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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, 32-bit values & 64-bit values
27 */
28 #define XFS_MASK32HI(n) xfs_mask32hi(n)
29 static inline __uint32_t xfs_mask32hi(int n)
30 {
31 return (__uint32_t)-1 << (32 - (n));
32 }
33 #define XFS_MASK64HI(n) xfs_mask64hi(n)
34 static inline __uint64_t xfs_mask64hi(int n)
35 {
36 return (__uint64_t)-1 << (64 - (n));
37 }
38 #define XFS_MASK32LO(n) xfs_mask32lo(n)
39 static inline __uint32_t xfs_mask32lo(int n)
40 {
41 return ((__uint32_t)1 << (n)) - 1;
42 }
43 #define XFS_MASK64LO(n) xfs_mask64lo(n)
44 static inline __uint64_t xfs_mask64lo(int n)
45 {
46 return ((__uint64_t)1 << (n)) - 1;
47 }
48
49 /* Get high bit set out of 32-bit argument, -1 if none set */
50 static inline int xfs_highbit32(__uint32_t v)
51 {
52 return fls(v) - 1;
53 }
54
55 /* Get high bit set out of 64-bit argument, -1 if none set */
56 static inline int xfs_highbit64(__uint64_t v)
57 {
58 return fls64(v) - 1;
59 }
60
61 /* Get low bit set out of 32-bit argument, -1 if none set */
62 static inline int xfs_lowbit32(__uint32_t v)
63 {
64 unsigned long t = v;
65 return (v) ? find_first_bit(&t, 32) : -1;
66 }
67
68 /* Get low bit set out of 64-bit argument, -1 if none set */
69 static inline int xfs_lowbit64(__uint64_t v)
70 {
71 __uint32_t w = (__uint32_t)v;
72 int n = 0;
73
74 if (w) { /* lower bits */
75 n = ffs(w);
76 } else { /* upper bits */
77 w = (__uint32_t)(v >> 32);
78 if (w && (n = ffs(w)))
79 n += 32;
80 }
81 return n - 1;
82 }
83
84 /* Return whether bitmap is empty (1 == empty) */
85 extern int xfs_bitmap_empty(uint *map, uint size);
86
87 /* Count continuous one bits in map starting with start_bit */
88 extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
89
90 /* Find next set bit in map */
91 extern int xfs_next_bit(uint *map, uint size, uint start_bit);
92
93 #endif /* __XFS_BIT_H__ */