Re: [hatari-devel] error reading video counter on TT since commit 5316b4081e9d3

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 24/07/2022 à 16:14, Thomas Huth a écrit :
> Am Sun, 24 Jul 2022 10:15:19 +0200
> schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:
>
> > Le 24/07/2022 à 08:31, Thomas Huth a écrit :
> >
> > > Looks good! ... but now I wonder whether we have an issue here in Falcon
> > > mode, too? Since VIDEL_VideoRasterHBL() does not take nStartHBL into account
> > > yet?
> >
> > VIDEL_VideoRasterHBL() does a "+=" every HBL, starting from
> > Video_GetScreenBaseAddr() so it should be good too (but this means it
> > increments videl.videoRaster on every HBL, even those where we only
> > display border and counter should not increment ; if so that's a small
> > bug that could be improved later)
>
> That's what I meant!

My bad, I didn't see you mentioned nStartHBL in your message :)

> Shall we add a patch like this there:
>
> diff a/src/falcon/videl.c b/src/falcon/videl.c
> --- a/src/falcon/videl.c
> +++ b/src/falcon/videl.c
> @@ -619,6 +619,9 @@ void VIDEL_VideoRasterHBL(void)
>          int lineoffset = IoMem_ReadWord(0xff820e) & 0x01ff; /* 9 bits */
>          int linewidth = IoMem_ReadWord(0xff8210) & 0x03ff;  /* 10 bits */
>   
> +       if (nHBL <= nStartHBL)
> +               return;
> +
>          videl.videoRaster += linewidth + lineoffset;

This would make sense ; but I'm not familiar enough with Falcon to tell 
if it's enough.
If Falcon's screen code is displaying color 0 during top border (as in 
STF/STE mode) then your patch is certainly needed.

Nicolas