introduce method call that includes setup

lib/virtual/instructions/control.rb

@@ -2,12 +2,22 @@ module Virtual
   
 
   # the first instruction we need is to stop. Off course in a real machine this would be a syscall, but that is just 
-  # an implementation (in a programm it would be a function). But in a virtual machine, not only do we need this instruction,
+  # an implementation (in a programm it would be a function). 
+  # But in a virtual machine, not only do we need this instruction,
   # it is indeed the first instruction as just this instruction is the smallest possible programm for the machine.
   # As such it is the next instruction for any first instruction that we generate.
   class Halt < Instruction    
   end
 
+  # MethodCall involves shuffling some registers about and doing a machine call
+  class MethodCall < Instruction
+    def initialize method
+      @method = method
+    end
+    attr_reader :method
+  end
+
+  # also the return shuffles our objects beck before actually transferring control
   class MethodReturn < Instruction
   end