Initial revision

Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 102 insertions, 0 deletions

diff --git a/libavcodec/i386/cputest.c b/libavcodec/i386/cputest.c
new file mode 100644
index 0000000000..9181f413d5
--- /dev/null
+++ b/libavcodec/i386/cputest.c
@@ -0,0 +1,102 @@
+/* Cpu detection code, extracted from mmx.h ((c)1997-99 by H. Dietz
+   and R. Fisher). Converted to C and improved by Gerard Lantau */
+
+#include <stdlib.h>
+#include "../dsputil.h"
+
+#define cpuid(index,eax,ebx,ecx,edx) \
+    asm ("cpuid" \
+         : "=a" (eax), "=b" (ebx), \
+           "=c" (ecx), "=d" (edx) \
+         : "a" (index) \
+         : "cc")
+
+/* Function to test if multimedia instructions are supported...  */
+int mm_support(void)
+{
+    int rval;
+    int eax, ebx, ecx, edx;
+    
+    
+    __asm__ __volatile__ (
+                          /* See if CPUID instruction is supported ... */
+                          /* ... Get copies of EFLAGS into eax and ecx */
+                          "pushf\n\t"
+                          "popl %0\n\t"
+                          "movl %0, %1\n\t"
+                          
+                          /* ... Toggle the ID bit in one copy and store */
+                          /*     to the EFLAGS reg */
+                          "xorl $0x200000, %0\n\t"
+                          "push %0\n\t"
+                          "popf\n\t"
+                          
+                          /* ... Get the (hopefully modified) EFLAGS */
+                          "pushf\n\t"
+                          "popl %0\n\t"
+                          : "=a" (eax), "=c" (ecx)
+                          :
+                          : "cc" 
+                          );
+    
+    if (eax == ecx)
+        return 0; /* CPUID not supported */
+    
+    cpuid(0, eax, ebx, ecx, edx);
+
+    if (ebx == 0x756e6547 &&
+        edx == 0x49656e69 &&
+        ecx == 0x6c65746e) {
+        
+        /* intel */
+    inteltest:
+        cpuid(1, eax, ebx, ecx, edx);
+        if ((edx & 0x00800000) == 0)
+            return 0;
+        rval = MM_MMX;
+        if (edx & 0x02000000) 
+            rval |= MM_MMXEXT | MM_SSE;
+        if (edx & 0x04000000) 
+            rval |= MM_SSE2;
+        return rval;
+    } else if (ebx == 0x68747541 &&
+               edx == 0x69746e65 &&
+               ecx == 0x444d4163) {
+        /* AMD */
+        cpuid(0x80000000, eax, ebx, ecx, edx);
+        if ((unsigned)eax < 0x80000001)
+            goto inteltest;
+        cpuid(0x80000001, eax, ebx, ecx, edx);
+        if ((edx & 0x00800000) == 0)
+            return 0;
+        rval = MM_MMX;
+        if (edx & 0x80000000)
+            rval |= MM_3DNOW;
+        if (edx & 0x00400000)
+            rval |= MM_MMXEXT;
+        return rval;
+    } 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) 
+            goto inteltest;
+        cpuid(0x80000001, eax, ebx, ecx, edx);
+        if ((eax & 0x00800000) == 0)
+            return 0;
+        rval = MM_MMX;
+        if (eax & 0x01000000)
+            rval |= MM_MMXEXT;
+        return rval;
+    } else {
+        return 0;
+    }
+}