Update on Pro

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Update on Pro

Post by admin » Wed Jan 07, 2004 12:58 pm

I promised on the Iyonix support groups to say a few words about the SOP with Aemulor Pro, so here's what's happening:
  • * filing system support coded and almost fully working; Aemulor's just rejecting as invalid at least one filing system that should work.

    * sound is fully coded, though not yet working properly; voices are registered and removed but there's a bug in the calling of the background handler. Shouldn't take long to find and correct, I just got sidetracked into trying to crash Iyonixes :wink:

    * low-bpp screen modes were, as we demoed at Wakefield, working; I say 'were' because the performance wasn't great and I'm part-way through reworking them using the knowledge gained from Cino so that the screen will be much smoother. The new approach also has the advantage that features of the VIDC20 (or even VIDC1), such as hardware scrolling can be implemented very easily which will help increase the number of games we can run.

    * IOC/IOMD emulation - since I think it won't be much extra work to include at least a basic emulation (and since half the required, namely the handling of data aborts in emulated code, is already there), I expect this will be included with the first release of Pro. This should also get a few more games going, at least those which work on the RiscPC. Earlier games may require more work because of OS and processor incompatibilities.

    And don't I wish I still had my old copies of E-Type and Holed Out! :cry: Though perhaps it's for the best that I don't; Cino playing alongside my source-editor is enough of a distraction!
Lastly, I've been working on a way to JIT compile 26-bit ARM code to 32-bit code that's also better tuned for the XScale core. Specifically, it knows about load-use delays and other dependencies (such as the extra issue cycle on a shifted register when that register is updated in the preceding clock cycle).

It also performs a few simple, machine-level optimisations such as unrolling short loops and inlining small functions. The sort of optimisations that I'd normally make to the output of a C compiler, typically giving a 2-fold speed increase for loops. So it should give a speed boost to C programs in particular (given the relative paucity of optimisations in Norcroft), and to assembler programs that haven't been re-tuned for the StrongARM (ie. most of them!)

As an aside, I recently had to rescue the tracks from an audio CD because it wasn't playing reliably. I thought the easiest way to do this would be on my PC but after downloading a couple of programs I still hadn't bullied anything into ripping the tracks properly. (It probably doesn't help that I haven't linked MS's coffers again since buying this copy of NT!)

So, anyway, I searched the web for a RISC OS solution and stumbled upon AudioFS 2. "Yay! Oh, it's 26-bit code," I thought, "Oh well, let's give it a whirl" expecting it to blow up horribly because it - I presume - sends low-level SCSI commands via CDFS. But it didn't blow up, it worked first time; up popped a nicer filer window of the audio tracks and I just copied them to my hard drive leaving Pro to do all the work, without even needing to know how this very nice filing system actually works. Brilliant! :D

So, that's where things stand at the moment. I know most of you probably want only one question answered - "When?" Right? Well, I think I'll be looking for beta testers in the latter half of this month. A couple of kind souls have already tried a prototype of the FS support - months and months ago, just before I started writing Cino - and I hope you'll be willing to help with a bit more testing.

Anyone else who wants to try out a demo copy (particularly anyone with a large collection of apps that need the new features - low-bpp screens, sound and FS support - rather than just extra oomph) please drop me an email.



PS. And one final comment - to the guy on the Iyonix support forum who's been playing Lemmings with Aemulor (you know who you are!)...."Ggggrrrrrr! Not fair!" My (older) copy of Lemmings doesn't run, and I wanted to be the first to play it again.... but I'm sure it's not the same without sound - "Oh no!" :wink:

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