ripple_carry_16_bit.v

`timescale 1ns / 1ps

//////////////////////////////////////
//16-bit Ripple Carry Adder 
/////////////////////////////////////
 
module ripple_carry_16_bit(a, b, cin,sum, cout);
input [15:0] a,b;
input cin;
output [15:0] sum;
output cout;
wire c1,c2,c3;
 
ripple_carry_4_bit rca1 (
.a(a[3:0]),
.b(b[3:0]),
.cin(cin), 
.sum(sum[3:0]),
.cout(c1));
 
ripple_carry_4_bit rca2(
.a(a[7:4]),
.b(b[7:4]),
.cin(c1),
.sum(sum[7:4]),
.cout(c2));
 
ripple_carry_4_bit rca3(
.a(a[11:8]),
.b(b[11:8]),
.cin(c2),
.sum(sum[11:8]),
.cout(c3));
 
ripple_carry_4_bit rca4(
.a(a[15:12]),
.b(b[15:12]),
.cin(c3),
.sum(sum[15:12]),
.cout(cout));
endmodule
 
////////////////////////////////////
//4-bit Ripple Carry Adder
////////////////////////////////////
 
module ripple_carry_4_bit(a, b, cin, sum, cout);
input [3:0] a,b;
input cin;
wire c1,c2,c3;
output [3:0] sum;
output cout;
 
full_adder fa0(.a(a[0]), .b(b[0]),.cin(cin), .sum(sum[0]),.cout(c1));
full_adder fa1(.a(a[1]), .b(b[1]), .cin(c1), .sum(sum[1]),.cout(c2));
full_adder fa2(.a(a[2]), .b(b[2]), .cin(c2), .sum(sum[2]),.cout(c3));
full_adder fa3(.a(a[3]), .b(b[3]), .cin(c3), .sum(sum[3]),.cout(cout));
endmodule
 
//////////////////////////////
//1bit Full Adder
/////////////////////////////
module full_adder(a,b,cin,sum, cout);
input a,b,cin;
output sum, cout;
wire x,y,z;
half_adder h1(.a(a), .b(b), .sum(x), .cout(y));
half_adder h2(.a(x), .b(cin), .sum(sum), .cout(z));
or or_1(cout,z,y);
endmodule
 
///////////////////////////
// 1 bit Half Adder
//////////////////////////
module half_adder(a,b, sum, cout );
input a,b;
output sum, cout;
xor xor_1 (sum,a,b);
and and_1 (cout,a,b);
endmodule