aboutsummaryrefslogtreecommitdiff
path: root/include/asm-generic/bitops
diff options
context:
space:
mode:
authorAlexander van Heukelum <heukelum@mailshack.com>2008-03-15 18:32:36 +0100
committerIngo Molnar <mingo@elte.hu>2008-04-26 19:21:16 +0200
commitd57594c203b1e7b54373080a797f0cbfa4aade68 (patch)
tree61610af68fc93280fb0be00a4f1b523715bef3db /include/asm-generic/bitops
parent56a6b1eb7bfb5ace0b5cb9c149f502fbd101b8ab (diff)
bitops: use __fls for fls64 on 64-bit archs
Use __fls for fls64 on 64-bit archs. The implementation for 64-bit archs is moved from x86_64 to asm-generic. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-generic/bitops')
-rw-r--r--include/asm-generic/bitops/fls64.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h
index 1b6b17ce242..86d403f8b25 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_ */