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56 lines
995 B
ArmAsm
56 lines
995 B
ArmAsm
; Tiny Cool - 32B demo
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; makes a pretty neat spinning pattern
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; not necessarily repeatable, it's walking through each memory page
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; and grabbing offset 32 or so as a shape table
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; what you get depends on contents of RAM
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; zero page locations
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HGR_SHAPE = $1A
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A5H = $45
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XREG = $46
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YREG = $47
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HGR_SCALE = $E7
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HGR_ROTATION = $F9
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FRAME = $FC
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XPOS = $FD
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YPOS = $FF
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; ROM calls
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HGR2 = $F3D8
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HPOSN = $F411
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XDRAW0 = $F65D
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RESTORE = $FF3F
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.zeropage
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tiny_tiny:
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jsr HGR2 ; Hi-res graphics, no text at bottom
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; Y=0, A=0 after this call
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iny
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sty HGR_SCALE
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tiny_loop:
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; setup X and Y co-ords for center of screen
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ldy #0 ; Y always 0
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ldx #140
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lda #96
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jsr HPOSN ; X= (y,x) Y=(a)
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ldx #<shape_table ; point to our shape
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rot_smc:
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lda #0 ; ROT=0
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tay ; ldy #>shape_table
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jsr XDRAW0 ; XDRAW 1 AT X,Y
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; Both A and X are 0 at exit
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; increment rotation
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inc rot_smc+1 ; oops also increments high byte of shape table
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jmp tiny_loop
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shape_table:
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.byte 18,0 ; shape data
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