VL Verilog Toolkit -- System Level Tests

These files do some testing of VL translations using a commerical Verilog
simulator (typically NCVerilog).  These are essentially system-level or
end-to-end, blackbox tests of VL.

You should be able to run the tests by just using "make", after first building
the VL Verilog Toolkit by running "make vl" in the acl2/books directory.

Each test is in its own directory:

  - The file spec.v will be translated by the "vl model" tool to build a new,
    impl.v file with the simplified modules.

  - The file compare.v will then be run on the Verilog simulator.  Typically
    compare.v should load spec.v and impl.v, and compare them in some way.

  - The test bench should print either "error" or "fail" if anything is wrong.
    The errcheck.pl script will look for this string in the Verilog output log
    to determine if the test passes.

Miscellaneous notes and tips:

  - To avoid name clashes when loading both spec.v and impl.v, the spec.v file
    should ordinarily have a parameter.  This will ensure that VL gives it a
    new name, e.g., \foo$size=1.

  - To suppress a failing test, simply rename spec.v to something else.  The
    presence of spec.v governs which directories will be run.
