This Game Cheats? Hal Labs' LeMans for Commodore 64 (Part 3)
790Finally we dig into the disassembled code of LeMans, with a focus on the time-keeping and scoring routines that are directly tied to this game's very flexible definition of a second. Can we conclusively show that this game cheats? Along the way we find a really neat trick for detecting multiples of 20,000 points, and other conventional and unconventional approaches to C64 game development. LeMans is one of the launch titles of the Commodore 64 and Commodore Max, released back in 1982, and it was developed by Hal Laboratory, possibly by Satoru Iwata himself.
This series:
Part 1: Dumping LeMans cartridge: https://youtu.be/YV9WN-dTNgk
Part 2: Making the binary RUNnable: https://youtu.be/UKG00SyA0fE
Part 3: This Game Cheats: This video!
BCD video: https://youtu.be/vnhyGt6URYc
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Index:
0:00 Recap
1:30 Since 8K is actually a lot of code...
3:17 EE10: Incrementing the BCD score
7:16 EE25: Checking for multiples of 20,000
13:29 F39E: 1000 bonus points
14:53 E182: Initializing time
17:08 EFEE: Tracking time
21:24 F462: Game over?
25:20 F564: Definition of a second: the "cheat"
28:58 E06D: CIA driven: 1.000000 MHz?
32:50 E802: 6 unused bytes: DDE?
35:14 Conclusion and thanks!