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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/**
@file AtomicInt32.h
@maintainer Morgan McGuire, http://graphics.cs.williams.edu
@created 2005-09-01
@edited 2006-06-21
*/
#ifndef G3D_ATOMICINT32_H
#define G3D_ATOMICINT32_H
#include "G3D/platform.h"
#include "G3D/g3dmath.h"
#if defined(G3D_WINDOWS)
# include <Windows.h>
#elif defined(G3D_OSX)
# include <libkern/OSAtomic.h>
#endif
namespace G3D {
/**
An integer that may safely be used on different threads without
external locking.
On Win32, Linux, FreeBSD, and Mac OS X this is implemented without locks.
<B>BETA API</B> This is unsupported and may change
*/
class AtomicInt32 {
private:
# if defined(G3D_WINDOWS)
volatile long m_value;
# elif defined(G3D_OSX)
int32_t m_value;
# else
volatile int32 m_value;
# endif
public:
/** Initial value is undefined. */
AtomicInt32() {}
/** Atomic set */
explicit AtomicInt32(const int32 x) {
m_value = x;
}
/** Atomic set */
AtomicInt32(const AtomicInt32& x) {
m_value = x.m_value;
}
/** Atomic set */
const AtomicInt32& operator=(const int32 x) {
m_value = x;
return *this;
}
/** Atomic set */
void operator=(const AtomicInt32& x) {
m_value = x.m_value;
}
/** Returns the current value */
int32 value() const {
return m_value;
}
/** Returns the old value, before the add. */
int32 add(const int32 x) {
# if defined(G3D_WINDOWS)
return InterlockedExchangeAdd(&m_value, x);
# elif defined(G3D_LINUX) || defined(G3D_FREEBSD)
# if defined(__aarch64__)
return __sync_fetch_and_add(&m_value, x);
# else
int32 old;
asm volatile ("lock; xaddl %0,%1"
: "=r"(old), "=m"(m_value) /* outputs */
: "0"(x), "m"(m_value) /* inputs */
: "memory", "cc");
return old;
# endif
# elif defined(G3D_OSX)
int32 old = m_value;
OSAtomicAdd32(x, &m_value);
return old;
# endif
}
/** Returns old value. */
int32 sub(const int32 x) {
return add(-x);
}
void increment() {
# if defined(G3D_WINDOWS)
// Note: returns the newly incremented value
InterlockedIncrement(&m_value);
# elif defined(G3D_LINUX) || defined(G3D_FREEBSD)
add(1);
# elif defined(G3D_OSX)
// Note: returns the newly incremented value
OSAtomicIncrement32(&m_value);
# endif
}
/** Returns zero if the result is zero after decrement, non-zero otherwise.*/
int32 decrement() {
# if defined(G3D_WINDOWS)
// Note: returns the newly decremented value
return InterlockedDecrement(&m_value);
# elif defined(G3D_LINUX) || defined(G3D_FREEBSD)
# if defined(__aarch64__)
return __sync_sub_and_fetch(&m_value, 1);
# else
unsigned char nz;
asm volatile ("lock; decl %1;\n\t"
"setnz %%al"
: "=a" (nz)
: "m" (m_value)
: "memory", "cc");
return nz;
# endif
# elif defined(G3D_OSX)
// Note: returns the newly decremented value
return OSAtomicDecrement32(&m_value);
# endif
}
/** Atomic test-and-set: if <code>*this == comperand</code> then <code>*this := exchange</code> else do nothing.
In both cases, returns the old value of <code>*this</code>.
Performs an atomic comparison of this with the Comperand value.
If this is equal to the Comperand value, the Exchange value is stored in this.
Otherwise, no operation is performed.
Under VC6 the sign bit may be lost.
*/
int32 compareAndSet(const int32 comperand, const int32 exchange) {
# if defined(G3D_WINDOWS)
return InterlockedCompareExchange(&m_value, exchange, comperand);
# elif defined(G3D_LINUX) || defined(G3D_FREEBSD) || defined(G3D_OSX)
# if defined(__aarch64__)
return __sync_val_compare_and_swap(&m_value, comperand, exchange);
# else
// Based on Apache Portable Runtime
// http://koders.com/c/fid3B6631EE94542CDBAA03E822CA780CBA1B024822.aspx
int32 ret;
asm volatile ("lock; cmpxchgl %1, %2"
: "=a" (ret)
: "r" (exchange), "m" (m_value), "0"(comperand)
: "memory", "cc");
return ret;
// Note that OSAtomicCompareAndSwap32 does not return a useful value for us
// so it can't satisfy the cmpxchgl contract.
# endif
# endif
}
};
} // namespace
#endif
|
