waitc: resb nproc ; waiting channel in Retro UNIX 8086 v1.
  2813 00006C08 <res 10h>           <1> 	p.link:	 resb nproc
  2814 00006C18 <res 10h>           <1> 	p.stat:	 resb nproc
  2815                              <1> 
  2816                              <1> 	; 06/05/2015 (Retro UNIX 386 v1 fetaure only !) 
  2817 00006C28 <res 40h>           <1> 	p.upage: resd nproc ; Physical address of the process's
  2818                              <1> 			    ; 'user' structure	
  2819                              <1> 
  2820                              <1> P_SIZE	equ $ - process
  2821                              <1> 
  2822                              <1> ; fsp table (original UNIX v1)
  2823                              <1> ;
  2824                              <1> ;Entry
  2825                              <1> ;          15                                      0
  2826                              <1> ;  1     |---|---------------------------------------|
  2827                              <1> ;        |r/w|       i-number of open file           |
  2828                              <1> ;        |---|---------------------------------------| 
  2829                              <1> ;        |               device number               |
  2830                              <1> ;        |-------------------------------------------|
  2831                              <1> ;    (*) | offset pointer, i.e., r/w pointer to file |
  2832                              <1> ;        |-------------------------------------------| 
  2833                              <1> ;        |  flag that says    | number of processes  |
  2834                              <1> ;        |   file deleted     | that have file open  |
  2835                              <1> ;        |-------------------------------------------| 
  2836                              <1> ;  2     |                                           |
  2837                              <1> ;        |-------------------------------------------| 
  2838                              <1> ;        |                                           |
  2839                              <1> ;        |-------------------------------------------|
  2840                              <1> ;        |                                           |
  2841                              <1> ;        |-------------------------------------------|
  2842                              <1> ;        |                                           |
  2843                              <1> ;        |-------------------------------------------| 
  2844                              <1> ;  3     |                                           | 
  2845                              <1> ;        |                                           |  
  2846                              <1> ;
  2847                              <1> ; (*) Retro UNIX 386 v1 modification: 32 bit offset pointer 
  2848                              <1> 
  2849                              <1> ; 15/04/2015
  2850 00006C68 <res 1F4h>          <1> fsp:	 resb nfiles*10 ; 11/05/2015 (8 -> 10)
  2851 00006E5C <res 20h>           <1> bufp:	 resd (nbuf+2) ; will be initialized 
  2852 00006E7C ????                <1> ii:	 resw 1
  2853                              <1> ;idev:	 resw 1 ; device number is 1 byte in Retro UNIX 8086 v1 !
  2854                              <1> ;cdev:	 resw 1 ; device number is 1 byte in Retro UNIX 8086 v1 !
  2855                              <1> ; 11/01/2022
  2856 00006E7E ??                  <1> idev:	 resb 1
  2857 00006E7F ??                  <1> cdev:	 resb 1
  2858                              <1> ; 18/05/2015
  2859                              <1> ; 26/04/2013 device/drive parameters (Retro UNIX 8086 v1 feature only!)
  2860                              <1> ; 'UNIX' device numbers (as in 'cdev' and 'u.cdrv')
  2861                              <1> ;	0 -> root device (which has Retro UNIX 8086 v1 file system)
  2862                              <1> ; 	1 -> mounted device (which has Retro UNIX 8086 v1 file system)
  2863                              <1> ; 'Retro UNIX 8086 v1' device numbers: (for disk I/O procedures)
  2864                              <1> ;	0 -> fd0 (physical drive, floppy disk 1), physical drive number = 0
  2865                              <1> ;	1 -> fd1 (physical drive, floppy disk 2), physical drive number = 1
  2866                              <1> ;	2 -> hd0 (physical drive, hard disk 1), physical drive number = 80h
  2867                              <1> ;	3 -> hd1 (physical drive, hard disk 2), physical drive number = 81h
  2868                              <1> ;	4 -> hd2 (physical drive, hard disk 3), physical drive number = 82h
  2869                              <1> ;	5 -> hd3 (physical drive, hard disk 4), physical drive number = 83h
  2870 00006E80 ??                  <1> rdev:	 resb 1 ; root device number ; Retro UNIX 8086 v1 feature only!
