From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: i386 emulation bug: mov reg, [addr]
Date: Wed, 16 Dec 2009 00:37:37 +0100 [thread overview]
Message-ID: <hg96k3$q12$1@ger.gmane.org> (raw)
In-Reply-To: <20091215212657.GC26319@shareable.org>
On 12/15/2009 10:26 PM, Jamie Lokier wrote:
> But that said, I'm not sure if this line from earlier breaks the test:
>
> index = ((code>> 3)& 7) | REX_X(s);
>
> When is REX_X(s) not zero, and does it break the index != 4 test?
When %r12 (4+8=12) is used as an index. That's a valid statement, so
it's okay to test index != 4 (when REX_X(s) is not zero it is always
eight, and you'd get index == 12):
0: 8b 04 65 11 22 33 44 mov 0x44332211(,%riz,2),%eax
7: 42 8b 04 65 11 22 33 44 mov 0x44332211(,%r12,2),%eax
(BTW %eiz/%riz are not accepted by my GAS, only produced by the
disassembler).
Paolo
next prev parent reply other threads:[~2009-12-15 23:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-15 18:48 [Qemu-devel] i386 emulation bug: mov reg, [addr] Clemens Kolbitsch
2009-12-15 19:54 ` Avi Kivity
2009-12-15 21:21 ` Jamie Lokier
2009-12-16 8:56 ` Clemens Kolbitsch
2009-12-16 9:05 ` Avi Kivity
2009-12-16 9:28 ` [Qemu-devel] " Paolo Bonzini
2009-12-15 21:26 ` [Qemu-devel] " Jamie Lokier
2009-12-15 22:24 ` malc
2009-12-15 23:37 ` Paolo Bonzini [this message]
2009-12-16 10:07 ` Avi Kivity
2010-03-06 17:02 ` Aurelien Jarno
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