Graduation Year
2012
Document Type
Thesis
Degree
M.S.Cp.
Degree Granting Department
Computer Science and Engineering
Major Professor
Nagarajan Ranganathan, Ph.D.
Committee Member
Srinivas Katkoori, Ph.D.
Committee Member
Hao Zheng, Ph.D.
Keywords
Ancilla Inputs, Garbage Outputs, Modified Fredkin Gate, Quantum Computing, Quantum Cost
Abstract
The reversible logic has the promising applications in emerging computing paradigm
such as quantum computing, quantum dot cellular automata, optical computing, etc. In
reversible logic gates there is a unique one-to-one mapping between the inputs and outputs.
To generate an useful gate function the reversible gates require some constant ancillary
inputs called ancilla inputs. Also to maintain the reversibility of the circuits some additional
unused outputs are required that are referred as the garbage outputs. The number of
ancilla inputs, number of garbage outputs and quantum cost plays an important role in
the evaluation of reversible circuits. Thus minimizing these parameters are important for
designing an efficient reversible circuit. Barrel shifter is an integral component of many
computing systems due to its useful property that it can shift and rotate multiple bits in a
single cycle.
The main contribution of this thesis is a set of design methodologies for the reversible
realization of reversible barrel shifters where the designs are based on the Fredkin gate and
the Feynman gate. The Fredkin gate can implement the 2:1 MUX with minimum quantum
cost, minimum number of ancilla inputs and minimum number of garbage outputs and the
Feynman gate can be used so as to avoid the fanout, as fanout is not allowed in reversible
logic. The design methodologies considered in this work targets 1.) Reversible logical right-
shifter, 2.) Reversible universal right shifter that supports logical right shift, arithmetic
right shift and the right rotate, 3.) Reversible bidirectional logical shifter, 4.) Reversible
bidirectional arithmetic and logical shifter, 5) Reversible universal bidirectional shifter that
supports bidirectional logical and arithmetic shift and rotate operations. The proposed
design methodologies are evaluated in terms of the number of the garbage outputs, the
number of ancilla inputs and the quantum cost. The detailed architecture and the design of
a (8,3) reversible logical right-shifter and the (8,3) reversible universal right shifter are
presented for illustration of the proposed methodologies.
Scholar Commons Citation
Kotiyal, Saurabh, "Design Methodologies for Reversible Logic Based Barrel Shifters" (2012). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/4106
