Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ico!vail!rcd
From: rcd@ico.isc.com (Dick Dunn)
Newsgroups: comp.unix.i386
Subject: Re: protected-mode instruction sets ...
Summary: 32-bit instructions in VP/ix
Message-ID: <1989Nov27.061726.2891@ico.isc.com>
Date: 27 Nov 89 06:17:26 GMT
References: <256D58FD.14619@maccs.dcss.mcmaster.ca> <128383@sun.Eng.Sun.COM> <16784@nuchat.UUCP>
Organization: Interactive Systems Corporation
Lines: 19

steve@nuchat.UUCP (Steve Nuchia) writes:
> plocher@sun.UUCP (John Plocher) writes:
> >No, DosMerge and VP/ix both run DOS in a virtual 8086 environment.
> What about the 32 bit instructions?  If one is content to live with
> the memory architecture of an 8086 can one generate code with 32 bit
> arithmetic instrucitons and such?

Yes.  According to the 80386 _Programmer's_Reference_Manual_, you can use
the new registers (e.g., FS, GS, and the segment overrides to access them),
32 bit operands, push immediate, push/pop all, multiply immediate, bit
operations, etc.  Just stay away from anything that smells like it might be
privileged, and remember that the segment registers work 8086-style.

I'd also suggest thinking carefully about where you're going with such
code.  It's not really 386 code; but neither is it going to run on a PC
(or XT or AT).
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...Never offend with style when you can offend with substance.