Design of an Efficient Reversible Logic Based Bidirectional Barrel Shifter

Embedded digital signal processors and general purpose processors will use barrel shifters to manipulate data. This paper will present the design of the barrel shifter that performs logical shift right, arithmetic shift right, rotate right, logical shift left, arithmetic shift left, and rotate left operations. The main objective of the upcoming designs is to increase the performance without proportional increase in power consumption. In this regard reversible logic has become most popular technology in the field of low power computing, optical computing, quantum computing and other computing technologies. Rotating and data shifting are required in many operations such as logical and arithmetic operations, indexing and address decoding etc. Hence barrel shifters which can shift and rotate multiple bits in a single cycle have become a common choice of design for high speed applications. The design has been done using reversible fredkin and feynman gates. In the design the 2:1 mux can be implemented by fredkin gate which reduce quantum cost, number of ancilla bits and number of garbage outputs. The feynman gate will remove the fanout. By comparing the quantum cost, number of ancilla bits and number of garbage outputs the design is evaluated. Keywordsbarrel shifters, quantum cost, ancilla bits, verilog.