corrected method enter and return and created those missing constants

lib/register/enter_implementation.rb

@@ -6,11 +6,9 @@ module Register
         next unless code.is_a? Virtual::MethodEnter
         # save return register and create a new frame
         to = RegisterReference.new(:r0)  # message base
-        tmp = RegisterReference.new(:r5) # tmp
         pc = RegisterReference.new(:pc)
-        move1 = RegisterMachine.instance.ldr( tmp , pc )
-        move2 = RegisterMachine.instance.ldr( tmp , to , 3 ) #TODO 3 == return reg, needs constant / layout
-        block.replace(code , [move1,move2] )
+        move1 = RegisterMachine.instance.str( pc , to , Virtual::Message::RETURN )
+        block.replace(code , [move1] )
       end
     end
   end

lib/register/return_implementation.rb

@@ -3,12 +3,11 @@ module Register
     def run block
       block.codes.dup.each do |code|
         next unless code.is_a? Virtual::MethodReturn
-        to = RegisterReference.new(:r0)
-        tmp = RegisterReference.new(:r5)
+        #load the return address into pc, affecting return. (other cpus have commands for this, but not arm)
+        message = RegisterReference.new(:r0)
         pc = RegisterReference.new(:pc)
-        move1 = RegisterMachine.instance.ldr( to , tmp , 3 ) #TODO 3 == return reg, needs constant / layout
-        move2 = RegisterMachine.instance.ldr( pc , tmp )
-        block.replace(code , [move1,move2] )
+        move1 = RegisterMachine.instance.ldr( pc ,message , Virtual::Message::RETURN )
+        block.replace(code , [move1] )
       end
     end
   end

lib/virtual/message.rb

@@ -20,6 +20,10 @@ module Virtual
   # During compilation Message and frame objects are created to do type analysis
 
   class Message
+    RETURN = 2
+    EXCEPTION = 3
+    SELF = 4
+
     def initialize me , normal , exceptional
       @me = me
       @next_normal = normal