1 files changed, 36 insertions, 0 deletions
diff --git a/include/ports/SkBarriers_arm.h b/include/ports/SkBarriers_arm.h
new file mode 100644
index 0000000000..386294e9b1
--- /dev/null
+++ b/include/ports/SkBarriers_arm.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBarriers_arm_DEFINED
+#define SkBarriers_arm_DEFINED
+
+static inline void sk_compiler_barrier() { asm volatile("" : : : "memory"); }
+
+template <typename T>
+T sk_acquire_load(T* ptr) {
+    T val = *ptr;
+    __sync_synchronize();  // Issue a full barrier, which is an overkill acquire barrier.
+    return val;
+}
+
+template <typename T>
+T sk_consume_load(T* ptr) {
+    T val = *ptr;
+    // Unlike acquire, consume loads (data-dependent loads) are guaranteed not to reorder on ARM.
+    // No memory barrier is needed, so we just use a compiler barrier.
+    // C.f. http://preshing.com/20140709/the-purpose-of-memory_order_consume-in-cpp11/
+    sk_compiler_barrier();
+    return val;
+}
+
+template <typename T>
+void sk_release_store(T* ptr, T val) {
+    __sync_synchronize();  // Issue a full barrier, which is an overkill release barrier.
+    *ptr = val;
+}
+
+#endif//SkBarriers_x86_DEFINED