Fallen Kingdom received patch that fixes game crash that occurred when entering the ending sequence when running the game using AltirraOS rom (default rom in Altirra emulator). This was caused by an error in the code that was overlooked because it was not causing an issue when using atarixl.rom (that I normally use).
Actually the game does not crash, because the fake “crash sequence” is part of the game ending, however it got stuck in infinite loop due to incorrect conditional jump. Even though there was a coding bug, in case of atarixl.rom the condition was evaluated differently and program jumped out of the repeating loop.
I was not aware of this issue at all, but recently I have found following youtube video showing full walkthrough with crash at the end of the game:
I had no idea what could cause this, but my first try was to switch the OS Rom and that was it :). Afterwards it was quite easy to find the line that caused this:
Note: x_ge is my own macro replacing the bcc/bcs conditional jumps. It basically means if X is greater/equal than/to operand1 jump to operand2:
.macro x_ge
cpx :1
jcs :2
.endmAs you can see above, the issue was missing # that turned immediate mode into zero page mode … and this particular zero page content differs between atarixl.rom and altirraos rom. In altirraos there was 0 so it had never left the loop between lines 2563 and 2564.
The proper ending (FK v1.2) recorded on Altirra with AltirraOS rom and NTSC:
NTSC Palette fix
I have implemented NTSC color matching in Binary Parasite, so when the game detects that it runs in NTSC mode, it adjusts the game speed and music speed as well as colors to match (as much as possible) the PAL mode for which it was originally designed.
Fallen Kingdom already had the speed parts implemented, however I decided to add also the color part… the game now looks much better, with less washed-out colors on NTSC:
