S390: Initial impl of S390 asm, masm, code-stubs,...

src/s390/interface-descriptors-s390.cc

-// Copyright 2014 the V8 project authors. All rights reserved.
+// Copyright 2015 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.
 
-#if V8_TARGET_ARCH_PPC
+#if V8_TARGET_ARCH_S390
 
 #include "src/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
 
 const Register CallInterfaceDescriptor::ContextRegister() { return cp; }
 
-
-const Register LoadDescriptor::ReceiverRegister() { return r4; }
-const Register LoadDescriptor::NameRegister() { return r5; }
-const Register LoadDescriptor::SlotRegister() { return r3; }
-
-
-const Register LoadWithVectorDescriptor::VectorRegister() { return r6; }
-
-
-const Register StoreDescriptor::ReceiverRegister() { return r4; }
-const Register StoreDescriptor::NameRegister() { return r5; }
-const Register StoreDescriptor::ValueRegister() { return r3; }
-
-
-const Register VectorStoreICTrampolineDescriptor::SlotRegister() { return r7; }
-
-
-const Register VectorStoreICDescriptor::VectorRegister() { return r6; }
-
-
-const Register VectorStoreTransitionDescriptor::SlotRegister() { return r7; }
-const Register VectorStoreTransitionDescriptor::VectorRegister() { return r6; }
-const Register VectorStoreTransitionDescriptor::MapRegister() { return r8; }
-
-
-const Register StoreTransitionDescriptor::MapRegister() { return r6; }
-
-
-const Register LoadGlobalViaContextDescriptor::SlotRegister() { return r5; }
-
-
-const Register StoreGlobalViaContextDescriptor::SlotRegister() { return r5; }
-const Register StoreGlobalViaContextDescriptor::ValueRegister() { return r3; }
-
-
-const Register InstanceOfDescriptor::LeftRegister() { return r4; }
-const Register InstanceOfDescriptor::RightRegister() { return r3; }
-
-
-const Register StringCompareDescriptor::LeftRegister() { return r4; }
-const Register StringCompareDescriptor::RightRegister() { return r3; }
-
-
-const Register ApiGetterDescriptor::function_address() { return r5; }
-
-
-const Register MathPowTaggedDescriptor::exponent() { return r5; }
-
+const Register LoadDescriptor::ReceiverRegister() { return r3; }
+const Register LoadDescriptor::NameRegister() { return r4; }
+const Register LoadDescriptor::SlotRegister() { return r2; }
+
+const Register LoadWithVectorDescriptor::VectorRegister() { return r5; }
+
+const Register StoreDescriptor::ReceiverRegister() { return r3; }
+const Register StoreDescriptor::NameRegister() { return r4; }
+const Register StoreDescriptor::ValueRegister() { return r2; }
+
+const Register VectorStoreICTrampolineDescriptor::SlotRegister() { return r6; }
+
+const Register VectorStoreICDescriptor::VectorRegister() { return r5; }
+
+const Register VectorStoreTransitionDescriptor::SlotRegister() { return r6; }
+const Register VectorStoreTransitionDescriptor::VectorRegister() { return r5; }
+const Register VectorStoreTransitionDescriptor::MapRegister() { return r7; }
+
+const Register StoreTransitionDescriptor::MapRegister() { return r5; }
+
+const Register LoadGlobalViaContextDescriptor::SlotRegister() { return r4; }
+
+const Register StoreGlobalViaContextDescriptor::SlotRegister() { return r4; }
+const Register StoreGlobalViaContextDescriptor::ValueRegister() { return r2; }
+
+const Register InstanceOfDescriptor::LeftRegister() { return r3; }
+const Register InstanceOfDescriptor::RightRegister() { return r2; }
+
+const Register StringCompareDescriptor::LeftRegister() { return r3; }
+const Register StringCompareDescriptor::RightRegister() { return r2; }
+
+const Register ApiGetterDescriptor::function_address() { return r4; }
+
+const Register MathPowTaggedDescriptor::exponent() { return r4; }
 
 const Register MathPowIntegerDescriptor::exponent() {
   return MathPowTaggedDescriptor::exponent();
 }
 
