I have been playing for a while with 6502 assembly and namely on Apple ][. Presently I got curious about how vertical position would be calculated in hires. Yes, some uses tables and got one of my own for both hires and text/lores. However hires table is created in basic, and I am more curious about calculating it without using table. Namely calculating with assembly and that horrible 8 bit register. Google didn't give out pure math (read none at all).
Unless somewhere in memory is table used by basic's hires graphics function, in which case that table will be handy. Didn't find anything resembling such table however, but would be memory saver if such thing exist.
If you are curious what I am doing right now, it is actually trying put up two functions. Hires versions of hlin and vlin. Byte accurate versions, not pixel. I am working with something? Well, won't give out details until all required snippets are gathered... nope...