44. Bus Error Checker

Using the case operator along with the bitwise XOR, we can determine presence of indefinite characters.

/*Write your code here*/
module error_checker_xz (
    input [7:0] bus,
    output all_known,
    output has_unknown,
    output [7:0] bus_if_known
);
    assign has_unknown = ^bus === 1'bx;
    assign all_known = ~has_unknown;
    assign bus_if_known = has_unknown? 8'b00: bus;
endmodule