44. Bus Error Checker

How do you plan to solve it?

module error_checker_xz(
    input [7:0]bus,
    output all_known,
    output  has_unknown,
    output [7:0]bus_if_known
);   
    wire p = ((^bus===1'bx) || (^bus===1'bz));
    assign has_unknown=p;
    assign all_known=~p;
    assign bus_if_known=all_known?bus:8'h00;
endmodule