WAGSR
a tool for generalized feed forward shift registers

What is WAGSR?

WAGSR (Web Application for Generalized feed forward Shift Registers) is an web application program to compute/solve various problems on GFFSR (Generalized Feed Forward Shift Register) by symbolic and logic simulation as follows.
  1. Design of GFFSR by means of logic expressions 
  2. Illustration of GFFSR 
  3. Computation for GFFSR
    • Symbolic simulation 
    • Logic simulation by partially specifying values 0, 1, and/or X to input/output sequence, initial state, and/or final state.

What is GFFSR?

GFFSR is a circuit with the form shown in this figure. It is a generalized form of linear feed forward shift registers. In this figure, f1, f2, ..., fk are arbitrary logic functions.

How to use WAGSR

WAGSR is a Web application.  You can use it from the following URL.
To use it, SVG Web browser is necessary. (Internet Explorer 9 or later, Firefox 1.5 or later, Safari 3 or later)

1. Design of GFFSR by means of logic expressions

  1. Circuit Designer button:  Start the design of a new circuit.
  2. Stage field:  Enter the number of flip-flops
  3. “by expressions” tab:  Enter the logic expressions in JavaScript form.
    Available operators:
      OR XOR AND NOT 
     Symbol | ^ & !
    Usage (IN|FF1) (IN^FF1) (IN&FF1) !IN
  • “Transform into ~” button:  The logic expression is transformed into Reed-Muller canonical form or CNF.
  • Circuit with feed-back can also be defined, but computation cannot be done.
  • “by XOR connection” tab:  circuit with XOR connection only can be designed easily by using ON/OFF of connections. (a tool specialized to linear circuits is open to the public SREEP)

2. Illustration of GFFSR

3. Computation for GFFSR

  • “Info” tab:  illustrate basic information
  • “Variable” tab:  symbolic simulation
  • “Calc” tab:  logic simulation by partially specifying values 0, 1, and/or X to input/output sequence, initial state, and/or final state. If inconsistency occurs, it becomes red.  

References

    1.  Katsuya Fujiwara and Hideo Fujiwara, "WAGSR: Web Application for Generalized Feed Forward Shift Registers," 13th IEEE Workshop on RTL and High Level Testing (WRTLT'12), pp. 1.2.1-1.2.7, Nov. 2012.
    2.  Katsuya Fujiwara and Hideo Fujiwara,"Generalized Feed Forward Shift Registers and their Application to Secure Scan Design," IEICE Trans. on Inf. and Syst., Vol. E96-D, No. 5, pp. 1125-1133, May 2013.
    

Copyright 2012, Katsuya FujiwaraandHideo Fujiwara.