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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] Re: Compile files only once: some planning
Date: Wed, 24 Mar 2010 14:56:55 +0000
References: <f43fc5581003231443x5492dd7eve541fd8104170a60@mail.gmail.com>
	<4BA9F52C.6070309@twiddle.net> <4BAA25A7.7000201@redhat.com>
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To: qemu-devel@nongnu.org
Cc: Blue Swirl <blauwirbel@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <rth@twiddle.net>

> On 03/24/2010 12:19 PM, Richard Henderson wrote:
> > On 03/24/2010 02:47 AM, Paolo Bonzini wrote:
> >> 1) make CPUState define only common fields. Include CPUState at the
> >> beginning of each per-target CPUXYZState.
> >
> > Irritatingly, the common fields contain quite big TLBs. And the
> > offsets from the start of env affect the compactness of the code
> > generated from TCG. We really really want the general registers
> > to come first to make sure that those offsets fit the host's
> > reg+offset addressing mode.
> 
> What about adding a 512-bytes (or more) block or something like that at
> the beginning of CPUState with a union, so you can put the per-target
> stuff there?

Is it really worth the hassle? Anything touching CPUState is probably going to 
be CPU specific anyway.

Paul