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Apple will start allowing emulators on the iOS App Store (9to5mac.com)

submitted 7 months ago by simple@lemm.ee to c/games@lemmy.world

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[-] kadu@lemmy.world 34 points 7 months ago

Do we know if these emulators will support JIT? JIT has always been prohibited on iOS (which is why there are no browsers other than Safari - Firefox and Chrome on iOS are just a Safari WebView plus a crappy interface on top).

Even when sideloading emulators, you only get JIT by paying for a special developer license or using exploits on very specific iOS versions.

Without JIT, sure, go nuts emulating the NES... But forget about anything more demanding than a GameCube, or using this to run a VM or something.

[-] nave@lemmy.ca 13 points 7 months ago* (last edited 7 months ago)

you only get JIT by paying for a special developer license or using exploits on very specific iOS versions.

Actually Altstore has AltJIT which works on all iOS versions altstore supports but requires you to be connected to the same network as a computer running altstore.

run a VM or something

UTM (which is based on QEMU) is already available on iOS.

[-] kadu@lemmy.world 6 points 7 months ago* (last edited 7 months ago)

but requires you to be connected to the same network as a computer running altstore.

So you mean iOS doesn't natively support JIT for App Store apps and requires hacky workarounds?

[-] WolfLink@lemmy.ml 1 points 6 months ago

iOS natively supports JIT (by which we mean writable and executable memory) but Apple locks it down to only two use cases:

The JavaScript engine in Safari
Support for running a debugger

AltStore launches a debugger and connects it to your phone. Even though it’s not actually doing anything with a debugger, that’s enough to convince iOS to let your app use memory that’s both writable and executable (the key feature needed for JIT).

Without JIT you need to either resort to a slower form of emulation or do something creative.

[-] nave@lemmy.ca 0 points 7 months ago* (last edited 7 months ago)

I was just pointing out that OPs list was incomplete. Also theoretically someone could include altjit in their app because the App Store guidelines don’t explicitly say you can’t (ofc this would most likely not work).

[-] tsonfeir@lemm.ee 1 points 7 months ago

Sadly jail breaking is required after iOS 11

[-] nave@lemmy.ca 4 points 7 months ago

For what?

[-] tsonfeir@lemm.ee 1 points 7 months ago

For for UTM

[-] nave@lemmy.ca 1 points 7 months ago

No I believe it also works with altstore (though I haven’t personally tried it).

[-] tsonfeir@lemm.ee 1 points 7 months ago

Hmm. I’ll give that a shot.

[-] Lojcs@lemm.ee 4 points 7 months ago* (last edited 7 months ago)

which is why there are no browsers other than Safari

Wasn't that explicitly forbidden? Browsers don't need jit to be fast enough

Edit: was jit explicitly forbidden? Or is it that running dynamically loaded code was forbidden in general and jit falls under that category? If they're letting emulators and other browser engines in that ban seems to be at least partially lifted

[-] echo64@lemmy.world 4 points 7 months ago

Yes, op is a little confused.

Browsers (were, still are in many regions) forbidden from using any engine other than the iOS provided webkit.
Dynamic recompilation is not possible on iOS because of how iOS does code signing. This basically blocks the entire concept of executing instructions that weren't part of the original signed code.