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1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
5 | |
6 /* GLOBAL FUNCTIONS: | |
7 ** DESCRIPTION: | |
8 ** PR Atomic operations | |
9 */ | |
10 | |
11 #ifndef pratom_h___ | |
12 #define pratom_h___ | |
13 | |
14 #include "prtypes.h" | |
15 #include "prlock.h" | |
16 | |
17 PR_BEGIN_EXTERN_C | |
18 | |
19 /* | |
20 ** FUNCTION: PR_AtomicIncrement | |
21 ** DESCRIPTION: | |
22 ** Atomically increment a 32 bit value. | |
23 ** INPUTS: | |
24 ** val: a pointer to the value to increment | |
25 ** RETURN: | |
26 ** the returned value is the result of the increment | |
27 */ | |
28 NSPR_API(PRInt32) PR_AtomicIncrement(PRInt32 *val); | |
29 | |
30 /* | |
31 ** FUNCTION: PR_AtomicDecrement | |
32 ** DESCRIPTION: | |
33 ** Atomically decrement a 32 bit value. | |
34 ** INPUTS: | |
35 ** val: a pointer to the value to decrement | |
36 ** RETURN: | |
37 ** the returned value is the result of the decrement | |
38 */ | |
39 NSPR_API(PRInt32) PR_AtomicDecrement(PRInt32 *val); | |
40 | |
41 /* | |
42 ** FUNCTION: PR_AtomicSet | |
43 ** DESCRIPTION: | |
44 ** Atomically set a 32 bit value. | |
45 ** INPUTS: | |
46 ** val: A pointer to a 32 bit value to be set | |
47 ** newval: The newvalue to assign to val | |
48 ** RETURN: | |
49 ** Returns the prior value | |
50 */ | |
51 NSPR_API(PRInt32) PR_AtomicSet(PRInt32 *val, PRInt32 newval); | |
52 | |
53 /* | |
54 ** FUNCTION: PR_AtomicAdd | |
55 ** DESCRIPTION: | |
56 ** Atomically add a 32 bit value. | |
57 ** INPUTS: | |
58 ** ptr: a pointer to the value to increment | |
59 ** val: value to be added | |
60 ** RETURN: | |
61 ** the returned value is the result of the addition | |
62 */ | |
63 NSPR_API(PRInt32) PR_AtomicAdd(PRInt32 *ptr, PRInt32 val); | |
64 | |
65 /* | |
66 ** MACRO: PR_ATOMIC_INCREMENT | |
67 ** MACRO: PR_ATOMIC_DECREMENT | |
68 ** MACRO: PR_ATOMIC_SET | |
69 ** MACRO: PR_ATOMIC_ADD | |
70 ** DESCRIPTION: | |
71 ** Macro versions of the atomic operations. They may be implemented | |
72 ** as compiler intrinsics. | |
73 ** | |
74 ** IMPORTANT NOTE TO NSPR MAINTAINERS: | |
75 ** Implement these macros with compiler intrinsics only on platforms | |
76 ** where the PR_AtomicXXX functions are truly atomic (i.e., where the | |
77 ** configuration macro _PR_HAVE_ATOMIC_OPS is defined). Otherwise, | |
78 ** the macros and functions won't be compatible and can't be used | |
79 ** interchangeably. | |
80 */ | |
81 #if defined(_WIN32) && !defined(_WIN32_WCE) && \ | |
82 (!defined(_MSC_VER) || (_MSC_VER >= 1310)) | |
83 | |
84 #include <intrin.h> | |
85 | |
86 #ifdef _MSC_VER | |
87 #pragma intrinsic(_InterlockedIncrement) | |
88 #pragma intrinsic(_InterlockedDecrement) | |
89 #pragma intrinsic(_InterlockedExchange) | |
90 #pragma intrinsic(_InterlockedExchangeAdd) | |
91 #endif | |
92 | |
93 #define PR_ATOMIC_INCREMENT(val) _InterlockedIncrement((long volatile *)(val)) | |
94 #define PR_ATOMIC_DECREMENT(val) _InterlockedDecrement((long volatile *)(val)) | |
95 #define PR_ATOMIC_SET(val, newval) \ | |
96 _InterlockedExchange((long volatile *)(val), (long)(newval)) | |
97 #define PR_ATOMIC_ADD(ptr, val) \ | |
98 (_InterlockedExchangeAdd((long volatile *)(ptr), (long)(val)) + (val)) | |
99 | |
100 #elif ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) && \ | |
101 ((defined(__APPLE__) && \ | |
102 (defined(__ppc__) || defined(__i386__) || defined(__x86_64__))) || \ | |
