[Ffmpeg-devel] [PATCH] Bug fix, SSE3 support in i386/cputest.c and dsputil.h

Zuxy Meng zuxy.meng
Wed Apr 26 13:13:06 CEST 2006


Hi,

Cyrix's "Extended MMX" is quite different than what AMD introduced in
their original K7. Few has used those instructions and binutils even
don't support them. Currently i386/cputest.c assumes that Cyrix's
Extended MMX == AMD's MMX2, which is absolutely wrong. The attached
patch fixes this problem and addes SSE3 support as well.

--
Zuxy
Beauty is truth,
While truth is beauty.
PGP KeyID: E8555ED6
-------------- next part --------------
--- ffmpeg/libavcodec/dsputil.h	2006-04-16 13:20:27.000000000 +0800
+++ ffmpeg.new/libavcodec/dsputil.h	2006-04-26 14:44:04.000000000 +0800
@@ -432,6 +432,7 @@
 #define MM_SSE    0x0008 /* SSE functions */
 #define MM_SSE2   0x0010 /* PIV SSE2 functions */
 #define MM_3DNOWEXT  0x0020 /* AMD 3DNowExt */
+#define MM_SSE3   0x0040 /* Prescott SSE3 functions */
 
 extern int mm_flags;
 
--- ffmpeg/libavcodec/i386/cputest.c	2006-03-07 09:03:00.000000000 +0800
+++ ffmpeg.new/libavcodec/i386/cputest.c	2006-04-26 18:55:52.000000000 +0800
@@ -64,6 +64,8 @@
             rval |= MM_MMXEXT | MM_SSE;
         if (std_caps & (1<<26))
             rval |= MM_SSE2;
+        if (ecx & 1)
+            rval |= MM_SSE3;
     }
 
     cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
@@ -76,38 +78,10 @@
             rval |= MM_3DNOWEXT;
         if (ext_caps & (1<<23))
             rval |= MM_MMX;
-    }
-
-    cpuid(0, eax, ebx, ecx, edx);
-    if (       ebx == 0x68747541 &&
-               edx == 0x69746e65 &&
-               ecx == 0x444d4163) {
-        /* AMD */
-        if(ext_caps & (1<<22))
-            rval |= MM_MMXEXT;
-    } else if (ebx == 0x746e6543 &&
-               edx == 0x48727561 &&
-               ecx == 0x736c7561) {  /*  "CentaurHauls" */
-        /* VIA C3 */
-        if(ext_caps & (1<<24))
-          rval |= MM_MMXEXT;
-    } else if (ebx == 0x69727943 &&
-               edx == 0x736e4978 &&
-               ecx == 0x64616574) {
-        /* Cyrix Section */
-        /* See if extended CPUID level 80000001 is supported */
-        /* The value of CPUID/80000001 for the 6x86MX is undefined
-           according to the Cyrix CPU Detection Guide (Preliminary
-           Rev. 1.01 table 1), so we'll check the value of eax for
-           CPUID/0 to see if standard CPUID level 2 is supported.
-           According to the table, the only CPU which supports level
-           2 is also the only one which supports extended CPUID levels.
-        */
-        if (eax < 2)
-            return rval;
-        if (ext_caps & (1<<24))
+        if (ext_caps & (1<<22))
             rval |= MM_MMXEXT;
     }
+
 #if 0
     av_log(NULL, AV_LOG_DEBUG, "%s%s%s%s%s%s\n",
         (rval&MM_MMX) ? "MMX ":"",



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