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Subject: Re: Noob question. Why is the for-pentium4 kernel built with 
	-march=i686 ?
From: Lee Revell <rlrevell@joe-job.com>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: 7eggert@gmx.de, ivan@yosifov.net, linux-kernel@vger.kernel.org
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Date: Tue, 19 Jul 2005 16:19:22 -0400
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On Tue, 2005-07-19 at 22:15 +0200, Jan Engelhardt wrote:
> >AFAIK it's not possible to use SSE and MME in kernel mode, since these
> >registers aren't preserved (it would be expensive).
> 
> Floating point is anyway a no-no in the kernel. 

However, there are a few exceptions like mmx_memcpy.

Lee