the classic 32 pixel height to 26, because there is not enough CPU time
left to do 32 pixel! We can do this because there is no 8 lines/scroll limit
when using the hardscroller.
to save space. But we do not shift the scroll buffer around. Instead
there are 416/16=26 different cases in the scroll buffer where the left
border of the scroller is. We simply use 26 different copy routines.
If you scroll now too far with the numpad, the copied scroller will
overwrite code, devpac or system. Crash ahoi!