| | 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 && (n = ffs(w))) |
| | 70 | n += 32; |
| | 71 | } |
| | 72 | return n - 1; |
| | 73 | } |
| | 74 | |
| | 75 | /* Return whether bitmap is empty (1 == empty) */ |
| | 76 | extern int xfs_bitmap_empty(uint *map, uint size); |
| | 77 | |
| | 78 | /* Count continuous one bits in map starting with start_bit */ |
| | 79 | extern int xfs_contig_bits(uint *map, uint size, uint start_bit); |
| | 80 | |
| | 81 | /* Find next set bit in map */ |
| | 82 | extern int xfs_next_bit(uint *map, uint size, uint start_bit); |
| | 83 | |
| | 84 | #endif /* __XFS_BIT_H__ */ |
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