Re: A86: Sprite XOR
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Re: A86: Sprite XOR
A. El-Helw wrote:
> Hello Everyone,
>
> I am converting the famous "DuckHunt" into 86 ASM, from my
> friends 83 aSM
> version. I did a lot, there is only one thing left - the sprites. In
> this
> program, it used something called SPRXOR, which detected - if a sprite
> was
> on screen when you loaded coords and name, it erased it, if not, it
> put it.
> i was wondering if someone (Dan ? Alan? Bill?) can convert this
> program
> to 86 aSM , to make my life easier, as well as a lot of other peoples'
> =).
> I am attaching Movax's original 83 source code.
It doesn't actually "DETECT" anything, the basic nature of XOR alows
that effect. notice:
AB AxorB
00 0
01 1
10 1
11 0
this is the basic idea of what you want to do...
HL = VidMem offset
DL = Pointer to Sprite
ld a,(de) ; get byte from pic
xor (hl) ; xor it with what's at the screen already
ld (hl),a ; save XORed value in vid memory
--
Trent Lillehaugen
Computer Engineering Major
California Polytechnic University, San Luis Obispo
<tllilleh@polymail.calpoly.edu>
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