mirror of
https://github.com/deater/dos33fsprogs.git
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135 lines
2.4 KiB
ArmAsm
135 lines
2.4 KiB
ArmAsm
; Tiny DSR
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; 82 bytes -- original
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; 77 bytes -- after some work (forgot to document)
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; 75 bytes -- count down frame counter
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; 73 bytes -- Y is 0 after HCLR
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; 72 bytes -- shave byte off page flip code
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; 70 bytes -- end by crashing to monitor
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; 67 bytes -- replace frame count with rotate
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; 64 bytes -- always increment scale
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; zero page locations
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HGR_SHAPE = $1A
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HGR_SHAPE2 = $1B
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HGR_BITS = $1C
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GBASL = $26
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GBASH = $27
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A5H = $45
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XREG = $46
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YREG = $47
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; C0-CF should be clear
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; D0-DF?? D0-D5 = HGR scratch?
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HGR_DX = $D0 ; HGLIN
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HGR_DX2 = $D1 ; HGLIN
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HGR_DY = $D2 ; HGLIN
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HGR_QUADRANT = $D3
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HGR_E = $D4
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HGR_E2 = $D5
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HGR_X = $E0
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HGR_X2 = $E1
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HGR_Y = $E2
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HGR_COLOR = $E4
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HGR_HORIZ = $E5
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HGR_PAGE = $E6
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HGR_SCALE = $E7
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HGR_SHAPE_TABLE = $E8
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HGR_SHAPE_TABLE2= $E9
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HGR_COLLISIONS = $EA
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; soft-switch
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PAGE1 = $C054
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; ROM calls
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HGR2 = $F3D8
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HGR = $F3E2
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HPOSN = $F411
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XDRAW0 = $F65D
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XDRAW1 = $F661
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RESTORE = $FF3F
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WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
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HCLR = $F3F2 ; A=0, Y=0 after, X unchanged
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OUR_ROT=$E0
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.zeropage
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.globalzp rot_smc
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; spinning dsr logo
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dsr_spin:
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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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sty HGR_SCALE ; 2 init scale to 0
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;=========================================
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; MAIN LOOP
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;=========================================
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main_loop:
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inc HGR_SCALE ; 2 ; increment scale
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inc rot_smc+1 ; 2 ; rotate
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inc rot_smc+1 ; 2
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;=======================
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; xdraw
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;=======================
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xdraw:
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; setup X and Y co-ords
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ldy #0 ; XPOSH always 0 for us
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ldx #110
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lda #96
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jsr HPOSN ; X= (y,x) Y=(a)
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; after, A=COLOR.BITS
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; Y = xoffset (140/7=20?)
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; X = remainder?
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jsr HCLR ; A=0 and Y=0 after, X=unchanged
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ldx #<shape_dsr ; point to our shape
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; ldy #>shape_dsr ; this is always zero since in zero page
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rot_smc:
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lda #$0 ; set rotation
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jsr XDRAW0 ; XDRAW 1 AT X,Y
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flip_page:
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; flip draw page $20/$40
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lda HGR_PAGE
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eor #$60
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sta HGR_PAGE
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; flip page
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; have $20/$40 want to map to C054/C055
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asl
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asl ; $20 -> C=1 $00
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asl ; $40 -> C=0 $00
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rol
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tax
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sta PAGE1,X
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; A and X are 0/1 here
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; if rot_smc not 64 then loop
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bit rot_smc+1 ; set V if bit 6 set
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bvc main_loop ; 2
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; fall through at end and crash
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shape_dsr:
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.byte $2d,$36,$ff,$3f
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.byte $24,$ad,$22,$24,$94,$21,$2c,$4d
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.byte $91,$3f,$36,$00
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