Thanks for all your help so far...I got it working, but the hacking
to get the display quite right alarms me. And when I tried to make it
less hacky, I had some odd results, maybe someone wants to look, it's
kind of intruguing.
I find that Erik's line
LDA (pointerP0ScoreOffset), Y
won't assemble... "Illegal Addressing mode" for that line, alas
So Chris's suggestion seemed to be the next best match for my
thinking. Except since it requires a dedicated register for the
memory offset, and I want to draw two scores, I decided to just
do a single nonlooping "5 line kernal".
You can get the full source and a binary at
http://alienbill.com/joustpong , final entry at the bottom.
I made it so every time you hit the button, both player's
score advance, so you can see all 10 digits.
The relevant (I think! ;-) lines are:
;early on...do I still need to have 2 bytes for each of these?
pointerP0ScoreOffset = $92
pointerP1ScoreOffset = $94
;
; in the vblank...
;
;--------------------------------------
;CALCULATE SCORE POINTERS
;--------------------------------------
LDA p0score ;accumulator = score
ASL ;accumulator = score * 2
ASL ;accumulator = score * 4
ADC p0score ;accumulator = (score * 4) + score = score * 5
STA pointerP0ScoreOffset
LDA p1score ;accumulator = score
ASL ;accumulator = score * 2
ASL ;accumulator = score * 4
ADC p1score ;accumulator = (score * 4) + score = score * 5
STA pointerP1ScoreOffset
;;;;;;;;;;;;;;then at the top of the kernal:
;--------------------------------------
;SCORE DISPLAY KERNAL
;--------------------------------------
STA WSYNC
LDX pointerP0ScoreOffset
LDY pointerP1ScoreOffset
INX
INX
INX
INX
INY
INY
INY
INY
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
STA WSYNC
LDA Score0Graphic,X
STA GRP0
LDA Score0Graphic,Y
STA GRP1
DEY
DEX
LDA #0
STA GRP0
STA GRP1
STA WSYNC
STA WSYNC
STA WSYNC
STA WSYNC
;flip p1 before game kernal
LDA #%00001000
STA REFP1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
I think I'm playing way too fast and lose with the time or something...
because when I tried to remove all the INX and INY and use
Score0Graphic+4 instead, it more or less worked fine, EXCEPT the left
most pixel of only the "0" digit was missing! Which doesn't make
any kind of intuitive sense to me.
Oy, anyway, I'm happy to see it more or less working,
I welcome any suggestions for tweaks to it. (I'm probably not going
to start down a totally different path if I can avoid it.)
Also, Z26 reports a pretty steady 242 scanlines...that's too few, innit?
Hrrm.
Thanks for your help! You guys are such a supportive bunch for
blunderers like me....
-Kirk
--
"My mind is especially empty today."
--goofy looking buddhist monk to second monk, New Yorker cartoon
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