From: Matthew Mastracci <mmastrac AT acs DOT ucalgary DOT ca>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Asm routine returns
Date: Mon, 6 Oct 1997 21:22:19 -0600
Organization: The University of Calgary
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On Mon, 6 Oct 1997, Sam Davies wrote:

> I know that this error is actually a result of calling my routine, since
> I can comment out the call to the function, and there's no problem...
> So I'm assuming it must be that I messed up within the routine...  I
> modify SI, DI, BP, and DS, but I push and pop all these at the beginning
> and end...  Is there anything else that I could be screwing up in my
> routine that is causing this strange behavior?  I don't have to save the
> other general registers, do I?

I'm just curious: are you saving the extended 32-bit registers as well?
Even if you only use the 16-bit registers, you should save and restore the
extended ones.  Your stack frame should look similar to this:

push ebp
mov ebp, esp

push ds
push edi
push esi

[program]

pop esi
pop edi
pop ds

mov esp, ebp
pop ebp

/\/\att /\/\astracci                  mmastrac AT acs DOT ucalgary DOT ca

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