diff --git a/src/runtime/runtime-utils.h b/src/runtime/runtime-utils.h
new file mode 100644
index 0000000..95d75f5
--- /dev/null
+++ b/src/runtime/runtime-utils.h
@@ -0,0 +1,147 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_RUNTIME_RUNTIME_UTILS_H_
+#define V8_RUNTIME_RUNTIME_UTILS_H_
+
+
+namespace v8 {
+namespace internal {
+
+#define RUNTIME_ASSERT(value) \
+  if (!(value)) return isolate->ThrowIllegalOperation();
+
+#define RUNTIME_ASSERT_HANDLIFIED(value, T) \
+  if (!(value)) {                           \
+    isolate->ThrowIllegalOperation();       \
+    return MaybeHandle<T>();                \
+  }
+
+// Cast the given object to a value of the specified type and store
+// it in a variable with the given name.  If the object is not of the
+// expected type call IllegalOperation and return.
+#define CONVERT_ARG_CHECKED(Type, name, index) \
+  RUNTIME_ASSERT(args[index]->Is##Type());     \
+  Type* name = Type::cast(args[index]);
+
+#define CONVERT_ARG_HANDLE_CHECKED(Type, name, index) \
+  RUNTIME_ASSERT(args[index]->Is##Type());            \
+  Handle<Type> name = args.at<Type>(index);
+
+#define CONVERT_NUMBER_ARG_HANDLE_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsNumber());             \
+  Handle<Object> name = args.at<Object>(index);
+
+// Cast the given object to a boolean and store it in a variable with
+// the given name.  If the object is not a boolean call IllegalOperation
+// and return.
+#define CONVERT_BOOLEAN_ARG_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsBoolean());      \
+  bool name = args[index]->IsTrue();
+
+// Cast the given argument to a Smi and store its value in an int variable
+// with the given name.  If the argument is not a Smi call IllegalOperation
+// and return.
+#define CONVERT_SMI_ARG_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsSmi());      \
+  int name = args.smi_at(index);
+
+// Cast the given argument to a double and store it in a variable with
+// the given name.  If the argument is not a number (as opposed to
+// the number not-a-number) call IllegalOperation and return.
+#define CONVERT_DOUBLE_ARG_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsNumber());      \
+  double name = args.number_at(index);
+
+// 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.
+#define CONVERT_NUMBER_CHECKED(type, name, Type, obj) \
+  RUNTIME_ASSERT(obj->IsNumber());                    \
+  type name = NumberTo##Type(obj);
+
+
+// Cast the given argument to PropertyDetails and store its value in a
+// variable with the given name.  If the argument is not a Smi call
+// IllegalOperation and return.
+#define CONVERT_PROPERTY_DETAILS_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsSmi());               \
+  PropertyDetails name = PropertyDetails(Smi::cast(args[index]));
+
+
+// Assert that the given argument has a valid value for a StrictMode
+// and store it in a StrictMode variable with the given name.
+#define CONVERT_STRICT_MODE_ARG_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsSmi());              \
+  RUNTIME_ASSERT(args.smi_at(index) == STRICT ||     \
+                 args.smi_at(index) == SLOPPY);      \
+  StrictMode name = static_cast<StrictMode>(args.smi_at(index));
+
+
+// Assert that the given argument is a number within the Int32 range
+// and convert it to int32_t.  If the argument is not an Int32 call
+// IllegalOperation and return.
+#define CONVERT_INT32_ARG_CHECKED(name, index) \
+  RUNTIME_ASSERT(args[index]->IsNumber());     \
+  int32_t name = 0;                            \
+  RUNTIME_ASSERT(args[index]->ToInt32(&name));
+
+
+// A mechanism to return a pair of Object pointers in registers (if possible).
+// How this is achieved is calling convention-dependent.
+// All currently supported x86 compiles uses calling conventions that are cdecl
+// variants where a 64-bit value is returned in two 32-bit registers
+// (edx:eax on ia32, r1:r0 on ARM).
+// In AMD-64 calling convention a struct of two pointers is returned in rdx:rax.
+// In Win64 calling convention, a struct of two pointers is returned in memory,
+// allocated by the caller, and passed as a pointer in a hidden first parameter.
+#ifdef V8_HOST_ARCH_64_BIT
+struct ObjectPair {
+  Object* x;
+  Object* y;
+};
+
+
+static inline ObjectPair MakePair(Object* x, Object* y) {
+  ObjectPair result = {x, y};
+  // Pointers x and y returned in rax and rdx, in AMD-x64-abi.
+  // In Win64 they are assigned to a hidden first argument.
+  return result;
+}
+#elif V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_32_BIT
+// For x32 a 128-bit struct return is done as rax and rdx from the ObjectPair
+// are used in the full codegen and Crankshaft compiler. An alternative is
+// using uint64_t and modifying full codegen and Crankshaft compiler.
+struct ObjectPair {
+  Object* x;
+  uint32_t x_upper;
+  Object* y;
+  uint32_t y_upper;
+};
+
+
+static inline ObjectPair MakePair(Object* x, Object* y) {
+  ObjectPair result = {x, 0, y, 0};
+  // Pointers x and y returned in rax and rdx, in x32-abi.
+  return result;
+}
+#else
+typedef uint64_t ObjectPair;
+static inline ObjectPair MakePair(Object* x, Object* y) {
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+  return reinterpret_cast<uint32_t>(x) |
+         (reinterpret_cast<ObjectPair>(y) << 32);
+#elif defined(V8_TARGET_BIG_ENDIAN)
+  return reinterpret_cast<uint32_t>(y) |
+         (reinterpret_cast<ObjectPair>(x) << 32);
+#else
+#error Unknown endianness
+#endif
+}
+#endif
+
+}
+}  // namespace v8::internal
+
+#endif  // V8_RUNTIME_RUNTIME_UTILS_H_