I've done more homework, and I've managed to write a parallax starfield using the same principles as the stars.asm example on Funet. I didn't copy any code from it, and I even had the file closed while coding my own program. I know it's nothing really important yet, but I learned a lot from coding it. (Like screen 5's sprite table adresses in the V9938 Technical Databook not matching the actual MSX adresses, grumble..)
For those who don't know stars.asm: My program displays a black screen 5 with 30 sprites on it. They're divided in three groups and every group has a different horizontal speed, giving it a parallax feel. To update the sprite-locations smoothly, a hook is set on FD9F. The hook calculates new sprite positions and when finished writes them to the sprite attribute table in VRAM.
I have a question, though. As the starfield animation is completely handled by the hook, is it possible to let that animation run smoothly during diskaccess? For example, can I use the starfield (or another hook-handled animation) as a "loading screen" while loading images to other pages in VRAM?
