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Re: [Qemu-devel] [PATCH] target-ppc: fix evmergelo and evmergelohi
From: |
Nathan Froyd |
Subject: |
Re: [Qemu-devel] [PATCH] target-ppc: fix evmergelo and evmergelohi |
Date: |
Tue, 7 Jul 2009 09:04:01 -0700 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
On Thu, Jun 04, 2009 at 01:46:41PM -0700, Nathan Froyd wrote:
> For 32-bit PPC targets, we translated:
>
> evmergelo rX, rX, rY
>
> as:
>
> rX-lo = rY-lo
> rX-hi = rX-lo
>
> which is wrong, because we should be transferring rX-lo first. This
> problem is fixed by swapping the order in which we write the parts of
> rX.
>
> Similarly, we translated:
>
> evmergelohi rX, rX, rY
>
> as:
>
> rX-lo = rY-hi
> rX-hi = rX-lo
>
> In this case, we can't swap the assignment statements, because that
> would just cause problems for:
>
> evmergelohi rX, rY, rX
>
> Instead, we detect the first case and save rX-lo in a temporary
> variable:
>
> tmp = rX-lo
> rX-lo = rY-hi
> rX-hi = tmp
>
> These problems don't occur on PPC64 targets because we don't split the
> SPE registers into hi/lo parts for such targets.
Ping again.
-Nathan
- Re: [Qemu-devel] [PATCH] target-ppc: fix evmergelo and evmergelohi,
Nathan Froyd <=