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편집 파일: fls64.h

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