Design of bit slice processor based on reconfigurable approximate carry look-ahead adder

Abstract

A highly efficient approximate addition plays a vital role in arithmetic operations. A special addition mechanism employed in the proposed work consists of both exact and approximate modes of operation suitable for both error tolerant and exact applications. The proposed adder is more area and power efficient compared with other conventional approximate carry look-ahead adders. It is constructed by splitting the input into two parts namely, approximate part and augmenting part. If both produce carry it will be exact output, while the carry produced by approximate part will be imprecise. Based on this mechanism an efficient reconfigurable carry look-ahead adder is designed and applied to a bit-slice processor. Bit slicing is technique to construct a processor by using n-bit CPU. The error rate is also minimized in the proposed technique by 10% compared to existing designs. Compared with conventional approximate adder, the proposed reconfigurable approximate adder produce better results in terms of area and power.