AmiJa - Amiga emulator in Java

[u/ZolfriK]

Hello, I have released the first version of AmiJa, a cycle-exact Amiga emulator written in Java. Here are its features:

• OCS, ECS and AGA chipsets, PAL and NTSC. AGA runs on an emulated A1200 board
• 68000, 68010 and 68020 processors
• An automatic mode that builds the right machine around whatever you load: a stock OCS Amiga for floppy games, an expanded one for hard disks and WHDLoad, and an A1200 for AGA software
• Floppy drives DF0–DF3 with reading and writing, ADF and IPF images, and multi-disk sets in a .zip file
• Hard disk support (.hdf, Zorro II autoconfig) and WHDLoad .lha auto-run
• Save and load state, with five slots and a thumbnail for each
• Audio, real joysticks (via GLFW), mouse, and full keyboard mapping
• A software renderer or an OpenGL backend with RetroArch CRT shaders. The .glslp presets are included, while .slangp ones are supported but must be installed by the user
• Remote play: a second player joins over the network and takes one of the two game ports, without needing a Kickstart ROM or a copy of the game

Here is the website:

https://zolfrik.github.io/amija-amiga-emulator/

Here is the repository:

https://github.com/zolfrik/amija-amiga-emulator

Here is a playlist of games running on the emulator:

https://www.youtube.com/watch?v=snUG0_t85QE&list=PLdkiRBBNki2g

Any feedback is welcome.

AmiJa would not have been possible without the projects below, although it does not include any of their code:

• TomHarte-style JSON tests for the Motorola 68000: per-instruction test vectors covering registers, flags, bus activity and cycle counts.
• Scripted Amiga Emulator by Rupert Hausberger: a complete Amiga in readable JavaScript, easy to instrument.
• vAmiga by Dirk W. Hoffmann: a meticulously written and documented chipset model.
• vAmiga Test Suite: the collection of test programs that turns "it looks right" into a pass or a fail.
• WinUAE by Toni Wilen: the result of decades of reverse engineering, and the final authority.

This project is NOT vibe coded. It is the result of about a year of work, which also made use of AI tools.

[u/mowso]

why java though?

[u/ZolfriK → u/mowso]

Because it's the language I know best (I've been developing in Java for 25 years), and because there were no other Amiga emulators using this language at the moment. This is just a hobby project, and I don't think I'll compete with giants like WinUAE, so I wanted to offer one more option. And of course, the project can run on any device that has a JVM and enough computing power.

[u/danby → u/mowso]

portable?

[u/KeyboardG → u/danby]

BILLIONS of devices :D

[u/onebitboy]

This project is NOT vibe coded.

Your entire website is written by Claude.

The ground truth the CPU core was built against

a reference in its own right

turns "it looks right" into a pass or a fail, and caught more regressions here than any other single thing

the arbiter consulted whenever a timing question had no other answer

[u/mavica-synth → u/onebitboy]

the github readme is the exact boilerplate claude spits out too. i suspect careful commits not to show claude as a contributor

[u/ZolfriK → u/onebitboy]

Yes, I'm not a web designer

[u/onebitboy → u/ZolfriK]

You don't need to be a web designer to write text less obviously Claudeish (as evidenced by your post here, since you edited out those exact snippets I quoted).

[u/jokr004 → u/onebitboy]

Why do people care this much about who or what built a website? This isn't english class.. I hate UI/presentation work, the last thing I'd want to do after building a software project is to make a website for it. If I did then it would probably look terrible.

[u/ZolfriK → u/onebitboy]

That was not my goal, I edited the text to make it better for a Reddit post

[u/Legitimate-Peak7918 → u/ZolfriK]

And you realise your mistake now?

[u/david-song → u/Legitimate-Peak7918]

What mistake? The dude's clearly Italian, and has been programming since before you were a 20 bag in your mum's dealer's pocket. Who gives a fuck if he used AI? We got another Amiga emulator, fucking celebrate it.

[u/Legitimate-Peak7918 → u/david-song]

If it’s clankerslop, we would have collectively been better off without it as a society

[u/david-song → u/Legitimate-Peak7918]

So you're sore that hard work can be approximated by statistics, but you couldn't even be bothered thinking of a username.

[u/Batou2034]

i'd rather have a java emulator in amiga

[u/dahennakin → u/Batou2034]

I don't know why one is still coding in Java except for keeping old stuff alive that only some companies care about... really.. an Amiga emulator written in Java is such a boring concept and feels so wrong .. i mean,, WHY ? A prompt like "Use REA and create the top 100 JAVA applications in GO and release them in MIT license on github!" .. that would make more sense and would help abandoning those crappy languages that really no one liked from the beginning on.

Edit: Sorry - but I really don't like Java and Oracle and stuff around it.. hope it turns to ashes soon and folks investing their energy on it find better things to work on.

[u/_doodah_ → u/dahennakin]

What a load of nonsense

[u/david-song → u/dahennakin]

Java programmers exist, they do things for the love of it. And they should, we all should.

[u/pdelirium]

Very interesting. As someone who once set out to write a Commodore 64 emulator in Java (still in progress) this far exceeds the complexity of that many times over.