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https://github.com/mrcook/chuckie-egg-disassembly

Chuckie Egg: annotated source code disassembly of this classic 8-bit game (1983, ZX Spectrum) W.I.P.
https://github.com/mrcook/chuckie-egg-disassembly

8-bit assembly disassembly game skoolkit source-code z80 zx-spectrum

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Chuckie Egg: annotated source code disassembly of this classic 8-bit game (1983, ZX Spectrum) W.I.P.

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# Chuckie Egg game disassembly



An unofficial disassembly of Chuckie Egg, the classic 8-bit computer game

released in 1983 for the 48K ZX Spectrum home computer, designed and developed

by Nigel Alderton.



[This W.I.P. disassembly](https://github.com/mrcook/chuckie-egg-disassembly/)

has been created from the raw binary data of the original ZX Spectrum

cassette tape, using the [SkoolKit](http://skoolkit.ca) disassembly toolkit.



## The Game



Chuckie Egg is an addictive platformer in which you have to navigate your hero,

Hen-House Harry, around each level collecting all 12 eggs, and as much corn as

you can, all while avoiding the nasty ostriches and crazy duck.



    Who'd  have  thought  a  country  farmyard

    could be so stressful? You must collect the

    eggs  before the nasties get out and eat up

    all your  corn. Watch  out  for  the  crazy

    duck -- if she gets out of the cage, you're

    in real trouble!



The game consists of eight unique levels, which rotate indefinitely.



After completing all 8 levels you play them again while being pursued by the

giant uncaged duck - thankfully there are no ostriches around for this run.

If you make it to the third pass, then both the ostriches and duck are after

you! There are additional ostriches to contend with for the fourth pass, and

finally for the fifth time, the duck and ostriches move at a greater speed.



Once you complete all 40 levels, you get to replay the last eight indefinitely.



Chuckie Egg was designed and developed by Nigel Alderton, and published by

A&F Software in 1984.



## Project Status



This is very much a **Work In Progress** effort.



- I believe all the data/code blocks have been split correctly.

- All text data has been annotated.

- Most graphics have been annotated (tiles, sprites, fonts, etc.).

- A good number of variables are understood and annotated (player lives, egg

  count, the farmers X/Y position, etc.) - but more work needs to be done here.

- The levels are annotated.

- Various buffers (levels, sprite animation) are annotated.

- Data for the two tunes (intro, death) are annotated.

- Many of the routines are either known, or I have a good idea of what they do.

  Some have detailed annotations, but plenty don't yet.



## Skoolkit Instructions



Executing the `.t2s` file will download the tape image and extract the a `.z80`

snapshot.



    $ tap2sna.py @chuckie-egg.t2s



If changes are made to the control file, a new `.skool` can be generated using

the `sna2skool.py` command.



For the Game Loader:



    $ sna2skool.py -c loader.ctl -Hl chuckie-egg.z80 > loader.skool



And for the main game itself:



    $ sna2skool.py -c chuckie-egg.ctl -Hl chuckie-egg.z80 > chuckie-egg.skool



## Copyright Information



This disassembly, comments and support files, Copyright © 2018-2021 Michael R. Cook.



Chuckie Egg is copyright (c) 1984 A&F Software.



Note: some comments (mostly audio related) were taken from

[Ritchie Swann's](https://github.com/Ritchie333/chuckie) disassembly project.