Re: [hatari-devel] ARM JIT

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 06/08/2014 11:12, Adam Klobukowski a écrit :
> Hi
>
> Have you guys considered adapting Cyclone m68k emulator?
> (http://notaz.gp2x.de/cyclone.php). It offers JIT on some popular ARM
> architectures. It seems thatHataroid guy already tried it
> (https://github.com/squalldc/hataroid/blob/master/Projects/jni/hatari/Android.mk).
> This CPU emulator may make running Hatari on RasPi more fluent (and
> other cheap ARM boards)
Hi,

no, unless it features a similar api to uae/winuae 68000 emulation, it 
would be too much work to maintain several cpu cores.
And we don't target a specific architecture such as arm, we try to have 
as much portable C code to compile on any architecture (and I'm not sure 
from its description that cyclone handles prefetch and sub cycle 
accuracy for all opcodes, which is required for proper emulation).
Maintaining JIT version in assembly at a time where computers / phones / 
tablets are more and more powerful every 6 months also looks IMO like a 
waste of time ; Hatari has reached a point where remaining issues are 
not about speed but about accuracy in very low level functions (ram 
speed, prefetch, rare video timings, ...).
Of course, there will always be some devices where you wished emulation 
would run faster, but there's a point where perfect accuracy requires 
cpu power in a higher order of mgnitude, and JIT will only bring a small 
increased compared to the need
Nicolas