anchor.diff:  // or by other means
   // 
   // Configuration.  
  +
   interface RingBuffer;
  -//   method Get#(CommandStruct);
  -//   method Put#(StatusStruct);
      method Bool notEmpty();
      method Bool notFull();
  -   method Action push(UInt num);
  -   method Action pop(UInt num);
  -   interface Reg#(Bit#(40)) expBufferFirst;
  -   interface Reg#(Bit#(40)) expBufferLast;
  +   method Action push(UInt#(8) num);
  +   method Action pop(UInt#(8) num);
  +   interface Reg#(Bit#(40)) bufferfirst;
  +   interface Reg#(Bit#(40)) bufferlast;
  +   interface Reg#(Bool) enable;
      interface RingBufferConfig configifc;
   endinterface
   
  
positive.code:       else if (regist == 1) bufferend <= addr;
        else if (regist == 2) bufferfirst <= addr;
        else if (regist == 3) bufferlast <= addr;
        else buffermask <= addr;
     endmethod
     
     method Bit#(40) get(Bit#(2) regist);
        if (regist == 0) return (bufferbase);
        else if (regist == 1) return (bufferend);
        else if (regist == 2) return (bufferfirst);
        else return(bufferlast);
     endmethod
     endinterface
  
  
negative.code:    Reg#(Bit#(40)) bufferfirst <- mkReg(0);
     Reg#(Bit#(40)) bufferlast <- mkReg(0);
     Reg#(Bit#(40)) buffermask <- mkReg(0);
     Reg#(Bool) hwenable <- mkReg(False);
     
     interface RingBufferConfig configifc;
     method Action set(Bit#(2) regist, Bit#(40) addr);
  