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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Lauro Ramos Venancio <lauro.venancio@indt.org.br>
Subject: Re: [Qemu-devel] qemu-arm: wrong execution of post-indexed loads when Rm and Rd are the same register
Date: Thu, 15 Mar 2007 20:03:20 +0000	[thread overview]
Message-ID: <200703152003.21276.paul@codesourcery.com> (raw)
In-Reply-To: <1173987324.9939.0.camel@edgy-laptop>

On Thursday 15 March 2007 19:35, Lauro Ramos Venancio wrote:
> Qemu-arm is wrongly executing post-indexed loads when Rm and Rd are
> the same register. For example:
>
> ldr r0, [r1], +r0
>
> Current behavior:
> r0 <- [r1]
> r1 <- r1 + r0
>
> Expected behavior:
> addr <- r1
> r1 <- r1 + r0
> r0 <- [addr]

This is still wrong. The writeback must happen after the load. Your 
implementation will give incorrect results if the load faults.

Paul

  parent reply	other threads:[~2007-03-15 20:04 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-15 19:35 [Qemu-devel] qemu-arm: wrong execution of post-indexed loads when Rm and Rd are the same register Lauro Ramos Venancio
2007-03-15 19:43 ` [Qemu-devel] " Lauro Ramos Venancio
2007-03-15 20:03 ` Paul Brook [this message]
2007-03-15 20:32   ` [Qemu-devel] " Rodrigo Vivi
2007-03-15 21:10     ` Paul Brook
2007-03-15 21:19       ` Rodrigo Vivi
2007-03-15 21:55       ` Laurent Desnogues
2007-03-15 22:04         ` Paul Brook
2007-03-16 20:42           ` Lauro Ramos Venancio

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