Abstract-Reversible logic has applications in various research areas including lowpower design and quantum computation. In this paper, a rule-based optimization approach for reversible circuits is proposed which uses both negative and positive control Toffoli gates during the optimization. To this end, a set of rules for removing NOT gates and optimizing sub-circuits with common-target gates are proposed. To evaluate the proposed approach, the best-reported synthesized circuits and the results of a recent synthesis algorithm which uses both negative and positive controls are used. Our experiments reveal the potential of the proposed approach in optimizing synthesized circuits.

Several algorithms have been proposed for the synthesis of reversible circuits. In this paper, a cycle-based synthesis algorithm for reversible logic, based on the NCT library, has been proposed. In other words, direct implementation of a single 3-cycle, a pair of 3-cycles and a pair of 2-cycles have been explored and used to propose an efficient Toffoli-based synthesis algorithm for reversible circuits. The synthesis algorithm decomposes a given large cycle into a set of single 3-cycles, pairs of 3-cycles and pair of 2-cycles and synthesizes the resulted cycles directly. Our experimental results show that the proposed synthesis algorithm can outperform the available 2-cycle-based approach about 34% on average. In addition, several discussions for the generalization of the proposed method to the 2 m -cycles are given.

Abstract-In this paper, a new non-search based synthesis algorithm for reversible circuits is proposed. Compared with the widely used search-based methods, our algorithm is guarantied to produce a result and can lead to a solution with much fewer steps. To evaluate the proposed method, several circuits taken from the literature are used. The experimental results corroborate the expected findings.