--- a/.hgignore	Sun Sep 06 23:14:14 2020 +0000
+++ b/.hgignore	Mon Sep 07 00:40:55 2020 +0000
@@ -15,6 +15,7 @@
 ^ueda/utils/cutelements$
 ^ueda/utils/instfileelem$
 
+^netdiff/convert/pads2donl$
 ^netdiff/convert/protel2donl$
 
 ^pads2gpcb/pads2gpcb$

--- a/netdiff/convert/Makefile	Sun Sep 06 23:14:14 2020 +0000
+++ b/netdiff/convert/Makefile	Mon Sep 07 00:40:55 2020 +0000
@@ -1,6 +1,6 @@
 CC=	gcc
 CFLAGS=	-O2
-PROGS=	protel2donl
+PROGS=	pads2donl protel2donl
 BINDIR=	/usr/local/bin
 
 all:	${PROGS}
@@ -14,4 +14,5 @@
 clean:
 	rm -f *.[ao] a.out core errs ${PROGS}
 
-protel2donl: protel2donl.c
+pads2donl:	pads2donl.c
+protel2donl:	protel2donl.c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netdiff/convert/pads2donl.c	Mon Sep 07 00:40:55 2020 +0000
@@ -0,0 +1,103 @@
+/*
+ * This program converts a PADS ASCII netlist into our
+ * Diff-Oriented Netlist (DONL) format.
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+#define	MAX_NETNAME	127
+
+static char *infname;
+static FILE *inf;
+static char linebuf[512], netname[MAX_NETNAME+1];
+static int lineno;
+
+static void
+process_signal_line()
+{
+	char *cp, *np;
+
+	cp = linebuf + 1;
+	while (*cp != '*')
+		cp++;
+	cp++;
+	if (!isspace(*cp)) {
+badsig:		fprintf(stderr, "%s line %d: malformed SIGNAL line\n",
+			infname, lineno);
+		exit(1);
+	}
+	while (isspace(*cp))
+		cp++;
+	if (!*cp)
+		goto badsig;
+	for (np = cp; *cp && !isspace(*cp); cp++)
+		;
+	if (*cp)
+		*cp = '\0';
+	if (strlen(np) > MAX_NETNAME) {
+		fprintf(stderr, "%s line %d: signal name too long\n",
+			infname, lineno);
+		exit(1);
+	}
+	strcpy(netname, np);
+}
+
+static void
+process_data_line()
+{
+	char *cp, *np;
+
+	for (cp = linebuf; ; ) {
+		while (isspace(*cp))
+			cp++;
+		if (!*cp)
+			break;
+		for (np = cp; *cp && !isspace(*cp); cp++)
+			;
+		if (*cp)
+			*cp++ = '\0';
+		printf("%s\t%s\n", netname, np);
+	}
+}
+
+main(argc, argv)
+	char **argv;
+{
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s pads-netlist-file\n", argv[0]);
+		exit(1);
+	}
+	infname = argv[1];
+	inf = fopen(infname, "r");
+	if (!inf) {
+		perror(infname);
+		exit(1);
+	}
+	for (;;) {
+		if (!fgets(linebuf, sizeof linebuf, inf))
+			break;
+		lineno++;
+		if (!index(linebuf, '\n')) {
+			fprintf(stderr, "%s line %d: missing newline\n",
+				infname, lineno);
+			exit(1);
+		}
+		if (linebuf[0] == '*') {
+			if (!strncmp(linebuf, "*END*", 5))
+				break;
+			if (!strncmp(linebuf, "*SIG*", 5) ||
+			    !strncmp(linebuf, "*SIGNAL*", 8))
+				process_signal_line();
+			else
+				netname[0] = '\0';
+			continue;
+		}
+		if (netname[0])
+			process_data_line();
+	}
+	exit(0);
+}