DOS ain't dead

INT 15.87 in protected mode (Developers)

posted by Rugxulo , Usono, 31.08.2011, 01:30

> > Hm, I tried it with cwsdpmi. Most probably with last version - r7.
> > I will try it with HDPMI32 too.
>
> cwsdpmi works as well. Why I know this? Because DEBUGX's DX command does
> exactly what you're trying to do - it calls Int 15h, ah=87h directly in
> real-mode and indirectly via int 31h, ax=300h in protected-mode. And the DX
> command works with cwsdpmi, hdpmi, Windows, ...

Okay, it's just confusing, esp. as (obviously) I have little to no experience with the innards of pmode.

It's just hard to understand, esp. when you know CWSDPMI and HDPMI do things differently. And certainly Windows is a whole other ball of wax.

Corrections welcome, this is a guess (not looking it up right now, too busy) ...

int 31h, 300h -> CWSDPMI switches back to real mode
int 31h, 300h -> HDPMI32 switches to V86 mode
int 31h, 300h -> Windows (which?) switches to V86 mode

But does Windows even truly call int 15h? I doubt it. I'm pretty sure it doesn't call the "real" BIOS. I'm pretty sure that most memory managers hide / "eat" int 15h anyways unless you're running raw (which isn't really the best choice, IMHO, to use DPMI).

Complete thread:

• INT 15.87 in protected mode - Laaca, 29.08.2011, 14:11 (Developers)
  • INT 15.87 in protected mode - Rugxulo, 29.08.2011, 23:28
    • INT 15.87 in protected mode - Japheth, 30.08.2011, 05:27
      • INT 15.87 in protected mode - Rugxulo, 30.08.2011, 05:37
      • INT 15.87 in protected mode - Laaca, 30.08.2011, 07:22
        • INT 15.87 in protected mode - Japheth, 30.08.2011, 08:47
          • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 01:30
            • INT 15.87 in protected mode - Laaca, 31.08.2011, 07:33
              • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 21:27
                • INT 15.87 in protected mode - Laaca, 02.09.2011, 07:10
                  • INT 15.87 in protected mode - marcov, 02.09.2011, 09:58
                    • INT 15.87 in protected mode - Rugxulo, 03.09.2011, 21:49
                      • INT 15.87 in protected mode - DOS386, 04.09.2011, 12:43
            • INT 15.87 in protected mode - Japheth, 31.08.2011, 10:11
              • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 21:25
                • INT 15.87 in protected mode - ecm, 01.09.2011, 02:17
                  • INT 15.87 in protected mode - Rugxulo, 01.09.2011, 04:31
                    • INT 15.87 in protected mode - Rugxulo, 01.09.2011, 05:00
  • INT 15.87 in protected mode - RayeR, 07.09.2011, 10:28
    • INT 15.87 in protected mode - Laaca, 07.09.2011, 12:28
      • INT 15.87 in protected mode - RayeR, 07.09.2011, 21:05
        • INT 15.87 in protected mode - Laaca, 08.09.2011, 07:33
          • INT 15.87 in protected mode - bretjohn, 08.09.2011, 18:19
            • INT 15.87 in protected mode - Laaca, 08.09.2011, 22:39
              • INT 15.87 in protected mode - Rugxulo, 08.09.2011, 22:50
          • INT 15.87 in protected mode - RayeR, 08.09.2011, 22:27
            • INT 15.87 in protected mode - bretjohn, 09.09.2011, 00:31
              • INT 15.87 in protected mode - RayeR, 09.09.2011, 01:51
                • INT 15.87 in protected mode - bretjohn, 09.09.2011, 20:09
                • INT 15.87 in protected mode - bretjohn, 09.09.2011, 23:17