fixed cpuid macro to allow PIC compiling

Originally committed as revision 10 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/i386/cputest.c b/libavcodec/i386/cputest.c
index 9181f41..78f3644 100644 (file)
--- a/libavcodec/i386/cputest.c
+++ b/libavcodec/i386/cputest.c
@@ -4,12 +4,18 @@
 #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")
+/* ebx saving is necessary for PIC. gcc seems unable to see it alone */
+static inline void cpuid(int index, int *eax, int *ebx, int *ecx, int *edx)
+{
+    asm ("pushl %%ebx\n\t"
+         "cpuid\n\t"
+         "movl %%ebx, %1\n\t"
+         "popl %%ebx\n\t"
+         : "=a" (*eax), "=m" (*ebx), 
+           "=c" (*ecx), "=d" (*edx)
+         : "a" (index)
+         : "cc");
+}
 
 /* Function to test if multimedia instructions are supported...  */
 int mm_support(void)
@@ -17,7 +23,6 @@ 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 */
@@ -42,7 +47,7 @@ int mm_support(void)
     if (eax == ecx)
         return 0; /* CPUID not supported */
     
-    cpuid(0, eax, ebx, ecx, edx);
+    cpuid(0, &eax, &ebx, &ecx, &edx);
 
     if (ebx == 0x756e6547 &&
         edx == 0x49656e69 &&
@@ -50,7 +55,7 @@ int mm_support(void)
         
         /* intel */
     inteltest:
-        cpuid(1, eax, ebx, ecx, edx);
+        cpuid(1, &eax, &ebx, &ecx, &edx);
         if ((edx & 0x00800000) == 0)
             return 0;
         rval = MM_MMX;
@@ -63,10 +68,10 @@ int mm_support(void)
                edx == 0x69746e65 &&
                ecx == 0x444d4163) {
         /* AMD */
-        cpuid(0x80000000, eax, ebx, ecx, edx);
+        cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
         if ((unsigned)eax < 0x80000001)
             goto inteltest;
-        cpuid(0x80000001, eax, ebx, ecx, edx);
+        cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
         if ((edx & 0x00800000) == 0)
             return 0;
         rval = MM_MMX;
@@ -89,7 +94,7 @@ int mm_support(void)
         */
         if (eax != 2) 
             goto inteltest;
-        cpuid(0x80000001, eax, ebx, ecx, edx);
+        cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
         if ((eax & 0x00800000) == 0)
             return 0;
         rval = MM_MMX;