module b1_demux_1_4_shift
(
    input      din, 
    input      [1:0] sel,
    output reg dout0, 
    output reg dout1,
    output reg dout2,
    output reg dout3
);

    always @(*)
        {dout3, dout2, dout1, dout0}= din<<sel;
        
endmodule