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Re: [Qemu-devel] [PATCH 1/3] [x86] Clean up vendor identification
From: |
Paul Brook |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] [x86] Clean up vendor identification |
Date: |
Mon, 11 Aug 2008 15:51:15 +0100 |
User-agent: |
KMail/1.9.9 |
> >> #define CPUID_VENDOR_INTEL_1 'Genu'
> >> ...
> >
> > Is that a real improvement? It won't make the code faster and the
> > readability doesn't improve that much either.
>
> I'd take it as a security improvement. One can easily commit a typo
> when editting magic numbers, either decimal or hexa.
I don't believe this argument at all. A bug is a bug, it's got nothing to do
with "security". If anything the hex values are more reliable because you
don't have to guess how the string is converted to an integer - this is
proved by the fact that the above suggestion is incorrect[1]. The hex values
are given in the cpu reference docs, so there shouldn't be any doubt whether
they are correct.
[1] As someone else mentioned (though not very clearly) gcc interprets 'Genu'
as a big-endian value, whereas the Intel docs define "Genu" as being
little-endian.
Paul
Re: [Qemu-devel] [PATCH 1/3] [x86] Clean up vendor identification, Paul Brook, 2008/08/11
Re: [Qemu-devel] [PATCH 1/3] [x86] Clean up vendor identification, M. Warner Losh, 2008/08/11