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Re: [Qemu-devel] [5949] target-ppc: memory load/store rework
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] [5949] target-ppc: memory load/store rework |
Date: |
Sat, 13 Dec 2008 09:25:54 +0200 |
On 12/13/08, Stuart Brady <address@hidden> wrote:
> On Mon, Dec 08, 2008 at 06:11:22PM +0000, Aurelien Jarno wrote:
> > - Don't swap values twice for bit-reverse load/store functions
> > in little endian mode.
>
> If I've read this correctly, it seems to me that we would still swap
> twice on little endian hosts when when emulating little endian mode or
> performing bit-reverse loads/stores. Bit-reverse loads/stores under
> little endian emulation on a little endian host would have actually
> resulted in *three* byteswaps!
>
> I'm not sure what the performance impact of this would be, but it's
> something that I've been wondering about while working on PA-RISC
> emulation, which will also need to provide a little endian mode.
Jocelyn sent a patch to address this. There were some (small) problems
with it, so please read the full thread:
http://lists.gnu.org/archive/html/qemu-devel/2007-10/msg00289.html