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 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 /*
29 * Architecture specific definition for bitmap related routines.
30 * These may be implemented using ISA specific instructions.
31 */
32 #include <sys/bitmap.h>
33
34 /*
35 * Find highest one bit set.
36 * Returns bit number + 1 of highest bit that is set, otherwise returns 0.
37 * High order bit is 31 (or 63 in _LP64 kernel).
38 */
39 int
highbit(ulong_t i)40 highbit(ulong_t i)
41 {
42 register int h = 1;
43
44 if (i == 0)
45 return (0);
46 #ifdef _LP64
47 if (i & 0xffffffff00000000ul) {
48 h += 32; i >>= 32;
49 }
50 #endif
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 lowest one bit set.
71 * Returns bit number + 1 of lowest bit that is set, otherwise returns 0.
72 * Low order bit is 0.
73 */
74 int
lowbit(ulong_t i)75 lowbit(ulong_t i)
76 {
77 register int h = 1;
78
79 if (i == 0)
80 return (0);
81
82 #ifdef _LP64
83 if (!(i & 0xffffffff)) {
84 h += 32; i >>= 32;
85 }
86 #endif
87 if (!(i & 0xffff)) {
88 h += 16; i >>= 16;
89 }
90 if (!(i & 0xff)) {
91 h += 8; i >>= 8;
92 }
93 if (!(i & 0xf)) {
94 h += 4; i >>= 4;
95 }
96 if (!(i & 0x3)) {
97 h += 2; i >>= 2;
98 }
99 if (!(i & 0x1)) {
100 h += 1;
101 }
102 return (h);
103 }
104