From: Animesh Karna <karna AT pobox DOT upenn DOT edu>
Posted-Date: Wed, 2 Jun 93 14:58:15 EDT
Subject: DPMI support
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Date: Wed, 2 Jun 93 14:58:15 EDT


I have some questions about the DPMI support in the latest DJGPP package:

-- Is there any way to get at the <1meg memory while in DPMI?  I
understand that the 0xE0000000 remapping doesn't work.  Is it
completely unavailable, or is it mapped to some other location?  (I guess
it might be possible to call DPMI and set up a selector that includes the
<1meg memory area, but I don't see any way to access memory in that
selector in C/C++: it would have to be done in assembly language)

-- Does floating point emulation work?

-- If I understand correctly, GO32 works the way it always did (complete
with mem being remapped to 0xE0000000) unless a DPMI host is detected (or
would it be more accurate to say "unless nothing else seems to work and a
DPMI host is detected"?).  Is there a way at runtime to detect whether the
DPMI host is sitting there?  The idea is that I would have one set of
routines that access <1meg memory via 0xE0000000 and another set that use
a special DPMI-obtained selector to access <1meg memory (if that is the
only way to get at the mem).  At runtime, if GO32 is in "DPMI mode", it
uses one set of routines, and otherwise uses the other.

Thanks!