Just some questions on how Dolphin works.

[shoesakaslick]

So I'm making an informal video on Dolphin and a little bit of history of the emulator, since it's always been my favorite emulator. Now my question is, when they began development on the emulator, how did they rip the operating system out of the gamecube to use in the emulator?

As well as how does emulating the CPU and hardware of the gamecube work?

What kind of legal troubles did they run into when they released the emulator?

What was the biggest obstacle in the beginning?

and maybe a few other questions as I get to writing it more and more.

thanks.

[AnyOldName3]

The basics of how the CPU emulation works is that we have a JIT (Just In Time) Recompiler, which keeps track of which bits of code we're about to run, and translates them into something the system Dolphin is running on can understand. This approach is taken as it means Dolphin knows the context in which the code is to be run when it's translating it which can help with optimisations, or sometimes even making the code work at all.

As for legal troubles, there basically aren't any. All of the work done on Dolphin is based on either publicly available information (such as officially published specifications and manuals for CPUs similar to the Wii's and GameCube's when the equivalent documentation for the exact chips is a trade secret between IBM and Nintendo) or clean-room reverse engineering (where things are learned by studying what the original consoles do without anyone involved having prior secret knowledge that they're not legally allowed to share). If anyone who'd known something secret about the consoles had been involved, Nintendo could claim they'd just shared the secret, and therefore violated their intellectual property, but as they weren't, everything was learned by just watching to see what the real hardware did in various situations, and Nintendo had sold them the hardware, so can't tell them that they weren't allowed to poke at it to see how it works.

[MayImilae]

shoesakaslick Wrote:how did they rip the operating system out of the gamecube to use in the emulator?

Actually, the GC and Wii don't have an operating system. The GC Main Menu and the Wii Menu are IPLs (Initial Program Loader), and that's all! The consoles can only run one program at a time, and whatever piece of software they are running has 100% control of the system. To be an operating system, you have to have the ability to run at least two things at once, so the OS can manage the running software behind the scenes. The GC/Wii (and curiously enough the Wii U!) don't have this ability, and to access the main menu (not including the menu that appears when you press the home button, that's an API trick to fake the appearance of an OS, the game is still the only thing running!) you have to close the currently running application. That is a clear sign that there is no operating system at all!

On a game console this can actually work pretty well. Especially with the menu that you press when you press the home menu - that's not the operating system, but an API that Nintendo requires games include. The game is still running! Only when you close the game and return to the Wii or Wii U menu does the game close and the menu appear.

Btw, the 3DS and Switch do have real operating systems! You are able to go to the main menu while leaving the game running, run other smaller programs like the eshop, and then return to the suspended game. That's 3 programs running at once!

[Delphinidae1]

Can't you guys create a xbox360 emulator as well? I know this isn't the place to ask but since Xenia's development is slower than a snail, and you developed this amazing emulator called Dolphin...I'm sure if you guys tried in like a month you'd be ahead of Xenia already.

[JosJuice]

(11-14-2017, 07:55 AM)Delphinidae1 Wrote: Can't you guys create a xbox360 emulator as well?

All of us? No, it's not going to happen.

(11-14-2017, 07:55 AM)Delphinidae1 Wrote: I'm sure if you guys tried in like a month you'd be ahead of Xenia already.

Creating an emulator doesn't happen that quickly.

[MayImilae]

Remember, Dolphin has been around since 2003! We certainly didn't get to where we are now overnight.

[Helios]

We don't even have functional netplay

[Delphinidae1]

help me