Scroll x 2 pixels, 4 pixels and 8 pixels (char level)

[britlion]

It very much depends on what you want to scroll (whole screen? Part?) and in which direction. Up and down are probably faster than left and right - to move up and down you copy screen data from one row into another. Sideways, unless it's 8 pixels, you have to rotate bits around, which is a bit more fiddly.

For alogorithms and code, you might want to ask the wider audience on world of spectrum. Here we can help on getting it to work with the compiler, but fewer heads for writing snippets of code.

That said, there's a lot of good stuff in the library wiki on this site. I put a chunk in there