  2871                              <1> 	        ; as above, for physical drives numbers in following table
  2872 00006E81 ??                  <1> mdev:	 resb 1 ; mounted device number ; Retro UNIX 8086 v1 feature only!
  2873                              <1> ; 15/04/2015
  2874 00006E82 ??                  <1> active:	 resb 1 
  2875 00006E83 ??                  <1> 	 resb 1 ; 09/06/2015
  2876 00006E84 ????                <1> mnti:	 resw 1
  2877 00006E86 ????                <1> mpid:	 resw 1
  2878 00006E88 ????                <1> rootdir: resw 1
  2879                              <1> ; 14/02/2014
  2880                              <1> ; Major Modification: Retro UNIX 8086 v1 feature only!
  2881                              <1> ;		      Single level run queue
  2882                              <1> ;		      (in order to solve sleep/wakeup lock)
  2883 00006E8A ????                <1> runq:	 resw 1
  2884 00006E8C ??                  <1> imod:	 resb 1
  2885 00006E8D ??                  <1> smod:	 resb 1
  2886 00006E8E ??                  <1> mmod:	 resb 1
  2887 00006E8F ??                  <1> sysflg:	 resb 1
  2888                              <1> 
  2889                              <1> alignb 4
  2890                              <1> 
  2891                              <1> user:
  2892                              <1> 	; 09/01/2022 (Retro UNIX 386 v1.1, Kernel v0.2.1.2)
  2893                              <1> 	; 04/12/2015 
  2894                              <1> 	; 18/10/2015
  2895                              <1> 	; 12/10/2015
  2896                              <1> 	; 21/09/2015
  2897                              <1> 	; 24/07/2015
  2898                              <1> 	; 16/06/2015
  2899                              <1> 	; 09/06/2015
  2900                              <1> 	; 11/05/2015
  2901                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - 32 bit modifications)
  2902                              <1> 	; 10/10/2013
  2903                              <1> 	; 11/03/2013. 
  2904                              <1> 	;Derived from UNIX v1 source code 'user' structure (ux).
  2905                              <1> 	;u.
  2906                              <1> 
  2907 00006E90 ????????            <1> 	u.sp:	  resd 1 ; esp (kernel stack at the beginning of 'sysent')
  2908 00006E94 ????????            <1> 	u.usp:	  resd 1 ; esp (kernel stack points to user's registers)
  2909 00006E98 ????????            <1> 	u.r0:	  resd 1 ; eax
  2910 00006E9C ????                <1> 	u.cdir:	  resw 1
  2911 00006E9E <res Ah>            <1> 	u.fp:	  resb 10
  2912 00006EA8 ????????            <1> 	u.fofp:	  resd 1
  2913 00006EAC ????????            <1> 	u.dirp:	  resd 1
  2914 00006EB0 ????????            <1> 	u.namep:  resd 1
  2915 00006EB4 ????????            <1> 	u.off:	  resd 1
  2916 00006EB8 ????????            <1> 	u.base:	  resd 1
  2917 00006EBC ????????            <1> 	u.count:  resd 1
  2918 00006EC0 ????????            <1> 	u.nread:  resd 1
  2919 00006EC4 ????????            <1> 	u.break:  resd 1 ; break
  2920 00006EC8 ????                <1> 	u.ttyp:	  resw 1 
  2921 00006ECA <res 10h>           <1> 	u.dirbuf: resb 16 ; 04/12/2015 (10 -> 16) 
  2922                              <1> 	;u.pri:	  resw 1 ; 14/02/2014
  2923 00006EDA ??                  <1> 	u.quant:  resb 1 ; Retro UNIX 8086 v1 Feature only ! (uquant)
  2924 00006EDB ??                  <1> 	u.pri:	  resb 1 ; 
  2925 00006EDC ????                <1> 	u.intr:	  resw 1
  2926 00006EDE ????                <1> 	u.quit:	  resw 1
  2927                              <1> 	;u.emt:	  resw 1 ; 10/10/2013
  2928 00006EE0 ????                <1> 	u.ilgins: resw 1
  2929                              <1> 	;u.cdrv:  resw 1 ; cdev
  2930 00006EE2 ??                  <1> 	u.cdrv:   resb 1 ; 09/01/2022
  2931 00006EE3 ??                  <1> 		  resb 1 ; 09/01/2022 (dword alignment)
  2932 00006EE4 ??                  <1> 	u.uid:	  resb 1 ; uid
  2933 00006EE5 ??                  <1> 	u.ruid:	  resb 1
  2934 00006EE6 ??                  <1> 	u.bsys:	  resb 1
  2935 00006EE7 ??                  <1> 	u.uno:	  resb 1
  2936 00006EE8 ????????            <1>         u.upage:  resd 1 ; 16/04/2015 - Retro Unix 386 v1 feature only !
