Fio 1.17.1
[fio.git] / fls.h
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90059d65
JA
1#ifndef _ASM_GENERIC_BITOPS_FLS_H_
2#define _ASM_GENERIC_BITOPS_FLS_H_
3
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 */
11
12static inline int fls(int x)
13{
14 int r = 32;
15
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}
40
41#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */