Crystal Castles Source File Overview

Recently Historical Source Code published the original source code for a couple Atari arcade games including Crystal Castles. In this post I will give an overview of the the files that are included in the archive. The files can be found here:

 https://github.com/historicalsource/crystal-castles

The archive contains three sets of files for Crystal Castles, the one in the root directory of the repository, which I will call the master set, and two others sets called version-2 and version-3. In this post I will focus on the master set, since the other two contain some different files. Using my assembler I was able to re-assemble the master set to produce the ROMs that match the MAME ccastles1 set. I still need to determine if the other two versions of the source match up with other MAME ROM sets. The main ROM set in MAME, ccastles, does not match any of the source in the archive. The first ROM has a copyright message in it and the MAME base set also contains the phrase "PIRATES BEWARE" which is not in any of the source. 

Here is an overview of the files in the archive:

372X1.DOC 

This appears to be some sort of standard form used by Atari to document game projects, since similar files appear in the repositories for other games. The file contains all the details of the ROMs that make up the game, a description of how to assemble the files and a signoff form at the bottom.

022X1.DAT

This contains a single line of ASCII data that provides details of the ROMs that make up the game. This file is referenced in 372X1.DOC and is called the "Verification control file". I still need to study this file some more to understand the format.

372BR.RS4

This file is referenced in 372X1.DOC and 022X1.DAT so has something to do with the verification process, but I am not sure what the data in it represents.

*.MAC

The .MAC files are the macro-assembler source files for the game. Most of the files are for the fixed ROM and the first ROM bank. C99.MAC and the .DAT files are for the second ROM bank. CRF.MAC is the root file, the other files are either included in CRF.MAC, or included into other includes. There was one file missing from the archive, CJTB.MAC, which is included into CRP.MAC. To be able to re-assemble the code I had to re-create this file from existing ROMs. I will look at these in more detail in a future post.

Cxx.DAT

These files contain the level data for the game and are included into C99.MAC. This is assembled separately and forms the second bank of ROM.

*.LDA

These are the binary output of the original assembler in a format that makes them linkable to other binaries to form the final output. I need to do some more research to figure out the format of these files.