Line data Source code
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 0 : if (x == 0)
29 0 : return 0;
30 0 : 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_ */
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