ia64/linux-2.6.18-xen.hg

view include/asm-generic/bitops/__ffs.h @ 782:9ab1c319531f

merge with linux-2.6.18-xen.hg
author Isaku Yamahata <yamahata@valinux.co.jp>
date Wed Jan 28 13:07:23 2009 +0900 (2009-01-28)
parents 831230e53067
children
line source
1 #ifndef _ASM_GENERIC_BITOPS___FFS_H_
2 #define _ASM_GENERIC_BITOPS___FFS_H_
4 #include <asm/types.h>
6 /**
7 * __ffs - find first bit in word.
8 * @word: The word to search
9 *
10 * Undefined if no bit exists, so code should check against 0 first.
11 */
12 static inline unsigned long __ffs(unsigned long word)
13 {
14 int num = 0;
16 #if BITS_PER_LONG == 64
17 if ((word & 0xffffffff) == 0) {
18 num += 32;
19 word >>= 32;
20 }
21 #endif
22 if ((word & 0xffff) == 0) {
23 num += 16;
24 word >>= 16;
25 }
26 if ((word & 0xff) == 0) {
27 num += 8;
28 word >>= 8;
29 }
30 if ((word & 0xf) == 0) {
31 num += 4;
32 word >>= 4;
33 }
34 if ((word & 0x3) == 0) {
35 num += 2;
36 word >>= 2;
37 }
38 if ((word & 0x1) == 0)
39 num += 1;
40 return num;
41 }
43 #endif /* _ASM_GENERIC_BITOPS___FFS_H_ */