1 files changed, 19 insertions, 0 deletions
diff --git a/checkbank0.pl b/checkbank0.pl
new file mode 100644
index 0000000..2f0d78a
--- /dev/null
+++ b/checkbank0.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl -w
+
+# Check a cart bank (normally bank0) and warn if there's a zero
+# byte in the 'cart present' location. According to the atari800
+# docs, sometimes bank 0 comes up mapped to the right cart area,
+# which means the OS might try to initialize/run it (which wouldn't
+# work).
+
+die "usage: $0 <filename>\n" unless @ARGV == 1;
+
+use bytes;
+
+undef $/;
+$_ = <>;
+$byte = ord substr($_, 8188, 1);
+if($byte == 0) {
+	warn "$0: $ARGV[0] has zero byte (cart present) in trailer (\$9ffc)\n";
+}
+exit 0;