[FLS64]: x86_64 version

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 1 deletions

diff --git a/include/asm-x86_64/bitops.h b/include/asm-x86_64/bitops.h
index 94b52c8ce97f..a4d5d0909453 100644
--- a/include/asm-x86_64/bitops.h
+++ b/include/asm-x86_64/bitops.h
@@ -340,6 +340,20 @@ static __inline__ unsigned long __ffs(unsigned long word)
         return word;
 }
 
+/*
+ * __fls: find last bit set.
+ * @word: The word to search
+ *
+ * Undefined if no zero exists, so code should check against ~0UL first.
+ */
+static __inline__ unsigned long __fls(unsigned long word)
+{
+        __asm__("bsrq %1,%0"
+                :"=r" (word)
+                :"rm" (word));
+        return word;
+}
+
 #ifdef __KERNEL__
 
 static inline int sched_find_first_bit(const unsigned long *b)
@@ -370,6 +384,19 @@ static __inline__ int ffs(int x)
 }
 
 /**
+ * fls64 - find last bit set in 64 bit word
+ * @x: the word to search
+ *
+ * This is defined the same way as fls.
+ */
+static __inline__ int fls64(__u64 x)
+{
+        if (x == 0)
+                return 0;
+        return __fls(x) + 1;
+}
+
+/**
  * hweightN - returns the hamming weight of a N-bit word
  * @x: the word to weigh
  *
@@ -409,7 +436,6 @@ static __inline__ int ffs(int x)
 
 /* find last set bit */
 #define fls(x) generic_fls(x)
-#define fls64(x) generic_fls64(x)
 
 #endif /* __KERNEL__ */