I disassembled QBert Qubes

Captain Cozmos · November 2, 2023

As opposed to disassembling it's pubes......

I disassembled most of it. It can be reassembled with a drag and drop onto TNIASM.

I did this as a favor for someone who came across a bug when reaching a certain high score. He asked me if I could look into it and I had a moment spare.

As far as the bug, I personally think it has to do with the limitations of the Z80 and BCD but this is just a guess. I've run across this same effect in other Parker Brother Games.

In this disassembly I did not spend a lot of time on it because I am engaged in other projects but I did identify two ram locations. One being the Bonus time left and the other is where it stores the Scoring.
All you have to do at this point is load the source into your editor and search for SCORING_RAM and it should take you to the area that accesses this memory address.

For now I leave it up to you guys to either read this for enjoyment or fix the bug.

I labelled a couple of things like Pattern Definitions and a few places I thought were related to scoring.

There is not a lot to this game.

Patterns load in at $2000 VRAM, Colors $0000 VRAM, Sprites at $3800 VRAM and the Sprite Attributes at $1E00 VRAM and the The Name Table (screen) at $1800
The Sound is direct to port $FF and controllers are a combination of direct input and BIOS.

So, here you go and as always.

Subscribe, Like, Learn....This was done, again, as a favor but also for you to learn from and not to sell.

O3 Cozmos

Q-Bert's QUBES.asm

Edited November 2, 2023 by Captain Cozmos