[A83] Re: Testing pixels

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Testing pixels
From: "Nicolas Gilles" <kingofhackers2k@hotmail.com>
Date: Sat, 09 Jun 2001 21:42:03 +0200
Reply-To: assembly-83@lists.ticalc.org


In asm should be easy...

make sure that the function is graphed also in the plotSScreen buffer...

ld hl, plotSScreen
B_CALL SaveDisp


; a - pixel row to check...
checkrow:
push hl
push de
push bc
ld h, 0
ld l, a
add hl,hl ; Multiply by two
add hl,hl ; by 4
ld d, h ; save for later
ld e, l
add hl,hl ; by 8
add hl,de ; adds 4x so that it gets to 12x
ld de, plotSScreen
add hl,de ; add offset to buffer
ld b, 12 ; (might need to be 11... just try.. )
ld e, $FF
checkrowloop:
ld a, (hl)
and e
ld e, a
djnz checkrowloop
ld a, e
pop bc
pop de
pop hl
cp $FF
ret

this should work, and pretty fast too... ( unlike my IPoint routine :( )

-Nicolas Gilles
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