68. 4-bit Comparator

How do you plan to solve it?

/*Write your code here*/
module mx(
    input [3:0] a,b,
    output [3:0] max
);
    assign max = (a[3]&(~b[3])) | 
                 ((a[3]~^b[3]) & (a[2]&(~b[2]))) | 
                 ((a[3]~^b[3]) & (a[2]~^b[2]) & (a[1]&(~b[1]))) | 
                 ((a[3]~^b[3]) & (a[2]~^b[2]) & (a[1]~^b[1]) & (a[0]&(~b[0]))) 
                 ? a : b;
endmodule

module mn(
    input [3:0] a,b,
    output [3:0] min
);
    assign min = (a[3]&(~b[3])) | 
                 ((a[3]~^b[3]) & (a[2]&(~b[2]))) | 
                 ((a[3]~^b[3]) & (a[2]~^b[2]) & (a[1]&(~b[1]))) | 
                 ((a[3]~^b[3]) & (a[2]~^b[2]) & (a[1]~^b[1]) & (a[0]&(~b[0]))) 
                 ? b : a;
endmodule

module maxmin4(
    input [3:0] a, b, c, d,
    output [3:0] max, min
);
    wire [3:0] mx1, mx2, mn1, mn2;
    mx m1(a, b, mx1);
    mx m2(c, d, mx2);
    mx m3(mx1, mx2, max);

    mn m4(a, b, mn1);
    mn m5(c, d, mn2);
    mn m66(mn1, mn2, min);


endmodule