[MPlayer-dev-eng] [PATCH] cpu detection for core2

[Zuxy Meng]

Hi,

2007/6/3, Loren Merritt <lorenm at u.washington.edu>:
> The configure code to detect core2 in 64bit mode was different from 32bit
> mode, and didn't work on my core2. This changes it to be the same as
> 32-bit mode, which works.

A simpler way to fix core2 detection is:
@@ -1845,7 +1845,7 @@
       AuthenticAMD)
         proc=k8;;
       GenuineIntel)
-        case "$pmodel" in
+        case "$pfamily" in
         6) proc=core2;;
         *)
           # 64-bit prescotts exist, but as far as GCC is concerned they

> Also, -march=k8 is faster than -march=nocona when run on a core2. Or
> should it be -mtune=k8 with no -march, to avoid amd-specific instructions?
> -march=k8 works for me, but that doesn't mean it's theoretically correct.
> (Of course -march=core2 is the most appropriate, but that's only in gcc
> >=4.2)

-march=k8 should work because without -fprefetch-loop-arrays, gcc
isn't able to generate any AMD specific instructions. But I can't
guarantee this :-) But as for Core2, isn't '-march=nocona
-mtune=pentium-m' faster?

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