  2937                              <1> 	; tty number (rtty, rcvt, wtty)
  2938 00006EEC ??                  <1> 	u.ttyn:	  resb 1 ; 28/07/2013 - Retro Unix 8086 v1 feature only !
  2939                              <1> 	; last error number
  2940 00006EED ????????            <1> 	u.error:  resd 1 ; 28/07/2013 - 09/03/2015 
  2941                              <1> 		        ; Retro UNIX 8086/386 v1 feature only!
  2942 00006EF1 ????????            <1> 	u.pgdir:  resd 1 ; 09/03/2015 (page dir addr of process)
  2943 00006EF5 ????????            <1> 	u.ppgdir: resd 1 ; 06/05/2015 (page dir addr of the parent process)
  2944 00006EF9 ????????            <1> 	u.pbase:  resd 1 ; 20/05/2015 (physical base/transfer address)
  2945 00006EFD ????                <1> 	u.pcount: resw 1 ; 20/05/2015 (byte -transfer- count for page)
  2946                              <1> 	;u.pncount: resw 1 
  2947                              <1> 		; 16/06/2015 (byte -transfer- count for page, 'namei', 'mkdir')
  2948                              <1> 	;u.pnbase:  resd 1 
  2949                              <1> 		; 16/06/2015 (physical base/transfer address, 'namei', 'mkdir')
  2950                              <1> 			 ; 09/06/2015
  2951 00006EFF ??                  <1> 	u.kcall:  resb 1 ; The caller is 'namei' (dskr) or 'mkdir' (dskw) sign		
  2952 00006F00 ??                  <1> 	u.brwdev: resb 1 ; Block device number for direct I/O (bread & bwrite)
  2953                              <1> 			 ; 24/07/2015 - 24/06/2015
  2954                              <1> 	;u.args:  resd 1 ; arguments list (line) offset from start of [u.upage]
  2955                              <1> 			 ; (arg list/line is from offset [u.args] to 4096 in [u.upage])
  2956                              <1> 			 ; ([u.args] points to argument count -argc- address offset)
  2957                              <1>  			 ; 24/06/2015	  	
  2958                              <1> 	;u.core:  resd 1 ; physical start address of user's memory space (for sys exec)
  2959                              <1> 	;u.ecore: resd 1 ; physical end address of user's memory space (for sys exec)
  2960                              <1> 			 ; 21/09/2015 (debugging - page fault analyze)
  2961 00006F01 ????????            <1> 	u.pfcount: resd 1 ; page fault count for (this) process (for sys geterr)
  2962                              <1> 
  2963 00006F05 ??????              <1> alignb 4
  2964                              <1> 
  2965                              <1> U_SIZE	equ $ - user
  2966                              <1> 
  2967                              <1> ; 18/10/2015 - Retro UNIX 386 v1 (local variables for 'namei' and 'sysexec')
  2968 00006F08 ????????            <1> pcore:  resd 1 ; physical start address of user's memory space (for sys exec)
  2969 00006F0C ????????            <1> ecore:  resd 1 ; physical start address of user's memory space (for sys exec)
  2970 00006F10 ????????            <1> nbase:	resd 1	; physical base address for 'namei' & 'sysexec'
  2971 00006F14 ????                <1> ncount: resw 1	; remain byte count in page for 'namei' & 'sysexec'
  2972                              <1> ;argc:	resw 1	; argument count for 'sysexec'
  2973 00006F16 ??                  <1> argc:	resb 1	; 12/01/2022 - Retro UNIX 386 v1.1 (Kernel v0.2.1.2)
  2974 00006F17 ??                  <1> 	resb 1 
  2975 00006F18 ????????            <1> argv:	resd 1	; argument list (recent) address for 'sysexec'
  2976                              <1> 
  2977                              <1> ; 03/06/2015 - Retro UNIX 386 v1 Beginning
  2978                              <1> ; 07/04/2013 - 31/07/2013 - Retro UNIX 8086 v1
  2979 00006F1C ??                  <1> rw: 	 resb 1 ;; Read/Write sign (iget)
  2980 00006F1D ??                  <1> rwdsk:	 resb 1 ;; Read/Write function number (diskio) - 16/06/2015
  2981 00006F1E ??                  <1> retry_count: resb 1 ; Disk I/O retry count - 11/06/2015
  2982 00006F1F ??                  <1> 	 resb 1 ;; Reserved (16/06/2015) 
  2983                              <1> 
  2984                              <1> ;alignb 4
  2985                              <1> 
  2986                              <1> ; 22/08/2015
  2987 00006F20 <res C30h>          <1> buffer: resb nbuf * 520
  2988                              <1> 
  2989 00007B50 ????????????????    <1> sb0:	resd 2
  2990                              <1> ;s:
  2991                              <1> ; (root disk) super block buffer
  2992                              <1> systm:
  2993                              <1> 	; 13/11/2015 (Retro UNIX 386 v1)	
  2994                              <1> 	; 11/03/2013. 
