/*
    Mux / Demux


    Mux

    a   b   sel |   out
    -------------------
    0   0   0   |   0
    1   0   0   |   1
    0   1   1   |   1
    1   0   1   |   0
    ...

*/

module mux_2n1 #(parameter N = 8) (
    input [N-1:0] a,
    input [N-1:0] b,
    input sel,
    output [N-1:0] out
);
    assign out = sel ? b : a;
endmodule

module demux_1n2 #(parameter N = 8) (
    input [N-1:0] in,
    input sel,
    output [N-1:0] a,
    output [N-1:0] b
);
    assign a = sel ? 0 : in;
    assign b = sel ? in : 0;
endmodule