Re: [hatari-devel] EKO System demo

[laurent.sallafranque@xxxxxxx]

I second Thomas here.

The current videl.c code only emulates the basics of the videl.

I've got some code at home on my harddrive that waits still 2 years or more for a much closer videl emulation, but as long as the cpu is not better accurate, I can't use it.
(The Videl timings are dependant to the CPU timings in hatari, as the cpu is the main clock of the emulator).
I wrote this code after the crossbar part on the same model.

Actually, I can think at least at 3 games that need more accuracy in the CPU to allow them to run with a better videl code :
 - pinball dream (for the upper HUD part)
 - vroom030 (for the upper HUD part)
 - badmood (for the lower HUD part)

There may be some more.

These games need to detect a stable HBL value to switch the screen address to the HUD part or the game part of the screen.


With my videl code, I can play pinball dream for example (but with a very bad trick in the code that is specific to this game for the HBL).

For example, in pinball dream, the HBL value is completly "bouncing" for 5 to 15-20 HBLs, which makes the game unplayable (that's why I added a specific hack to tell pinballdream that the HBL value is fixed to the specific value it's waiting for, but that's not the good way to do it of course :) )

A better accurate 68030 interrests me a lot, because I could rework this videl code again and add it into hatari.

Another point for a better general falcon accuracy: reading the videl doc on Mikro's website (in the documentation section) tells us how the Videl reads the "screen" memory (every x cycles and y words read at once). I don't think this is currently taken into account into hatari (the videl time in 320*240 true color is about 1/3 of the total VBL time). This could have a very big impact on the current hatari timings.  

Regards

Laurent.



----- Mail original -----
De: "Thomas Huth" <th.huth@xxxxxx>
À: hatari-devel@xxxxxxxxxxxxxxxxxxx
Envoyé: Mardi 19 Août 2014 08:30:19
Objet: Re: [hatari-devel] EKO System demo

Am Tue, 19 Aug 2014 01:00:21 +0200
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:
 
> BTW, speaking about falcon's emulation, I see videl.c was based on 
> Aranym 0.9.4 from 2006, but since then they made some updates, 
> especially in 0.9.8
> 
> Did someone backport changes from Aranym into Hatari, or are we still 
> using the version from 0.9.4 (+ some modifications specific to
> Hatari) ?

I think we never synced again. Not sure whether a full sync would still
make sense since they have a different objective in Aranym than Hatari
(concerning the speed of the code vs. accuracy of the hardware
emulation).

 Thomas