| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | #ifndef _ASM_GENERIC_BITOPS_FLS64_H_ |
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| 3 | #define _ASM_GENERIC_BITOPS_FLS64_H_ |
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| 4 | |
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| 5 | #include <asm/types.h> |
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| 6 | |
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| 7 | /** |
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| 8 | * fls64 - find last set bit in a 64-bit word |
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| 9 | * @x: the word to search |
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| 10 | * |
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| 11 | * This is defined in a similar way as the libc and compiler builtin |
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| 12 | * ffsll, but returns the position of the most significant set bit. |
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| 13 | * |
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| 14 | * fls64(value) returns 0 if value is 0 or the position of the last |
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| 15 | * set bit if value is nonzero. The last (most significant) bit is |
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| 16 | * at position 64. |
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| 17 | */ |
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| 18 | #if BITS_PER_LONG == 32 |
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| 19 | static __always_inline int fls64(__u64 x) |
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| 20 | { |
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| 21 | __u32 h = x >> 32; |
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| 22 | if (h) |
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| 23 | return fls(x: h) + 32; |
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| 24 | return fls(x); |
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| 25 | } |
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| 26 | #elif BITS_PER_LONG == 64 |
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| 27 | static __always_inline int fls64(__u64 x) |
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| 28 | { |
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| 29 | if (x == 0) |
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| 30 | return 0; |
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| 31 | return __fls(x) + 1; |
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| 32 | } |
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| 33 | #else |
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| 34 | #error BITS_PER_LONG not 32 or 64 |
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| 35 | #endif |
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| 36 | |
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| 37 | #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */ |
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| 38 | |
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