@kamelito
Daniel aka Daytona wrote in the youtube message stream that for now he didn't encounter any performance issue with the Tabor while porting Wings and Tower 57
That's not entirely correct
I did not mention Wings in that context. It was about T57, at least I meant it to be about T57 only.
Of course I encountered performance issues - but I was able to solve them by coming up with the native SPE build of T57. With that build there are no performance issues
@Niding
He did comment that he wasnt overly excited by the CPU choice, but at the end of the day he seemed content with the performance of the Tabor.
Right, of course I'd prefer a CPU with a std. FPU, who wouldn't. First of all that SPE thingy means lots of trouble.
The AOS4 pre-release version I got contains a first version of the FPU emulation. It's performance is good enough as long as not too much FPU code has to be emulated. But most important: it works reliable.
However, at this moment I am only happy with the Tabor's float-performanceif the code is either SPE native or only contains few FPU instructions to be emulated.
But, luckily, Thomas Frieden is working on, let's call it "FPU turbo emulation" (I don't know how much I'm allowed to say) and I know that he's making good progress with that. I'm pretty confident that this thing will solve most performance issues with non-native code.
And that's what I mean with "at the end of the day":
While at the moment the performance is fine for my T57 adventure, I'm confident that once Thomas finishes the work on emu-v2 it will also be good for most other float-hungry non-native stuff.
I'd suggest to give the Tabor a chance to show its full potential, and that means:
let the Hyperion guys first finish their work on the OS and don't be so negative yet. I bet they weren't overly excited by the CPU choice neither - but they are actually solving those issues, I guess some moral support won't hurt
The Tabor's CPU is pretty fast so IMHO chances are good that at the end of the day we'll end up with a system that performs ~ up to 1.5 times as fast as the 460 for native- or int-code and around 460-speed for code with rather huge amounts of code to be emulated in one way or the other.
Don't nail me on any of this though, it's just my opinion / my guess based on what I saw / experienced / know so far. We'll see.
So much to my opinion. Regarding those two games on Tabor:
T57: when using SPE directly then the performance is nice. When using std. FPU commands then performance is low, although not as low as one might expect considering all those exceptions and emulated FPU commands.
Wings: I didn't even try it on Tabor yet
The problem with Wings is that it's based on good old Warp3D. So internally it does looooots of vertex transformations and stuff like that. This would be too much to ask from the current FPU emulation.
Now you might say: then do like you did for T57 and compile it for SPE.
Unfortunately that isn't that easy as it is for T57.
To make a long story short: compiled for SPE = code without those 32 FPU registers (SPE uses the GPRs). And this becomes a problem when calling library functions (e.g. Warp3D) which expect floats in FPU registers...
So either the game's float-code was emulated - then the data ended up in the emulated registers and all is good - but slow.
Or the game's float-code was SPE native - then the data ended up in a GPR - but the lib-function expects it inside an (emulated) FPU rgister, where it never appeared.
With T57 it was much easier because I do almost everything in software myself and the few libs I rely on aren't critical (or I wrote replacement functions).
I'll wait for the new turbo-emu before playing around with Wings on Tabor.
