// Linear feedback shift register.
//
// Useful as a simple psuedo-random number generator.
module LFSR #(
    parameter WIDTH = 16,
    parameter POLY = 16'hD008
) (
    input rst,
    input clk,
    input [WIDTH-1:0] seed,
    output reg [WIDTH-1:0] r
);
    wire feedback = ^(r & POLY);

    always @(posedge clk) begin
        if(rst) begin
            r <= seed;
        end else begin
            r <= {r[WIDTH-2:0], feedback};
        end
    end
endmodule