[hatari-devel] EKO System

Thomas Huth huth at users.berlios.de
Wed Jun 24 22:34:09 CEST 2009


On Wed, 24 Jun 2009 08:52:14 +0200
Laurent Sallafranque <laurent.sallafranque at free.fr> wrote:

> In complement to my precedent mail, it's funny, but when I have a
> look at eko system demo,
> it seems to me that when it runs at 32 Mhz, it's like if it was the
> real 16 Mhz of the real falcon.
> 
> If you look carefully at the synchro between music and text in the
> "Eko present a new demo" part, you can notice that at 32 Mhz,
> everything is perfectly synchro.
> But at 16 Mhz, display changes every other music synchro.
> 
> Can't the 32 Mhz frequency in hatari be the real 16 Mzh ?

No the frequency scaling itself should be just fine. The problem is
certainly something different. Some things that come to my mind:

1)
The cycle time emulation for 68030 mode might not be very accurate yet.
The code is based on a old version of UAE, and we (first me, later
Nicolas) have spent a lot of time in getting the 68000 timings right.
But concerning the 68030 timings, nobody had a closer look at them yet.

2)
Somewhat related and maybe even more important: UAE core does not
emulate the cache of the 68030. So if you have some code that is very
cache optimized, the timings might differ a lot between a real 68030
and Hatari.

3)
What about the DSP : CPU relation in DSP_Run() ? Have you played
already with this setting again?

 Thomas



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