adding sources to register instructions

lib/register/instructions/set_slot.rb

@@ -17,7 +17,8 @@ module Register
     # If you had a c array and index offset
     # the instruction would do array[index] = register
     # So SetSlot means the register (first argument) moves to the slot (array and index)
-    def initialize register , array , index
+    def initialize source , register , array , index
+      super(source)
       @register = register
       @array = array
       @index = index
@@ -35,11 +36,11 @@ module Register
   # Produce a SetSlot instruction.
   # From and to are registers or symbols that can be transformed to a register by resolve_to_register
   # index resolves with resolve_index.
-  def self.set_slot from , to , index
-    index = resolve_index( to , index)
+  def self.set_slot source , from , to , index
     from = resolve_to_register from
+    index = resolve_index( to , index)
     to = resolve_to_register to
-    SetSlot.new( from , to , index)
+    SetSlot.new( source, from , to , index)
   end
 
 end