This is the mail archive of the
libc-alpha@sources.redhat.com
mailing list for the glibc project.
Re: [PATCH] PPC64 Use hardware sqrt.
- From: Steve Munroe <sjmunroe at us dot ibm dot com>
- To: Paul Mackerras <paulus at samba dot org>
- Cc: Kumar Gala <kumar dot gala at freescale dot com>, libc-alpha at sources dot redhat dot com, Tom Gall <tom_gall at vnet dot ibm dot com>
- Date: Tue, 11 May 2004 20:38:19 -0500
- Subject: Re: [PATCH] PPC64 Use hardware sqrt.
Kumar Gala <kumar.gala@freescale.com> wrote on 05/07/2004 12:10:32 AM:
> > I would consider a single AT_HWCAP bit for the PPC_FEATURE_HAS_FPU_OPT
> > but
> > I am not interested in ala-cart. If the implementation does not
> > implement
> > all the optional FP instructions then the bit is OFF.
> >
> > sqrt is the second highest contributor to SPEC-FP so I am not willing
> > to
> > give up the performance boost I get from the hardware.
> >
> > Steven J. Munroe
> > Linux on Power Toolchain Architect
> > IBM Corporation, Linux Technology Center
>
> I think this is perfectly reasonable.
>
Paul do you agree to adding PPC_FEATURE_HAS_FPU_OPT to AT_HWCAP?
For current PPC64 processors it will always be true. If/when a PPC64
processor is shipped that does implement the full set of the Optional FP
instructions we will need to add logic for the kernel to detect this. I
suspect the landscape is more complex for PPC32.
Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center