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From:	Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Why the call instruction points 2 bytes before to the real start sub-routine ?
Date:	2 Nov 2005 17:53:23 GMT
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Diego Cueva <dcueva AT todo1 DOT com> wrote:

> com file not are my final objective. My Objective is creating a small
> operating system to educational purposes, and I need compile C programs
> with GCC that can execute in booting time.

In that case, .com files are not just not your final goal, they're not
even likely to be particularly useful as a stepping stone getting there.

Code compiled by the DJGPP version of GCC strictly assumes a DPMI-like
environment.  You'ld have to recreate basically all of a DPMI server,
and large parts of DOS, before this code will run reliably.  To get an
idea of what that means, have a good look at the CWSDPMI sources.

It might end up being easier to embed FreeDOS, CWSDPMI and your
program into a single binary image, instead.

> To this moment I have a IPL program with a group small routines in
> assemble compiled/linked with "as/ld". This is working fine. 

Working fine in what kind of environment?  Called from DOS?

> But link that with C compiled code is the WALL to climb now.

Exactly.  Wherein "WALL" is not just some bedroom wall or something
--- it's more like the Eiger North side.

-- 
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.

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