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Dr.j
Registered: Feb 2003
Posts: 277 |
help with delay table making tech tech
Hey there again. i want to do a little tech tech effect.
i think i manage Ok with the charsets (took me some time to
arrange right the chars) and i have $d018 and $d016 tables
the main problem is now.. Delay tables . i use this routine
what is the best technique to do "Fine tune" the delays?
i will gladly hear your ideas to do fast delay tables.
i first tried to replace $d016+$d018 with $d021 but it didnt help me much. please don't send me to "missing cycles" article..hehe . btw i don't have any problems to make "rasters" delays but here its different.
ldx #$00
loop:
lda d018tab,x
sta $d018
lda d016,x
sta $d016
ldy delaytab,x
dey
bne *-1
inx
cpx #$2f
bne loop
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Dr.j
Registered: Feb 2003
Posts: 277 |
Okey i got it guyz. delay tables suck in this case (and i believe in more cases) i will unroll the loop ,7 for
normal line and 8th for "bad line" (21 cycles) thanks
for the help ! appricated |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
i think this delaytable thing really only works ok for simple rasterbars type of things... and even then its probably often shorter to unroll the loop. (for some tricky counterexamples, check crossbows supersmall fli display routine on codebase :)) |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
count = *+$0001
ldx #$00
loop
ldy d018tab,x
lda d016tab,x
ldx $d012
cpx $d012
beq *-3
sty $d018
sta $d016
inc count
ldx count
cpx #$2f
bne loop
start this one raster line before where effect should start. |
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tlr
Registered: Sep 2003
Posts: 1790 |
@flavioweb: I can imagine that as being not entierly glitch free... ;) |
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Danzig
Registered: Jun 2002
Posts: 440 |
what tlr said. |
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Oswald
Registered: Apr 2002
Posts: 5094 |
why mess up x with d012 compare?
edit: oh I see now. |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Quote: @flavioweb: I can imagine that as being not entierly glitch free... ;)
Maybe it don't work, i have not tested, but what you see wrong in this code? Do you think there is a timing problem, or you see some other error? |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
you should try it out :) use d020 and d021 for testing, you'll see what the problem is then :) |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Quote: you should try it out :) use d020 and d021 for testing, you'll see what the problem is then :)
I can't test now, but i know isn't stable. But i also think we have sufficient time to set registers before raster reach visible area so for a tech-tech effect may work.
May be wrong... of course =} |
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Radiant
Registered: Sep 2004
Posts: 639 |
Flavioweb: http://thedarkside.ath.cx/commodore/vic/vic_article_3.4.htm#3.5. |
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