def op( operator , right)
      ret = Risc.op( "operator #{operator}" , operator , self , right)
      builder.add_code(ret) if builder
      ret
    end
def op( operator , right)
      ret = Risc.op( "operator #{operator}" , operator , self , right)
      builder.add_code(ret) if builder
      ret
    end
create operator instruction for self and add
 doesn't read quite as smoothly as one would like, but better than the compiler version