Ruffin Bailey wrote::
> I also used some fancy AND'ing to make sure the frames were
> increased every 8/60th (?? - every 8th frame written to the
> NTSC screen) of a second.
That's correct.
>(though I'm only using 3 bits so Thomas will probably
>shoot me for sacrilege):
Bang! :-)
>So anyhow I feel sufficiently happy with the
>way that I did that that I'm betting there's a better way. Go
>ahead and bring me off of my high. :^)
You begged for it. ;-)
A minimal improvement would be (saves 2 bytes):
lda SWCHA
cmp #%11110000 ; we don't care for the lower bits
bcs dontIncreaseFrame ; CF=1, if all 4 upper bits are set
That code has a bug:
lda p0FrameCount
adc #%00001000 ; ... increase the frame count
"by one frame" (16 dec, $10)
and #%00111000 ; but don't let it get over
"three frames" (48 dec, $30)
sta p0FrameCount ; put back into p0FrameCount
Instead of 4 frames, you get 8 frames here
(%00001000 = $08, %00111000 = $38).
But you don't need to do that complicated stuff with
p0FrameCount:
dec p0FrameCount
bpl .skipReset
lda #NUM_FRAMES-1 ; = 3
sta p0FrameCount
.skipReset
This doesn't save space, but IMO is better readable.
And instead of using a magic number ($08) for the offset you
better should write:
clc ; not necessary, CF = 0 already
adc #<player0data ;
That makes the code more readable and maintainable.
Have fun!
Thomas
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