Carry-Propagation-Free Adder Based on an Asymmetric High-Radix Signed-Digit Number System

Abstract

We propose an asymmetric high-radix signed-digit (AHSD) number system for fast binary addition and array multiplication. Practical implementation of a carry-propagation-free adder and an array multipler is discussed and a radix-4 example is designed. AHSD has the advantage of simple conversion such that a practical carry-propagation-free adder and fast multiplier can be achieved. Besides, multiple-valued current-mode circuits are especially suited to our designs which result in very high-performance practical arithmetic circuits.