From 269d3ed460487b43a339dcc80d8f4c9d2bff5078 Mon Sep 17 00:00:00 2001
From: Lars Brinkhoff <lars@nocrew.org>
Date: Sat, 19 Mar 2022 19:14:54 +0100
Subject: [PATCH] Support for reading tape errors and gaps.

---
 tape-word.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tape-word.c b/tape-word.c
index 4640b94..9cf7a6f 100644
--- a/tape-word.c
+++ b/tape-word.c
@@ -23,6 +23,8 @@ static int reclen = 0;
 static int beginning_of_tape = 1;
 static int marks = 0;
 
+static int get_tape_record (FILE *f, word_t **buffer);
+
 static int
 get_byte (FILE *f)
 {
@@ -79,6 +81,18 @@ static void write_reclen (FILE *f, int n)
   fputc ((n >> 24) & 0377, f);
 }
 
+static int tape_error (int code, FILE *f, word_t **buffer)
+{
+  fprintf (stderr, "Tape error %06x.\n", code);
+  return get_tape_record (f, buffer);
+}
+
+static int tape_gap (int code, FILE *f, word_t **buffer)
+{
+  fprintf (stderr, "Tape gap (%06x).\n", code);
+  return get_tape_record (f, buffer);
+}
+
 int get_9track_record (FILE *f, word_t **buffer)
 {
   int i, x, reclen;
@@ -87,6 +101,11 @@ int get_9track_record (FILE *f, word_t **buffer)
   reclen = get_reclen (f);
   if (reclen == 0)
     return 0;
+  else if (((reclen >> 24) & 0xFF) == 0x80)
+    return tape_error (reclen & 0xFFFFFF, f, buffer);
+  else if (((reclen >> 24) & 0xFF) == 0xFF)
+    return tape_gap (reclen & 0xFFFFFF, f, buffer);
+
   if (reclen % 5)
     {
       fprintf (stderr, "Not a CORE DUMP tape image.\n"
@@ -185,6 +204,11 @@ int get_7track_record (FILE *f, word_t **buffer)
   reclen = get_reclen (f);
   if (reclen == 0)
     return 0;
+  else if (((reclen >> 24) & 0xFF) == 0x80)
+    return tape_error (reclen & 0xFFFFFF, f, buffer);
+  else if (((reclen >> 24) & 0xFF) == 0xFF)
+    return tape_gap (reclen & 0xFFFFFF, f, buffer);
+
   if (reclen % 6)
     {
       fprintf (stderr, "Not a 7-track tape image.\n"