Re: [hatari-devel] Testing "Transbeauce II" demo on 2/4 MB STF

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 13/04/2017 à 18:16, Christian Zietz a écrit :
> Nicolas Pomarède schrieb:
>
> > while recently running the Transbeauce II demo, I noticed it now fails
> > when using a different memory config than 512 KB or 1 MB.
> >
> > This is because Hatari now emulates the MMU at FF8001 and from looking
> > at the demo's code, it force MMU config to either 4 (512 KB) or 5 (1
> > MB), which will cause a crash when using 2 MB RAM banks.
> >
> > Could someone try this demo on a 2 or 4 MB STF to confirm it crashes too
> > (before the loader with the red balls appear) ?
>
> As you might know, I have an STFm which can be switched between 1 MB and
> 4 MB. Thus, I can in fact confirm that the demo [1] crashes before the
> red balls appear in the 4 MB setting, while the red balls do appear in
> the 1 MB setting.
> So Hatari now emulates this correctly.

Great (or not for the demo coder !), thanks for confirming this.

At first, I thought I added regression in Hatari while adding MMU support.

The protection in this demo is quite evolved, but I'm rather surprised 
they decided to mess with FF8001 in their loader and didn't check it 
failed on 2MB STF for example (as it was possible at this time to have 
more than 1 MB, even if it was expensive).

Or they just tested it with 2/4 MB STE, which unfortunately don't map 
the RAM in the same way and would not crash in that case.

I will add a note about this in Hatari's compatibility doc.

Nicolas