Re: FPU emulator unsafe for SMP?

[Ralf Baechle <ralf@oss.sgi.com>]

On Tue, Feb 19, 2002 at 11:32:22PM -0500, Daniel Jacobowitz wrote:

> > If you do use floating point, I think it is pretty common to have
> > only process that uses fpu and runs for very long.  In that case,
> > leaving FPU owned by the process also saves quite a bit.
> 
> Not true.  For instance, on a processor with hardware FPU, setjmp()
> will save FPU registers.  That means most processes will actually end
> up taking the FPU at least once.

The cleassic reason to take the FPU is the ctc1 $0, $31 instruction used
to initalize the FPU control register rsp. it's equivalent on other
architectures.  This should be fixed in glibc since a few years.

   Ralf