Re: [hatari-devel] Relocation warning + program failing when run from GEMDOS HD

["Roger Burrows" <anodyne@xxxxxxxxxxxx>]

On 28 Sep 2022 at 11:16, Eero Tamminen wrote:

> Hi,
>
> Gah, now I got "c64_show.prg" to work also from GEMDOS HD, with 4MB RAM,
> with the following procedure:
>
> 1. First autostart it with:
>     $ hatari -s 4 -m --fast-forward on ./c64_show.prg
> 2. After it crashes, disable fast-forwarding and start it from the
> desktop with double click
> 3. Press key when prompted
>     => working slideshow
>
> That procedure works both with real TOS and EmuTOS.
>
> Just waiting long time before starting the program is not enough, it
> actually needs to crash first.
>
> WTF???
>
There's some apparently crap coding where d0 is used to get data from the
screen, then flip the bits and store it back.  Unfortunately, d0 is also used
as the loop control (via dbra) for that loop.  I never bothered to try to
figure out why it worked, perhaps it was some really clever trick that I didn't
understand ...

If you need to the know exactly where that is in the code, let me know & I'll
figure it out again.

Roger