fix tests (just using local gem)

lib/register/builtin/integer.rb

@@ -7,7 +7,7 @@ module Register
           plus_function = Virtual::MethodSource.create_method(:Integer,:plus , [Virtual::Integer] )
           plus_function.source.return_type = Virtual::Integer
           plus_function.source.receiver = Virtual::Integer
-          plus_function.source.add_code Register::Math.new( plus_function, :add , 0 )
+          plus_function.source.add_code Register::OperatorInstruction.new( plus_function, :add , 0 , 0 )
 
           return plus_function
         end

lib/register/instruction.rb

@@ -49,3 +49,4 @@ require_relative "instructions/function_return"
 require_relative "instructions/save_return"
 require_relative "instructions/register_transfer"
 require_relative "instructions/branch"
+require_relative "instructions/operator_instruction"

lib/register/instructions/operator_instruction.rb

@@ -0,0 +1,18 @@
+module Register
+
+  class OperatorInstruction < Instruction
+    def initialize source , operator , left , right
+      super(source)
+      @operator = operator
+      @left = left
+      @right = right
+    end
+    attr_reader :left , :right
+
+    def to_s
+      "OperatorInstruction: #{left} #{operator} #{right}"
+    end
+
+  end
+
+end

lib/virtual/boot.rb

@@ -157,9 +157,10 @@ module Virtual
       @space.get_class_by_name(:Word).add_instance_method Register::Builtin::Word.send(:putstring , nil)
 
       obj = @space.get_class_by_name(:Integer)
-      [:putint,:fibo].each do |f|
+      [:putint,:fibo , :plus].each do |f|
         obj.add_instance_method Register::Builtin::Integer.send(f , nil)
       end
+#      obj.alias :plus , :+
 
     end
   end