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
179
180
181
182
183
184
185
186
187
188
189
|
/*
Copyright (c) 2007-2009 FastMQ Inc.
This file is part of 0MQ.
0MQ is free software; you can redistribute it and/or modify it under
the terms of the Lesser GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
0MQ is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Lesser GNU General Public License for more details.
You should have received a copy of the Lesser GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ZS_ATOMIC_PTR_HPP_INCLUDED__
#define __ZS_ATOMIC_PTR_HPP_INCLUDED__
#include "platform.hpp"
#if defined ZS_FORCE_MUTEXES
#define ZS_ATOMIC_PTR_MUTEX
#elif (defined __i386__ || defined __x86_64__) && defined __GNUC__
#define ZS_ATOMIC_PTR_X86
#elif 0 && defined __sparc__ && defined __GNUC__
#define ZS_ATOMIC_PTR_SPARC
#elif defined ZS_HAVE_WINDOWS
#define ZS_ATOMIC_PTR_WINDOWS
#elif defined ZS_HAVE_SOLARIS
#define ZS_ATOMIC_PTR_SOLARIS
#else
#define ZS_ATOMIC_PTR_MUTEX
#endif
#if defined ZS_ATOMIC_PTR_MUTEX
#include "mutex.hpp"
#elif defined ZS_ATOMIC_PTR_WINDOWS
#include "windows.hpp"
#elif defined ZS_ATOMIC_PTR_SOLARIS
#include <atomic.h>
#endif
namespace zs
{
// This class encapsulates several atomic operations on pointers.
template <typename T> class atomic_ptr_t
{
public:
// Initialise atomic pointer
inline atomic_ptr_t ()
{
ptr = NULL;
}
// Destroy atomic pointer
inline ~atomic_ptr_t ()
{
}
// Set value of atomic pointer in a non-threadsafe way
// Use this function only when you are sure that at most one
// thread is accessing the pointer at the moment.
inline void set (T *ptr_)
{
this->ptr = ptr_;
}
// Perform atomic 'exchange pointers' operation. Pointer is set
// to the 'val' value. Old value is returned.
inline T *xchg (T *val_)
{
#if defined ZS_ATOMIC_PTR_WINDOWS
return (T*) InterlockedExchangePointer (&ptr, val_);
#elif defined ZS_ATOMIC_PTR_SOLARIS
return (T*) atomic_swap_ptr (&ptr, val_);
#elif defined ZS_ATOMIC_PTR_X86
T *old;
__asm__ volatile (
"lock; xchg %0, %2"
: "=r" (old), "=m" (ptr)
: "m" (ptr), "0" (val_));
return old;
#elif defined ZS_ATOMIC_PTR_SPARC
T* newptr = val_;
volatile T** ptrin = &ptr;
T* tmp;
T* prev;
__asm__ __volatile__(
"ld [%4], %1\n\t"
"1:\n\t"
"mov %0, %2\n\t"
"cas [%4], %1, %2\n\t"
"cmp %1, %2\n\t"
"bne,a,pn %%icc, 1b\n\t"
"mov %2, %1\n\t"
: "+r" (newptr), "=&r" (tmp), "=&r" (prev), "+m" (*ptrin)
: "r" (ptrin)
: "cc");
return prev;
#elif defined ZS_ATOMIC_PTR_MUTEX
sync.lock ();
T *old = (T*) ptr;
ptr = val_;
sync.unlock ();
return old;
#else
#error
#endif
}
// Perform atomic 'compare and swap' operation on the pointer.
// The pointer is compared to 'cmp' argument and if they are
// equal, its value is set to 'val'. Old value of the pointer
// is returned.
inline T *cas (T *cmp_, T *val_)
{
#if defined ZS_ATOMIC_PTR_WINDOWS
return (T*) InterlockedCompareExchangePointer (
(volatile PVOID*) &ptr, val_, cmp_);
#elif defined ZS_ATOMIC_PTR_SOLARIS
return (T*) atomic_cas_ptr (&ptr, cmp_, val_);
#elif defined ZS_ATOMIC_PTR_X86
T *old;
__asm__ volatile (
"lock; cmpxchg %2, %3"
: "=a" (old), "=m" (ptr)
: "r" (val_), "m" (ptr), "0" (cmp_)
: "cc");
return old;
#elif defined ZS_ATOMIC_PTR_SPARC
volatile T** ptrin = &ptr;
volatile T* prev = ptr;
__asm__ __volatile__(
"cas [%3], %1, %2\n\t"
: "+m" (*ptrin)
: "r" (cmp_), "r" (val_), "r" (ptrin)
: "cc");
return prev;
#elif defined ZS_ATOMIC_PTR_MUTEX
sync.lock ();
T *old = (T*) ptr;
if (ptr == cmp_)
ptr = val_;
sync.unlock ();
return old;
#else
#error
#endif
}
private:
volatile T *ptr;
#if defined ZS_ATOMIC_PTR_MUTEX
mutex_t sync;
#endif
atomic_ptr_t (const atomic_ptr_t&);
void operator = (const atomic_ptr_t&);
};
}
// Remove macros local to this file.
#if defined ZS_ATOMIC_PTR_WINDOWS
#undef ZS_ATOMIC_PTR_WINDOWS
#endif
#if defined ZS_ATOMIC_PTR_SOLARIS
#undef ZS_ATOMIC_PTR_SOLARIS
#endif
#if defined ZS_ATOMIC_PTR_X86
#undef ZS_ATOMIC_PTR_X86
#endif
#if defined ZS_ATOMIC_PTR_SPARC
#undef ZS_ATOMIC_PTR_SPARC
#endif
#if defined ZS_ATOMIC_PTR_MUTEX
#undef ZS_ATOMIC_PTR_MUTEX
#endif
#endif
|
