38 lines
860 B
C
38 lines
860 B
C
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/* 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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