DOS ain't dead

386SWAT debugger (Developers)

posted by mrichard, 28.03.2024, 10:46

> > The 386SWAT debugger seems to be able to continue tracing a real-mode
> (not
> > V86) program that goes into protected mode, but I don't quite understand
> > how to configure 386SWAT with 67h INTs, and I can't find any assembly
> > language examples.
>
> Looking at https://sudleyplace.com/swat/swatdoc.html
>
> here are some thoughts:
>
> http://www.sudleyplace.com/swat/swatinv.html
>
> you can invoke 386swat with ctrl-alt-pad5 while it is waiting in the
> background, or run to-be-debugged apps via SWATRUN.

Thanks for your help. In order for Ctrl-Alt-Pad5 to interrupt in RM, I need to put "RMLIDT" in the 386SWAT.PRO configuration file.

>
> http://www.sudleyplace.com/swat/swatmon.html
>
> you can tell 386swat to trigger when an expression becomes true, but this
> will make everything slow while 386swat looks out for the trigger. You can
> do stuff like
>
> gm [.csip == 67cd && ax == somevalue
>
> to trigger when the upcoming instruction is INT 67 while AX has a value of
> your choice.
>
> http://www.sudleyplace.com/swat/swatpro.html
>
> you can tell 386swat to trigger on a subset of things triggering GPF, which
> includes (if you are in vm86 while emm386 is active) things like
> interrupts, interrupt flag changing things and I/O port access to watched
> ports. Usually, emm386 will not watch ports, but things like a virtual
> sound blaster or emm386 assisting a virtual soundblaster will watch ports.
>
> You can also tell 386swat to trigger on various protected mode faults,
> interrupts and exceptions with trap... options and you can use vmsint and
> vmscount to trigger on switches to protected mode via VCPI.

Yes, I tried all the options in the 386SWAT.PRO configuration file, but none of the interrupts I tried after switching to PM 32b worked. The INT 67h DEF0, DEF2 and DEF3 are essential to indicate to the debugger that the segment registers are now selectors, these INT 67h are accepted but are not taken into consideration. That's why I'm mainly looking to see if anyone has already encountered this problem and solved it.

>
> Maybe one of those ideas gets you on the right track, I have not tested
> them myself.

Complete thread:

• 386SWAT debugger - mrichard, 27.03.2024, 22:00 (Developers)
  • 386SWAT debugger - mceric, 28.03.2024, 00:50
    • 386SWAT debugger - mrichard, 28.03.2024, 10:46
  • 386SWAT debugger - Japheth, 28.03.2024, 06:25
    • 386SWAT debugger - mrichard, 28.03.2024, 10:07
    • 386SWAT debugger - mrichard, 29.03.2024, 15:40
      • 386SWAT debugger - JWasm releases - ecm, 29.03.2024, 18:59
        • 386SWAT debugger - JWasm releases - mrichard, 29.03.2024, 19:58
          • 386SWAT debugger - JWasm releases - ecm, 29.03.2024, 20:29
      • 386SWAT debugger - Japheth, 29.03.2024, 21:52
        • 386SWAT debugger - mrichard, 29.03.2024, 22:33
  • 386SWAT debugger - CandyMan, 28.03.2024, 16:54
    • 386SWAT debugger - mrichard, 28.03.2024, 21:30