Novel reversible CLA, optimized RCA and parallel adder/subtractor circuits

• Published in: Serbian Journal of Electrical Engineering
• Main Authors: Gharajeh Mohammad Samadi, Haghparast Majid
• Format: Article in Journal/Newspaper
• Language: English
• Published: Faculty of Technical Sciences in Cacak 2020
• Subjects: reversible circuit design; carry look-ahead adder; ripple carryadder; parallel adder/subtractor; Electrical engineering. Electronics. Nuclear engineering; TK1-9971; Orca
• Online Access: https://doi.org/10.2298/SJEE2003259G; https://doaj.org/article/c91e63d14530452dacb62f5be90bc2f9

This paper proposes reversible circuit designs of the three most commonly used adders: carry look-ahead adder (CLA adder), ripple carry adder (RCA adder), and parallel adder/subtractor. The n-bit reversible CLA adder, called CLA-GH, is designed using the Peres and Fredkin gates. The n-bit optimized reversible RCA adder, called ORCA-GH, is designed using the reversible circuit of a parity-preserving reversible full adder. Both circuits reduce the quantum cost. However, the ORCA-GH circuit also improves the number of constant inputs. Furthermore, the n-bit reversible parallel adder/subtractor, called PAS-GH, is designed using the Feynman, Peres, and Fredkin gates. It decreases the number of garbage outputs and quantum cost. The transistor realizations of the CLA-GH and PAS-GH circuits are provided accordingly. The evaluation results indicate that the proposed circuits surpass the existing works in all figures of merit.