[PATCH] use hw instructions for ieee754_sqrt on s390.

Martin Schwidefsky schwidefsky@de.ibm.com
Fri Jun 18 08:30:00 GMT 2004





Ulrich Drepper <drepper@redhat.com> wrote on 18/06/2004 01:49:44 AM:

> Martin Schwidefsky wrote:
>
> > use the hardware square root instructions sqdbr and sqebr
> > for __ieee754_sqrt and __ieee754_sqrtf. They are faster
> > than the generic C implementation.
>
> I can do it even faster:
>
> double sqrt(double x) { return 1.0; }

Yes that is even faster ;-) But serious the hw instruction should
be exact to the last bit. The math test run fine. I have to ask
some hardware guys to make really sure about it though.
After I checked I'll post a new patch with the inline implementation.

blue skies,
   Martin

Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH
Schönaicherstr. 220, D-71032 Böblingen, Telefon: 49 - (0)7031 - 16-2247
E-Mail: schwidefsky@de.ibm.com



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