Implement Atomics API

src/runtime/runtime-utils.h

Index: src/runtime/runtime-utils.h
diff --git a/src/runtime/runtime-utils.h b/src/runtime/runtime-utils.h
index 3fe32975e678d4f2687ccc5fbf4c3ad6ad345728..4b072b1eb600f1f0998ff5ec291dae6c5821c7d5 100644
--- a/src/runtime/runtime-utils.h
+++ b/src/runtime/runtime-utils.h
@@ -55,6 +55,17 @@ namespace internal {
   RUNTIME_ASSERT(args[index]->IsNumber());      \
   double name = args.number_at(index);
 
+
+// Cast the given argument to a size_t and store its value in a variable with
+// the given name.  If the argument is not a size_t call IllegalOperation and
+// return.
+#define CONVERT_SIZE_ARG_CHECKED(name, index)            \
+  RUNTIME_ASSERT(args[index]->IsNumber());               \
+  Handle<Object> name##_object = args.at<Object>(index); \
+  size_t name = 0;                                       \
+  RUNTIME_ASSERT(TryNumberToSize(isolate, *name##_object, &name));
+
+
 // Call the specified converter on the object *comand store the result in
 // a variable of the specified type with the given name.  If the
 // object is not a Number call IllegalOperation and return.