--- libmpeg2/cpu_accel.c
+++ libmpeg2/cpu_accel.c
@@ -31,6 +31,17 @@
 
 #ifdef ACCEL_DETECT
 #ifdef ARCH_X86
+#ifdef __x86_64__
+static inline uint32_t arch_accel (void)
+{
+  uint32_t caps;
+  /* No need to test for this on AMD64, we know what the
+     platform has.  */
+  caps = MPEG2_ACCEL_X86_MMX | MPEG2_ACCEL_X86_MMXEXT;
+
+  return caps;
+}
+#else
 static inline uint32_t arch_accel (void)
 {
     uint32_t eax, ebx, ecx, edx;
@@ -106,6 +117,7 @@
 
     return caps;
 }
+#endif /* __x86_64__ */
 #endif /* ARCH_X86 */
 
 #if defined(ARCH_PPC) || defined(ARCH_SPARC)