--- a/.hgignore	Thu Feb 27 04:27:18 2020 +0000
+++ b/.hgignore	Thu Feb 27 07:59:47 2020 +0000
@@ -34,6 +34,7 @@
 ^miscutil/fc-vm2hex$
 ^miscutil/imei-luhn$
 ^miscutil/mokosrec2bin$
+^miscutil/srec-regions$
 
 ^ringtools/fc-e1decode$
 ^ringtools/fc-e1gen$

--- a/miscutil/Makefile	Thu Feb 27 04:27:18 2020 +0000
+++ b/miscutil/Makefile	Thu Feb 27 07:59:47 2020 +0000
@@ -1,7 +1,7 @@
 CC=	gcc
 CFLAGS=	-O2
 PROGS=	fc-fr2tch fc-gsm2vm fc-rgbconv fc-serterm fc-tch2fr fc-vm2hex imei-luhn\
-	mokosrec2bin
+	mokosrec2bin srec-regions
 SCRIPTS=c139explore pirexplore
 
 INSTALL_PREFIX=	/opt/freecalypso
@@ -42,6 +42,9 @@
 mokosrec2bin:	mokosrec2bin.c
 	${CC} ${CFLAGS} -o $@ $@.c
 
+srec-regions:	srec-regions.c
+	${CC} ${CFLAGS} -o $@ $@.c
+
 install:
 	mkdir -p ${INSTBIN}
 	install -c ${PROGS} ${SCRIPTS} ${INSTBIN}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/miscutil/srec-regions.c	Thu Feb 27 07:59:47 2020 +0000
@@ -0,0 +1,179 @@
+/*
+ * This program parses an S-record file (TI's *.m0 or otherwise), identifies
+ * the set of discontiguous regions into which this SREC image deposits bits,
+ * and lists these identified regions.
+ */
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <strings.h>
+#include <stdlib.h>
+
+char *infname;
+FILE *inf;
+char srecbuf[1024];
+u_char srecbin[256];
+int lineno, state;
+u_long region_start, region_end;
+
+decode_hex_byte(s)
+	char *s;
+{
+	register int u, l;
+
+	if (!isxdigit(s[0]) || !isxdigit(s[1]))
+		return(-1);
+	if (isdigit(s[0]))
+		u = s[0] - '0';
+	else if (isupper(s[0]))
+		u = s[0] - 'A' + 10;
+	else
+		u = s[0] - 'a' + 10;
+	if (isdigit(s[1]))
+		l = s[1] - '0';
+	else if (isupper(s[1]))
+		l = s[1] - 'A' + 10;
+	else
+		l = s[1] - 'a' + 10;
+	return((u << 4) | l);
+}
+
+srec2bin()
+{
+	register int i, l, b;
+
+	l = decode_hex_byte(srecbuf + 2);
+	if (l < 1) {
+		fprintf(stderr, "%s line %d: S-record length octet is bad\n",
+			infname, lineno);
+		exit(1);
+	}
+	srecbin[0] = l;
+	for (i = 1; i <= l; i++) {
+		b = decode_hex_byte(srecbuf + i*2 + 2);
+		if (b < 0) {
+			fprintf(stderr, "%s line %d: hex decode error\n",
+				infname, lineno);
+			exit(1);
+		}
+		srecbin[i] = b;
+	}
+	return(0);
+}
+
+srec_cksum()
+{
+	u_char accum;
+	register int i, len;
+
+	len = srecbin[0] + 1;
+	accum = 0;
+	for (i = 0; i < len; i++)
+		accum += srecbin[i];
+	if (accum != 0xFF) {
+		fprintf(stderr, "%s line %d: bad checksum\n", infname, lineno);
+		exit(1);
+	}
+	return(0);
+}
+
+main(argc, argv)
+	char **argv;
+{
+	register int i;
+	u_long curaddr;
+	int datalen;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s image.m0\n", argv[0]);
+		exit(1);
+	}
+	infname = argv[1];
+	inf = fopen(infname, "r");
+	if (!inf) {
+		perror(infname);
+		exit(1);
+	}
+
+	state = 0;
+	for (lineno = 1; ; lineno++) {
+		if (!fgets(srecbuf, sizeof srecbuf, inf)) {
+			fprintf(stderr, "%s: premature EOF\n", infname);
+			exit(1);
+		}
+		if (srecbuf[0] != 'S') {
+			fprintf(stderr, "%s line %d: not an S-record\n",
+				infname, lineno);
+			exit(1);
+		}
+		switch (srecbuf[1]) {
+		case '0':
+			if (state == 0)
+				break;
+			else
+				goto badtype;
+		case '3':
+			if (state == 0)
+				goto badtype;
+			else
+				break;
+		case '7':
+			if (state == 2)
+				break;
+			else
+				goto badtype;
+		default:
+		badtype:
+			fprintf(stderr,
+				"%s line %d: S-record type unexpected\n",
+				infname, lineno);
+			exit(1);
+		}
+		srec2bin();
+		srec_cksum();
+		switch (srecbuf[1]) {
+		case '0':
+			state = 1;
+			continue;
+		case '3':
+			if (srecbin[0] < 6) {
+				fprintf(stderr,
+					"%s line %d: S3 record is too short\n",
+					infname, lineno);
+				exit(1);
+			}
+			curaddr = (srecbin[1] << 24) | (srecbin[2] << 16) |
+				  (srecbin[3] << 8) | srecbin[4];
+			datalen = srecbin[0] - 5;
+			if (state < 2) {
+				region_start = curaddr;
+				region_end = curaddr + datalen;
+				state = 2;
+				continue;
+			}
+			if (curaddr < region_end) {
+				fprintf(stderr,
+					"%s line %d: address going backwards\n",
+					infname, lineno);
+				exit(1);
+			}
+			if (curaddr > region_end) {
+				printf("0x%08lX to 0x%08lX (%lu bytes)\n",
+					region_start, region_end,
+					region_end - region_start);
+				region_start = curaddr;
+			}
+			region_end = curaddr + datalen;
+			continue;
+		case '7':
+			printf("0x%08lX to 0x%08lX (%lu bytes)\n",
+				region_start, region_end,
+				region_end - region_start);
+			exit(0);
+		default:
+			abort();
+		}
+	}
+}