This file should be read first.
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COPYRIGHT

    VHDL Code for a Linear-Feedback Shift Register
        accompanying WL Tech Report WL-TR-91-5037

    (c) Copyright 1991, Karen M. Serafino and Michael A. Dukes

        Unlimited rights are granted to the United States Government.
        Material prepared pursuant to official duties of Michael A.
        Dukes, Captain, U.S. Army, as an officer of the U.S.
        Government and Karen M. Serafino, Captain, U.S. Air Force,
        as an officer of the U.S. Government.

        The fitness of this software is not warranted for any
        particular purpose or application.

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The contents of this directory contain the VHDL code for a small
linear-feedback shift register, VHDL code for the proposed standard
of WAVES (Vers 3.3.2), command files for execution of Intermetrics
VHDL (Vers 2.1) under VMS (Vers 5.4) and SunOS (Rel 4.1), and
documentation.

    lfsr           VHDL code for LFSR and WAVES
    lfsr/COMS      Command files
    lfsr/RESULTS   Our Results from running the code
    lfsr/DOC       Documentation

AUTHORS

Captain Karen M. Serafino
WL/ELED
Wright-Patterson AFB OH 45433-6543
(513) 255-8635

Captain Michael A. Dukes
WL/ELED
Wright-Patterson AFB OH 45433-6543
(513) 255-8626

DISCLAIMER

There is no warrantly, implied or otherwise, as to the fitness of the
code provided.  This code is freely offered to all who are interested
in WAVES and in no way is meant to be an interpretation or recommendation
of the IEEE or the U.S. Government.

What do we believe the copyright means?  We believe that the copyright
notice allows all interested individuals to copy this code and use
it in pursuit of understanding WAVES and VHDL.  This means academia and
research institutions may use this code freely for education and
research.  Private individuals may use this code for their own personal
advancement for greater knowledge.  We also believe that the use of this
VHDL code is strictly NOT-FOR-PROFIT.

RESULTS

There are three indicators for a successful run.  The first is that the
quiescent state is reached after 7090 ns.  The second indicator is
that the file lfsr.out from the simulation run matches RESULTS/lfsr.out.
The last is that the file waves.out from the simulation run matches
RESULTS/waves.out.

BUGS

The following lists a few errors that may occur and possible fixes.


BUG 1

Symptom

%VHDSIM-N-SIGTRAN Signal Tracing turned on 
%VHDSIM-E-EFOPENI Error opening external file  after 0 fs
    in procedure WAVEFORM at line 12 in package body
    <<DUKES.LFSR>>WAVES_GENERATOR on line 33
    from WAVES on line 115
    from design unit <<DUKES.LFSR>>TEST(TEST) on line 115

Fix

The waves_external file should reside wherever "sim test" is performed.
On the sun, the file should be "waves_external" not "waves_external."
with a period after the filename.  This is different for VMS.

