Added option for reduction of long clock sequences in wavedrom converter

Signed-off-by: Wojciech Gryncewicz <wgryncewicz@antmicro.com>

scripts/python-skywater-pdk/skywater_pdk/cells/generate/vcd2wavedrom.py

@@ -18,6 +18,7 @@ import sys
 import argparse
 import pathlib
 import wavedrom
+import re
 from contextlib import contextmanager
 
 
@@ -83,7 +84,33 @@ def readVCD (file):
 
     return vcd
 
-def parsetowavedrom (file, savetofile = False):
+
+def reduce_clock_sequences (wave) :
+    ''' Remove clock seqnces longer than 2 cycles
+        not accompanied by other signals changes
+
+    Parameters:
+        wave - dictionary 'signal'->['list of states'] [dict]
+    '''
+    for v in wave:
+        sig   = wave[v] # analized signal
+        other = [wave[i] for i in wave if i!=v] # list of other signals
+        other = [''.join(s) for s in zip(*other)]  # list of concatenated states
+        other = [len(s.replace('.','')) for s in other] # list of state changes count
+        sig   = [s if o==0 else ' ' for s,o in zip(sig,other)] # keep only when no changes in other
+        sig   = "".join(sig)
+        cuts  = []
+        for m in re.finditer("(10){2,}",sig):
+            cuts.append( (m.start()+1, m.end()-1) ) # area to be reduced, leave 1..0
+        cuts.reverse()
+        for cut in cuts:
+            for v,w in wave.items():              # reduce cuts from all signals
+                wave[v] = w[ :cut[0]] + w[cut[1]: ]
+
+    return wave
+
+
+def parsetowavedrom (file, savetofile = False, reduce_clock = False):
     ''' Reads and simplifies VCD waveform
         Generates wavedrom notation.
 
@@ -140,7 +167,8 @@ def parsetowavedrom (file, savetofile = False):
             if len(line)>=2:
                 wave [ varsubst[line[1]] ][-1] = line[0]
 
-    # TODO: add "double interval support"
+    if reduce_clock:
+        wave = reduce_clock_sequences(wave)
 
     signals  = []
     for v in wave.keys():
@@ -160,6 +188,9 @@ def parsetowavedrom (file, savetofile = False):
 def quoted_strings_wavedrom (wdr) :
     ''' Convert wavedrom script to more restrictive
         version of JSON with quoted keywords
+
+    Parameters:
+        wdr - wavedrom script [str]
     '''
     wdr = wdr.replace(' signal:',' "signal":')
     wdr = wdr.replace(' name:',' "name":')
@@ -190,6 +221,11 @@ def main():
             "--savesvg",
             help="generate .svg image",
             action="store_true")
+    parser.add_argument(
+            "-r",
+            "--reduceclk",
+            help="reduce clock sequences",
+            action="store_true")
     parser.add_argument(
             "infile",
             help="VCD waveform file",
@@ -209,7 +245,7 @@ def main():
     errors = 0
     for f in infile:
         try:
-            wdr = parsetowavedrom(f, args.wavedrom)
+            wdr = parsetowavedrom(f, args.wavedrom, args.reduceclk)
             if args.savesvg:
                 svg = wavedrom.render( quoted_strings_wavedrom(wdr) )
                 outfile = f.with_suffix(".svg")