1/*
2 * Copyright 2014 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkBarriers_arm_DEFINED
9#define SkBarriers_arm_DEFINED
10
11static inline void sk_compiler_barrier() { asm volatile("" : : : "memory"); }
12
13template <typename T>
14T sk_acquire_load(T* ptr) {
15    T val = *ptr;
16    __sync_synchronize();  // Issue a full barrier, which is an overkill acquire barrier.
17    return val;
18}
19
20template <typename T>
21T sk_consume_load(T* ptr) {
22    T val = *ptr;
23    // Unlike acquire, consume loads (data-dependent loads) are guaranteed not to reorder on ARM.
24    // No memory barrier is needed, so we just use a compiler barrier.
25    // C.f. http://preshing.com/20140709/the-purpose-of-memory_order_consume-in-cpp11/
26    sk_compiler_barrier();
27    return val;
28}
29
30template <typename T>
31void sk_release_store(T* ptr, T val) {
32    __sync_synchronize();  // Issue a full barrier, which is an overkill release barrier.
33    *ptr = val;
34}
35
36#endif//SkBarriers_x86_DEFINED
37