In almost all the Digital Signal Processing (DSP) applications, the vital operations involve multiplications and accumulations. Consequently, there is a demand for dedicated hardware in processors to enhance the speed with which these multiplications and accumulations are performed. In the present world of irreversible circuits, the Multiply Accumulate Unit multiplies the two operands, adds the product to the previously accumulated result and stores back the new result in the Accumulator all in a single clock cycle. On the other hand, implementation of digital circuits in reversible logic is gaining popularity with the arrival of quantum computing and reversible logic. In this paper, we propose a novel Reversible Multiply Accumulate (MAC) unit. We also build a Reversible Vedic MAC unit and compare various possible implementations of the reversible MAC unit in terms of Quantum Cost, number of Garbage Outputs and Depth.
In almost all the Digital Signal Processing (DSP) applications, the vital operations involve multiplications and accumulations. Consequently, there is a demand for dedicated hardware in processors to enhance the speed with which these multiplications and accumulations are performed. In the present world of irreversible circuits, the Multiply Accumulate Unit multiplies the two operands, adds the product to the previously accumulated result and stores back the new result in the Accumulator all in a single clock cycle. On the other hand, implementation of digital circuits in reversible logic is gaining popularity with the arrival of quantum computing and reversible logic. In this paper, we propose a novel Reversible Multiply Accumulate (MAC) unit. We also build a Reversible Vedic MAC unit and compare various possible implementations of the reversible MAC unit in terms of Quantum Cost, number of Garbage Outputs and Depth.
There are many arithmetic operations which are performed, on a computer arithmetic unit, through the use of multipliers (e.g., exponential and trigonometric functions). Consequently, optimized multipliers are on demand while designing an arithmetic unit. On the other hand, given the advent of quantum computer and reversible logic, design and implementation of digital circuits in this logic has gained popularity. In reversible circuit design, decreasing three parameters is of interest: quantum cost, depth of the circuit and the number of garbage outputs. In this paper, we propose a novel reversible multiplier with the aim of decreasing the depth of the circuit while neither scarifying any extra quantum cost nor garbage outputs. The partial products, as is the case for prior works, are generated in parallel using Peres gates and thereafter a reversible multi-operand adder consisting of reversible full-adders and half-adders produces the final product.
In recent years, there has been an increasing tendency towards designing circuits based on reversible logic, and has received much attention because of preventing internal power dissipation. In digital computing systems, multiplier circuits are one of the most fundamental and practical circuits used in the development of a wide range of hardware such as arithmetic circuits and Arithmetic Logic Unit (ALU). Vedic multiplier, which is based on Urdhva Tiryakbhayam (UT) algorithm, has many applications in circuit designing because of its high speed in performing multiplication compared to other multipliers. In Vedic multipliers, partial products are obtained through vertical and cross multiplication. In this paper, we propose four [Formula: see text] reversible Vedic multiplier blocks and use each one of them in its right place. Then, we propose a [Formula: see text] reversible Vedic multiplier using the four aforementioned multipliers. We prove that our design leads to better results in terms of quantum cost, number of constant inputs and number of garbage outputs, compared to the previous ones. We also expand our proposed design to [Formula: see text] multipliers which enable us to develop our proposed design in every dimension. Moreover, we propose a formula in order to calculate the quantum cost of our proposed [Formula: see text] reversible Vedic multiplier, which allows us to calculate the quantum cost even before designing the multiplier.
Quantum computation is modeled by quantum circuits. All the quantum operations are reversible so the quantum circuits can be built using reversible logic gates. Reversible computing is the emerging technology, its major role is in the field of quantum computing, optical computing, and design of low power nanocircuits. The most frequently used computational unit for digital signal processing and multimedia applications is multiplier. To compute square of an operand, regular multipliers are used in general. This paper proposes a dedicated quantum circuit for computing square of an operand efficiently compared to the existing multipliers in the literature. The squaring unit is mathematically modeled and its metrics quantum cost, garbage outputs and ancilla input, gate count are calculated. We compared the proposed design with the existing multipliers to compute square and found that proposed square unit is efficient in terms of quantum cost, garbage outputs, ancilla inputs and gate count. The proposed reversible square circuit has 63% to 85% improvement of quantum cost, garbage outputs, ancilla inputs and gate count over existing reversible multiplier circuits.
