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  */
__ffs(unsigned long word)12 static __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