Re: [hatari-devel] VDI resolution limits

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On 05/11/2018 06:53 PM, Thorsten Otto wrote:
> On Freitag, 11. Mai 2018 16:00:46 CEST Eero Tamminen wrote:
> > Latest Hatari version where 1024x768 VDI mode works with TOS v1.04
> > is v0.90, and it doesn't anymore work in v1.0.
>
> Wow, that is really old. Many thanks for tracking that down.
>
> > I'll add a small buffer after VDI screen to avoid this, and
> >   remove the VDI screen size limits with old TOS versions.
>
> Does that also mean that the 300k limit can be lifted? it is still there.

Not without testing with multiple TOS versions (1.x - 3.x & EmuTOS)
and several popular GEM programs + some NVDI versions.

Any volunteers? :-)


> > Any idea why these mouse related reads happen only with VDI mode,
>
> When not using VDI mode, Hatari (and also TOS) uses a screen buffer size of
> 0x8000 bytes. Since the actual screen size then in all resolutions is only
> 32000 bytes, that already includes a gap of 768 bytes.
>
> > and only when mouse moves *horizontally* in this area?
>
> I would bet that the vertical limit is restricted to not exceed the screen
> height, but in the horizontal direction you may need to read an additional
> word, and the logic only masks the values out if it is out of screen bounds,
> but the read is still performed.

Thanks, that makes perfect sense.

I just wonder should there really be the same amount of bytes (768)
padding as with TOS, currently I added just enough for the mouse
pointer (16x16 pixels).


	- Eero