From:	"Charles Sandmann" <sandmann AT clio DOT rice DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: help! FPU emulation worries... (RHIDE?)
Date:	Thu, 15 May 1997 22:32:17
Organization:	Aspen Technology, Inc.
Lines:	24
Message-ID:	<337b8ef1.sandmann@clio.rice.edu>
References:	<337AD12B DOT 65DB AT Mathematik DOT tu-chemnitz DOT de>
Reply-To:	sandmann AT clio DOT rice DOT edu
NNTP-Posting-Host:	spica.dmccorp.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

> Or is there any way for me to simulate the software FPU even when
> I have a 486 DX?

SET 387=n

> And to your problem with the exception. As far as I understand
> the software FP software, it works by generating an exception
> for any floating point code. Since it is under DJGPP not possible
> (I don't know if this will fixed in the future) to debug programs
> which use exceptions, you have really a problem when you try to debug 
> a program which uses the software FP code.

It's even worse than that - the FPU emulator doesn't understand "far"
so can't live in a separate CS/DS/SS very well, and it doesn't emulate
debug flags at all.  WMEMU fixes some, but not all, of these problems.

> And at last: If there is someone who can tell me, how I can
> simulate this situation on a processor, which has the FP unit
> on it, I would do my best to fix that problem.

It's a very complex problem which needs a lot of hacking.  While it's not
a nice thing to do - DJGPP does not support DEVELOPMENT of FPU code on a
non-FPU box.  It is run-time FPU emulation only.  Sorry.  With FPUs being
essentially free, its impossible to justify spending any time on this.

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