103 (defined(__linux__) && \ | |
104 ((defined(__i386__) && \ | |
105 defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \ | |
106 defined(__ia64__) || defined(__x86_64__) || \ | |
107 defined(__powerpc__) || \ | |
108 (defined(__arm__) && \ | |
109 defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \ | |
110 defined(__aarch64__) || defined(__alpha) || \ | |
111 (defined(__mips__) && \ | |
112 defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))))) | |
113 | |
114 /* | |
115 * Because the GCC manual warns that some processors may support | |
116 * reduced functionality of __sync_lock_test_and_set, we test for the | |
117 * processors that we believe support a full atomic exchange operation. | |
118 */ | |
119 | |
120 #define PR_ATOMIC_INCREMENT(val) __sync_add_and_fetch(val, 1) | |
121 #define PR_ATOMIC_DECREMENT(val) __sync_sub_and_fetch(val, 1) | |
122 #define PR_ATOMIC_SET(val, newval) __sync_lock_test_and_set(val, newval) | |
123 #define PR_ATOMIC_ADD(ptr, val) __sync_add_and_fetch(ptr, val) | |
124 | |
125 #else | |
126 | |
127 #define PR_ATOMIC_INCREMENT(val) PR_AtomicIncrement(val) | |
128 #define PR_ATOMIC_DECREMENT(val) PR_AtomicDecrement(val) | |
129 #define PR_ATOMIC_SET(val, newval) PR_AtomicSet(val, newval) | |
130 #define PR_ATOMIC_ADD(ptr, val) PR_AtomicAdd(ptr, val) | |
131 | |
132 #endif | |
133 | |
134 /* | |
135 ** LIFO linked-list (stack) | |
136 */ | |
137 typedef struct PRStackElemStr PRStackElem; | |
138 | |
139 struct PRStackElemStr { | |
140 PRStackElem *prstk_elem_next; /* next pointer MUST be at offset 0; | |
141 assemb
ly language code relies on this */ | |
142 }; | |
143 | |
144 typedef struct PRStackStr PRStack; | |
145 | |
146 /* | |
147 ** FUNCTION: PR_CreateStack | |
148 ** DESCRIPTION: | |
149 ** Create a stack, a LIFO linked list | |
150 ** INPUTS: | |
151 ** stack_name: a pointer to string containing the name of the stack | |
152 ** RETURN: | |
153 ** A pointer to the created stack, if successful, else NULL. | |
154 */ | |
155 NSPR_API(PRStack *) PR_CreateStack(const char *stack_name); | |
156 | |
157 /* | |
158 ** FUNCTION: PR_StackPush | |
159 ** DESCRIPTION: | |
160 ** Push an element on the top of the stack | |
161 ** INPUTS: | |
162 ** stack: pointer to the stack | |
163 ** stack_elem: pointer to the stack element | |
164 ** RETURN: | |
165 ** None | |
166 */ | |
167 NSPR_API(void) PR_StackPush(PRStack *stack, PRStackElem *stack_
elem); | |
168 | |
169 /* | |
170 ** FUNCTION: PR_StackPop | |
171 ** DESCRIPTION: | |
172 ** Remove the element on the top of the stack | |
173 ** INPUTS: | |
174 ** stack: pointer to the stack | |
175 ** RETURN: | |
176 ** A pointer to the stack element removed from the top of the stack, | |
177 ** if non-empty, | |
178 ** else NULL | |
179 */ | |
180 NSPR_API(PRStackElem *) PR_StackPop(PRStack *stack); | |
181 | |
182 /* | |
183 ** FUNCTION: PR_DestroyStack | |
184 ** DESCRIPTION: | |
185 ** Destroy the stack | |
186 ** INPUTS: | |
187 ** stack: pointer to the stack | |
188 ** RETURN: | |
189 ** PR_SUCCESS - if successfully deleted | |
190 ** PR_FAILURE - if the stack is not empty | |
191 ** PR_GetError will return | |
192 ** PR_INVALID_STATE_ERROR - stack i
s not empty | |
193 */ | |
194 NSPR_API(PRStatus) PR_DestroyStack(PRStack *stack); | |
195 | |
196 PR_END_EXTERN_C | |
197 | |
198 #endif /* pratom_h___ */ | |
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