1 /* 2 * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc. 3 * All Rights Reserved. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 #ifndef __XFS_BIT_H__ 19 #define __XFS_BIT_H__ 20 21 /* 22 * XFS bit manipulation routines. 23 */ 24 25 /* 26 * masks with n high/low bits set, 64-bit values 27 */ 28 static inline uint64_t xfs_mask64hi(int n) 29 { 30 return (uint64_t)-1 << (64 - (n)); 31 } 32 static inline uint32_t xfs_mask32lo(int n) 33 { 34 return ((uint32_t)1 << (n)) - 1; 35 } 36 static inline uint64_t xfs_mask64lo(int n) 37 { 38 return ((uint64_t)1 << (n)) - 1; 39 } 40 41 /* Get high bit set out of 32-bit argument, -1 if none set */ 42 static inline int xfs_highbit32(uint32_t v) 43 { 44 return fls(v) - 1; 45 } 46 47 /* Get high bit set out of 64-bit argument, -1 if none set */ 48 static inline int xfs_highbit64(uint64_t v) 49 { 50 return fls64(v) - 1; 51 } 52 53 /* Get low bit set out of 32-bit argument, -1 if none set */ 54 static inline int xfs_lowbit32(uint32_t v) 55 { 56 return ffs(v) - 1; 57 } 58 59 /* Get low bit set out of 64-bit argument, -1 if none set */ 60 static inline int xfs_lowbit64(uint64_t v) 61 { 62 uint32_t w = (uint32_t)v; 63 int n = 0; 64 65 if (w) { /* lower bits */ 66 n = ffs(w); 67 } else { /* upper bits */ 68 w = (uint32_t)(v >> 32); 69 if (w) { 70 n = ffs(w); 71 if (n) 72 n += 32; 73 } 74 } 75 return n - 1; 76 } 77 78 /* Return whether bitmap is empty (1 == empty) */ 79 extern int xfs_bitmap_empty(uint *map, uint size); 80 81 /* Count continuous one bits in map starting with start_bit */ 82 extern int xfs_contig_bits(uint *map, uint size, uint start_bit); 83 84 /* Find next set bit in map */ 85 extern int xfs_next_bit(uint *map, uint size, uint start_bit); 86 87 #endif /* __XFS_BIT_H__ */ 88