Re: [hatari-devel] Re: Lethal Xcess sync scroll fails on ST

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 01/09/2018 à 16:08, Vincent Rivière a écrit :
> Le 25/03/2018 à 03:17, Vincent Rivière a écrit :
> > On 28/05/2014 à 12:01, Nicolas Pomarède wrote:
> > > Lethal Xcess has a calibration routine at start to compute values to
> > > remove top border and this calibration is rather short. Result is rather
> > > random, it works often in STF mode and works sometimes in STE mode.
> >
> > Sorry to insist again...
> >
> > I can't get Lethal Xcess working in ST mode (while it works fine in 
> > STe mode). Is it expected?
> >
> > Using latest Hatari HG, freshly recompiled for Cygwin.
>
> I still can't get Lethal Xcess working in ST mode. The sync scroll fails 
> with skewed, unstable display.
> Is this a known bug?
>
> On the other hand, it works perfectly in STe mode.

It used to work before more or less by luck, then I think some more 
precise emulation broke the way top border is removed (before, 2 less 
precise effects were kind of "compensating" each other)

In STF mode the game uses hardscroll and try to selfcalibrate on the STF 
model's speed. Unfortunately this selfcalibration is not very good and 
it depends on some kind of "jitter" between mfp timer and cpu (due to 
the fact that the MFP timers and the CPU don't share a common freq).

I have some kind of hack for this which I can try to use in a future 
version.

Nicolas