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		<title>F64Summer - Revision history</title>
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		<updated>2026-05-14T16:22:32Z</updated>
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		<id>http://fileformats.archiveteam.org/index.php?title=F64Summer&amp;diff=49363&amp;oldid=prev</id>
		<title>Parchivist: Created page with &quot;{{FormatInfo |subcat=Error detection and correction |released=2018 }} '''F64Summer''' by Felix Palmen (aka Zirias) is a type-in program checker for Commodore used by the Germa...&quot;</title>
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				<updated>2024-09-08T06:15:24Z</updated>
		
		<summary type="html">&lt;p&gt;Created page with &amp;quot;{{FormatInfo |subcat=Error detection and correction |released=2018 }} &amp;#039;&amp;#039;&amp;#039;F64Summer&amp;#039;&amp;#039;&amp;#039; by Felix Palmen (aka Zirias) is a type-in program checker for Commodore used by the Germa...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{FormatInfo&lt;br /&gt;
|subcat=Error detection and correction&lt;br /&gt;
|released=2018&lt;br /&gt;
}}&lt;br /&gt;
'''F64Summer''' by Felix Palmen (aka Zirias) is a type-in program checker for Commodore used by the German-language mazine Weihnachten auf dem Commodore (Christmas on the Commodore), a joint project by Christian Gleinser (aka ZeHa) and Forum64 members.&lt;br /&gt;
&lt;br /&gt;
It displays a four-digit checksum for each entered line&lt;br /&gt;
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Version 2 was released in November 2019, which can now optionally ignore comments in the program (REM commands) when creating checksums and when entering them.&lt;br /&gt;
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It uses a 16-bit Galois LFSR. Spaces outside strings are ignored. Checksum is created after tokenization, so equivalent commands like PRINT and ? are treated the same.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For each character read, an inner loop iterates over all 8 bits. The LFSR is shifted once with feedback for each bit, but the output bit is also XORed with the respective bit of the character currently being processed before the feedback.&lt;br /&gt;
&lt;br /&gt;
There are currently 4 different variants of the F64Summer that can be run on VC20, C64 , C16 / C116 / Plus/4 and C128. There is also a 32-bit Windows application &amp;quot;mksums.exe&amp;quot; with which the creator of a listing can calculate the checksums for all lines of a BASIC file in PRG format. These checksums can then be combined with the listing to be printed. The source is also available to be ported to any platform&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
== Sample Output ==&lt;br /&gt;
[[File:F64Summer.gif]]&lt;br /&gt;
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== Links ==&lt;br /&gt;
* [https://csdb.dk/release/?id=173072 CSDb]&lt;br /&gt;
* [http://plus4world.powweb.com/software/F64Summer Plus/4 World]&lt;br /&gt;
* [https://www.c64-wiki.de/wiki/F64Summer German C64 wiki article]&lt;br /&gt;
* [https://www.c64-wiki.com/wiki/F64Summer English C64 wiki article]&lt;br /&gt;
* [https://www.forum64.de/index.php?thread/85546-f64summer-neuer-checksummer-zum-abtippen-von-basic-zeilen/ Release thread on Forum64.de] (Includes details on how algorithm works)&lt;br /&gt;
* [https://github.com/Zirias/f64summer Source on github]&lt;br /&gt;
* [https://youtu.be/LnruDfxLSCU Youtube video of F64Summer in action]&lt;/div&gt;</summary>
		<author><name>Parchivist</name></author>	</entry>

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