--- Ben Larson <wazzapfool@xxxxxxxxx> wrote:
> I really want to do this, but I'm having a hard time
> coming up with a simple bitmasking routine for the
> whole screen (The fact that I'm packing both PF0
> nibbles into one byte probably doesn't help the
> situation.) to use for a given X value. If I could
> come up with something here, that would probably
> also
> enable me to simplify the initial terrain drawing
> routing as well.
OK, actually I sat down and thought it out, and I
suppose it wouldn't be as hard as I originally
thought...basically just treat the whole 40 column
playfield as a giant register and just do ROLs and
RORs to get the masking bit where I want it. The fact
that the PF0 bits are packed into one byte will be a
minor inconvenience, but shouldn't be anything too
bad...
I suppose I will try to implement this strategy first
for the playfield drawing routine, since that's a big
ROM hog right now...
Ben
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