Chexsum

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'''Chexsum''' is a type-in program checker for the Commodore 64 and 16, Amstrad CPC 464 and 664, Atari 130XE, and MSX used by Melbourne House Publishers.
 
'''Chexsum''' is a type-in program checker for the Commodore 64 and 16, Amstrad CPC 464 and 664, Atari 130XE, and MSX used by Melbourne House Publishers.
  
It displays a four-digit checksum for each entered line.
+
It displays a four-digit checksum for each entered line based on the tokenized BASIC, so it ignores extraneous spaces, REM statements, etc.
  
It can sometimes see a '.' as a ',' and a ';' as a ':' if they fall on certain positions in a program line.
+
It can sometimes see a '.' as a ',' and a ';' as a ':' or even a '9' as a ')' if they fall on certain positions in a program line.
  
 
There are different versions in each book.
 
There are different versions in each book.
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== Links ==
 
== Links ==
 +
* [https://www.youtube.com/watch?v=uMzgK8J6pjI Let's Type Castle of Doom (1983) – The Strangest C64 Game I've Typed In] - demonstration of the program in use at 2:12 and 8:25, also a mod to make it automatically pause every 10 lines
 
* [https://archive.org/details/commodore-64-games-book/page/n13/mode/2up Commodore 64 Games Book pg 4] ([https://github.com/OldSkoolCoder/Melbourne-House-Commodore-64-Games-Book/tree/master/Book alternate source])
 
* [https://archive.org/details/commodore-64-games-book/page/n13/mode/2up Commodore 64 Games Book pg 4] ([https://github.com/OldSkoolCoder/Melbourne-House-Commodore-64-Games-Book/tree/master/Book alternate source])
 
* [https://archive.org/details/commodore-64-games-book-2/page/n13/mode/2up Commodore 64 Games Book 2 pg 7] ([https://github.com/OldSkoolCoder/Melbourne-House-Commodore-64-Games-Book-2/tree/master/Book alternate source])
 
* [https://archive.org/details/commodore-64-games-book-2/page/n13/mode/2up Commodore 64 Games Book 2 pg 7] ([https://github.com/OldSkoolCoder/Melbourne-House-Commodore-64-Games-Book-2/tree/master/Book alternate source])

Latest revision as of 02:04, 16 April 2026

File Format
Name Chexsum
Ontology
Released 1983

Chexsum is a type-in program checker for the Commodore 64 and 16, Amstrad CPC 464 and 664, Atari 130XE, and MSX used by Melbourne House Publishers.

It displays a four-digit checksum for each entered line based on the tokenized BASIC, so it ignores extraneous spaces, REM statements, etc.

It can sometimes see a '.' as a ',' and a ';' as a ':' or even a '9' as a ')' if they fall on certain positions in a program line.

There are different versions in each book.


[edit] Sample Output

Chexsum.gif


[edit] Links

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