//--------------------------------------------------
//4-bit register for Non-blocking Procedural Assignment
//Filename : reg_nbp.v
//--------------------------------------------------
module reg4_nbp(Qout, CLK, RESET, Din);
output [3:0] Qout;
input CLK, RESET;
input Din;

reg [3:0] Qout;

 
always @ (posedge CLK or posedge RESET)
//Positive edge CLK and asynchronous RESET
 if (RESET)
   Qout <= 4'b0000;
 else
  begin
   Qout[0] <= Din;
   Qout[1] <= Qout[0];
   Qout[2] <= Qout[1];
   Qout[3] <= Qout[2];
  end
endmodule