Subject: Re: CVS commit: src/lib/libc/arch/x86_64/sys
To: None <>
From: Jaromir Dolecek <>
List: source-changes
Date: 03/15/2003 16:04:24
Does movl really zero extend? According to 80386 docs I read recently,
movb/movw don't touch the upper part of the resiter, i.e. for example
movb $1, %al wouldn't change %ah part and leave old contents there.
Is x86_64 different, and does it zero the upper part of register instead?


Frank van der Linden wrote:
> Module Name:	src
> Committed By:	fvdl
> Date:		Sat Mar 15 12:34:33 UTC 2003
> Modified Files:
> 	src/lib/libc/arch/x86_64/sys: __sigtramp1.S
> Log Message:
> No need to use movq for the small immediate values here, they'll be
> zero-extended with movl.
> To generate a diff of this commit:
> cvs rdiff -r1.3 -r1.4 src/lib/libc/arch/x86_64/sys/__sigtramp1.S
> Please note that diffs are not public domain; they are subject to the
> copyright notices on the relevant files.

Jaromir Dolecek <>  
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