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Mail Archives: djgpp/1993/04/26/18:27:25

From: sandmann AT clio DOT rice DOT edu (Charles W. Sandmann)
Subject: dpmi GO32 questions
To: djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp)
Date: Mon, 26 Apr 1993 17:14:36 -0600 (CDT)

> 2) For the people that are trying to get the dpmi-kinda-compliant go32.com
> working: does this DOS extender support floating point emulation?  In
> addition, does it support direct access to the < 1M memory space?

The current DPMI GO32 does not support floating emulation.  I believe it
is possible (I haven't checked the details) but it is low on my priority list.
I don't even have a non-floating machine available to write it with.

It does not, nor will it ever with DPMI 0.9, support direct access to the
first 1Mb memory space in a linear fashion.  A selector (aka segment register)
can be set up to point to 64K at a time in the 1Mb area, but that would 
mean writing 32 bit assembler interfaces or some other specific kludge that
would not work with the current non-DPMI GO32.

So anything that works with 0xe0000000 type addresses will break with the
DPMI version.  So far, this code seems limited to screen access, clock(),
and graphics/event routines.  It might be possible to capture the exceptions
and emulate this access but I don't feel like writing GO32 emulators...

I would suggest this won't get fully resolved until 2.0, but some new 
fully compatible method (yet unspecified) should be compatible
with both types of extenders.

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