| /* |
| * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code 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 GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP |
| #define SHARE_VM_RUNTIME_ATOMIC_HPP |
| |
| #include "memory/allocation.hpp" |
| |
| class Atomic : AllStatic { |
| public: |
| // Atomic operations on jlong types are not available on all 32-bit |
| // platforms. If atomic ops on jlongs are defined here they must only |
| // be used from code that verifies they are available at runtime and |
| // can provide an alternative action if not - see supports_cx8() for |
| // a means to test availability. |
| |
| // Atomically store to a location |
| inline static void store (jbyte store_value, jbyte* dest); |
| inline static void store (jshort store_value, jshort* dest); |
| inline static void store (jint store_value, jint* dest); |
| // See comment above about using jlong atomics on 32-bit platforms |
| inline static void store (jlong store_value, jlong* dest); |
| inline static void store_ptr(intptr_t store_value, intptr_t* dest); |
| inline static void store_ptr(void* store_value, void* dest); |
| |
| inline static void store (jbyte store_value, volatile jbyte* dest); |
| inline static void store (jshort store_value, volatile jshort* dest); |
| inline static void store (jint store_value, volatile jint* dest); |
| // See comment above about using jlong atomics on 32-bit platforms |
| inline static void store (jlong store_value, volatile jlong* dest); |
| inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest); |
| inline static void store_ptr(void* store_value, volatile void* dest); |
| |
| // See comment above about using jlong atomics on 32-bit platforms |
| inline static jlong load(volatile jlong* src); |
| |
| // Atomically add to a location, return updated value |
| inline static jint add (jint add_value, volatile jint* dest); |
| inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest); |
| inline static void* add_ptr(intptr_t add_value, volatile void* dest); |
| // See comment above about using jlong atomics on 32-bit platforms |
| static jlong add (jlong add_value, volatile jlong* dest); |
| |
| // Atomically increment location |
| inline static void inc (volatile jint* dest); |
| static void inc (volatile jshort* dest); |
| inline static void inc_ptr(volatile intptr_t* dest); |
| inline static void inc_ptr(volatile void* dest); |
| |
| // Atomically decrement a location |
| inline static void dec (volatile jint* dest); |
| static void dec (volatile jshort* dest); |
| inline static void dec_ptr(volatile intptr_t* dest); |
| inline static void dec_ptr(volatile void* dest); |
| |
| // Performs atomic exchange of *dest with exchange_value. Returns old prior value of *dest. |
| inline static jint xchg(jint exchange_value, volatile jint* dest); |
| static unsigned int xchg(unsigned int exchange_value, volatile unsigned int* dest); |
| |
| inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest); |
| inline static void* xchg_ptr(void* exchange_value, volatile void* dest); |
| |
| // Performs atomic compare of *dest and compare_value, and exchanges *dest with exchange_value |
| // if the comparison succeeded. Returns prior value of *dest. Guarantees a two-way memory |
| // barrier across the cmpxchg. I.e., it's really a 'fence_cmpxchg_acquire'. |
| static jbyte cmpxchg (jbyte exchange_value, volatile jbyte* dest, jbyte compare_value); |
| inline static jint cmpxchg (jint exchange_value, volatile jint* dest, jint compare_value); |
| // See comment above about using jlong atomics on 32-bit platforms |
| inline static jlong cmpxchg (jlong exchange_value, volatile jlong* dest, jlong compare_value); |
| |
| static unsigned int cmpxchg(unsigned int exchange_value, |
| volatile unsigned int* dest, |
| unsigned int compare_value); |
| |
| inline static intptr_t cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value); |
| inline static void* cmpxchg_ptr(void* exchange_value, volatile void* dest, void* compare_value); |
| }; |
| |
| // To use Atomic::inc(jshort* dest) and Atomic::dec(jshort* dest), the address must be specially |
| // aligned, such that (*dest) occupies the upper 16 bits of an aligned 32-bit word. The best way to |
| // achieve is to place your short value next to another short value, which doesn't need atomic ops. |
| // |
| // Example |
| // ATOMIC_SHORT_PAIR( |
| // volatile short _refcount, // needs atomic operation |
| // unsigned short _length // number of UTF8 characters in the symbol (does not need atomic op) |
| // ); |
| |
| #ifdef VM_LITTLE_ENDIAN |
| #define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \ |
| non_atomic_decl; \ |
| atomic_decl |
| #else |
| #define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \ |
| atomic_decl ; \ |
| non_atomic_decl |
| #endif |
| |
| #endif // SHARE_VM_RUNTIME_ATOMIC_HPP |