Parallel saturating multioperand adders

Abstract

This paper presents designs for parallel saturating multioperand adders. These adders have only a single carry-propagate adder on the critical delay path, yet produce the same results that would be obtained if the additions were performed serially with saturation after each operation. When used with parallel saturating multipliers or multiply-accumulate units, these adders significantly improve the performance of GSM speech coders. They can also easily be modified to perform either saturating or wraparound multioperand addition, based on an input control signal. Since parallel saturating multioperand adders have more area and less delay than serial saturating multioperand adders, they are suitable for high-performance digital signal processing systems.