[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: hwcap supporting architectures?

At Sat, 25 Dec 2004 21:59:41 -0600,
Marcelo E. Magallon <mmagallo@debian.org> wrote:
>  Since the optimized i386 library does use MMX (it does perform runtime
>  checking) and is compiled with -mcpu=i686 [0] (gcc doesn't seem to be
>  emitting CMOVs though) I think the proper place is
>  /usr/lib/i686/mmx/cmov (I have no intention of babysitting the
>  generation of cmovs with each difference compiler release, therefore
>  mmx/cmov instead of just mmx)

If it uses i686 and mmx code, /usr/lib/i686/mmx/cmov is OK.

Note that MMX will be removed from the next glibc 2.3.4 upload.  It
will provide only SSE2 (and CMOV, debian-specific for only VIA C3
processor).  If you want to keep adding mmx, we may need discussion
about this issue in future.  But nowadays many processors can use
SSE2, so I guess changing cmov to SSE2 can fix the problem.

>  My understanding is that this is also significant on sparc (-mcpu=v9)
>  and that this belongs in /usr/lib/v9.  Is this right?

Sparc defines HWCAP_SPARC_V9 and HWCAP_SPARC_ULTRA3.  So v9 is right.
See glibc sparc packages.

>  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.

>  It also uses -mcpu=603 on powerpc.  From my understanding this is a lot
>  hairier than other architectures since there's a whole load more
>  subarchitectures which are potentially incompatible with each other.

Powerpc does not define any hwcaps, too.

-- gotom

Reply to: