Emulator

I got a video of it now that looks pretty well, pretty much straight to the point with how it works.

http://youtu.be/j91SG_a-02c

kostamarino, can we control the JIT backend in gameinis? Forcing JitIL might be a good idea since Jit64 makes the game not 100% completable.

It's technically completable, don't get me wrong, but you absolutely need savestates if you're going to try.

(not that this doesn't need to be fixed in Jit64, but that might be a good first step)

It's FloatingPoint that has the problem, used debug mode in dolphin and disabled that one to trigger. Instead of changing to JITIL, maybe should fix that in INTERPRETER AND JIT.

To summarize discussion on IRC:

The issue is caused by inaccurate emulation of the frsqrte instruction. The correct behavior exists in the interpreter, but is currently hidden behind a define because it's somewhat complicated (uses a lookup table) and was not previously known to make a difference in any games. It does not exist in JitIL: x86 RSQRTSS (a single-precision operation), used by JitIL, is more accurate than the naive solution (in double precision), used by Jit64 and the interpreter without the define, at emulating fsqrte (a double-precision operation) in this specific instance, but this is probably not reliable. Since fsqrte does not seem to be used that often, interpreting it would probably work; after making this change on my machine running Sunshine under Jit64, Interpreter::frsqrtex only takes up 0.1% CPU.

Can you disable a function for a game? I don't think we could do that, but it'd be good, JITIL is 30% slower than JIT64 in Sunshine.

Enforcing jitil is easy, if someone can fix it though i suppose there is no need for that.