anchor.diff:    rule stop_fsm if (stop_wire);
       fsm_deparse_ethernet.abort;
     endrule
  -  method Action start();
  -     start_wire.send();
  -  endmethod
  -  method Action stop();
  -     stop_wire.send();
  -  endmethod
  +  method start = start_wire.send;
  +  method stop = stop_wire.send;
     interface deparse_ipv4 = toGet(deparse_ipv4_fifo);
   endmodule
   
  
positive.code: function Tuple2#(Ipv4T, Ipv4T) toIpv4(MetadataT meta);
     Ipv4T ipv4 = defaultValue;
     Ipv4T mask = defaultMask;
     ipv4.protocol = fromMaybe(?, meta.protocol);
     mask.protocol = 0;
     return tuple2(ipv4, mask);
  endfunction
  
  
negative.code:     let curr_data = masked_data | pack(curr_meta);
      //Ipv4T ipv4_t = unpack(pack(masked_data));
      data_this_cycle.data = {pack(unused), pack(curr_data)};
      $display("(%0d) compute_next_state dstAddr", $time, fshow(meta_fifo.first.dstAddr));
      dataout.enq(data_this_cycle);
      state <= StateDeparseIdle;
      meta_fifo.deq;
  