protected-mode instruction sets ...

Dick Dunn rcd at
Mon Nov 27 17:17:26 AEST 1989

steve at nuchat.UUCP (Steve Nuchia) writes:
> plocher at 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 at    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...Never offend with style when you can offend with substance.

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