diff --git a/libdrm/xf86drm.h b/libdrm/xf86drm.h
index f9dd1bf..6226be1 100644
--- a/libdrm/xf86drm.h
+++ b/libdrm/xf86drm.h
@@ -325,29 +325,26 @@ typedef struct _drmSetVersion {
 
 #elif defined(__alpha__)
 
-#define	DRM_CAS(lock, old, new, ret) 		\
- 	do {					\
- 		int old32;                      \
- 		int cur32;			\
- 		__asm__ __volatile__(		\
- 		"       mb\n"			\
- 		"       zap   %4, 0xF0, %0\n"   \
- 		"       ldl_l %1, %2\n"		\
- 		"       zap   %1, 0xF0, %1\n"   \
-                "       cmpeq %0, %1, %1\n"	\
-                "       beq   %1, 1f\n"		\
- 		"       bis   %5, %5, %1\n"	\
-                "       stl_c %1, %2\n"		\
-                "1:     xor   %1, 1, %1\n"	\
-                "       stl   %1, %3"		\
-                : "=r" (old32),                 \
-		  "=&r" (cur32),		\
-                   "=m" (__drm_dummy_lock(lock)),\
-                   "=m" (ret)			\
- 		: "r" (old),			\
- 		  "r" (new));			\
- 	} while(0)
-
+#define DRM_CAS(lock, old, new, ret)		\
+	do {					\
+		int current;			\
+		__asm__ __volatile__(		\
+			"mb\n\t"		\
+			"mov	$31, %0\n\t"	\
+			"ldl_l	%1, %2\n\t"	\
+			"cmpeq	%1, %4, %1\n\t"	\
+			"beq	%1, 1f\n\t"	\
+			"stl_c	%3, %2\n\t"	\
+			"addq	%0, 1, %0\n\t"	\
+			"1:"			\
+			: "=&r" (ret),		\
+			  "=&r" (current),	\
+			  "=m" (__drm_dummy_lock(lock))	\
+			: "r" (new),		\
+			  "r" (old)		\
+		);				\
+	} while (0)
+	
 #elif defined(__sparc__)
 
 #define DRM_CAS(lock,old,new,__ret)				\