1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Copyright (c) 2014 by Delphix. All rights reserved.
29 */
30
31 /*
32 * Architecture specific definition for bitmap related routines.
33 * These may be implemented using ISA specific instructions.
34 */
35 #include <sys/bitmap.h>
36
37 /*
38 * Find highest one bit set.
39 * Returns bit number + 1 of highest bit that is set, otherwise returns 0.
40 */
41 int
highbit64(uint64_t i)42 highbit64(uint64_t i)
43 {
44 int h = 1;
45
46 if (i == 0)
47 return (0);
48 if (i & 0xffffffff00000000ULL) {
49 h += 32; i >>= 32;
50 }
51 if (i & 0xffff0000) {
52 h += 16; i >>= 16;
53 }
54 if (i & 0xff00) {
55 h += 8; i >>= 8;
56 }
57 if (i & 0xf0) {
58 h += 4; i >>= 4;
59 }
60 if (i & 0xc) {
61 h += 2; i >>= 2;
62 }
63 if (i & 0x2) {
64 h += 1;
65 }
66 return (h);
67 }
68
69 /*
70 * Find highest one bit set.
71 * Returns bit number + 1 of highest bit that is set, otherwise returns 0.
72 * High order bit is 31 (or 63 in _LP64 kernel).
73 */
74 int
highbit(ulong_t i)75 highbit(ulong_t i)
76 {
77 register int h = 1;
78
79 if (i == 0)
80 return (0);
81 #ifdef _LP64
82 if (i & 0xffffffff00000000ul) {
83 h += 32; i >>= 32;
84 }
85 #endif
86 if (i & 0xffff0000) {
87 h += 16; i >>= 16;
88 }
89 if (i & 0xff00) {
90 h += 8; i >>= 8;
91 }
92 if (i & 0xf0) {
93 h += 4; i >>= 4;
94 }
95 if (i & 0xc) {
96 h += 2; i >>= 2;
97 }
98 if (i & 0x2) {
99 h += 1;
100 }
101 return (h);
102 }
103
104 /*
105 * Find lowest one bit set.
106 * Returns bit number + 1 of lowest bit that is set, otherwise returns 0.
107 * Low order bit is 0.
108 */
109 int
lowbit(ulong_t i)110 lowbit(ulong_t i)
111 {
112 register int h = 1;
113
114 if (i == 0)
115 return (0);
116
117 #ifdef _LP64
118 if (!(i & 0xffffffff)) {
119 h += 32; i >>= 32;
120 }
121 #endif
122 if (!(i & 0xffff)) {
123 h += 16; i >>= 16;
124 }
125 if (!(i & 0xff)) {
126 h += 8; i >>= 8;
127 }
128 if (!(i & 0xf)) {
129 h += 4; i >>= 4;
130 }
131 if (!(i & 0x3)) {
132 h += 2; i >>= 2;
133 }
134 if (!(i & 0x1)) {
135 h += 1;
136 }
137 return (h);
138 }
139