-
-const Register GrowArrayElementsDescriptor::ObjectRegister() { return r3; }
-const Register GrowArrayElementsDescriptor::KeyRegister() { return r6; }
-
+const Register GrowArrayElementsDescriptor::ObjectRegister() { return r2; }
+const Register GrowArrayElementsDescriptor::KeyRegister() { return r5; }
 
 void FastNewClosureDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
+  Register registers[] = {r4};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void FastNewContextDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void FastNewObjectDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r3, r5};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void FastNewRestParameterDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void FastNewSloppyArgumentsDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void FastNewStrictArgumentsDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void ToNumberDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+// static
+const Register ToLengthDescriptor::ReceiverRegister() { return r2; }
+
+// static
+const Register ToStringDescriptor::ReceiverRegister() { return r2; }
+
+// static
+const Register ToNameDescriptor::ReceiverRegister() { return r2; }
+
+// static
+const Register ToObjectDescriptor::ReceiverRegister() { return r2; }
+
+void NumberToStringDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void TypeofDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
   Register registers[] = {r5};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
-
-void FastNewContextDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-void FastNewObjectDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r6};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-void FastNewRestParameterDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-void FastNewSloppyArgumentsDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-void FastNewStrictArgumentsDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-void ToNumberDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-
-// static
-const Register ToLengthDescriptor::ReceiverRegister() { return r3; }
-
-
-// static
-const Register ToStringDescriptor::ReceiverRegister() { return r3; }
-
-
-// static
-const Register ToNameDescriptor::ReceiverRegister() { return r3; }
-
-
-// static
-const Register ToObjectDescriptor::ReceiverRegister() { return r3; }
-
-
-void NumberToStringDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-
-void TypeofDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r6};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-
 void FastCloneRegExpDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r6, r5, r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r5, r4, r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void FastCloneShallowArrayDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r6, r5, r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r5, r4, r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void FastCloneShallowObjectDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r6, r5, r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r5, r4, r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CreateAllocationSiteDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r5, r6};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r4, r5};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CreateWeakCellDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r5, r6, r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r4, r5, r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallFunctionDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallFunctionWithFeedbackDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r6};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r5};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallFunctionWithFeedbackAndVectorDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r6, r5};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r5, r4};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallConstructDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  // r3 : number of arguments
-  // r4 : the function to call
-  // r5 : feedback vector
-  // r6 : slot in feedback vector (Smi, for RecordCallTarget)
-  // r7 : new target (for IsSuperConstructorCall)
+  // r2 : number of arguments
+  // r3 : the function to call
+  // r4 : feedback vector
+  // r5 : slot in feedback vector (Smi, for RecordCallTarget)
+  // r6 : new target (for IsSuperConstructorCall)
   // TODO(turbofan): So far we don't gather type feedback and hence skip the
   // slot parameter, but ArrayConstructStub needs the vector to be undefined.
-  Register registers[] = {r3, r4, r7, r5};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r2, r3, r6, r4};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallTrampolineDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  // r3 : number of arguments
-  // r4 : the target to call
-  Register registers[] = {r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  // r2 : number of arguments
+  // r3 : the target to call
+  Register registers[] = {r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ConstructStubDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  // r3 : number of arguments
-  // r4 : the target to call
-  // r6 : the new target
-  // r5 : allocation site or undefined
-  Register registers[] = {r4, r6, r3, r5};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  // r2 : number of arguments
+  // r3 : the target to call
+  // r5 : the new target
+  // r4 : allocation site or undefined
+  Register registers[] = {r3, r5, r2, r4};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ConstructTrampolineDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  // r3 : number of arguments
-  // r4 : the target to call
-  // r6 : the new target
-  Register registers[] = {r4, r6, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  // r2 : number of arguments
+  // r3 : the target to call
+  // r5 : the new target
+  Register registers[] = {r3, r5, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void RegExpConstructResultDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r5, r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r4, r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void TransitionElementsKindDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
