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Date: Tue, 27 Jan 2009 14:37:37 +0000
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] [PATCH] Enabled building of x86_64 code on Mac OS X
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To: qemu-devel@nongnu.org
Cc: Paul Brook <paul@codesourcery.com>

Alexander Graf wrote:
> As for the plus in code size on x86_64 - that doesn't really apply to
> tcg, as that still generates 32-bit code when only 32-bit code is
> necessary, which still looks the same on x86_64. Plus it does simplify
> 64-bit operations.

TCG doesn't use the available x86_64 registers when generating code
for 32-bit operations on an x86_64 host?

> I would be very surprised if the improvement of emulating x86_64 on x86
> vs. x86_64 is only ~10%.

So would I.

By the way, with KVM, can QEMU (the I/O model) be a 32-bit app while
the KVM kernel module provides an x86_64 CPU?

That might be useful, if there are advantages to QEMU itself being
32-bit on MacOS X and if there's a KVM module for it.

-- Jamie