Added scripts to convert the statistics blocks to monte carlo
parameters that are compatible with ngspice syntax. 1st attempt;
application of the scripts is commented out in the makefile. Under
test and review.
diff --git a/sky130/custom/scripts/mismatch_params.py b/sky130/custom/scripts/mismatch_params.py
new file mode 100755
index 0000000..1cb5ad8
--- /dev/null
+++ b/sky130/custom/scripts/mismatch_params.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+#
+#--------------------------------------------------------------------
+# Parse the SPICE model files from sky130 and use the (commented out)
+# statistics block to generate the correct monte carlo expressions
+# in the device models for mismatch.
+#--------------------------------------------------------------------
+
+import os
+import re
+import sys
+
+mm_switch_param = 'MC_MM_SWITCH'
+
+walkpath = 'sky130A/libs.ref/sky130_fd_pr/spice'
+
+if len(sys.argv) > 1:
+ walkpath = sys.argv[1]
+
+mismatch_params = []
+
+mmrex = re.compile('^\*[ \t]*mismatch[ \t]+\{')
+endrex = re.compile('^\*[ \t]*\}')
+
+filelist = []
+
+#--------------------------------------------------------------------
+# Step 1. Gather variables
+#--------------------------------------------------------------------
+
+for dirpath, dirnames, filenames in os.walk(walkpath):
+ for filename in filenames:
+ if os.path.splitext(filename)[1] == '.spice':
+ infile_name = os.path.join(dirpath, filename)
+ filelist.append(infile_name)
+
+ infile = open(infile_name, 'r')
+
+ state = 'before_mismatch'
+ line_number = 0
+ replaced_something = False
+
+ for line in infile:
+ line_number += 1
+
+ if state == 'before_mismatch':
+ mmatch = mmrex.match(line)
+ if mmatch:
+ state = 'in_mismatch'
+ elif state == 'in_mismatch':
+ ematch = endrex.match(line)
+ if ematch:
+ state = 'after_mismatch'
+ else:
+ tokens = line.split()
+ if 'vary' in tokens:
+ if ('dist=gauss' in tokens) or ('gauss' in tokens):
+ mismatch_param = tokens[2]
+ std_dev = float(tokens[-1].split('=')[-1])
+ replacement = '{}*AGAUSS(0,{!s},1)'.format(mm_switch_param, std_dev)
+ mismatch_params.append((mismatch_param, replacement))
+
+ infile.close()
+
+print('')
+print('Mismatch parameters found:')
+for (mismatch_param, replacement) in mismatch_params:
+ print(mismatch_param + ' : ' + replacement)
+print('')
+
+#--------------------------------------------------------------------
+# Step 2. Make replacements
+#--------------------------------------------------------------------
+
+for infile_name in filelist:
+
+ filepath = os.path.split(infile_name)[0]
+ outfile_name = os.path.join(filepath, 'temp')
+
+ infile = open(infile_name, 'r')
+ outfile = open(outfile_name, 'w')
+
+ state = 'before_mismatch'
+ line_number = 0
+ replaced_something = False
+
+ for line in infile:
+ line_number += 1
+
+ if state == 'before_mismatch':
+ outfile.write(line)
+ mmatch = mmrex.match(line)
+ if mmatch:
+ state = 'in_mismatch'
+ elif state == 'in_mismatch':
+ outfile.write(line)
+ ematch = endrex.match(line)
+ if ematch:
+ state = 'after_mismatch'
+ elif state == 'after_mismatch':
+ newline = line
+ for (param, replacement) in mismatch_params:
+ if param in newline:
+ newline = newline.replace(param, replacement)
+ replaced_something = True
+ print(" Line {}: Found mismatch parameter '{}' and replaced with '{}'.".format(line_number, param, replacement))
+ outfile.write(newline)
+
+ infile.close()
+ outfile.close()
+ if replaced_something:
+ print("Something was replaced in '{}', backed up original file and replaced with processed one.".format(infile_name))
+ os.rename(infile_name, infile_name + '.orig')
+ os.rename(outfile_name, infile_name)
+ else:
+ print("Nothing was replaced in '{}'.".format(infile_name))
+ os.remove(outfile_name)
+
