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 x_or_z;
    assign x_or_z = ^(bus^bus)===1'bx;
    assign all_known = ~x_or_z;
    assign has_unknown = x_or_z;
    assign bus_if_known = {8{all_known}}&bus;
endmodule