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Mail Archives: djgpp/2003/01/08/15:45:20

From: Martin Str|mberg <ams AT speedy DOT ludd DOT luth DOT se>
Subject: Re: Generate real-mode 386 DOS executables?
Newsgroups: comp.os.msdos.djgpp
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Date: 08 Jan 2003 19:31:37 GMT
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Vinzent Hoefler <JeLlyFish DOT software AT gmx DOT net> wrote:
: Ben Peddell wrote:
: [32-Bit Real Mode]
:> But be warned, as soon as you call something that switches to
:> protected mode, Big Real Mode goes *poof*.

: The main problem is, as soon as you call BIOS or something it goes 
: *poof* because the called code assumes a 16-bit-code-segment. So 
: probably the first timer/keyboard/harddisk/whatever interrupt would 
: already crash you. That's what I said.

Not quite. The problem is that as soon you restore a segment register
in real mode its big real mode properties go poff. If you're lucky you
might have fs and gs untouched (mainly because of DOZE's
8086-ness). But e. g. FreeDOS kernel compiled for 386 or higher
probably uses them, or any other 386-aware program might, so just
forget about it.


The real problem is of course what this has to do with DJGPP?


Right,

						MartinS

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