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 /**
5 * ffs - find first bit set
6 * @x: the word to search
7 *
8 * This is defined the same way as
9 * the libc and compiler builtin ffs routines, therefore
10 * differs in spirit from the above ffz (man ffs).
11 */
12 static inline int ffs(int x)
13 {
14 int r = 1;
16 if (!x)
17 return 0;
18 if (!(x & 0xffff)) {
19 x >>= 16;
20 r += 16;
21 }
22 if (!(x & 0xff)) {
23 x >>= 8;
24 r += 8;
25 }
26 if (!(x & 0xf)) {
27 x >>= 4;
28 r += 4;
29 }
30 if (!(x & 3)) {
31 x >>= 2;
32 r += 2;
33 }
34 if (!(x & 1)) {
35 x >>= 1;
36 r += 1;
37 }
38 return r;
39 }
41 #endif /* _ASM_GENERIC_BITOPS_FFS_H_ */