VLSI Implementation of ALU using Reversible Logic with Vedic Mathematics

VLSI Implementation of ALU using Reversible Logic with Vedic Mathematics
Authors:SRAVANTHI, T.VENKATA LAKSHMI

Abstract: High speed and power efficient ALU plays a vital role in microcontrollers, microprocessors, central processing units. In CPU one of the most important blocks is arithmetic and logic unit hence it is requisite to have fast and efficient ALU. Information lossless (or) reversible circuits have applications in communications, digital signal processing, and computer graphics. Reversible logic is used to reduce the power dissipation that occurs in normal circuits by preventing the loss of information. In this paper arithmetic and logical unit designed by using reversible logic with Vedic mathematics. This ALU is not only efficient in power and speed but also in area. In arithmetic unit basic operations are addition, subtraction, multiplication among these operations multiplication plays major role in ALU the speed of the ALU will depends upon the speed of the multiplier. There are so many multiplier techniques among that Vedic Urdhva Tiryakbhayam algorithm is best one it generates partial products parallel and concurrent addition of these partial prodect is done. All the modules are designed by using reversible gates. This ALU is able to perform four arithmetic and 16 logical operations. The proposed arithmetic and logical unit is coded in Verilog HDL synthesized and simulated using XilinxISE software. 

Keywords: ALU, UT Technique, Subtractor, Comparator, Area. 

 INTRODUCTION 

          ALU is a complex arithmetic structure, which is reflected in its moderately more signal propagation delay, more power dissipation, and high area requirement. When choosing a ALU for a digital system, the bit width of the ALU is required to be at least as wide as the largest operand of the applications that are to be executed on that digital system. The digital ALU is a ubiquitous arithmetic unit in microprocessors, digital signal processors, and emerging media processors [2]–[3]. It is also a kernel operator in application specific data path of video and audio codecs, digital filters, computer graphics, and embedded systems [6]–[9]. Com- pared with many other arithmetic operations, multiplication is time-consuming and power hungry. The critical paths dominated by digital multipliers often impose a speed limit on the entire design. Hence, VLSI design of high-speed multipliers, with low energy dissipation, is still a popular research subject. Now a day‟s all CPU units, any machinery parts utilizes a basic arithmetic operations like addition, subtraction, multiplications. ALU plays a vital role in CPU‟s, Microprocessors, Microcontrollers so ALU is the heart of the processor. The central processing unit speed is greately depends upon the ALU so we need to have fast and efficient ALU.

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