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