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 */
xfs_mask64hi(int n)16 static inline uint64_t xfs_mask64hi(int n)
17 {
18 return (uint64_t)-1 << (64 - (n));
19 }
xfs_mask32lo(int n)20 static inline uint32_t xfs_mask32lo(int n)
21 {
22 return ((uint32_t)1 << (n)) - 1;
23 }
xfs_mask64lo(int n)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 */
xfs_highbit32(uint32_t v)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 */
xfs_highbit64(uint64_t v)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 */
xfs_lowbit32(uint32_t v)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 */
xfs_lowbit64(uint64_t v)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