| 1 |
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| 2 | #ifndef _ASM_GENERIC_BITOPS_FFS_H_
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| 3 | #define _ASM_GENERIC_BITOPS_FFS_H_
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| 4 |
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| 5 | |
| 6 | * generic_ffs - find first bit set
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| 7 | * @x: the word to search
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| 8 | *
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| 9 | * This is defined the same way as
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| 10 | * the libc and compiler builtin ffs routines, therefore
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| 11 | * differs in spirit from ffz (man ffs).
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| 12 |
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| 13 | static inline __attribute_const__ int generic_ffs(int x)
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| 14 | {
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| 15 | int r = 1;
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| 16 |
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| 17 | if (!x)
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| 18 | return 0;
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| 19 | if (!(x & 0xffff)) {
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| 20 | x >>= 16;
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| 21 | r += 16;
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| 22 | }
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| 23 | if (!(x & 0xff)) {
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| 24 | x >>= 8;
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| 25 | r += 8;
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| 26 | }
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| 27 | if (!(x & 0xf)) {
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| 28 | x >>= 4;
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| 29 | r += 4;
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| 30 | }
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| 31 | if (!(x & 3)) {
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| 32 | x >>= 2;
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| 33 | r += 2;
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| 34 | }
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| 35 | if (!(x & 1)) {
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| 36 | x >>= 1;
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| 37 | r += 1;
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| 38 | }
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| 39 | return r;
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| 40 | }
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| 41 |
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| 42 | #ifndef __HAVE_ARCH_FFS
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| 43 | #define ffs(x) generic_ffs(x)
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| 44 | #endif
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| 45 |
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| 46 | #endif
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