
Trap Flag Logging for MS-DOS.
This utility can be used to run a program and record CPU
state per instruction (using the 8086 trap flag and INT 1
trap interrupt).

WARNING: There are a million ways anti-debugger tricks can
         defeat this program's tracing. This program is not
         expected to correctly handle those programs. It is
         intended for use with the test routines also
         present in this directory.

NOTE: To avoid reentrancy issues or excess tracing data, this
      code will NOT trace into the MS-DOS/BIOS system calls.

There are several versions of this code, one for each general
class of processor.

tfl8086.com ......... Minimalist tracing for 8086/8088 processors.
                      It can be run on 286 and higher processors,
                      but if the test program involves switching
                      to protected mode the program will not trace
                      execution correctly. On 386 or higher systems,
                      this code will work but will only capture the
                      lower 16-bit portions of the CPU registers.

tfl286.com .......... Tracing utility for 286 or higher processors.
                      Captures machine status word in addition to
                      other 16-bit registers. Also contains code to
                      detect switching to protected mode (LMSW)
                      and bail out appropriately.

tfl386.com .......... Tracing utility for 386 or higher processors.
                      CPU state capture includes 32-bit registers,
                      segment registers (CS,DS,ES,FS,GS,SS), control
                      and debug registers. Also contains code to
                      detect switching to protected mode and bail
                      out appropriately.

tfl386f.com ......... Tracing utility for 386 or higher processors.
                      CPU state capture includes 32-bit registers,
                      segment registers (CS,DS,ES,FS,GS,SS), control
                      and debug registers as well as FPU floating
                      point registers and status. Also contains code
                      to detect switching to protected mode and bail
                      out appropriately.

