A86: how does find pixel work?!?
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A86: how does find pixel work?!?
Could someone please comment and explain whats happening here or tell me
how to find out. I am coming from the TI-85, not that it is too much
different. I have made some pretty cool games for the 85 using putsprite
which uses find pixel, but I have never really known how it works. I
think that it is time that I learn. This knowledge is what seperates
people who know what they are doing from those who are just screwing
around. I want to be one of those who knows what is going on. You can
make plenty of cool stuff w/o knowing this crap, but like Matt Johnson
says in his assembly tutorial having someone elses code in yours is a
crappy feeling. I should at least know how it works. Thanks, Mike
FIND_PIXEL:
push bc
push de
ld hl,ExpTable
ld d,0
ld a,b
and $07
ld e,a
add hl,de
ld e,(hl)
ld h,d
srl b
srl b
srl b
ld a,c
add a,a
add a,a
ld l,a
add hl,hl
add hl,hl
ld a,e
ld e,b
add hl,de
pop de
pop bc
ret
ExpTable:
.db $80,$40,$20,$10,$08,$04,$02,$01
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