1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc. 4 * All Rights Reserved. 5 */ 6 #ifndef __XFS_BIT_H__ 7 #define __XFS_BIT_H__ 8 9 /* 10 * XFS bit manipulation routines. 11 */ 12 13 /* 14 * masks with n high/low bits set, 64-bit values 15 */ 16 static inline uint64_t xfs_mask64hi(int n) 17 { 18 return (uint64_t)-1 << (64 - (n)); 19 } 20 static inline uint32_t xfs_mask32lo(int n) 21 { 22 return ((uint32_t)1 << (n)) - 1; 23 } 24 static inline uint64_t xfs_mask64lo(int n) 25 { 26 return ((uint64_t)1 << (n)) - 1; 27 } 28 29 /* Get high bit set out of 32-bit argument, -1 if none set */ 30 static inline int xfs_highbit32(uint32_t v) 31 { 32 return fls(v) - 1; 33 } 34 35 /* Get high bit set out of 64-bit argument, -1 if none set */ 36 static inline int xfs_highbit64(uint64_t v) 37 { 38 return fls64(v) - 1; 39 } 40 41 /* Get low bit set out of 32-bit argument, -1 if none set */ 42 static inline int xfs_lowbit32(uint32_t v) 43 { 44 return ffs(v) - 1; 45 } 46 47 /* Get low bit set out of 64-bit argument, -1 if none set */ 48 static inline int xfs_lowbit64(uint64_t v) 49 { 50 uint32_t w = (uint32_t)v; 51 int n = 0; 52 53 if (w) { /* lower bits */ 54 n = ffs(w); 55 } else { /* upper bits */ 56 w = (uint32_t)(v >> 32); 57 if (w) { 58 n = ffs(w); 59 if (n) 60 n += 32; 61 } 62 } 63 return n - 1; 64 } 65 66 /* Return whether bitmap is empty (1 == empty) */ 67 extern int xfs_bitmap_empty(uint *map, uint size); 68 69 /* Count continuous one bits in map starting with start_bit */ 70 extern int xfs_contig_bits(uint *map, uint size, uint start_bit); 71 72 /* Find next set bit in map */ 73 extern int xfs_next_bit(uint *map, uint size, uint start_bit); 74 75 #endif /* __XFS_BIT_H__ */ 76