anchor.diff:  
   interface FibIndication;
       method Action fibresult(Bit#(32) v);
  +    method Action fibnote(Bit#(32) v);
   endinterface
   
   interface FibRequest;
  
positive.code:    endfunction
  
     rule fib1 (fibstate == FIBSTATE1);
        $display("FIBSTATE1");
       if (fibn == 0)
  	fibreturn(1);
       else if (fibn == 1)
  	fibreturn(1);
       else
  
negative.code:    
     Stmt callfibstmt =
     seq
  //      $display("FIBCALL");
        stack.store(fsoffsetn, fibn);
        stack.store(fsoffsettmp1, fibtmp1);
        stack.store(fsoffsetnext, zeroExtend(pack(fibcallreturnto)));
  //      par
  	 stack.push();
  	 fibn <= fibcallarg;
  	 fibstate <= FIBSTATE1;
  //      endpar
     endseq;
     
     FSM callFibFSM <- mkFSM(callfibstmt);
     
     Stmt fibreturnstmt =
     seq
  //      $display("FIBRETURN");
        stack.pop();
  //      $display("FIBRETURN pop");
        stack.loadstart(fsoffsetn);
        action
  	 let t <- stack.loadfinish();
  	 stack.loadstart(fsoffsettmp1);
  	 fibn <= t;
        endaction
  //      $display("FIBRETURN n");
        action
  	 let t <- stack.loadfinish();
  	 stack.loadstart(fsoffsetnext);
  	 fibtmp1 <= t;
        endaction
  //      $display("FIBRETURN tmp1");
        action
  	 let t <- stack.loadfinish();
  //	 $display("FIBRETURN set state %d", t);
  	 fibstate <= unpack(truncate(t));
        endaction
     endseq;
  