Diego Biurrun <[email protected]> writes: > On Fri, Dec 16, 2011 at 06:18:27PM +0000, Måns Rullgård wrote: >> Diego Biurrun <[email protected]> writes: >> > >> > --- a/configure >> > +++ b/configure >> > @@ -2275,7 +2275,7 @@ elif enabled x86; then >> > # targets that do support conditional mov (cmov) >> > - >> > i686|pentiumpro|pentium[23]|pentium-m|athlon|athlon-tbird|athlon-4|athlon-[mx]p|athlon64*|k8*|opteron*|athlon-fx|core2|amdfam10|barcelona|atom) >> > + >> > i686|pentiumpro|pentium[23]|pentium-m|athlon|athlon-tbird|athlon-4|athlon-[mx]p|athlon64*|k8*|opteron*|athlon-fx|core2|amdfam10|barcelona|atom|c3-2) >> > cpuflags="-march=$cpu" >> > enable cmov >> > enable fast_cmov >> >> Perhaps, but is it fast? I can't find timing information for that core >> anywhere. > > How high is the risk?
I'd say the risk it's slow is about 70%. That core is not designed for speed. > It seems to me that most i686 cores are fast_cmov, so I consider it Except where it's not, which includes all AMD prior to K8. > safe enough to assume C3-2 is as well... On the cores where it's slow, it's REALLY FUCKING SLOW, so no, this is not a safe assumption. -- Måns Rullgård [email protected] _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
