Date: Wed, 17 Mar 93 08:17:31 EST
From: DJ Delorie <dj AT ctron DOT com>
To: sandmann AT clio DOT rice DOT edu
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: DPMI & new GO32

>I have been agonizing over the DPMI stuff, and have a couple of thoughts, but
>have not checked them out fully.  One idea would be to have limited DPMI 
>support for text mode only programs that don't expect memory at any fixed
>location (almost pure unix ports, for example).  Best case is this could be
>done with a one size fits all GO32 and library, worse case would require
>a special library and "link" step (and be DPMI only?)

Worst case.  I've looked at DPMI 0.9, and I think some programs might
work, but they'd have to be NMAGIC instead of ZMAGIC executables
(that's a special link switch), and go32 doesn't support NMAGIC at the
moment.  Also, DPMI 0.9 would REQUIRE that you preset a fixed stack
size.

>Another thought involves a program that comes with one of the MIT ports of 
>GNU C - it converts .o file format to 32 bit .obj format which can then be
>used with the LINK386 program that comes with OS/2.  Maybe this could be
>modified to make .obj files for creating 32 bit Windows applications?  I
>am not sure where the Windows linker, libraries or API code would come 
>from, however.

One of the fundamental problems is that GNUC doesn't know about
segments, and DPMI 0.9 assumes you do.  DPMI 1.0 adds linear address
mappings, which allows the huge gap between heap and stack.

>I also have a question - last time I checked the event library (from the
>GRX package) did not work with VCPI and 1.09; my editor port uses a patched
>event library and I am thus stuck with 1.08 currently (since I haven't had
>time to try and fix VCPI + event support in 1.09).  Has anyone fixed this yet?
>I would like to test a merged copy to prevent merged problems before posting
>a diff.

Yes, it's a bug.  Yes, I have a patch (that was posted to djgpp).
Yes, it will be fixed in 1.10.  Can someone post a test program that
only works when the event library is working?  Something short would
be nice.

DJ