Article View: alt.msdos.programmer
Article #447Re: 386 instructions
From: Tor Brekke
Date: Wed, 17 Jan 1990 10:27
Date: Wed, 17 Jan 1990 10:27
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1335 bytes
In article <1451@gould.doc.ic.ac.uk> dds@cc.ic.ac.uk (Diomidis Spinellis) writes:
>Sorry, but the above is not exactly correct. It is true that most of the
>386 instructions can be used in the real mode, but the segment limit is
>still limited to 64K.
^^^
Sorry, byt this is not correct either. It is possible to trick the 386
into beliving that it's segments are larger than 64K in real mode. It
involves a trip into protected mode though. If a descriptor i set up
with a limit larger than 64K and left in one of the segment registers
when reentering real mode, the processor will still believe that the
segment has the old size. I have not done this myself, but a friend of
mine has and it worked fine.
Tor Brekke
Email : torb@idt.unit.no
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arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!sunic!nuug!sigyn.idt.unit.no!torbReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!sunic!nuug!sigyn.idt.unit.no!torb From: torb@idt.unit.no (Tor Brekke) Newsgroups: alt.msdos.programmer Subject: Re: 386 instructions Message-ID: <1990Jan17.102756.8171@idt.unit.no> Date: 17 Jan 90 10:27:56 GMT References: <13346@garnet.BBN.COM> <580@watserv1.waterloo.edu> <6142@internal.Apple.COM> <8166@portia.Stanford.EDU> <1451@gould.doc.ic.ac.uk> Reply-To: torb@grimne.UUCP (Tor Brekke) Organization: Div. of CS & Telematics, Norwegian Institute of Technology Lines: 16