1
2#ifndef _TOOLS_LINUX_ASM_GENERIC_BITOPS___FFS_H_
3#define _TOOLS_LINUX_ASM_GENERIC_BITOPS___FFS_H_
4
5#include <asm/types.h>
6#include <asm/bitsperlong.h>
7
8
9
10
11
12
13
14static __always_inline unsigned long __ffs(unsigned long word)
15{
16 int num = 0;
17
18#if __BITS_PER_LONG == 64
19 if ((word & 0xffffffff) == 0) {
20 num += 32;
21 word >>= 32;
22 }
23#endif
24 if ((word & 0xffff) == 0) {
25 num += 16;
26 word >>= 16;
27 }
28 if ((word & 0xff) == 0) {
29 num += 8;
30 word >>= 8;
31 }
32 if ((word & 0xf) == 0) {
33 num += 4;
34 word >>= 4;
35 }
36 if ((word & 0x3) == 0) {
37 num += 2;
38 word >>= 2;
39 }
40 if ((word & 0x1) == 0)
41 num += 1;
42 return num;
43}
44
45#endif
46