Atari 2600 Football (Soccer)

[Andrew Davie]

Most, but not all.  CDFJ games are a mix of assembler and C/C++.
This game is assembler. I was referring to the WAY the systems are written, not the language in which they are written. The techniques used to achieve the display are perhaps a bit different to what I would have done myself were I starting from scratch.

Just curious, how to you open up the rom to see the code?  What software? 

The source code is a text file. This text file is converted to binary numbers by an assembler (dasm). So you can view the source code in any text editor you want. I use Visual Studio Code with the Atari Developer Studio plugin, these days. But in reality - any text editor will do just fine.

[Living Room Arcade]

"The source code is a text file. This text file is converted to binary numbers by an assembler (dasm). So you can view the source code in any text editor you want. I use Visual Studio Code with the Atari Developer Studio plugin, these days. But in reality - any text editor will do just fine."

If I open the .bin file of our soccer game with Notepad, it looks like this



What is that? 

[Andrew Davie]

If I open the .bin file of our soccer game with Notepad, it looks like this
What is that? 

Because the .bin file is not the source code. The bin file is the binary file. You can't do what you're trying to do with that file!

The source code is what the programmer writes. It's written in a programming langauge - in this case, 6507 assembly code. The source code is passed to a program called an assembler (in this case, 'dasm'), which processes that source code and produces the .bin file.  It's that .bin file which is run on the Atari 2600, or an emulator.

Typically the process of writing a game is to write your program (in assembly) in a text file, then assemble the text file (using dasm), and then testing the output binary file with an emulator (Stella, or Gopher).  While some people do actually modify the binary file directly, this is usually because they do not have the source code available. Modifying directly is very difficult and extremely restricted in what can be changed.  Another option is to 'disassemble' the binary file, and produce source code directly from the binary. And then you can go through the originally mentioned process - editing the source code, assembling, testing the binary.  Disassembling is also quite tricky and involves a fair bit of work to get from a binary into a fully correct source code file.

[Living Room Arcade]

Thank you for that clear explanation.

You mean this one?



You shared it in the AA thread here
https://forums.atariage.com/topic/90363-atari-2600-soccer/?do=findComment&comment=4544911

So this is what the assembly code looks like? 

[Thomas Jentzsch]

That's part of it. Here constants are defined. The code follows further down.

[Living Room Arcade]

Understood. 

[Andrew Davie]

You mean this one?
So this is what assembly code looks like? 

Yes, that is the source code (= assembly code).

[Living Room Arcade]

Hello Andrew and everybody!
I hope everybody had a good holiday.

Andrew PM'd me and asked me to put a mention in the Atari Age thread about this soccer game, so who knows, maybe some people from there will come here to discuss it? 

[Yurkie]

This game is awesome. Thanks @Living Room Arcade for letting me know about this thread and to @Andrew Davie for allowing me to join your forum.

[Yurkie]

Any updates Andrew?

[Andrew Davie]

Any updates Andrew?

Post #6 has the latest version.
I am not actively working on this, other than addressing bug-fixes and requests.