+  Register registers[] = {r2, r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void AllocateHeapNumberDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  data->InitializePlatformSpecific(0, nullptr, nullptr);
+}
+
+void AllocateInNewSpaceDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void ArrayConstructorConstantArgCountDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  // register state
+  // r2 -- number of arguments
+  // r3 -- function
+  // r4 -- allocation site with elements kind
   Register registers[] = {r3, r4};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
-
-void AllocateHeapNumberDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  data->InitializePlatformSpecific(0, nullptr, nullptr);
-}
-
-
-void AllocateInNewSpaceDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  Register registers[] = {r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-
-void ArrayConstructorConstantArgCountDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  // register state
-  // r3 -- number of arguments
-  // r4 -- function
-  // r5 -- allocation site with elements kind
-  Register registers[] = {r4, r5};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
-
 void ArrayConstructorDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   // stack param count needs (constructor pointer, and single argument)
-  Register registers[] = {r4, r5, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r4, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void InternalArrayConstructorConstantArgCountDescriptor::
     InitializePlatformSpecific(CallInterfaceDescriptorData* data) {
   // register state
-  // r3 -- number of arguments
-  // r4 -- constructor function
-  Register registers[] = {r4};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  // r2 -- number of arguments
+  // r3 -- constructor function
+  Register registers[] = {r3};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void InternalArrayConstructorDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   // stack param count needs (constructor pointer, and single argument)
-  Register registers[] = {r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CompareDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+void CompareNilDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ToBooleanDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void BinaryOpDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void BinaryOpWithAllocationSiteDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r5, r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r4, r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void StringAddDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
-  Register registers[] = {r4, r3};
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+  Register registers[] = {r3, r2};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void KeyedDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r5,  // key
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+      r4,  // key
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void NamedDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r5,  // name
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+      r4,  // name
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void CallHandlerDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // receiver
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+      r2,  // receiver
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ArgumentAdaptorDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r4,  // JSFunction
-      r6,  // the new target
-      r3,  // actual number of arguments
-      r5,  // expected number of arguments
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+      r3,  // JSFunction
+      r5,  // the new target
+      r2,  // actual number of arguments
+      r4,  // expected number of arguments
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ApiFunctionDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // callee
-      r7,  // call_data
-      r5,  // holder
-      r4,  // api_function_address
-      r6,  // actual number of arguments
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
-
+      r2,  // callee
+      r6,  // call_data
+      r4,  // holder
+      r3,  // api_function_address
+      r5,  // actual number of arguments
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void ApiAccessorDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // callee
-      r7,  // call_data
-      r5,  // holder
-      r4,  // api_function_address
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
+      r2,  // callee
+      r6,  // call_data
+      r4,  // holder
+      r3,  // api_function_address
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
 
 void InterpreterDispatchDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
       kInterpreterAccumulatorRegister, kInterpreterRegisterFileRegister,
       kInterpreterBytecodeOffsetRegister, kInterpreterBytecodeArrayRegister,
       kInterpreterDispatchTableRegister};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 void InterpreterPushArgsAndCallDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // argument count (not including receiver)
-      r5,  // address of first argument
-      r4   // the target callable to be call
+      r2,  // argument count (not including receiver)
+      r4,  // address of first argument
+      r3   // the target callable to be call
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 void InterpreterPushArgsAndConstructDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // argument count (not including receiver)
-      r6,  // new target
-      r4,  // constructor to call
-      r5   // address of the first argument
+      r2,  // argument count (not including receiver)
+      r5,  // new target
+      r3,  // constructor to call
+      r4   // address of the first argument
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 void InterpreterCEntryDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {
-      r3,  // argument count (argc)
-      r5,  // address of first argument (argv)
-      r4   // the runtime function to call
+      r2,  // argument count (argc)
+      r4,  // address of first argument (argv)
+      r3   // the runtime function to call
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
+
 }  // namespace internal
 }  // namespace v8
 
-#endif  // V8_TARGET_ARCH_PPC
+#endif  // V8_TARGET_ARCH_S390