Types Of Adders with Verilog Code

Adders in Vlsi are basic components for an ALU . There are N number of adders each with their own advantages & disadvantages. When two numbers are to be added and if each of them is of N bits than we can add them in Two different ways :

1. Serial
2. Parallel

In serial addition the LSB's are added first than the carry created are propagated to the next higher bits. Whereas in parallel addition every it added in parallel without waiting for carry and different algorithms are used to compensate for the carry.

                        

                          Carry bits are to handled properly so that the resulting answer after addition is correct.But as we know that for each addition there can be a carry generated can it has to be accounted for. When we try doing this the major criteria to be kept in mind are propagation time and time taken to calculate the carry. Here are few Verilog codes for different types of adders:

>>>Verilog code for Half adder

>>>Verilog code for Full adder

>>>Verilog code for Parallel adder

>>>Verilog code for CLA(carry look ahead affer)

>>>Verilog code for RCA(Ripple carry adder)

>>>Verilog code for 32 Bit Pipelined Floating Point Adder 

>>>Verilog code for BCD Adder 

>>> Verilog code for Carry Save Adder 

>>>Verilog Code for Carry Select Adder