Re: [hatari-devel] Improved cycle counting / rasters for 16/32 MHz

On Sat, Aug 6, 2016 at 8:37 PM, Nicolas Pomarède <npomarede@xxxxxxxxxxxx> wrote:

Le 06/08/2016 à 18:24, Thomas Huth a écrit :

Am Wed, 3 Aug 2016 23:56:00 +0200
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:

Hello

I just committed some changes for some better cycle counting when
using x2 or x4 cpu speed. This should help later for better 68030
cycles accuracy.

Hi Nicolas,

thanks, that's pretty cool news! I guess we could now also have a more
cycle-exact 68060 mode now (where most instructions are supposed to
take one cycle)? Or emulate more than 32 MHz (like 64 MHz or 128 MHz)?

Hi

yes, by multiplying other components' clock instead of dividing number of cpu cycle, it means we can have higher cpu clock without loosing precision (for example <<3 or <<4) ; we could even do x1.5 (non integer values), but that would be slower than using << to shift values)

As for a better 68060 emulation, as the 68060 mode takes 1 cycle for all instructions at the moment, this would not give a real accuracy gain. But at least you would see that a 68060 running at 32 MHz is really faster than a 68060 running at 16 MHz for example (before, you would get 1 cycle in both cases and no speed difference in the end)

Thomas

PS: It's been quite a while since the last public release ... do you
already have any plans for a public version 2.0 ?

That's almost 1 year since Hatari 1.9 ; I don't have any plan now wrt a release date, but it would be nice to release someday.

In the current state, I don't think the devel version should be named 2..0, I would call it 1.10 (as I don't think there're so many changes visible to the user) and keep 2.0 for the release were Falcon cycles are really accurate (including correct cycle ratio with DSP)

If we were to release a new version with current state, I think it could be made around mid september.

If we wait for progress in the 68030 CE mode for Falcon, it could be much later, maybe near end of the year (I have no clear idea of the time I can spend coding on this part in the next months).

Nicolas