On Thursday, November 22, 2001, at 09:30  PM, David P. Harris wrote:

> I wrote a 4x8 character display routine in assembler for the Apple II 
> for Forth, so we could get a reasonable char/line.  It worked ok, but 
> had to use a lot of tricks and that addressing is mighty messy!  A lot 
> of work to cram the bits into the display memory.

Well, in practice all you do is build a table of offsets, load the 
y-offset into the index register and use an indexed indirect mode to get 
to the correct byte.  The trick is making whatever you want to look 
good, because of the peculiarities in the color map.