DOS ain't dead

386SWAT debugger (Developers)

posted by mrichard, 28.03.2024, 21:30

> The 386SWAT debugger was also used in the D3X dos extender (code in PM32
> mode). See the SWAT.INC file which can be found in the archive for download
> from here:
>
> https://board.flatassembler.net/download.php?id=7858
> https://board.flatassembler.net/download.php?id=7859
>
> on web:
>
> https://board.flatassembler.net/topic.php?t=14416
>
> When detecting the presence of 386 SWAT, you must first check whether
> interrupt 67h is supported and then specify which descriptors in GDT are
> reserved for this debugger and which descriptors point to interrupts int
> 01h and 03h in IDT. Then, when you enter protected mode, you can invoke one
> of these interrupts.
>
> Good luck.

Thanks for your help.
INT 67h DEF0 returns V6.01 for 386SWAT because that's the version I'm using. I also have a version 6.06 which crashes at startup with certain computers.. I add 30 empty descriptors at the end of my GDT, then with INT 67h DEF2 I point ES:DI to the start of these 30 new descriptors, but in BX I don't understand if I should put a selector there that points to the IDT of the PM. Then INT 67h DEF3 selects for example int 3 with BX, but in ES:DI I don't know if I should point to the PM's IDT or a new IDT reserved for SWAT? (because I think I understand that in the help). In PM 32b, I make a far call using a selector for the start of GDT of SWAT with the linear address that INT 67h DEF2 returned in EDX, but is this correct? An int3 displays a smiley which proves that my IDT is recognized and working, but it does not break 386SWAT. Maybe because now INT3 doesn't do the same thing as before? (for INT1, etc. my IDT contains IRETD everywhere).
I haven't tried your version yet because it's still too confusing for me in terms of INT DEF2, DEF3 and the far call to be made in PM, etc. Please, can you give me a little information more ?

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