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5291 x86 {high,low}bit rely on undefined behavior
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--- old/usr/src/uts/intel/asm/bitmap.h
+++ new/usr/src/uts/intel/asm/bitmap.h
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License, Version 1.0 only
6 6 * (the "License"). You may not use this file except in compliance
7 7 * with the License.
8 8 *
9 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 10 * or http://www.opensolaris.org/os/licensing.
11 11 * See the License for the specific language governing permissions
12 12 * and limitations under the License.
13 13 *
14 14 * When distributing Covered Code, include this CDDL HEADER in each
15 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 16 * If applicable, add the following below this CDDL HEADER, with the
17 17 * fields enclosed by brackets "[]" replaced with your own identifying
18 18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 19 *
20 20 * CDDL HEADER END
21 21 */
22 22 /*
23 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 24 * Use is subject to license terms.
25 25 * Copyright 2014 Nexenta Systems, Inc. All rights reserved.
26 26 */
27 27
28 28 #ifndef _ASM_BITMAP_H
29 29 #define _ASM_BITMAP_H
30 30
31 31 #include <sys/ccompile.h>
32 32 #include <sys/types.h>
33 33
34 34 #ifdef __cplusplus
35 35 extern "C" {
36 36 #endif
37 37
38 38 #if !defined(__lint) && defined(__GNUC__)
39 39
40 40 #if defined(__amd64)
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41 41 #define __SUF "q"
42 42 #elif defined(__i386)
43 43 #define __SUF "l"
44 44 #else
45 45 #error "port me"
46 46 #endif
47 47
48 48 extern __GNU_INLINE int
49 49 highbit(ulong_t i)
50 50 {
51 - long value = -1l;
51 + long value;
52 + uint8_t zf;
52 53
53 54 __asm__(
54 - "bsr" __SUF " %1,%0"
55 - : "+r" (value)
56 - : "r" (i)
55 + "bsr" __SUF " %2,%0;"
56 + "setz %1"
57 + : "=r" (value), "=q" (zf)
58 + : "mr" (i)
57 59 : "cc");
58 60
59 - return ((int)(value + 1));
61 + return (zf ? 0 : (value + 1));
60 62 }
61 63
62 64 extern __GNU_INLINE int
63 65 lowbit(ulong_t i)
64 66 {
65 - long value = -1l;
67 + long value;
68 + uint8_t zf;
66 69
67 70 __asm__(
68 - "bsf" __SUF " %1,%0"
69 - : "+r" (value)
70 - : "r" (i)
71 + "bsf" __SUF " %2,%0;"
72 + "setz %1"
73 + : "=r" (value), "=q" (zf)
74 + : "mr" (i)
71 75 : "cc");
72 76
73 - return ((int)(value + 1));
77 + return (zf ? 0 : (value + 1));
74 78 }
75 79
76 80 extern __GNU_INLINE uint_t
77 81 atomic_btr32(uint32_t *memory, uint_t bitnum)
78 82 {
79 83 uint8_t value;
80 84
81 85 __asm__ __volatile__(
82 86 "lock;"
83 87 "btrl %2,%0;"
84 88 "setc %1"
85 89 : "+m" (*memory), "=r" (value)
86 90 : "ir" (bitnum)
87 91 : "cc");
88 92
89 93 return ((uint_t)value);
90 94 }
91 95
92 96 #undef __SUF
93 97
94 98 #endif /* !__lint && __GNUC__ */
95 99
96 100 #ifdef __cplusplus
97 101 }
98 102 #endif
99 103
100 104 #endif /* _ASM_BITMAP_H */
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