/* Example 8: by karttu, Dec 12 2004.
              Show the successive Fibonacci numbers when
              the user presses the rightmost push button.
 */

module esim8bb(CLK,PB_IN,SEG_OUT,DIGIT_OUT);
input CLK;
input PB_IN;
output [7:0] SEG_OUT;
output [3:0] DIGIT_OUT;

reg [15:0] f_even = 0;
reg [15:0] f_odd  = 1;

reg odd_one = 0;

wire PB_DEB; // State of the debounced push button.
reg pb_deb_prev = 0; // is saved here also.

debounced_button DBB(CLK,PB_IN,PB_DEB);

shw16decbb DECDISPLAY(CLK,PB_DEB,(odd_one ? f_odd : f_even),SEG_OUT,DIGIT_OUT);

always @(posedge CLK)
  begin
   if(PB_DEB && ~pb_deb_prev) // Only on @(posedge PB_DEB)
    begin // Do the thing.
     if(odd_one) f_even <= f_even + f_odd;
     else        f_odd  <= f_even + f_odd;
     odd_one <= ~odd_one;
    end
   pb_deb_prev <= PB_DEB;
  end

endmodule