1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef prbit_h___
#define prbit_h___
#include "prtypes.h"
PR_BEGIN_EXTERN_C
/*
** Replace compare/jump/add/shift sequence with compiler built-in/intrinsic
** functions.
*/
#if defined(_WIN32) && (_MSC_VER >= 1300) && \
(defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM) || \
defined(_M_ARM64))
# include <intrin.h>
# pragma intrinsic(_BitScanForward,_BitScanReverse)
__forceinline static int __prBitScanForward32(unsigned int val)
{
unsigned long idx;
_BitScanForward(&idx, (unsigned long)val);
return( (int)idx );
}
__forceinline static int __prBitScanReverse32(unsigned int val)
{
unsigned long idx;
_BitScanReverse(&idx, (unsigned long)val);
return( (int)(31-idx) );
}
# define pr_bitscan_ctz32(val) __prBitScanForward32(val)
# define pr_bitscan_clz32(val) __prBitScanReverse32(val)
# define PR_HAVE_BUILTIN_BITSCAN32
#elif ((__GNUC__ >= 4) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) && \
(defined(__i386__) || defined(__x86_64__) || defined(__arm__) || \
defined(__aarch64__))
# define pr_bitscan_ctz32(val) __builtin_ctz(val)
# define pr_bitscan_clz32(val) __builtin_clz(val)
# define PR_HAVE_BUILTIN_BITSCAN32
#endif /* MSVC || GCC */
/*
** A prbitmap_t is a long integer that can be used for bitmaps
*/
typedef unsigned long prbitmap_t;
#define PR_TEST_BIT(_map,_bit) \
((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
#define PR_SET_BIT(_map,_bit) \
((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
#define PR_CLEAR_BIT(_map,_bit) \
((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (PR_BITS_PER_LONG-1))))
/*
** Compute the log of the least power of 2 greater than or equal to n
*/
NSPR_API(PRIntn) PR_CeilingLog2(PRUint32 i);
/*
** Compute the log of the greatest power of 2 less than or equal to n
*/
NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i);
/*
** Macro version of PR_CeilingLog2: Compute the log of the least power of
** 2 greater than or equal to _n. The result is returned in _log2.
*/
#ifdef PR_HAVE_BUILTIN_BITSCAN32
#define PR_CEILING_LOG2(_log2,_n) \
PR_BEGIN_MACRO \
PRUint32 j_ = (PRUint32)(_n); \
(_log2) = (j_ <= 1 ? 0 : 32 - pr_bitscan_clz32(j_ - 1)); \
PR_END_MACRO
#else
#define PR_CEILING_LOG2(_log2,_n) \
PR_BEGIN_MACRO \
PRUint32 j_ = (PRUint32)(_n); \
(_log2) = 0; \
if ((j_) & ((j_)-1)) \
(_log2) += 1; \
if ((j_) >> 16) \
(_log2) += 16, (j_) >>= 16; \
if ((j_) >> 8) \
(_log2) += 8, (j_) >>= 8; \
if ((j_) >> 4) \
(_log2) += 4, (j_) >>= 4; \
if ((j_) >> 2) \
(_log2) += 2, (j_) >>= 2; \
if ((j_) >> 1) \
(_log2) += 1; \
PR_END_MACRO
#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
/*
** Macro version of PR_FloorLog2: Compute the log of the greatest power of
** 2 less than or equal to _n. The result is returned in _log2.
**
** This is equivalent to finding the highest set bit in the word.
*/
#ifdef PR_HAVE_BUILTIN_BITSCAN32
#define PR_FLOOR_LOG2(_log2,_n) \
PR_BEGIN_MACRO \
PRUint32 j_ = (PRUint32)(_n); \
(_log2) = 31 - pr_bitscan_clz32((j_) | 1); \
PR_END_MACRO
#else
#define PR_FLOOR_LOG2(_log2,_n) \
PR_BEGIN_MACRO \
PRUint32 j_ = (PRUint32)(_n); \
(_log2) = 0; \
if ((j_) >> 16) \
(_log2) += 16, (j_) >>= 16; \
if ((j_) >> 8) \
(_log2) += 8, (j_) >>= 8; \
if ((j_) >> 4) \
(_log2) += 4, (j_) >>= 4; \
if ((j_) >> 2) \
(_log2) += 2, (j_) >>= 2; \
if ((j_) >> 1) \
(_log2) += 1; \
PR_END_MACRO
#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
/*
** Macros for rotate left and right. The argument 'a' must be an unsigned
** 32-bit integer type such as PRUint32.
**
** There is no rotate operation in the C Language, so the construct
** (a << 4) | (a >> 28) is frequently used instead. Most compilers convert
** this to a rotate instruction, but MSVC doesn't without a little help.
** To get MSVC to generate a rotate instruction, we have to use the _rotl
** or _rotr intrinsic and use a pragma to make it inline.
**
** Note: MSVC in VS2005 will do an inline rotate instruction on the above
** construct.
*/
#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \
defined(_M_X64) || defined(_M_ARM) || defined(_M_ARM64))
#include <stdlib.h>
#pragma intrinsic(_rotl, _rotr)
#define PR_ROTATE_LEFT32(a, bits) _rotl(a, bits)
#define PR_ROTATE_RIGHT32(a, bits) _rotr(a, bits)
#else
#define PR_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits))))
#define PR_ROTATE_RIGHT32(a, bits) (((a) >> (bits)) | ((a) << (32 - (bits))))
#endif
PR_END_EXTERN_C
#endif /* prbit_h___ */
|
