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
// ============================================================
module xor_gate (
    input  a, b,
    output y
);
    wire w1, w2;
    wire d1, d2;
    not_gate u1(.a(a),.y(d1));
    not_gate u2(.a(b),.y(d2));
    and_gate u3(.a(a),.b(d2),.y(w1));
    and_gate u4(.a(d1),.b(b),.y(w2));
    or_gate  u5(.a(w1),.b(w2),.y(y));

endmodule