1.2.0 Pre-release

[Lramseyer]

Features

• File parsing uses the wellen library compiled to wasm. Benefits include:
  • FST file support 🎉
  • Improves file parsing speed and drastically improves memory efficiency for VCD files
• Removed checkboxes for scope [module] items in netlist viewer to reduce confusion
• Variables loaded into viewer show up before waveform data is loaded as a better visual acknowledgement to user action

Notes

In this version, I ripped out a lot of code, and replaced it with WASM code. It's much faster, but data structures have moved, and some features may have broken. I wanted to get this out for those of you really wanting to get your hands on a working version with proper FST support. I will be cleaning up a few things here and there, as well as implementing features from the latest version of wellen (that just released as I was putting this release together.)

Known issues

• Searching signals via netlist path name is not yet implemented
• Variables that are subsets of multi-bit variables do not yet load
• Documentation has not yet been updated to reflect all of the changes I have made to internal data structures

Special thanks to @ekiwi for all of the support with the wellen library!

As always, please let me know if you run into any other issues!

---

This discussion was created from the release 1.2.0 Pre-release.

[koni-ey]

Wow, vcd's now really load way faster, super nice!!
I wanted to try out the fst format, but ran into an issue while trying to open a file:
"Unable to open xxxx.fst - Calling WASM function vscode:example#loaodfst failed."

The file seems to be valid, as it opens in gtkwave without any problems. I am running VScode Version 1.93.0 through WSL.

Thank you for this extension and keep up the great work!

[Lramseyer]

If you were able to load a VCD with the same setup, but not a FST, then that seems to indicate that it's not a WASM build issue. To isolate the problem, try loading the FST file into Surfer. Both of us use the same file parsing library. So if you also encounter an error with surfer, then you will have to file a bug report here. Mention that it breaks both in Surfer and Vaporview. But if it works in Sufer, then it's an issue with my code, and I'm more than happy to help debug! But let me know your findings either way!

Regardless of where you report the bug, Can you also provide some additional information:

How big is the FST file?
Was it converted to VCD before being converted to FST?
How was the FST file generated? What simulator was used to generate the initial waveform dump?

Lastly, there are a bunch of example FST files in the fst-native repo (which is owned and maintained by the guy who owns the wellen library) and these files are known to work with wellen. If you have trouble opening these files with Vaporview, it's probably a bug in my code.

[koni-ey]

Thanks for getting back to me!

I tried loading it in surfer, and the same fst works there.
BUT I then reinstalled the extension again (same vsix as before) and it now works through WSL, but weirdly not when using the "native" windows version. I also tried the scope_with_comment.vcd.fst from the fst-native repo you mentioned. The error I get now is: "The editor could not be opened due to an unexpected error: A dynamic import callback was not specified.". Don't think its related to the FST parsing part, because it gives me the same error when i try to load a vcd (also checkt for validity by loading it into surfer before). Maybe it's a Windows Problem? What OS are you developing on?

So TL;DR:
FST loading works like a charm on Windows through WSL.
FST and VCD currently don't load for me on Windows without WSL.

Additionally: I am working mostly with the output of GHDL. It can dump vcd or also fst directly. One problem I am facing in all viewers I tried so far (surfer, gtkwave, vaporwave) is that when I try to open a vcd while the simulation is still running, the file may be in an uncomplete state which crashes the viewers. Don't know if this is unavoidable with the vcd format, but that would be an issue for the wellen library i guess.
Cheers and have a nice day,
Konstantin

[Lramseyer]

I am developing on windows 10.

The issue may have to do with where you install the extension. If I recall correctly, WSL works similar to a VScode remote session. In future versions, I do plan to make sure that the remote experience is more stable, but I am the only active contributor at this time, so my priority right now is the wellen integration.

Another thing you could try is activating/deactivating the extension when you get the session active. I call Webassembly.compile() (the JS function, not the Rust compiler) on activation of the extension, but I am not sure what the implications are of doing that with remote sessions that may have different "kernels".

[ekiwi]

when I try to open a vcd while the simulation is still running, the file may be in an uncomplete state which crashes the viewers.

Currently, wellen does not support loading incomplete files. That feature may be added in the future, if I find time to do so, or if a community contributor steps up to implement it.