1 #ifndef _ASM_GENERIC_BITOPS_FLS64_H_
2 #define _ASM_GENERIC_BITOPS_FLS64_H_
3 
4 #include <asm/types.h>
5 
6 /**
7  * fls64 - find last set bit in a 64-bit word
8  * @x: the word to search
9  *
10  * This is defined in a similar way as the libc and compiler builtin
11  * ffsll, but returns the position of the most significant set bit.
12  *
13  * fls64(value) returns 0 if value is 0 or the position of the last
14  * set bit if value is nonzero. The last (most significant) bit is
15  * at position 64.
16  */
17 #if BITS_PER_LONG == 32
18 static __always_inline int fls64(__u64 x)
19 {
20 	__u32 h = x >> 32;
21 	if (h)
22 		return fls(h) + 32;
23 	return fls(x);
24 }
25 #elif BITS_PER_LONG == 64
26 static __always_inline int fls64(__u64 x)
27 {
28 	if (x == 0)
29 		return 0;
30 	return __fls(x) + 1;
31 }
32 #else
33 #error BITS_PER_LONG not 32 or 64
34 #endif
35 
36 #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
37