diff --git a/src/radeon_exa.c b/src/radeon_exa.c
index 4da4841..7695f42 100644
--- a/src/radeon_exa.c
+++ b/src/radeon_exa.c
@@ -99,10 +99,17 @@ static __inline__ int
 RADEONLog2(int val)
 {
 	int bits;
-
+#if (defined __i386__ || defined __x86_64__) && (defined __GNUC__)
+	__asm volatile("bsrl	%1, %0"
+		: "=r" (bits)
+		: "c" (val)
+	);
+	return bits;
+#else
 	for (bits = 0; val != 0; val >>= 1, ++bits)
 		;
 	return bits - 1;
+#endif
 }
 
 static __inline__ CARD32 F_TO_DW(float val)
diff --git a/src/radeon_render.c b/src/radeon_render.c
index a80d136..0908d20 100644
--- a/src/radeon_render.c
+++ b/src/radeon_render.c
@@ -250,10 +250,17 @@ static __inline__ int
 ATILog2(int val)
 {
 	int bits;
-
+#if (defined __i386__ || defined __x86_64__) && (defined __GNUC__)
+	__asm volatile("bsrl	%1, %0"
+		: "=r" (bits)
+		: "c" (val)
+	);
+	return bits;
+#else
 	for (bits = 0; val != 0; val >>= 1, ++bits)
 		;
 	return bits - 1;
+#endif
 }
 
 static void