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Re: Scrolling HGR Screen Up 8 Lines
Christer Ericson <christer_ericson@playstation.sony.nospam.com> wrote:
> You definitely do *not* want to do it this way!
How do you know what I want? :-)
My purpose was not to write the fastest possible way of doing this, just
a reasonable implementation that would do the task required, without
being too huge.
I initially thought of doing a faster move, but decided in favour of a
prettier one, with no attempts at optimization. This is left as an
exercise for the reader.
> Indirect-comma-Y addressing is the slowest addressing mode.
No it isn't. Pre-indexed indirect (with X) is one cycle slower, except
in the case where post-indexed indirect (with Y) crosses a page
boundary, when they are equally bad.
--
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand