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comparison: src/share/vm/runtime/atomic.hpp
src/share/vm/runtime/atomic.hpp
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| 1 /* | |
| 2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. | |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 20 * or visit www.oracle.com if you need additional information or have any | |
| 21 * questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP | |
| 26 #define SHARE_VM_RUNTIME_ATOMIC_HPP | |
| 27 | |
| 28 #include "memory/allocation.hpp" | |
| 29 | |
| 30 class Atomic : AllStatic { | |
| 31 public: | |
| 32 // Atomic operations on jlong types are not available on all 32-bit | |
| 33 // platforms. If atomic ops on jlongs are defined here they must only | |
| 34 // be used from code that verifies they are available at runtime and | |
| 35 // can provide an alternative action if not - see supports_cx8() for | |
| 36 // a means to test availability. | |
| 37 | |
| 38 // Atomically store to a location | |
| 39 inline static void store (jbyte store_value, jbyte* dest); | |
| 40 inline static void store (jshort store_value, jshort* dest); | |
| 41 inline static void store (jint store_value, jint* dest); | |
| 42 // See comment above about using jlong atomics on 32-bit platforms | |
| 43 inline static void store (jlong store_value, jlong* dest); | |
| 44 inline static void store_ptr(intptr_t store_value, intptr_t* dest); | |
| 45 inline static void store_ptr(void* store_value, void* dest); | |
| 46 | |
| 47 inline static void store (jbyte store_value, volatile jbyte* dest); | |
| 48 inline static void store (jshort store_value, volatile jshort* dest); | |
| 49 inline static void store (jint store_value, volatile jint* dest); | |
| 50 // See comment above about using jlong atomics on 32-bit platforms | |
| 51 inline static void store (jlong store_value, volatile jlong* dest); | |
| 52 inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest); | |
| 53 inline static void store_ptr(void* store_value, volatile void* dest); | |
| 54 | |
| 55 // See comment above about using jlong atomics on 32-bit platforms | |
| 56 inline static jlong load(volatile jlong* src); | |
| 57 | |
| 58 // Atomically add to a location, return updated value | |
| 59 inline static jint add (jint add_value, volatile jint* dest); | |
| 60 inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest); | |
| 61 inline static void* add_ptr(intptr_t add_value, volatile void* dest); | |
| 62 // See comment above about using jlong atomics on 32-bit platforms | |
| 63 static jlong add (jlong add_value, volatile jlong* dest); | |
| 64 | |
| 65 // Atomically increment location | |
| 66 inline static void inc (volatile jint* dest); | |
| 67 static void inc (volatile jshort* dest); | |
| 68 inline static void inc_ptr(volatile intptr_t* dest); | |
| 69 inline static void inc_ptr(volatile void* dest); | |
| 70 | |
| 71 // Atomically decrement a location | |
| 72 inline static void dec (volatile jint* dest); | |
| 73 static void dec (volatile jshort* dest); | |
| 74 inline static void dec_ptr(volatile intptr_t* dest); | |
| 75 inline static void dec_ptr(volatile void* dest); | |
| 76 | |
| 77 // Performs atomic exchange of *dest with exchange_value. Returns old prior value of *dest. | |
| 78 inline static jint xchg(jint exchange_value, volatile jint* dest); | |
| 79 static unsigned int xchg(unsigned int exchange_value, volatile unsigned int* dest); | |
| 80 | |
| 81 inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest); | |
| 82 inline static void* xchg_ptr(void* exchange_value, volatile void* dest); | |
| 83 | |
| 84 // Performs atomic compare of *dest and compare_value, and exchanges *dest with exchange_value | |
| 85 // if the comparison succeeded. Returns prior value of *dest. Guarantees a two-way memory | |
| 86 // barrier across the cmpxchg. I.e., it's really a 'fence_cmpxchg_acquire'. | |
| 87 static jbyte cmpxchg (jbyte exchange_value, volatile jbyte* dest, jbyte compare_value); | |
| 88 inline static jint cmpxchg (jint exchange_value, volatile jint* dest, jint compare_value); | |
| 89 // See comment above about using jlong atomics on 32-bit platforms | |
| 90 inline static jlong cmpxchg (jlong exchange_value, volatile jlong* dest, jlong compare_value); | |
| 91 | |
| 92 static unsigned int cmpxchg(unsigned int exchange_value, | |
| 93 volatile unsigned int* dest, | |
| 94 unsigned int compare_value); | |
| 95 | |
| 96 inline static intptr_t cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value); | |
| 97 inline static void* cmpxchg_ptr(void* exchange_value, volatile void* dest, void* compare_value); | |
| 98 }; | |
| 99 | |
| 100 // To use Atomic::inc(jshort* dest) and Atomic::dec(jshort* dest), the address must be specially | |
| 101 // aligned, such that (*dest) occupies the upper 16 bits of an aligned 32-bit word. The best way to | |
| 102 // achieve is to place your short value next to another short value, which doesn't need atomic ops. | |
| 103 // | |
| 104 // Example | |
| 105 // ATOMIC_SHORT_PAIR( | |
| 106 // volatile short _refcount, // needs atomic operation | |
| 107 // unsigned short _length // number of UTF8 characters in the symbol (does not need atomic op) | |
| 108 // ); | |
| 109 | |
| 110 #ifdef VM_LITTLE_ENDIAN | |
| 111 #define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \ | |
| 112 non_atomic_decl; \ | |
| 113 atomic_decl | |
| 114 #else | |
| 115 #define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \ | |
| 116 atomic_decl ; \ | |
| 117 non_atomic_decl | |
| 118 #endif | |
| 119 | |
| 120 #endif // SHARE_VM_RUNTIME_ATOMIC_HPP |