  2995                              <1> 	;Derived from UNIX v1 source code 'systm' structure (ux).
  2996                              <1> 	;s.
  2997                              <1> 
  2998 00007B58 ????                <1> 	resw 1
  2999 00007B5A <res 168h>          <1> 	resb 360 ; 2880 sectors ; original UNIX v1 value: 128
  3000 00007CC2 ????                <1> 	resw 1
  3001 00007CC4 <res 20h>           <1> 	resb 32	 ; 256+40 inodes ; original UNIX v1 value: 64
  3002                              <1> eofitab equ $ - systm ; 11/02/2022 (end of inode table)
  3003 00007CE4 ????????            <1> 	s.time:	 resd 1
  3004 00007CE8 ????????            <1> 	s.syst:	 resd 1
  3005 00007CEC ????????            <1>         s.wait_: resd 1 ; wait
  3006 00007CF0 ????????            <1> 	s.idlet: resd 1
  3007 00007CF4 ????????            <1> 	s.chrgt: resd 1
  3008 00007CF8 ????                <1> 	s.drerr: resw 1
  3009                              <1> 
  3010                              <1> S_SIZE	equ $ - systm
  3011                              <1> 
  3012 00007CFA <res 5Eh>           <1> 	resb 512-S_SIZE ; 03/06/2015	 
  3013                              <1> 
  3014 00007D58 ????????????????    <1> sb1:	resd 2
  3015                              <1> ; (mounted disk) super block buffer
  3016                              <1> mount:	
  3017 00007D60 <res 200h>          <1> 	resb 512  ; 03/06/2015
  3018                              <1> 
  3019                              <1> ;/ ux -- unix
  3020                              <1> ;
  3021                              <1> ;systm:
  3022                              <1> ;
  3023                              <1> ;	.=.+2
  3024                              <1> ;	.=.+128.
  3025                              <1> ;	.=.+2
  3026                              <1> ;	.=.+64.
  3027                              <1> ;	s.time: .=.+4
  3028                              <1> ;	s.syst: .=.+4
  3029                              <1> ;	s.wait: .=.+4
  3030                              <1> ;	s.idlet:.=.+4
  3031                              <1> ;	s.chrgt:.=.+4
  3032                              <1> ;	s.drerr:.=.+2
  3033                              <1> ;inode:
  3034                              <1> ;	i.flgs: .=.+2
  3035                              <1> ;	i.nlks: .=.+1
  3036                              <1> ;	i.uid:  .=.+1
  3037                              <1> ;	i.size: .=.+2
  3038                              <1> ;	i.dskp: .=.+16.
  3039                              <1> ;	i.ctim: .=.+4
  3040                              <1> ;	i.mtim: .=.+4
  3041                              <1> ;	. = inode+32.
  3042                              <1> ;mount:	.=.+1024.
  3043                              <1> ;proc:
  3044                              <1> ;	p.pid:  .=.+[2*nproc]
  3045                              <1> ;	p.dska: .=.+[2*nproc]
  3046                              <1> ;	p.ppid: .=.+[2*nproc]
  3047                              <1> ;	p.break:.=.+[2*nproc]
  3048                              <1> ;	p.link: .=.+nproc
  3049                              <1> ;	p.stat: .=.+nproc
  3050                              <1> ;tty:
  3051                              <1> ;	. = .+[ntty*8.]
