From: DavMac AT iname DOT com (Davin McCall)
Newsgroups: alt.lang.asm,comp.os.msdos.djgpp,comp.os.msdos.programmer
Subject: Re: NASM + DJGPP linking
Date: Wed, 30 Jun 1999 02:15:04 GMT
Organization: Monash Uni
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To: djgpp AT delorie DOT com
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On Tue, 29 Jun 1999 14:01:12 -0400, "John S. Fine"
<johnfine AT erols DOT com> wrote:

>  DJGPP is a 32-bit environment.  That means you must use
>esp instead of sp, ebp instead of bp, and ebp+8 instead of
>bp+4.

For some reason I missed that. Must be too used to 16-bit assembly
code.

>  DJGPP is a protected mode environment.  Instructions like
>"int 10h" cannot go directly to the BIOS.  They must be
>intercepted by the DOS extender and redispatched in V86 or
>real mode.

I think you are incorrect - any interrupts under DPMI are echoed
through to V86/real mode with the same register values; it is only the
functions which use pointers which have to be caught by a DOS
extender.

Of course, issuing interrupts this way is probably not the recommended
way of calling BIOS services, it would be better to use the DPMI
functions.

>  DJGPP code can be run several different environments (such
>as CWSDPMI or Windows DOS boxes etc.).  I don't remember whether
>all, some or none of them redispatch int 10h's for you.  I
>expect it is in the FAQ.

As far as I understand it, they all should as it's part of the DPMI
specification.

Davin.

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