recently I've found some old disks with a backup from my STE hard disk. Many thanks again to ggn for providing the backup program so that I was able to restore it.
So if anyone is interested in old demo code
you'll find the complete source of the 3D part of the E605 (STE) demo here:https://bitbucket.org/AnimaInCorpore/ste3ddemo
It's a Eclipse CDT project for the m68k-atari-mint cross compiler tools (http://vincent.riviere.free.fr/soft/m68k-atari-mint/
Here's a link to the Pouet database entry:http://pouet.net/prod.php?which=14448
And finally a video to see what I'm talking about (not recorded by me):http://www.youtube.com/watch?v=uVD-nR8t9C4
Please don't expect any highly optimized code.