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 | |