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37 lines
860 B
37 lines
860 B
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _ASM_GENERIC_BITOPS_FLS64_H_ |
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#define _ASM_GENERIC_BITOPS_FLS64_H_ |
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#include <asm/types.h> |
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/** |
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* fls64 - find last set bit in a 64-bit word |
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* @x: the word to search |
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* |
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* This is defined in a similar way as the libc and compiler builtin |
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* ffsll, but returns the position of the most significant set bit. |
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* |
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* fls64(value) returns 0 if value is 0 or the position of the last |
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* set bit if value is nonzero. The last (most significant) bit is |
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* at position 64. |
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*/ |
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#if BITS_PER_LONG == 32 |
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static __always_inline int fls64(__u64 x) |
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{ |
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__u32 h = x >> 32; |
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if (h) |
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return fls(h) + 32; |
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return fls(x); |
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} |
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#elif BITS_PER_LONG == 64 |
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static __always_inline int fls64(__u64 x) |
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{ |
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if (x == 0) |
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return 0; |
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return __fls(x) + 1; |
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} |
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#else |
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#error BITS_PER_LONG not 32 or 64 |
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#endif |
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#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
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