DOS ain't dead - With DPMI into protect mode and back

With DPMI into protect mode and back (Developers)

posted by Laaca , Czech republic, 13.08.2010, 10:36

I have a 16 bit realmode program. It would be nice for it to add possibility for writing a info about installed DPMI manager. But the problem is than I can't call the INT31h interrupts from real mode (nor from VM86 mode).

If I understand the documentation correct, I can switch into protect mode by calling address provided in INT2Fh/AX=1687h but there is no transparent way how to get back into real (VM86) mode.
The only way is just to terminate the application. But I don't want to terminate it. Maybe is possible to run some child process but I don't want to call any external EXE file.
So,
Japheth (or anybode else),
could you write for our, dummies, some example program which starts in real mode, somewhat switch into protect, writes some info about DPMI environment, switch back into real, writes "still alive" and only after it ends?

---
DOS-u-akbar!

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Complete thread:

With DPMI into protect mode and back - Laaca, 13.08.2010, 10:36 (Developers)
- With DPMI into protect mode and back - EDIT: example - ecm, 13.08.2010, 14:30
  - With DPMI into protect mode and back - EDIT: example - DOS386, 26.08.2010, 09:18
    - With DPMI into protect mode and back - EDIT: example - ecm, 26.08.2010, 14:35
      - With DPMI into protect mode and back - EDIT: example - DOS386, 27.08.2010, 03:33
        With DPMI into protect mode and back - EDIT: example - ecm, 30.08.2010, 21:51
        With DPMI into protect mode and back | physical memory - DOS386, 06.09.2010, 20:08
        With DPMI into protect mode and back | physical memory - ecm, 07.09.2010, 17:04
        With DPMI into protect mode and back | physical memory - DOS386, 08.09.2010, 00:51
        With DPMI into protect mode and back | physical memory - ecm, 08.09.2010, 20:53
        With DPMI into protect mode and back | physical memory - DOS386, 11.09.2010, 01:02
        With DPMI into protect mode and back | physical memory - ecm, 11.09.2010, 01:25
- With DPMI into protect mode and back - Japheth, 18.08.2010, 08:04
  - With DPMI into protect mode and back - Japheth, 18.10.2010, 11:17
    - With DPMI into protect mode and back - Rugxulo, 18.10.2010, 23:07
      - With DPMI into protect mode and back - Japheth, 19.10.2010, 09:58
        With DPMI into protect mode and back - Rugxulo, 19.10.2010, 10:09
        With DPMI into protect mode and back - Japheth, 19.10.2010, 10:20
        Possible CWSDPMI design flaw - Japheth, 19.10.2010, 17:59