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Date: Wed, 14 Feb 2007 15:17:59 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
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To: Benjamin LaHaise <bcrl@kvack.org>
cc: Russell King <rmk+lkml@arm.linux.org.uk>, Ingo Molnar <mingo@elte.hu>,
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Subject: Re: [patch 06/11] syslets: core, documentation
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On Wed, 14 Feb 2007, Benjamin LaHaise wrote:

> On Wed, Feb 14, 2007 at 01:06:59PM -0800, Davide Libenzi wrote:
> > Bear with me Ben, and let's follow this up :) If you are in the middle of 
> > an MMX copy operation, inside the syscall, you are:
> > 
> > - Userspace, on task A, calls sys_async_exec
> > 
> > - Userspace in _not_ doing any MMX stuff before the call
> 
> That's an incorrect assumption.  Every task/thread in the system has FPU 
> state associated with it, in part due to the fact that glibc has to change 
> some of the rounding mode bits, making them different than the default from 
> a freshly initialized state.

IMO I still belive this is not a huge problem. FPU state propagation/copy 
can be done in a clever way, once we detect the in-async condition.



- Davide