X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Fasm-generic%2Fbitops%2Ffls64.h;h=86d403f8b256815761270e822b84b438cc87f5d2;hb=252815b0cfe711001eff0327872209986b36d490;hp=1b6b17ce2428091e605c8cbda7103b1d42836780;hpb=a54baa1487c51c8306dd6f457c1b5d5fcd539fff;p=linux-2.6

diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h
index 1b6b17ce24..86d403f8b2 100644
--- a/include/asm-generic/bitops/fls64.h
+++ b/include/asm-generic/bitops/fls64.h
@@ -3,6 +3,18 @@
 
 #include <asm/types.h>
 
+/**
+ * fls64 - find last set bit in a 64-bit word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffsll, but returns the position of the most significant set bit.
+ *
+ * fls64(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 64.
+ */
+#if BITS_PER_LONG == 32
 static inline int fls64(__u64 x)
 {
 	__u32 h = x >> 32;
@@ -10,5 +22,15 @@ static inline int fls64(__u64 x)
 		return fls(h) + 32;
 	return fls(x);
 }
+#elif BITS_PER_LONG == 64
+static inline int fls64(__u64 x)
+{
+	if (x == 0)
+		return 0;
+	return __fls(x) + 1;
+}
+#else
+#error BITS_PER_LONG not 32 or 64
+#endif
 
 #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */