Reversible Full Adder/Subtractor

This paper proposes two novel designs of Adder/Subtractor using reversible logic gates. The first design is an implementation of two's complement Adder/Subtractor suitable for signed/unsigned numbers. The other design proposes a novel reversible gate that can work singly as a reversible Full Adder/Subtractor unit. The proposed Full Adder/Subtractor is then applied to design a reversible 4-bit ripple Adder/Subtractor.