ia64/linux-2.6.18-xen.hg

view include/asm-generic/bitops/fls.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_FLS_H_
2 #define _ASM_GENERIC_BITOPS_FLS_H_
4 /**
5 * fls - find last (most-significant) bit set
6 * @x: the word to search
7 *
8 * This is defined the same way as ffs.
9 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
10 */
12 static inline int fls(int x)
13 {
14 int r = 32;
16 if (!x)
17 return 0;
18 if (!(x & 0xffff0000u)) {
19 x <<= 16;
20 r -= 16;
21 }
22 if (!(x & 0xff000000u)) {
23 x <<= 8;
24 r -= 8;
25 }
26 if (!(x & 0xf0000000u)) {
27 x <<= 4;
28 r -= 4;
29 }
30 if (!(x & 0xc0000000u)) {
31 x <<= 2;
32 r -= 2;
33 }
34 if (!(x & 0x80000000u)) {
35 x <<= 1;
36 r -= 1;
37 }
38 return r;
39 }
41 #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */