anchor.diff:  
   interface FibIndication;
       method Action fibresult(Bit#(32) v);
  -    method Action fibnote(Bit#(32) v);
   endinterface
   
   interface FibRequest;
  
positive.code: 	   frame.doreturn();
  	end
       else
  	frame.docall(FIBSTATE1, FIBSTATE2, frame.args - 1, 0);
       endrule
  
  
negative.code:     *   if n == 0 return 0  // fibstate1
      *   if n == 1 return 1
      *   tmp1 = fib(n-1)
      *   tmp2 = fib(n-2)     // fibstate2
      *   return tmp1 + tmp2  // fibstate3
      */
  
     rule fib1 (frame.pc == FIBSTATE1);
        //$display("FIBSTATE1 %d", frame.args);
  