remove MethodCall and thus all virtual instructions

lib/register/instructions/function_call.rb

@@ -13,6 +13,12 @@ module Register
     def to_s
       "FunctionCall: #{method.name}"
     end
+  end
 
+  def self.issue_call caller , callee
+    # move the current new_message to message
+    caller.source.add_code RegisterTransfer.new(caller, Register.new_message_reg , Register.message_reg )
+    # do the register call
+    caller.source.add_code FunctionCall.new( caller , callee )
   end
 end