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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 0 : 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 0 : 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 0 : 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 0 : 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 : assembly 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 0 : 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 0 : 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 0 : 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 is not empty
193 : */
194 0 : NSPR_API(PRStatus) PR_DestroyStack(PRStack *stack);
195 :
196 : PR_END_EXTERN_C
197 :
198 : #endif /* pratom_h___ */
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