| 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__ */ |