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,has_unknown, output [7:0]bus_if_known);
    wire any_xz = (^(bus ^ bus)) === 1'bx;

    assign has_unknown  = any_xz;
    assign all_known    = ~any_xz;
    assign bus_if_known = {8{all_known}} & bus;  // pass when known, else 00
endmodule