module maxmin4(
input [3:0] a, b, c, d,
output reg [3:0] max,
output reg [3:0] min
);
reg [3:0] max_ab, min_ab, max_cd, min_cd;
always @* begin
// AB pair
max_ab = (a >= b) ? a : b;
min_ab = (a < b) ? a : b;
// CD pair
max_cd = (c >= d) ? c : d;
min_cd = (c < d) ? c : d;
// Final
max = (max_ab >= max_cd) ? max_ab : max_cd;
min = (min_ab < min_cd) ? min_ab : min_cd;
end
endmodule