Bounty for JIT enabled E-UAE for AmigaOS4.1

[Piru]

Since OS4.x already has a JIT, is there any way in which Petunia could be employed for the purpose of emulating the 68K?

In practice no. Petunia (and Trance) try to be as fast as possible. Adding some address translation and trapping of specific addresses (custom, cia etc) to all memory accesses would generate ton of extra code. In any case it would require a lot of work on the actual JIT engine itself. This is unlikely to happen.

For any OS component to be usable for GPL application it first needs to be released as part of the OS. Also, releasing such update just to circumvent the GPL license would not be seen as very sportsmanlike I'd think.

[Piru]

However the guys that wrote Petunia and Trance would have a head start over the rest when it comes to attempting this one, methinks.

Of course, but I think it is very unlikely you'll see anything from them.

I was thinking purely from a technical angle rather than a open v closed source political one.

Fair enough.

You know, it's a bit of a pity that the respective operating systems don't provide API's into the JIT that let you build your own emulated 68K based "machine" applications around the OS provided JIT core. I realise there's no requirement for this from the OS point of view, it'd just be really cool to play with.

As I was trying to explain it is not possible to add this to JIT and not have a huge performance hit. As such you'd pretty much end up with two completely separate engines; one for OS stuff and one for emulation. Just writing one JIT engine is hard enough.

[Piru]

You could implement a 68K to 68K compiler that treats Petunia as the target architecture, replacing all legacy hardware code with calls into the core E-UAE emulator. The performance hit still sounds atrocious, though.

As I understand your idea all memory accesses would result in calls to UAE. Only instructions without any memory accesses could be left as-is. I'd estimate it'd be slower than UAE itself, except for some very specific tight computational loops.

Re: GPL, I don't see any conflicts. Petunia is an operating system service, just like file I/O and memory allocation.

Petunia - as it is now - cannot be used in any sensible way (and neither Trance before someone asks).