The development of an innovative adder design evaluated using programmable logic.

Abstract

THE DEVELOPMENT OF AN INNOVATIVE ADDER DESIGN EVALUATED USING PROGRAMMABLE LOGIC James A. Haas April 23 , 2004 This research evaluates an innovative binary adder design and compares it against five standard adder designs. It begins with an algorithmic description of the five standard designs followed by the innovative design. It uses two metrics, speed and size, to establish a fair comparison among the designs and draw conclusions about the performance and usability of the innovative design. The metrics are applied to theory, simulation, and implementation of the adder designs. The latter part of the research draws conclusions from the analysis of these metrics to establish a fair comparison between the innovative and existing designs. The five standard designs are the carry-ripple, carry-complete, carry-Iookahead, carry-select, and pyramid. The carry-ripple design is the fundamental and most straightforward approach to addition. The carry-complete takes the carry-ripple design and adds a signal to detect when the addition is complete. The carry-Iookahead design uses some intermediate signals to add multiple bits concurrently. The carry-select design is a brute force approach that allows high speed for a large gate count. Lastly, the pyramid design divides the addition into multiple stages, each calculating a single step of the addition process. The innovative design, called the carry-feedback, works by starting with the