From owner-freebsd-stable  Thu Aug 16 15: 0:53 2001
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Date: Thu, 16 Aug 2001 18:00:40 -0400 (EDT)
From: Kenneth W Cochran <kwc@world.std.com>
Message-Id: <200108162200.SAA21031@world.std.com>
To: Kris Kennaway <kris@obsecurity.org>
Subject: Re: New kernel option CPU_ENABLE_SSE
Cc: freebsd-stable@freebsd.org
References: <200108162020.QAA14274@world.std.com>
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Ok, so how can I tell if a given CPU supports that feature?

I see a "feature list" in the kernel startup, and in the
case of a Pentium-III, SSE is at the "end" of that list; is
that the Definitive Indicator?  If so, what's to keep the
kernel from detecting and enabling it (per config-option,
for example)?  (kernel complexity, for example...)

Am I correct in assuming that "older generation" 686 CPUs
(i.e. pre-Pentium-III) don't support SSE & that SSE is a
function/enhancement of "newer generation" CPUs?

-kc

>Date: Thu, 16 Aug 2001 14:28:44 -0700
>From: Kris Kennaway <kris@obsecurity.org>
>To: Kenneth W Cochran <kwc@world.std.com>
>Cc: freebsd-stable@FreeBSD.ORG
>Subject: Re: New kernel option CPU_ENABLE_SSE
>
>On Thu, Aug 16, 2001 at 04:20:35PM -0400, Kenneth W Cochran wrote:
>> Assuming CPU_ENABLE_SSE is a Good Thing, why not make it
>> "default" with the "cpu I686_CPU" kernel config directive
>> (similar to F00F_HACK auto-include with I586_CPU)?
>
>Because not all i686'es support SSE.
>
>Kris

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