Design a Quadruple-2x1Mux in Verilog (by behavioral modeling), using a call of the following (ready to use) single 2x1mux module:

module m21 ( DO, D1, S, Y) ;

input wire DO, D1, S:

output reg Y;

always @ (DO or D1 or S)

begin

if(s)

Y= D1;

else

Y=DO :

end

endmodule

B; B, B, B. Mode = 0 FOR Add Mode = 1 for Subtract 9's Complementer (See Problem 4.18) Select Select = 1 Select = 0 Az A A, A Quadruple 2 x 1 MUX C BCD Adder (See Fig. 4.14) Figure 1 BCD adder-subtractor circuit