Re: FP in kernelspace

From: Avi Kivity
Date: Sun Jul 30 2006 - 11:19:48 EST


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

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