# Efficient Design of Reversible Adder and Multiplier Using Peres Gates
## 6 Functionality Verification
The outcomes of these analyses contribute to the broader understanding of reversible logic circuits and their applications in emerging computational paradigms. In Figure 37, Levels 1, 2, and 3 on the Y-axis represent low, moderate, and high levels, respectively. From this figure, we can conclude that the Vedic multiplier is the best reversible multiplier with low gate count, quantum cost, gate level delay, hardware complexity, scalability, area, and number of Ancilla bits with high garbage outputs, which can be neglected as the reversibility efficiency provided by this circuit is high. The ripple carry adder constructed using reversible logic has all metrics considered to be at a moderate level, but it provides higher gate level delays, which can be neglected as the hardware complexity and area in terms of gates is also less. After examining all the adders and multiplier circuits using Toffoli and Peres gates, a comparison table for designing various adders and multipliers using reversible logic is prepared and presented in terms of a chart, as shown in Figure 37. The key parameters considered in the design of reversible circuits include all the metrics used to measure the performance of these circuits. When comparing the power needs of circuits based on Peres gates to those using other reversible logic gates, several factors must be considered, including gate design, energy consumption per operation, and overall circuit efficiency. Peres gates help to minimize the number of gates needed for certain operations, which lowers the switching activity and dynamic power consumption in circuits. Since fewer gates often result in fewer transitions,  
Figure 37: Comparative analysis of different adders and multiplier configurations. this reduces overall energy usage. Hence, in quantum computing, implementing Peres gates sometimes requires fewer resources than traditional gates, potentially allowing for lower power requirements when executing some specific algorithms. Generally, the power consumption of reversible gates depends on the switching activity. The gates that require multiple transitions, like Toffoli gates, consume more power due to increased switching activity compared to a circuit optimized with Peres gates. Also, the circuits built using other reversible gates require overall more gates to achieve the same functionality, potentially leading to higher power needs. More gates mean more transitions and, therefore, greater dynamic power consumption, leading to better-optimized circuits. Peres gate-based circuits often have the potential to lower power consumption due to fewer transitions and gate count, but the specific performance depends on the design and implementation details of the overall circuit. As a matter of fact, the reversible ripple carry adder is suitable for low-power applications but has a higher delay due to the sequential carry propagation. The reversible carry look-ahead adder is faster than ripple carry due to parallel carry calculation but requires more gates and garbage outputs. The reversible carry-save adder is used in multi-operand addition scenarios, like in multipliers, but with higher complexity. The reversible multiplier is a simple design but has a high gate count and quantum cost. The reversible adder and multiplier design using Vedic mathematics are optimized for high-speed operations but at the cost of significantly increased hardware complexity and power consumption. Figure 38 shows the performance comparison between the different metrics used for different reversible logic gates used in this. The parameter levels are shown with bars of heights 1, 2, and 3 representing low, moderate, and high, respectively, for respective reversible logic gates. Fewer gates are required due to the Peres gate's dual function of AND and XOR, which further minimizes the quantum cost and also fewer garbage outputs than Toffoli and Fredkin-based designs. From this chart, it is quite clear that the use of the Peres gate for the design of adders and multipliers outperforms the other reversible gates.