Add VCD support to Simulation framework
Right now we have TCL wave files. These are converted to GHW wave files. However, when debugging e.g. sanity test, simulation performance is very bad (about two orders of magnitude worse than modelsim). This is caused by dumping all the waves in GHW file.
- Long simulation time -> Hard to debug. Advantages:
- All waves are dumped -> Able to display next wave in the middle of simulation
GHDL also supports dumping in VCD format which may be filtered.
The aims of this task are:
- Write parser for TCL files which would create a file that can be used with "--read-wave-opt=". GHDL should only dump signals which are part of this TCL file!
- Embed this dumping to Python test framework. There will be two options for wave files (GHW or VCD), GHW will dump everything and only display what is in TCL file. VCD will only dump what is in the TCL file and also display it in GTKWave.
As this is next feature of the test framework (which is quite generic) though it might be handy to re-factor the test framework before implementing it. By refactoring I namely mean separating test specific stuff from common framework/simulation stuff.