  3052                              <1> ;fsp:	.=.+[nfiles*8.]
  3053                              <1> ;bufp:	.=.+[nbuf*2]+6
  3054                              <1> ;sb0:	.=.+8
  3055                              <1> ;sb1:	.=.+8
  3056                              <1> ;swp:	.=.+8
  3057                              <1> ;ii:	.=.+2
  3058                              <1> ;idev:	.=.+2
  3059                              <1> ;cdev:	.=.+2
  3060                              <1> ;deverr: .=.+12.
  3061                              <1> ;active: .=.+2
  3062                              <1> ;rfap:	.=.+2
  3063                              <1> ;rkap:	.=.+2
  3064                              <1> ;tcap:	.=.+2
  3065                              <1> ;tcstate:.=.+2
  3066                              <1> ;tcerrc: .=.+2
  3067                              <1> ;mnti:	.=.+2
  3068                              <1> ;mntd:	.=.+2
  3069                              <1> ;mpid:	.=.+2
  3070                              <1> ;clockp: .=.+2
  3071                              <1> ;rootdir:.=.+2
  3072                              <1> ;toutt:	.=.+16.
  3073                              <1> ;touts: .=.+32.
  3074                              <1> ;runq:	.=.+6
  3075                              <1> ;
  3076                              <1> ;wlist:	.=.+40.
  3077                              <1> ;cc:	.=.+30.
  3078                              <1> ;cf:	.=.+31.
  3079                              <1> ;cl:	.=.+31.
  3080                              <1> ;clist:	.=.+510.
  3081                              <1> ;imod:	.=.+1
  3082                              <1> ;smod:	.=.+1
  3083                              <1> ;mmod:	.=.+1
  3084                              <1> ;uquant: .=.+1
  3085                              <1> ;sysflg: .=.+1
  3086                              <1> ;pptiflg:.=.+1
  3087                              <1> ;ttyoch: .=.+1
  3088                              <1> ; .even
  3089                              <1> ; .=.+100.; sstack:
  3090                              <1> ;buffer: .=.+[ntty*140.]
  3091                              <1> ;	.=.+[nbuf*520.]
  3092                              <1> ;
  3093                              <1> ; . = core-64.
  3094                              <1> ;user:
  3095                              <1> ;	u.sp:    .=.+2
  3096                              <1> ;	u.usp:   .=.+2
  3097                              <1> ;	u.r0:    .=.+2
  3098                              <1> ;	u.cdir:  .=.+2
  3099                              <1> ;	u.fp:    .=.+10.
  3100                              <1> ;	u.fofp:  .=.+2
  3101                              <1> ;	u.dirp:  .=.+2
  3102                              <1> ;	u.namep: .=.+2
  3103                              <1> ;	u.off:   .=.+2
  3104                              <1> ;	u.base:  .=.+2
  3105                              <1> ;	u.count: .=.+2
  3106                              <1> ;	u.nread: .=.+2
  3107                              <1> ;	u.break: .=.+2
  3108                              <1> ;	u.ttyp:  .=.+2
  3109                              <1> ;	u.dirbuf:.=.+10.
  3110                              <1> ;	u.pri:   .=.+2
  3111                              <1> ;	u.intr:  .=.+2
  3112                              <1> ;	u.quit:  .=.+2
  3113                              <1> ;	u.emt:   .=.+2
  3114                              <1> ;	u.ilgins:.=.+2
  3115                              <1> ;	u.cdev:  .=.+2
  3116                              <1> ;	u.uid:   .=.+1
  3117                              <1> ;	u.ruid:  .=.+1
  3118                              <1> ;	u.bsys:  .=.+1
  3119                              <1> ;	u.uno:   .=.+1
  3120                              <1> ;. = core
  2763                                  
  2764                                  ; 27/12/2021
  2765                                  ;buffer: resb (nbuf*520)
  2766                                  
  2767                                  bss_end:
  2768                                  
  2769                                  ; 02/01/2022
  2770                                  BSS_SIZE equ bss_end - bss_start
  2771                                  
  2772                                  ; 27/12/2013
  2773                                  _end:  ; end of kernel code (and read only data, just before bss)
