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https://github.com/deater/dos33fsprogs.git
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57 lines
1.1 KiB
ArmAsm
57 lines
1.1 KiB
ArmAsm
; 16B interesting XDRAW pattern
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; it starts out sorta looking like hhhh? Or is it just me?
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; by Vince `deater` Weaver / dSr
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; for Lovebyte 2024
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; zero page locations
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GBASL = $26
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GBASH = $27
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HGR_SCALE = $E7
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HGR_COLLISIONS = $EA
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; ROM locations
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HGR2 = $F3D8
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HPOSN = $F411
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XDRAW0 = $F65D
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XDRAW1 = $F661
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HPLOT0 = $F457
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field15:
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; we load at zero page $E7 which is HGR_SCALE
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; this means the scale is $20 (JSR)
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; $20 $D8 $F3
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jsr HGR2 ; Hi-res, full screen ; 3
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; Y=0, A=0 after this call
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; A and Y are 0 here.
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; X is left behind by the boot process?
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; set GBASL/GBASH
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; we really have to call this, otherwise it won't run
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; on some real hardware depending on setup of zero page at boot
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jsr HPLOT0 ; set screen position to X= (y,x) Y=(a)
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; saves X,Y,A to zero page
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; after Y= orig X/7
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; A and X are ??
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tiny_loop:
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lda #$E3 ; ROT=$E3
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tay ;
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dey ; Y=$E2
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tax ; X=$E3
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jsr XDRAW0 ; XDRAW, A =ROTATE, X/Y = point to shape
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; Both A and X are 0 at exit
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; Z flag set on exit
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; Y varies
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beq tiny_loop ; bra
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