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Re: hwcap supporting architectures?

At Tue, 11 Jan 2005 11:27:28 +0100,
Falk Hueffner wrote:
> > Marcelo E. Magallon <mmagallo@debian.org> wrote:
> >>  Mesa upstream uses -mcpu=ev5 -mieee on alpha.  Is that ok?  Where does
> >>  this belong into? /usr/lib/ev5?
> >
> > IIRC, alpha does not define any hwcaps.
> There's a patch for this, which works fine, but wasn't committed yet:
> http://lists.debian.org/debian-glibc/2004/03/msg00143.html
> Sensible options are ev56 and ev67; ev5 is not particularly useful, since
> it has the same instruction set as the baseline ev4, only different scheduling.
> -mieee is default anyway on Debian's gcc.

Yes, we don't support it currently, but I think it should be available
after sarge.

BTW, this patch does not enable HWCAP_IMPORTANT - so the answer of
first question from Marcelo is: alpha does not support library HWCAP
directory loading even if this patch is applied.  If other libraries
like mesa and libssl want to use /usr/lib/ev67 and so on, we may
consider to add HWCAP_IMPORTANT.  However, be careful that if we add
one entry into HWCAP_IMPORTANT, the library lookup cost increases
twice.  If you're unsure about this issue, please check various
applications with strace command.  One example is loading
/usr/lib/gconv .so files to search iconv plugin.  Looking up about .so
is a lot on i386.  This is the reason why I hate to add CMOV into i386
HWCAP_IMPORTANT list because CMOV processor is only affected to VIA C3
corrupted processor, but the most i686 based system pay worthless look
up cost for searching cmov directory.

-- gotom

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