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From: Blue Swirl <blauwirbel@gmail.com>
Date: Tue, 18 Jan 2011 17:17:41 +0000
Message-ID: <AANLkTim9ZLDEQscwcO4hswzz4nJbP-KLnYJ_cU-MYNEw@mail.gmail.com>
Subject: Re: [Qemu-devel] Changing the content of target cpu registers
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To: Stefano Bonifazi <stefboombastic@gmail.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>

On Tue, Jan 18, 2011 at 9:29 AM, Stefano Bonifazi
<stefboombastic@gmail.com> wrote:
> Hi all!
> =C2=A0I am working on qemu-user (qemu-ppc).
> I'd like to edit the values of target registers during the execution. Can=
 I
> do that by simply changing the content of env->gpr[] or do these only
> contain a copy of the values of the registers?
> In this last case, where are the real values of the target registers stor=
ed
> so that by modifying them I can alter the behavior of the target code
> execution?

env->gpr is the canonical location, but the translator assigns TCG
variables to them (cpu_gpr[] in translate.c), so GPR contents may be
cached to these. But when helpers are called or the TB finishes,
env->gpr should be valid again.