[MPlayer-dev-eng] [PATCH] fast_cmov should be set on x86_64

[Zuxy Meng]

Hi,

2008/12/24 Reimar Döffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> On Wed, Dec 24, 2008 at 05:47:54PM +0800, Zuxy Meng wrote:
>> 2008/12/23 Reimar Döffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
>> > Index: configure
>> > ===================================================================
>> > --- configure   (revision 28181)
>> > +++ configure   (working copy)
>> > @@ -1935,6 +1938,7 @@
>> >     else
>> >        cpuopt=-mcpu
>> >     fi
>> > +    test $_fast_cmov = "auto" && _fast_cmov=yes
>> >     if test "$_runtime_cpudetection" = no ; then
>> >       case "$pvendor" in
>> >       AuthenticAMD)
>> > @@ -1946,7 +1950,6 @@
>> >           # 64-bit prescotts exist, but as far as GCC is concerned they
>> >           # have the same capabilities as a nocona.
>> >           proc=nocona
>> > -          test $_fast_cmov = "auto" && _fast_cmov=no
>> >           ;;
>> >         esac
>> >         ;;
>>
>> Hmmm so we don't care for those who bought a 64-bit P4.
>
> At the expense of everyone else who made sane buying decisions?
> Certainly not!

Intel has so far shipped only Family 6 and Family 15 64-bit CPUs so if
it isn't a core2 it must be a P4.

> Also even Intel recommends to use cmov if in doubt, so if even Intel
> thinks it best :-P.
> If you know how and have the motivation to extend the check to disable
> fast_cmov on P4 _and only_ on P4, I'm happy.
> Something like this might work, but I doubt it catches all (and I
> suspect that some of those cases are missing from the 32 bit case as
> well).
>

-- 
Zuxy
Beauty is truth,
While truth is beauty.
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