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