Karate Champ (DataEast, 1985)

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A karate simulation. Written for the Apple II by Quicksilver Software in 1985. That game has been rewritten for the IIgs by the French band named F.U.C.K.


PROTECTION TYPE
On a standard 16 disk:
- desynchro routine


BOOT TRACE
- 9600<C600.C6FFM
- 96FB: AD E8 C0 60
- 9600G

At $0800, data from T0/S1 to T0/S5 are loaded from $BB00 to $BFFF. Then code goes to $084B, $BB1A clears memory from $0900 to $BAFF ! Then other data are loaded with the use of the Quicksilver file loader:
- A contains the file name to load
- X the low address in RAM
- Y the high address in RAM
JSR $BB00

The VTOC is located on T11/SF just like the DOS 3.3 one.

Please read the code at $BB00, then discover a call to $BF00 at $BDDE. Then read the code at $BF00: that is desynchro protection scheme searching for the pattern: D5 E7 E7 E7 EE FC EE EE FC E7 EE FC E7. You leave the routine with the carry clear if the original disk is in the drive, with the carry set instead.