Output-Wired Inverter

The book describes the importance of arithmetic functions in modern digital VLSI system. Many research efforts have focused on designing faster and more efficient adder architectures and resulted in a larger number of adder architectures. Some examples of architectures are the Ripple carry adder which, generates carries in series, the carry look-ahead adder which attempts to speed-up the carry propagation by using additional logics, group generate and propagate, and the parallel prefix adder which extends from the idea of carry look-ahead computation. The parallel prefix adders are a more general form where a network is used to pre-calculate the carry signals.