280 lines
5.2 KiB
ArmAsm
280 lines
5.2 KiB
ArmAsm
; Race the Beam
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; try for 40x192 15-color graphics on stock Apple II / Apple II+
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; this means, no double-hires
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; by racing the beam we can possibly update at least 10 blocks
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; per line to the 192-line resolution
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; we can get 40x96 resolution simply by page flipping
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; this all requires vapor lock cycle-counting
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; by deater (Vince Weaver) <vince@deater.net>
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; Zero Page
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FRAMEBUFFER = $00 ; $00 - $0F
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YPOS = $10
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YPOS_SIN = $11
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CH = $24
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CV = $25
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GBASL = $26
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GBASH = $27
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BASL = $28
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BASH = $29
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FRAME = $60
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WAITING = $62
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LETTERL = $63
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LETTERH = $64
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LETTERX = $65
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LETTERY = $66
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LETTERD = $67
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LETTER = $68
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BLARGH = $69
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HGR_COLOR = $E4
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STATE = $ED
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DRAW_PAGE = $EE
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LASTKEY = $F1
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PADDLE_STATUS = $F2
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TEMP = $FA
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WHICH = $FB
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; Soft Switches
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KEYPRESS= $C000
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KEYRESET= $C010
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SPEAKER = $C030
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SET_GR = $C050 ; Enable graphics
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SET_TEXT= $C051 ; Enable text
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FULLGR = $C052 ; Full screen, no text
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TEXTGR = $C053 ; Split screen
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PAGE0 = $C054 ; Page0
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PAGE1 = $C055 ; Page1
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LORES = $C056 ; Enable LORES graphics
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HIRES = $C057 ; Enable HIRES graphics
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PADDLE_BUTTON0 = $C061
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PADDL0 = $C064
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PTRIG = $C070
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; ROM routines
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;HGR = $F3E2
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;HPLOT0 = $F457
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;HGLIN = $F53A
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;COLORTBL= $F6F6
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TEXT = $FB36 ;; Set text mode
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HOME = $FC58 ;; Clear the text screen
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WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
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;==================================
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;==================================
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setup_background:
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;===================
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; init screen
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jsr TEXT
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jsr HOME
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bit LORES
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bit SET_GR
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bit FULLGR
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bit PAGE0
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bit KEYRESET
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;===================
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; init vars
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lda #0
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sta DRAW_PAGE
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sta STATE
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sta WAITING
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;=============================
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; Load graphic page0
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; lda #$0c
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; sta BASH
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; lda #$00
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; sta BASL ; load image to $c00
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; lda #<bg_final_low
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; sta GBASL
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; lda #>bg_final_low
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; sta GBASH
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; jsr load_rle_gr
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; lda #4
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; sta DRAW_PAGE
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; jsr gr_copy_to_current ; copy to page1
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; GR part
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; bit PAGE1
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; bit LORES ; 4
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; bit SET_GR ; 4
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; bit FULLGR ; 4
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; jsr wait_until_keypressed
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;=============================
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; Load graphic page1
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; lda #$0c
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; sta BASH
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; lda #$00
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; sta BASL ; load image to $c00
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; lda #<bg_final_high
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; sta GBASL
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; lda #>bg_final_high
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; sta GBASH
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; jsr load_rle_gr
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; lda #0
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; sta DRAW_PAGE
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; jsr gr_copy_to_current
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; GR part
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; bit PAGE0
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; jsr wait_until_keypressed
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;==============================
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; setup graphics for vapor lock
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;==============================
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jsr vapor_lock ; 6
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; vapor lock returns with us at beginning of hsync in line
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; 114 (7410 cycles), so with 5070 lines to go
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; so we have 5070 + 4550 = 9620 to kill
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jsr gr_copy_to_current ; 6+ 9292
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; now we have 322 left
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; GR part
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bit LORES ; 4
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bit SET_GR ; 4
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bit FULLGR ; 4
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; 322 - 12 = 310
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; - 3 for jmp
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; 307
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; Try X=9 Y=6 cycles=307
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ldy #6 ; 2
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loopA:
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ldx #9 ; 2
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loopB:
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dex ; 2
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bne loopB ; 2nt/3
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dey ; 2
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bne loopA ; 2nt/3
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jmp display_loop ; 3
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.align $100
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;================================================
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; Display Loop
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;================================================
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; each scan line 65 cycles
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; 1 cycle each byte (40cycles) + 25 for horizontal
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; Total of 12480 cycles to draw screen
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; Vertical blank = 4550 cycles (70 scan lines)
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; Total of 17030 cycles to get back to where was
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; We want to alternate between page1 and page2 every 65 cycles
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; vblank = 4550 cycles to do scrolling
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; 2 + 48*( (4+2+25*(2+3)) + (4+2+23*(2+3)+4+5)) + 9)
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; 48*[(6+125)-1] + [(6+115+10)-1]
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display_loop:
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;===================================
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; 192 lines, alternate PAGE0/PAGE1 every 2 lines
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;===================================
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ldy #96 ; *2=192 lines ; 2
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; we set PAGE0 (4) then want to NOP (61) for a total of 65
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bouter_loop:
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bit PAGE0 ; 4
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ldx #12 ; 65 cycles with PAGE0 ; 2
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bpage0_loop: ; delay 61+bit
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dex ; 2
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bne bpage0_loop ; 2/3
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;=============
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; 6+(12*5)-1=65
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; we set PAGE1 (4) as well as dey (2) and bne (3) then nop (55)
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;
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bit PAGE1 ; 4
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ldx #11 ; 65 cycles with PAGE1 ; 2
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bpage1_loop:
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dex ; 2
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bne bpage1_loop ; 2/3
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;=============
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; 6+(11*5)-1=60
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dey ; 2
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bne bouter_loop ; 2/3
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;==============
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; 5 to make 65
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;======================================================
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; We have 4550 cycles in the vblank, use them wisely
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;======================================================
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; 4550
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; +1 fallthrough
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; -2 for ldy in previous
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; -35 call through jumptable
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; -7 keyboard
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; -3 jmp
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; ========
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; 4504
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;========================
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; each subunit should take 4504 cycles
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firework_state_machine:
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check_keyboard:
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lda KEYPRESS ; 4
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bpl no_keypress ; 3
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jmp restart
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no_keypress:
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jmp display_loop ; 3
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restart:
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jmp setup_background
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.include "gr_hline.s"
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;.include "../asm_routines/gr_unrle.s"
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;.include "../asm_routines/keypress.s"
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.include "gr_copy.s"
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;.include "random16.s"
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.include "vapor_lock.s"
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.include "delay_a.s"
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