1#ifndef _ASM_GENERIC_BITOPS___FFS_H_
2#define _ASM_GENERIC_BITOPS___FFS_H_
3
4#include <asm/types.h>
5
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 */
12static __always_inline unsigned long __ffs(unsigned long word)
13{
14	int num = 0;
15
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}
42
43#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
44