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 */
16static inline uint64_t xfs_mask64hi(int n)
17{
18	return (uint64_t)-1 << (64 - (n));
19}
20static inline uint32_t xfs_mask32lo(int n)
21{
22	return ((uint32_t)1 << (n)) - 1;
23}
24static 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 */
30static 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 */
36static 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 */
42static 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 */
48static 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) */
67extern int xfs_bitmap_empty(uint *map, uint size);
68
69/* Count continuous one bits in map starting with start_bit */
70extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
71
72/* Find next set bit in map */
73extern int xfs_next_bit(uint *map, uint size, uint start_bit);
74
75#endif	/* __XFS_BIT_H__ */
76