65. Ripple Carry Adder

How do you plan to solve it?

// 1-bit Full Adder (to be used by the 4-bit RCA)
module full_adder_1bit (
    input  a, b, cin,
    output sum, cout
);
    // TODO: implement 1-bit full adder (structural or dataflow)
   assign sum  = a ^ b ^ cin;
   assign cout = (a & b) | (b & cin) | (a & cin);

endmodule

// 4-bit Ripple Carry Adder – chain 4 full adders
module rca4_chain (
    input  [3:0] a,
    input  [3:0] b,
    input        cin,
    output [3:0] sum,
    output       cout
);
    // TODO: Declare internal ripple carries

    // TODO: instantiate 4 full adders and chain carries
    wire  c0,w4,w5,w6,c4;
    assign c0 =  cin;
    full_adder_1bit fa1(a[0],b[0],c0,sum[0],w4);
    full_adder_1bit fa2(a[1],b[1],w4,sum[1],w5);
    full_adder_1bit fa3(a[2],b[2],w5,sum[2],w6);
    full_adder_1bit fa4(a[3],b[3],w6,sum[3],c4);
    assign cout = c4;



    // TODO: drive cout
endmodule