Structural Description

Structural Description 

module MUX4to1_struct (Y, I0, I1, I2, I3, S);

input  I0, I1, I2, I3;

input  [1:0] S;

output Y;

wire n0, n1;

wire t0, t1, t2, t3;

not N0 (n0, S[0]);

not N1 (n1, S[1]);

and A0 (t0, I0, n1, n0);

and A1 (t1, I1, n1, S[0]);

and A2 (t2, I2, S[1], n0);

and A3 (t3, I3, S[1], S[0]);

or  O0 (Y, t0, t1, t2, t3);

endmodule

Test bench ->

module TB_MUX4to1_struct();

reg  I0, I1, I2, I3;

reg  [1:0] S;

wire Y;

MUX4to1_struct dut (Y, I0, I1, I2, I3, S);

initial begin

     I0 = 0; I1 = 1; I2 = 0; I3 = 1;

     S  = 2'b00; #10

     S  = 2'b01; #10

     S  = 2'b10; #10

     S  = 2'b11; #10

#20 $finish;

end

endmodule

OUTPUT WAVEFORM:---