dobiestation

Technical Insight: The PS2's CDVD Drive and Loading Times

Shoutout to the GTA V Online team for inspiring this post.

The fifth generation of home consoles popularized the use of disc media in consoles. Cartridges were more expensive and unreliable to produce - publishers would have to predict how many units would sell and order that many cartridges - and discs had far greater capacity. The original PlayStation had around 700 MB of disc capacity, and by contrast, the Nintendo 64's largest games were only 64 MB. The PS2 has even more ca...

On the Silence

I'm not interested in making a sappy post, so I'll get to the point: I haven't had much motivation to do anything over the past several months, DobieStation included. I suspect that this is due to the world event that's been happening since last year, but I digress. I'm sorry that I don't have anything to show for all of this time, and I know I should have made an update on this sooner.

I don't blame you if you decide to withdraw your support. If you don't, know that the money does help...

Technical Insight: The PS2 GIF and its Massive Bandwidth

The PlayStation 2's design seems almost reactionary to that of the PSX's. While the PSX GPU has a low fillrate, the Graphics Synthesizer (GS) outputs so many pixels, it can compete with the PS3's GPU in some cases! This increased fillrate requires a lot more bandwidth, so much that a single data provider isn't enough. Thus, the PS2 has not one, but three different ways data can be sent to the GS.

The GS Interface (GIF) is responsible for arbitrating between the different data providers ...

Sins of the PS2: Knockout Kings 2001

It's not often you get a game that disables an interrupt and expects it to remain enabled.

Greetings, dear reader. Sins of the PS2 is about all those games with crippling bugs that just happen to work on a real PS2 but fail horribly on emulators. Today's article is a real doozy, involving a rather decent boxing game called Knockout Kings 2001. On an emulator, the game softlocks on the intro screen: music still plays, but it is impossible to progress further. Without a memory card insert...

Teaser

You may recall on the last post that I mentioned a super secret project. We've made faster progress than we expected, but it's still not quite ready for a release. Have an image:

I'll give a hint, too. It's something that's useful for every PS2 emulator, but DobieStation and PCSX2 will benefit most from it.

DobieStation has a compatibility list!

I am pleased to announce a compatibility list for Dobie that is being maintained by RedDevilus, as well as a few loyal testers. Let's jump right into the numbers first.

As of this writing, 353 games have been tested. This means that 78% of games go ingame! It might seem underwhelming for there to be zero playable games, but that is because of strict criteria for a game to be considered Playable...

Sins of the PS2: Harry Potter and the Prisoner of Azkaban

Every console has its sins, and the PS2 is no exception. Whether it be caused by tight deadlines imposed by the publisher or bad design practices, video games often have bugs hiding in them that are only exposed when running them in an emulator. Older consoles tend to be quite forgiving when a game uses undocumented or illegal behavior, which is a pain for emudevs as it then means figuring out what the console is supposed to do when it's fed invalid data.

The bugs in many PS2 games are ...

Sins of the PS2: Ecco the Dolphin

Sometimes, bugs just have no reason to exist.

Welcome to Sins of the PS2, a series that exposes the horrific crimes against humanity that lurk within video games. This is dedicated to problematic games that break on emulators but only work on real hardware due to coincidence. Ecco the Dolphin: Defender of the Future is one of those games, suffering from an evil timing bug. Even with decent timings, Ecco will fail to pass the initial loading screen, which means as of this moment, every m...

Roadmap for the First DobieStation Release

To sum things up, we are planning to have an official v0.1 release, though there is no deadline on this. What we have in mind is more a list of features that are either essential or nice to have for the first release. DobieStation has been in development for over two years, and in that time it has went from barely scraping by trying to boot a few games to supporting a large portion of the PS2 library, even fixing games that don't work on other emulators like True Crime: Streets of L.A. Though...

Sins of the PS2: True Crime Streets of L.A.

What happened to [this game] was a true crime...

The most enjoyable thing about PS2 emulation is how broken PS2 games are. It always seems like there's something new to uncover, and each game is different from the last. Some games are so broken, they deserve to have an article written about their sins. True Crime: Streets of L.A. is one of those games, and last year I wanted to see why it never worked on PCSX2. No matter what settings were used, the game would always crash on m...

Sins of the PS2: Dead or Alive 2

Boasting a library of thousands of games, the PlayStation 2 can be taken to two extremes that cause trouble for emulators. The first end is one of optimization: using every trick in the book, and many more unwritten tricks, to bring about the best performance and graphical fidelity possible. Games like Jak and Daxter as well as Ratchet and Clank would fall in this category. The other end, however, has sloppy, inefficient, and overall buggy code written only to meet deadlines. Some of this cod...

Shadow of the VUlossus: Fixing unfixable PS2 games

The Vector Units (VUs) are the soul of the PS2. They are SIMD processors embedded in the Emotion Engine (EE) responsible for quickly performing vector and matrix operations. VU0 and VU1, as they are called, have different responsibilities: VU0, being available as a coprocessor and having more limited memory, is intended for physics, AI, and other dynamic calculations, whereas VU1, being more independent and able to feed graphical data directly to the GPU, is intended for processing background...

GS JIT - 400% speedup in Shadow of the Colossus

It's been a little while, hasn't it? We've been working hard and haven't had time for any updates. To get straight to the point, Shadow of the Colossus has gone from 1 to 5 FPS on my 2015 Mac laptop.

This is thanks to the GS JIT that I've been working on, as well as water111's new scanline-based triangle rasterizer that is sign...

The VU Recompiler has been merged!

As of today, the VU recompiler has been merged. You can check out the PR here, if you wish: https://github.com/PSI-Rockin/DobieStation/pull/129

This is exciting stuff! After two months of hard work, DobieStation has passed an important milestone. And it wasn't done alone: refraction, a member ...

Recompiler progress

After spending a week trying to figure out why the ground refused to render, I'm proud to announce that the VU JIT works for Final Fantasy X. This is significantly faster than the interpreter, going at double speed in most scenes. Note that the EE interpreter and software renderer remain bottlenecks for full FPS.

FFX is a fairly simple game, technically speaking. It doesn't pull any weird tricks and only uses a subset of the full instruction set of the VUs, so that's why I used it as a ...

Status as of January 6, 2019

As the current description states, I'm working on the EE and VU recompilers. DobieStation has achieved an acceptable level of accuracy for its first release: it's also become difficult to find bugs in games partly because they take so long to execute. I already have the framework for the IR, x64 emitter, and code execution set up; all that remains is implementing the whole VU instruction set.

My first recompiler is for the VUs. The PS2 VUs are used for physics, AI, and lighting as well ...