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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _ASM_GENERIC_BITOPS_FLS64_H_3#define _ASM_GENERIC_BITOPS_FLS64_H_4 5#include <asm/types.h>6 7/**8 * fls64 - find last set bit in a 64-bit word9 * @x: the word to search10 *11 * This is defined in a similar way as the libc and compiler builtin12 * ffsll, but returns the position of the most significant set bit.13 *14 * fls64(value) returns 0 if value is 0 or the position of the last15 * set bit if value is nonzero. The last (most significant) bit is16 * at position 64.17 */18#if BITS_PER_LONG == 3219static __always_inline int fls64(__u64 x)20{21 __u32 h = x >> 32;22 if (h)23 return fls(h) + 32;24 return fls(x);25}26#elif BITS_PER_LONG == 6427static __always_inline int fls64(__u64 x)28{29 if (x == 0)30 return 0;31 return __fls(x) + 1;32}33#else34#error BITS_PER_LONG not 32 or 6435#endif36 37#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */38