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Date: Fri, 2 Oct 2009 13:07:12 -0700
From: Nathan Froyd <froydnj@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 1/3] tcg: add ext{8,16,32}u_i{32,64} TCG ops
Message-ID: <20091002200712.GC9327@codesourcery.com>
References: <e388f3bbe334e3781ff318ce92d1474be6aaa99a.1254512633.git.aurelien@aurel32.net>
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To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org

On Wed, Sep 30, 2009 at 11:09:35PM +0200, Aurelien Jarno wrote:
> Currently zero extensions ops are implemented by a and op with a
> constant. This is then catched in some backend, and replaced by
> a zero extension instruction. While this works well on RISC
> machines, this adds a useless register move on non-RISC machines.
> 
> This patch adds ext{8,16,32}u_i{32,64} TCG ops that can be
> implemented in the backends to avoid emitting useless register
> moves.

I have to ask--does this make things go faster?

-Nathan