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From: Aurelien Jarno <aurelien@aurel32.net>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [patch] Alpha : fix cmpbge instruction
Date: Mon, 10 Nov 2008 12:11:06 +0100	[thread overview]
Message-ID: <20081110111106.GA20280@hall.aurel32.net> (raw)
In-Reply-To: <Pine.LNX.4.44.0811100146240.20447-100000@cacao.csl.cornell.edu>

On Mon, Nov 10, 2008 at 01:48:28AM -0500, Vince Weaver wrote:
> Hello
> 
> The cmpbge instruction should compare all 8 bytes of one 64-bit value with
> another.  However, we were looping with a < 7 condition which was skipping
> the top byte.  So if we were doing a compare where the top byte was
> important, we could get the wrong result (this notably breaks the strlen()
> function with certain sized strings).
> 
> Attached is a patch

Thanks, applied.

> Index: target-alpha/op_helper.c
> ===================================================================
> --- target-alpha/op_helper.c	(revision 5666)
> +++ target-alpha/op_helper.c	(working copy)
> @@ -330,7 +330,7 @@
>      int i;
> 
>      res = 0;
> -    for (i = 0; i < 7; i++) {
> +    for (i = 0; i < 8; i++) {
>          opa = op1 >> (i * 8);
>          opb = op2 >> (i * 8);
>          if (opa >= opb)
> 
> 
> 
> 

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net

      reply	other threads:[~2008-11-10 11:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-10  6:48 [Qemu-devel] [patch] Alpha : fix cmpbge instruction Vince Weaver
2008-11-10 11:11 ` Aurelien Jarno [this message]

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