1*fb7df12dSIngo Molnar /* SPDX-License-Identifier: GPL-2.0 */ 2de1e17b1SArnaldo Carvalho de Melo #ifndef _ASM_GENERIC_BITOPS_FLS64_H_ 3de1e17b1SArnaldo Carvalho de Melo #define _ASM_GENERIC_BITOPS_FLS64_H_ 4de1e17b1SArnaldo Carvalho de Melo 5de1e17b1SArnaldo Carvalho de Melo #include <asm/types.h> 6de1e17b1SArnaldo Carvalho de Melo 7de1e17b1SArnaldo Carvalho de Melo /** 8de1e17b1SArnaldo Carvalho de Melo * fls64 - find last set bit in a 64-bit word 9de1e17b1SArnaldo Carvalho de Melo * @x: the word to search 10de1e17b1SArnaldo Carvalho de Melo * 11de1e17b1SArnaldo Carvalho de Melo * This is defined in a similar way as the libc and compiler builtin 12de1e17b1SArnaldo Carvalho de Melo * ffsll, but returns the position of the most significant set bit. 13de1e17b1SArnaldo Carvalho de Melo * 14de1e17b1SArnaldo Carvalho de Melo * fls64(value) returns 0 if value is 0 or the position of the last 15de1e17b1SArnaldo Carvalho de Melo * set bit if value is nonzero. The last (most significant) bit is 16de1e17b1SArnaldo Carvalho de Melo * at position 64. 17de1e17b1SArnaldo Carvalho de Melo */ 18de1e17b1SArnaldo Carvalho de Melo #if BITS_PER_LONG == 32 fls64(__u64 x)19de1e17b1SArnaldo Carvalho de Melostatic __always_inline int fls64(__u64 x) 20de1e17b1SArnaldo Carvalho de Melo { 21de1e17b1SArnaldo Carvalho de Melo __u32 h = x >> 32; 22de1e17b1SArnaldo Carvalho de Melo if (h) 23de1e17b1SArnaldo Carvalho de Melo return fls(h) + 32; 24de1e17b1SArnaldo Carvalho de Melo return fls(x); 25de1e17b1SArnaldo Carvalho de Melo } 26de1e17b1SArnaldo Carvalho de Melo #elif BITS_PER_LONG == 64 fls64(__u64 x)27de1e17b1SArnaldo Carvalho de Melostatic __always_inline int fls64(__u64 x) 28de1e17b1SArnaldo Carvalho de Melo { 29de1e17b1SArnaldo Carvalho de Melo if (x == 0) 30de1e17b1SArnaldo Carvalho de Melo return 0; 31de1e17b1SArnaldo Carvalho de Melo return __fls(x) + 1; 32de1e17b1SArnaldo Carvalho de Melo } 33de1e17b1SArnaldo Carvalho de Melo #else 34de1e17b1SArnaldo Carvalho de Melo #error BITS_PER_LONG not 32 or 64 35de1e17b1SArnaldo Carvalho de Melo #endif 36de1e17b1SArnaldo Carvalho de Melo 37de1e17b1SArnaldo Carvalho de Melo #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */ 38