How do you plan to solve it?
module maxmin4(
input wire [3:0] a,
input wire [3:0] b,
input wire [3:0] c,
input wire [3:0] d,
output reg [3:0] max,
output reg [3:0] min
);
reg [3:0] max_ab, min_ab;
reg [3:0] max_cd, min_cd;
always @(*) begin
// Compare a & b
if (a > b) begin
max_ab = a;
min_ab = b;
end else begin
max_ab = b;
min_ab = a;
end
// Compare c & d
if (c > d) begin
max_cd = c;
min_cd = d;
end else begin
max_cd = d;
min_cd = c;
end
// Final max
max = (max_ab > max_cd) ? max_ab : max_cd;
// Final min
min = (min_ab < min_cd) ? min_ab : min_cd;
end
endmodule