[Gtkwave-users] Problem with viewing FST generated by Icarus Verilog in GTKWAVE

[Ron B. <rbu...@ea...>]

I've partially switched over from using LXT2 files to using FST files in 
running simulations in Icarus, but can't do so entirely because of a 
little problem I'm having viewing the FST dumpfiles in GTKWAVE.

The problem can be reproduced with the files at this Google Drive link: 
https://drive.google.com/open?id=1sif-JU89qnlCuG_Rn3dWDskXoo9Rs6_j. To 
see the problem, you have to view agc.fst in GTKWAVE, using test.gtkw, 
making sure that instruction_trans_decoder.py is in the same directory.  
What you should see is what's in screenshot.png (which I got by viewing 
agc.lxt2), but what I actually get is an error message from GTKWAVE reading:

    ERROR: Group End encountered with no matching start. Ignoring.

What's going on in this example is that a Python script 
(instruction_trans_decoder.py) has been provided that decodes the 
signals in the dumpfile, and displays them in GTKWAVE as CPU opcodes.  
This works when I view the LXT2 file, but fails when I view the FST 
file.  The signals in the dumpfile are fine, as far as I know, but the 
decoded instructions simply won't show up when viewing the FST file.

This also fails if I use fst2vcd and vcd2lxt2 to create an LXT2 file 
from the FST file, and then try to view the newly-created LXT2 file.

Is this a problem with the format of my gtkw file?  With GTKWAVE?  With 
Icarus?

-- Ron

P.S., I'm using the latest Icarus release candidate and GTKWAVE 3.3.95.