[PATCH xf86-video-ati] Calculate log base 2 in radeon.h based on clz for all platforms

[Jochen Rollwagen]

This commit replaces the inline assembler code (for x86 platforms) and 
loop (for non-x86 platforms) in RADEONLog2 with a one-liner version 
based on clz (count leading zeroes).
---
  src/radeon.h |   13 +------------
  1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/src/radeon.h b/src/radeon.h
index 5797bed..23ecfeb 100644
--- a/src/radeon.h
+++ b/src/radeon.h
@@ -935,18 +935,7 @@ enum {
  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
+    return (31 - __builtin_clz(val));
  }

  #define RADEON_TILING_MASK                0xff
-- 
1.7.9.5

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