9. XOR Gate Using Basic Gates

How do you plan to solve it?

// ============================================================
// Basic Gates (given)
// ============================================================
module and_gate(input a, b, output y);
    assign y = a & b;
endmodule

module or_gate(input a, b, output y);
    assign y = a || b;

endmodule

module not_gate(input a, output y);
    assign y = ~a;

endmodule

// ============================================================
// XOR Gate
// ============================================================
// ============================================================
// XOR Gate
// ============================================================
module xor_gate (
    input  a, b,
    output y
);
    // Intermediate wires
    wire not_a, not_b;
    wire and1, and2;

    // NOT gates
    not_gate n1 (.a(a), .y(not_a));
    not_gate n2 (.a(b), .y(not_b));

    // AND gates
    and_gate a1 (.a(a),     .b(not_b), .y(and1));
    and_gate a2 (.a(not_a), .b(b),     .y(and2));

    // OR gate
    or_gate  o1 (.a(and1), .b(and2), .y(y));

endmodule