From: Avi Kivity <avi@argo.co.il>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Jiri Slaby <jirislaby@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: FP in kernelspace
Date: Sun, 30 Jul 2006 18:21:22 +0300 [thread overview]
Message-ID: <44CCCE72.8030808@argo.co.il> (raw)
In-Reply-To: <1154271283.2941.27.camel@laptopd505.fenrus.org>
Arjan van de Ven wrote:
>
> > > So 2 questions are:
> > > 1) howto FP in kernel
> > >
> > kernel_fpu_begin();
> > c = d * 3.14;
> > kernel_fpu_end();
> >
>
> unfortunately this only works for MMX not for real fpu (due to exception
> handling uglies)
>
Perhaps there should be a comment to that effect? Neither the code nor
Documentation/preemt-locking (which mentions the fpu) says anything
about this little fact.
It's also broken for x86-64, which uses sse for floating point, not the
x87 fpu.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2006-07-30 15:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-30 11:28 FP in kernelspace Jiri Slaby
2006-07-30 11:31 ` Jiri Slaby
2006-07-30 14:32 ` Arjan van de Ven
2006-07-30 14:40 ` Avi Kivity
2006-07-30 14:54 ` Arjan van de Ven
2006-07-30 15:09 ` Jiri Slaby
2006-07-30 15:20 ` Arjan van de Ven
2006-07-30 15:23 ` Avi Kivity
2006-07-30 15:21 ` Avi Kivity [this message]
2006-07-30 17:34 ` Andi Kleen
2006-07-30 18:11 ` Avi Kivity
2006-07-30 18:15 ` Andi Kleen
2006-07-30 18:30 ` Avi Kivity
2006-07-30 18:17 ` Jan Engelhardt
2006-07-30 17:33 ` Andi Kleen
2006-07-30 18:18 ` Jan Engelhardt
2006-07-30 18:28 ` Avi Kivity
2006-07-30 23:11 ` Jan Engelhardt
2006-07-30 17:32 ` Andi Kleen
2006-07-31 0:33 ` Steven Rostedt
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