Commodore 64: Seuck Game Tape loader

@DrWatson

Published in 

C64 tape formats

 · 21 May 2021

Used by tapes created with the Shoot'em Up Construction Kit.

--------------------------------------------------------------------------------

Threshold : $2E ($170 (368) clock cycles)
Bit 0 : $20
Bit 1 : $41

Endianess : LSbF
Pilot : $E3 (*256)
Sync : $AC

After the Sync byte the data starts immediately...

63226 bytes : Data

Notes :

• SEUCK Game loader is 'hardwired' to load just 1 file (63226 bytes) from $0900-$FFF9 (inclusive).
• The loader runs the game with a JMP $4048 (sys 16456).
  
• before the 256 pilot bytes there appears to be another stretch of pilot bytes which terminate in several very strange value bytes, This whole area is not useful or used in any way and may exist purely as some kind of rubbish copy protection.
  
• Sadly there is no checksum.
  
• TAPs Ive looked at (1 genuine and 1 made using VICE 1.1) appear to contain at least 1 pulse that sits exactly on the threshold ($2D), I'm not exactly sure which bit this will interpret as when loaded.
  

Final TAP will recognise and complain about this.