Commodore 64: Snakeload V5.1 loader

@DrWatson

Published in 

C64 tape formats

 · 3 years ago

Found on..

• Final Blow
• Rodland
• SWIV
• Double Dragon 3
• Indy Heat

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• Bit 0 : $28
• Bit 1 : $48
• Endianess : MSbF
• Pilot : Bit 0 (*2055)
• Sync : Bit 1

Then...

• 8 bytes: Identifier, read backwards. 3 of them have been found:

 B2 B4 B2 D4 CE CF D2 C6 ("FRONT242" - Uppercase and reversed) in "Final Blow", "Rod Land (Side1)"  
 85 8C 8C 85 88 83 89 8D ("MICHELLE" - Lowercase and reversed) in "S.W.I.V. (Side1)"  
 C8 C3 D4 C9 D2 C4 CC C5 ("ELDRITCH" - Uppercase and reversed) in "Rod Land (Side2)", "Double Dragon 3", "Indy Heat" 

• 1 byte : File ID
• 2 bytes : End address (MSBF)
• 2 bytes : Load address (MSBF)
• n bytes : Data
• 1 byte : Checksum

Its value is calculated by XORing Data bytes and adding 1 to the XOR checksum AFTER a byte is stored at an address with low byte being #$FF (eg. $08FF, $7DFF, etc.).

Trailer:
Bit 0's.