Re: [hatari-devel] IMP chipset (in)compatibility

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi Christian,

This Team Suzuki (preview) version works fine with Hatari MegaST emulation:
http://www.atarimania.com/game-atari-st-team-suzuki_30711.html

Which I think should be mentioned in the compatibility note.


And the version of Team Suzuki you linked, works also with Hatari 
MegaSTE emulation (which should also be noted), not just ST & STE 
emulation.  It bus errors only with MegaST emulation.

Whereas G-Loc doesn't work either with MegaST or MegaSTE.

=> Are you sure IMP is the issue with both of the games?


	- Eero

On 10.3.2021 21.21, Christian Zietz wrote:
> over in a German forum [1], a user wondered why two games (G-Loc and
> Team Suzuki) wouldn't run on his (real) MegaST. And he was able to
> confirm this with Hatari: Runs on emulated ST, doesn't run on emulated
> MegaST.
>
> Wild theories were discussed (regarding Blitter and RTC), but in the
> end, this turned out to be a chipset issue, both in Hatari as in the
> real HW. I checked both games: they reset the (STE-only) 'linewidth'
> register $FF820E/FF820F. This is harmless on an ST/MegaST with Ricoh
> chipset but causes a bus error on an IMP chipset, as confirmed by your
> tests:
>
> https://git.tuxfamily.org/hatari/hatari.git/tree/tests/buserror/results/st_w.txt 
>
> (Ricoh)
> https://git.tuxfamily.org/hatari/hatari.git/tree/tests/buserror/results/mst4_w.txt 
>
> (IMP)
>
> This explains the user's observation, as Hatari emulates the MegaST with
> an IMP chipset, but the ST with a Ricoh chipset. Furthermore, the user
> confirms that his real MegaST indeed has an IMP chipset. Note that I'm
> therefore *not* saying Hatari is wrong here (you had to make a choice).
>   I'm proposing a patch (attached) to compatibility.html.
>
> Regards
> Christian
>
> [1]
> <https://forum.atari-home.de/index.php/topic,16426.msg255046.html#msg255046> 
>
> --
> Christian Zietz  -  CHZ-Soft  -  czietz@xxxxxxx
> WWW: https://www.chzsoft.de/
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