listamsb: tweak a warning, expand DIAGNOSTICS in man page.

3 files changed, 37 insertions, 5 deletions

diff --git a/listamsb.1 b/listamsb.1
index ca92ee6..a21fb5a 100644
--- a/listamsb.1
+++ b/listamsb.1
@@ -84,10 +84,26 @@ BASIC file.
 .INDENT 0.0
 .IP \(bu 2
 not an AMSB file: first byte not $00
+.sp
+Pretty self\-explanatory: if the file doesn\(aqt begin with a \fI$00\fP byte,
+it\(aqs not a tokenized AMSB file.
 .IP \(bu 2
 not an AMSB file: too big (\fIN\fP bytes), won\(aqt fit in Atari memory
+.sp
+The file can\(aqt be a tokenized AMSB file because there was no way
+for it to be created. It must be some other kind of file that begins
+with a \fI$00\fP byte.
 .IP \(bu 2
 not an AMSB file: program size too small (\fIN\fP). Atari BASIC file?
+.sp
+The program header claims the file is 0, 1, 3, or 4 bytes long. This
+is impossible, so this isn\(aqt an AMSB file. A lot of Atari BASIC
+programs begin with three \fI$00\fP bytes, so that might be what this is.
+.IP \(bu 2
+program length is 2, no code in file (SAVE after NEW)
+.sp
+Probably, someone did a SAVE when there was no program in memory. It
+could also mean this isn\(aqt an AMSB file at all.
 .UNINDENT
 .SS Warnings
 .sp
@@ -109,11 +125,11 @@ line number out range
 The program contains a line number that\(aqs greater than \fI63999\fP\&. How
 did that happen?
 .IP \(bu 2
-line \fIN\fP has character \fIC\fP outside of a string, maybe not an AMSB file?
+line \fIN\fP has character \fIC\fP outside of a string. maybe Atari BASIC?
 .sp
 This happens when ATASCII codes 0 to 31 (\fI$1f\fP) appear in the program.
 AMSB can create files like this, but at runtime, it\(aqs a syntax error.
-It could also mean it\(aqs not really an AMSB file.
+More likely, it means this is an Atari BASIC file.
 .IP \(bu 2
 actual program size doesn\(aqt match program size in header
 .sp
diff --git a/listamsb.c b/listamsb.c
index 268aae6..91e7d1c 100644
--- a/listamsb.c
+++ b/listamsb.c
@@ -206,7 +206,7 @@ int next_line(void) {
 			if(byte < 0x20) {
 				/* ATASCII graphics outside of a string */
 				fprintf(stderr, "%s: line %d has character %d outside of a string, "
-						"maybe not an AMSB file?\n",
+						"maybe Atari BASIC?\n",
 						self, lineno, byte);
 				warnings++;
 			}
diff --git a/listamsb.rst b/listamsb.rst
index ad0c897..acf3718 100644
--- a/listamsb.rst
+++ b/listamsb.rst
@@ -69,10 +69,26 @@ BASIC file.
 
 - not an AMSB file: first byte not $00
 
+  Pretty self-explanatory: if the file doesn't begin with a *$00* byte,
+  it's not a tokenized AMSB file.
+
 - not an AMSB file: too big (*N* bytes), won't fit in Atari memory
 
+  The file can't be a tokenized AMSB file because there was no way
+  for it to be created. It must be some other kind of file that begins
+  with a *$00* byte.
+
 - not an AMSB file: program size too small (*N*). Atari BASIC file?
 
+  The program header claims the file is 0, 1, 3, or 4 bytes long. This
+  is impossible, so this isn't an AMSB file. A lot of Atari BASIC
+  programs begin with three *$00* bytes, so that might be what this is.
+
+- program length is 2, no code in file (SAVE after NEW)
+
+  Probably, someone did a SAVE when there was no program in memory. It
+  could also mean this isn't an AMSB file at all.
+
 Warnings
 --------
 
@@ -93,11 +109,11 @@ continues processing.
   The program contains a line number that's greater than *63999*. How
   did that happen?
 
-- line *N* has character *C* outside of a string, maybe not an AMSB file?
+- line *N* has character *C* outside of a string. maybe Atari BASIC?
 
   This happens when ATASCII codes 0 to 31 (*$1f*\) appear in the program.
   AMSB can create files like this, but at runtime, it's a syntax error.
-  It could also mean it's not really an AMSB file.
+  More likely, it means this is an Atari BASIC file.
 
 - actual program size doesn't match program size in header