A Novel Nanometric Reversible Four-bit Signed-magnitude Adder/Subtractor

The reversible logic plays a significant role in the synthesis of circuits for quantum computing. Reversible gates have been widely used in low power CMOS design, optical information processing, and bioinformatics, quantum computing and nanotechnology-based systems. A new 3x3 reversible two's complement gate is suggested in this paper. Two quantum models are offered for two's complement gate. These quantum models differ from each other with respect to the quantum cost. Two novel reversible four-bit signed-magnitude adders/subtractors with HNG and ADD/SUB gates are also proposed for the first time. The proposed circuits detect overflow and produce a correct result for inputs in the range of [-7, 7]. The proposed two's complement gate is used in part of the reversible four-bit signed-magnitude adder/subtractor design. The proposed reversible 4-bit signed-magnitude adders/subtractors are evaluated in terms of number of reversible gates, number of garbage outputs, number of constant inputs, quantum cost and hardware complexity. All the scales are in the nanometric area. [Boroumand S. A Novel Nanometric Reversible Four-bit Signed-magnitude Adder/Subtractor. Life Sci J 2012;9(3):1646-1655]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 240