code: def CMN(self, params):
          
          Ra, Rb = self.get_two_parameters(self.TWO_PARAMETER_COMMA_SEPARATED, params)
  
          self.check_arguments(low_registers=(Ra, Rb))
  
          # CMN Ra, Rb
          def CMN_func():
              self.set_NZCV_flags(self.register[Ra], self.register[Rb],
                                  self.register[Ra] + self.register[Rb], 'add')
  
          return CMN_func
docs: CMN Ra, Rb
  
          Add the two registers and set the NZCV flags
          The result is discarded
          Ra and Rb must be low registers