listamsb: complain more about lines >255 bytes long.

3 files changed, 35 insertions, 5 deletions

diff --git a/listamsb.1 b/listamsb.1
index 324ab3f..015a492 100644
--- a/listamsb.1
+++ b/listamsb.1
@@ -139,6 +139,18 @@ line \fIL\fP: EOL address \fIA\fP <= previous \fIB\fP
 .sp
 Corrupt file, or not an AMSB file.
 .IP \(bu 2
+line \fIL\fP is suspiciously long
+.sp
+The line is >128 bytes long, but less than 256. AMSB can execute
+lines of this length, but it\(aqs impossible to actually enter them
+in the editor, because a logical line can\(aqt be longer than 3
+screen lines. Possibly corrupted file.
+.IP \(bu 2
+line \fIL\fP is impossibly long
+.sp
+The line is >= 256 bytes long. AMSB will crash, if you try to
+LOAD the file. Corrupted file.
+.IP \(bu 2
 line \fIL\fP EOL address doesn\(aqt match actual line length \fIN\fP
 .sp
 Same as above: corrupt, or not AMSB.
diff --git a/listamsb.c b/listamsb.c
index efcaf00..207c3bb 100644
--- a/listamsb.c
+++ b/listamsb.c
@@ -33,11 +33,13 @@
    even with cart-based AMSB2 and no DOS loaded. */
 #define MAX_PROGLEN 30000
 
-/* there should never be a valid line of BASIC longer than this many
+/* there should never be a valid line of BASIC longer than MAX_LINE_LEN
    bytes, since there would be no way to enter it in the editor. AMSB
    uses the standard E: device, which limits you to 4 screen lines, or
-   max 120 bytes. */
+   max 120 bytes. there *cannot* be a line longer than MAX_LINE_LEN_HARD,
+   because AMSB would crash when you try to LOAD such a program. */
 #define MAX_LINE_LEN 0x80
+#define MAX_LINE_LEN_HARD 0xff
 
 /* a program whose header has a length less than MIN_PROGLEN can't be
    a real AMSB program. EMPTY_PROGLEN is what you get if you
@@ -273,9 +275,13 @@ int next_line(void) {
 	}
 
 	if(len > MAX_LINE_LEN) {
-		fprintf(stderr, "%s: line %d is suspiciously long (length %d > %d)\n",
-			self, lineno, len, MAX_LINE_LEN);
-		warnings++;
+		int hard = len > MAX_LINE_LEN_HARD;
+		fprintf(stderr, "%s: line %d is %s long (length %d > %d)\n",
+			self,
+			lineno,
+			hard ? "impossibly" : "supiciously",
+			len,
+			hard ? MAX_LINE_LEN : MAX_LINE_LEN_HARD);
 	}
 
 	if(last_ptr != -1) {
diff --git a/listamsb.rst b/listamsb.rst
index bf3863b..c5177e0 100644
--- a/listamsb.rst
+++ b/listamsb.rst
@@ -123,6 +123,18 @@ continues processing.
 
   Corrupt file, or not an AMSB file.
 
+- line *L* is suspiciously long
+
+  The line is >128 bytes long, but less than 256. AMSB can execute
+  lines of this length, but it's impossible to actually enter them
+  in the editor, because a logical line can't be longer than 3
+  screen lines. Possibly corrupted file.
+
+- line *L* is impossibly long
+
+  The line is >= 256 bytes long. AMSB will crash, if you try to
+  LOAD the file. Corrupted file.
+
 - line *L* EOL address doesn't match actual line length *N*
 
   Same as above: corrupt, or not AMSB.