in Verilog

What is a full adder and how do I implement a 4-bit and 8-bit adder in Verilog?

by (300 points)

A full adder is a circuit thats able to accept 2 bits and a carry bit as input, and output the result and a carry bit.

``wire [ 3 : 0 ]   x , y; wire [ 4 : 0 ]   result; // one bit longer then x and y to prevent overflow.assign result = x + y;``
``wire [ 7 : 0 ]   x , y; wire [ 8 : 0 ]   result; // one bit longer then x and y to prevent overflow.assign result = x + y;``
``module full_adder (    input a,    input b,    input cin,    output sum,    output cout);    assign sum = a ^ b ^ cin;    assign cout = (a & b) | (b & cin) | (a & cin);endmodule``
``module adder #(    parameter DATA_WIDTH = 8) (    input [DATA_WIDTH-1:0] a,    input [DATA_WIDTH-1:0] b,    input cin,    output [DATA_WIDTH-1:0] sum,    output cout);    genvar i;    wire [DATA_WIDTH:0] carries;    assign carries[0] = cin;    generate      for (i = 0; i < DATA_WIDTH; i = i + 1) begin : full_adder_instances        full_adder full_adder_inst(            .a(a[i]),            .b(b[i]),            .cin(carries[i]),            .sum(sum[i]),            .cout(carries[i+1])        );      end    endgenerate  assign cout = carries[DATA_WIDTH];endmodule``
``module adder #(  parameter DATA_WIDTH = 8) (    input [DATA_WIDTH-1:0] a,    input [DATA_WIDTH-1:0] b,    input cin,    output [DATA_WIDTH-1:0] sum,    output cout);  assign {cout, sum} = a + b + cin;endmodule``