Partial Product Generation Utilizing the Sum of Operands for Reduced Area Parallel Multipliers

Abstract

We propose a novel method to generate partial products for reduced area parallel multipliers. Our method reduces the total number of partial product bits of parallel multiplication by about half. We call partial products generated by our method Compound Partial Products (CPPs). Each CPP has four candidate values: zero, a part of the multiplicand, a part of the multiplier and a part of the sum of the operands. Our method selects one from the four candidates according to a pair of a multiplicand bit and a multiplier bit. Multipliers employing the CPPs are approximately 30% smaller than array multipliers without radix-4 Booth's method, and approximately up to 10% smaller than array multipliers with radix-4 Booth's method. We also propose an acceleration method of the multipliers using CPPs.