This reworks (and simplifies) plru_tb to use the new plrufn module
instead of the old (and now unused) plru module.
The latter is now removed completely.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Jacob Lifshay found a couple of issues with the PLRU implementation:
- The tree array is one bit too long. This is harmless as this bit is never
accessed and thus should be optimized out
- The PLRU read is using the wrong nodes when going down the tree, which leads
to incorrect results.
This fixes it and improves the test bench a bit. I have verified the expected
output using a hand-written tree states, observed the mismatch with the
current implementation and verified the fix.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The VUnit log package is a SW style logging framework in VHDL and the check package is an assertion library doing its error reporting with VUnit logging.
These testbenches don't use, and do not need, very advanced logging/checking features but the following was possible to improve
- Checking equality in VHDL can be quite tedious with a lot of type conversions and long message strings to explain the data received and what was expected.
VUnit's check_equal procedure allow comparison between same or similar types and automatically create the error message for you.
- The code has report statements used for testbench progress reporting and debugging. These were replaced with the info and debug procedures.
info logs are visible by default while debug is not. This means that debug logs don't have to be commented, which they are now, when not used.
Instead there is a show procedure making debug messages visible. The show procedure has been commented to hide the debug messages but a more elegant
solution is to control visibility from a generic and then set that generic from the command line. I've left this as a TODO but the run script allow you to
extend the standard CLI of VUnit to add new options and you can also set generics from the run script.
- VUnit log messages are color coded if color codes are supported by the terminal. It makes it quicker to spot messages of different types when there are many log messages.
Error messages will always be made visible on the terminal but you must use the -v (verbose) to see other logs.
- Some tests have a lot of "metvalue detected" warning messages from the numeric_std package and these clutter the logs when using the -v option. VUnit has a simulator independent
option allowing you to suppress those messages. That option has been enabled.
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
This commit also removes the dependencies these testbenches have on VHPIDIRECT.
The use of VHPIDIRECT limits the number of available simulators for the project. Rather than using
foreign functions the testbenches can be implemented entirely in VHDL where equivalent functionality exists.
For these testbenches the VHPIDIRECT-based randomization functions were replaced with VHDL-based functions.
The testbenches recognized by VUnit can be executed in parallel threads for better simulation performance using
the -p option to the run.py script
Signed-off-by: Lars Asplund <lars.anders.asplund@gmail.com>
Benjamin Herrenschmidt