Re: [hatari-devel] Hatari screen test

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 27/05/2020 à 20:43, Thomas Huth a écrit :

> I haven't completely looked through that code, but to my understanding,
> such fullscreen routines do something in almost each and every line of
> the screen... there are certainly some spots where you could try to fit
> such a natfeats instruction (e.g. right before the final "move.w
> #$2300,(SP)" instruction), and in the worst case you could also
> sacrifice the last line and not open the borders there to gain some
> spare time ... but still, if the routine is then not working on a real
> ST anymore, that's rather unfortunate, I think.

I think it's possible to set an exception for illegal instruction to 
catch the natfeats under a real ST (or when natfeats is disabled) and 
then you can call it after the last fullscreen line. In all cases, last 
fullscreen line will be HBL 307 (or 309 by going to 60 Hz again, I don't 
think flix's code is doing that).

So, once on HBL 310 for example, there shouldn't be any cycle accuracy 
required, fullscreen code should just wait for the next VBL and calling 
natfeats function should not have an impact.

Nicolas