From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Quick inline asm question...
Date:	Tue, 17 Sep 1996 19:43:25 -0700
Organization:	Three pounds of chaos and a pinch of salt
Lines:	25
Message-ID:	<323F61CD.797B@cs.com>
References:	<51mrb2$o5f AT news DOT cais DOT com>
Reply-To:	fighteer AT cs DOT com
NNTP-Posting-Host:	ppp211.cs.com
Mime-Version:	1.0
To:	David Charlton <charlton AT the-hermes DOT net>
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

David Charlton wrote:
> 
>         Okay, I have a quick question, if it's really easy or stupid
> please don't flame me... anyway, suppose I wanted to add one of the
> 16-bit registers to a 32-bit register (this is for a basic graphics
> routine) -- how would I do that? I've tried "addw %%ax, %%eax", and "addl
> %%ax, %%eax", but it doesn't work. I have a feeling it should be simple,
> but if it's simple it isn't obvious (to me) ;)... so what do I do?

Well, in as much as I understand 16 vs 32-bit assembly, the 'e*x'
registers
are simply 32-bit extended versions of the '*x' registers.  So, %%ax is
in
actuality the lower 16 bits of %%eax.  What you are trying to do is add
the register to itself, which I doubt will work.

-- 
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