44. Bus Error Checker

How do you plan to solve it?

/*Write your code here*/
module error_checker_xz(
    input [7:0]bus,
    output all_known,
    output has_unknown,
    output [7:0]bus_if_known
);

    wire xz = (^(bus ^ bus)) === 1'bx;

    assign has_unknown = xz;
    assign all_known = ~xz;
    assign bus_if_known = {8{all_known}} & bus;
endmodule