diff --git a/lib/arm/arm_machine.rb b/lib/arm/arm_machine.rb
index 224d34dc..d8e5deea 100644
--- a/lib/arm/arm_machine.rb
+++ b/lib/arm/arm_machine.rb
@@ -34,8 +34,8 @@ module Arm
 
     def main_start context
       entry = Vm::Block.new("main_entry",nil,nil)
-      entry.do_add mov(  :fp ,  0 )
-      entry.do_add call( context.function )
+      entry.add_code mov(  :fp ,  0 )
+      entry.add_code call( context.function )
       entry
     end
     def main_exit context
@@ -44,11 +44,11 @@ module Arm
       exit
     end
     def function_entry block, f_name
-        block.do_add  push( [:lr] )
+        block.add_code  push( [:lr] )
         block
     end
     def function_exit entry , f_name
-      entry.do_add   pop(  [:pc] )
+      entry.add_code   pop(  [:pc] )
       entry
     end
 
@@ -93,8 +93,8 @@ module Arm
       # This is very arm specific, syscall number is passed in r7, other arguments like a c call ie 0 and up
       sys = Vm::Integer.new( Vm::RegisterReference.new(:r7) )
       ret = Vm::Integer.new( Vm::RegisterReference.new(RETURN_REG) )
-      block.do_add  mov(  sys , num )
-      block.do_add  swi(  0 )
+      block.add_code  mov(  sys , num )
+      block.add_code  swi(  0 )
       #todo should write type into r1 according to syscall
       ret
     end
diff --git a/lib/boot/object.rb b/lib/boot/object.rb
index 439c4398..90e8bd15 100644
--- a/lib/boot/object.rb
+++ b/lib/boot/object.rb
@@ -39,7 +39,7 @@ module Boot
         return get_function
       end
 
-      def _set_instance_variable(context , name , value)
+      def _set_instance_variable(context , name = Vm::Integer , value = Vm::Integer )
         set_function = Vm::Function.new(:_set_instance_variable , Vm::Integer , [ Vm::Integer , Vm::Integer] , Vm::Integer )
         me = set_function.receiver
         var_name = set_function.args.first
diff --git a/lib/vm/block.rb b/lib/vm/block.rb
index b9add585..e38eb0b9 100644
--- a/lib/vm/block.rb
+++ b/lib/vm/block.rb
@@ -41,7 +41,7 @@ module Vm
       ret
     end
 
-    def do_add kode
+    def add_code kode
       kode.assigns.each { |a| (@assigns << a) unless @assigns.include?(a) }
       kode.uses.each { |use| (@uses << use) unless (@assigns.include?(use) or @uses.include?(use)) }
       #puts "IN ADD #{name}#{uses}" 
diff --git a/lib/vm/function.rb b/lib/vm/function.rb
index a328debf..cfa375ea 100644
--- a/lib/vm/function.rb
+++ b/lib/vm/function.rb
@@ -140,7 +140,7 @@ module Vm
     def add_code(kode)
       raise "alarm #{kode}" if kode.is_a? Word
       raise "alarm #{kode.class} #{kode}" unless kode.is_a? Code
-      @insert_at.do_add kode
+      @insert_at.add_code kode
       self
     end
 
diff --git a/lib/vm/values/reference.rb b/lib/vm/values/reference.rb
index a2c86772..35069e31 100644
--- a/lib/vm/values/reference.rb
+++ b/lib/vm/values/reference.rb
@@ -1,9 +1,11 @@
 module Vm
   class Reference < Word
     # needs to be here as Word's constructor is private (to make it abstract)
-    def initialize reg
-      super
+    def initialize reg , clazz = nil
+      super(reg)
+      @clazz = clazz
     end
+    attr_accessor :clazz
 
   end
 end