64-bit carry-select adder with reduced area

Abstract

A carry-select adder can be implemented by using a single ripple-carry adder and an add-one circuit instead of using dual ripple-carry adders. A multiplexer-based add-one circuit is proposed to reduce the area with negligible speed penalty. The proposed 64 bit carry-select adder requires 42% fewer transistors than the conventional carry-select adder.