Scroll Down

[MrVertigo]

Is it possible to make the screen scroll down using basic on the ZX81, or only up? Like for a skiing program using scroll. Does the skier always have to be at the top of the screen for that simple BASIC trick, or is there a way to have the skier at the bottom?

[Paul]

In pure basic only scrolling up is possible in a reasonable time.
So Horace is always on top of the Hill, not at the bottom

[MrVertigo]

Is there an unpure BASIC way to do it, or does it need full machine code?

[Paul]

There are small machine code routines that offer scrolling in any direction and much more.

Search for
"Inline" BASIC Extensions

[MrVertigo]

Brilliant! Thanks.

[Moggy]

Here's an 8-way scroll routine in M/Code, it should be easy enough for you to adapt to your needs.

[MrVertigo]

Thanks very much