DOS ain't dead

INT 15.87 in protected mode (Developers)

posted by Japheth , Germany (South), 31.08.2011, 10:11

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

Why are you making guesses if you have no experience in the matter? To show the OP that somebody cares about his/her issues? I'm aware that Americans have a strong believe in the power of words, but it shouldn't be exaggerated THAT much, IMO.

> 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

If the DPMI host runs as VCPI client, it will switch "back" to v86-mode ( hopefully using the VCPI API ), because anything else will cause disaster. I don't think that cwsdpmi or hdpmi differ in this regard.

> But does Windows even truly call int 15h? I doubt it. I'm pretty sure it
> doesn't call the "real" BIOS.

A v86-monitor program - and NTVDM is such a type of program, although it runs in non-privileged mode and hence needs the help of the OS for a few tasks - will always emulate int 15h.87h. The memory functions ( int 15h.88h, ... ) are sometimes also intercepted. However, the rest of Int 15h may be called "really".

---
MS-DOS forever!

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