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|
module mux2 (S,A,B,Y);
input S;
input A,B;
output reg Y;
always @(*)
Y = (S)? B : A;
endmodule
module mux4 ( S, D, Y );
input[1:0] S;
input[3:0] D;
output Y;
reg Y;
wire[1:0] S;
wire[3:0] D;
always @*
begin
case( S )
0 : Y = D[0];
1 : Y = D[1];
2 : Y = D[2];
3 : Y = D[3];
endcase
end
endmodule
module mux8 ( S, D, Y );
input[2:0] S;
input[7:0] D;
output Y;
reg Y;
wire[2:0] S;
wire[7:0] D;
always @*
begin
case( S )
0 : Y = D[0];
1 : Y = D[1];
2 : Y = D[2];
3 : Y = D[3];
4 : Y = D[4];
5 : Y = D[5];
6 : Y = D[6];
7 : Y = D[7];
endcase
end
endmodule
module mux16 (D, S, Y);
input [15:0] D;
input [3:0] S;
output Y;
assign Y = D[S];
endmodule
module top (
input [3:0] S,
input [15:0] D,
output M2,M4,M8,M16
);
mux2 u_mux2 (
.S (S[0]),
.A (D[0]),
.B (D[1]),
.Y (M2)
);
mux4 u_mux4 (
.S (S[1:0]),
.D (D[3:0]),
.Y (M4)
);
mux8 u_mux8 (
.S (S[2:0]),
.D (D[7:0]),
.Y (M8)
);
mux16 u_mux16 (
.S (S[3:0]),
.D (D[15:0]),
.Y (M16)
);
endmodule
|