Quantum computers provide considerable potential to enhance computing technology, anticipated to surpass conventional computers by resolving intricate challenges that existing systems cannot tackle. They use quantum algorithms for improved performance and depend on reversible computations based on quantum physics and linear algebra. In contrast to traditional computing, which may include irreversible processes, quantum computing relies on unitary operations that are fundamentally reversible. The parity-preserving feature enables the identification of both permanent and transient defects within circuits. The parity-preserving feature ensures that the input and output states are equal in reversible circuits. Vedic multipliers offer a crucial foundation in the design and implementation of digital circuits, recognized for their speed, efficiency, ease of calculations, reduction of errors, and broad applicability. Prior investigations of quantum Vedic multipliers have faced obstacles like elevated Quantum Cost (QC), substantial Garbage Output (GO), Constant Input (CI), augmented Gate Count (GC), and CNOT-V/V+ count, resulting in more resource use and implementation intricacy. These inefficiencies hinder the scalability and feasibility of quantum multipliers in high-performance computing applications. A proposed solution to these issues is to introduce a cost-effective, parity-preserving reversible quantum block synthesized through an established method that produces a network list of multi-controlled Toffoli (MCT) gates. This Toffoli-based network is then optimized using various techniques, ultimately transforming it into a network of fundamental quantum gates. This approach decreases quantum expenses, eliminates unnecessary outputs, and enhances quantum gate efficiency. Integrating this innovative technique into the reversible quantum Vedic multipliers offers a more efficient, cost-effective, and scalable solution than current approaches. All proposed designs, such as a half adder-subtractor, a ripple carry adder (RCA), and two-bit and four-bit Vedic multipliers, are suggested based on functional blocks and pre-existing components. The suggested structures undergo evaluation in comparison to existing state-of-the-art procedures, demonstrating their cost-effectiveness. The observed average savings for two-bit and four-bit Vedic multipliers, with respect to QC, number of CNOT-V/V+ count, GO, CI, and GC, are 20.01%, 19.38%, 37.51%, 37.51%, and 54.89%, and 22.71%, 18.78%, 27.23%, 31.10%, and 42.38%, respectively when compared to previous studies. Furthermore, all suggested circuits are evaluated and confirmed using the IBM quantum laboratory.
Reversible logic circuits have received significant attention in quantum computing, low power CMOS design, optical information processing, DNA computing, bioinformatics, and nanotechnology. This paper presents two new 4 × 4 bit reversible multiplier designs which have lower hardware complexity, less garbage bits, less quantum cost and less constant inputs than previous ones, and can be generalized to construct efficient reversible n × n bit multipliers. An implementation of reversible HNG is also presented. This implementation shows that the full adder design using HNG is one of the best designs in term of quantum cost. An implementation of MKG is also presented in order to have a fair comparison between our proposed reversible multiplier designs and the existing counterparts. The proposed reversible multipliers are optimized in terms of quantum cost, number of constant inputs, number of garbage outputs and hardware complexity. They can be used to construct more complex systems in nanotechnology.
In EDA, Reversible logic has its applications in designing computer graphics, digital signal processing, quantum computing, nanotechnology and cryptography. It is a prospective design style in quantum computing and modern nanotechnology. Although noteworthy proposals have been put forth towards defining new reversible logic gates and sub units of ALUs, design of efficient Multiplier block remains crucial to the realization of a high-performance Reversible Logic ALU that can be leveraged by Deep Neural Networks for high performance MAC operations. This paper proposes the design and comparison of a component scalable Reversible Logic Multiplier using the proposed SAK gate. The verification and simulation have been carried out using Vivado® by Xilinx and further implemented on an Artix®-7 based cost effective FPGA. The proposed design has 27% lesser Gate Count and 12.5% lesser Quantum Cost compared to prior designs.