dos33fsprogs/racebeam/racebeam.s

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2019-03-06 17:44:31 +00:00
; Race the Beam
; try for 40x192 15-color graphics on stock Apple II / Apple II+
; this means, no double-hires
; by racing the beam we can possibly update at least 10 blocks
; per line to the 192-line resolution
; we can get 40x96 resolution simply by page flipping
; this all requires vapor lock cycle-counting
; by deater (Vince Weaver) <vince@deater.net>
; Zero Page
FRAMEBUFFER = $00 ; $00 - $0F
YPOS = $10
YPOS_SIN = $11
CH = $24
CV = $25
GBASL = $26
GBASH = $27
BASL = $28
BASH = $29
FRAME = $60
WAITING = $62
LETTERL = $63
LETTERH = $64
LETTERX = $65
LETTERY = $66
LETTERD = $67
LETTER = $68
BLARGH = $69
HGR_COLOR = $E4
STATE = $ED
DRAW_PAGE = $EE
LASTKEY = $F1
PADDLE_STATUS = $F2
TEMP = $FA
WHICH = $FB
; Soft Switches
KEYPRESS= $C000
KEYRESET= $C010
SPEAKER = $C030
SET_GR = $C050 ; Enable graphics
SET_TEXT= $C051 ; Enable text
FULLGR = $C052 ; Full screen, no text
TEXTGR = $C053 ; Split screen
PAGE0 = $C054 ; Page0
PAGE1 = $C055 ; Page1
LORES = $C056 ; Enable LORES graphics
HIRES = $C057 ; Enable HIRES graphics
PADDLE_BUTTON0 = $C061
PADDL0 = $C064
PTRIG = $C070
; ROM routines
;HGR = $F3E2
;HPLOT0 = $F457
;HGLIN = $F53A
;COLORTBL= $F6F6
TEXT = $FB36 ;; Set text mode
HOME = $FC58 ;; Clear the text screen
WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
;==================================
;==================================
setup_background:
;===================
; init screen
jsr TEXT
jsr HOME
bit LORES
bit SET_GR
bit FULLGR
bit PAGE0
bit KEYRESET
;===================
; init vars
lda #0
sta DRAW_PAGE
sta STATE
sta WAITING
;=============================
; Load graphic page0
; lda #$0c
; sta BASH
; lda #$00
; sta BASL ; load image to $c00
; lda #<bg_final_low
; sta GBASL
; lda #>bg_final_low
; sta GBASH
; jsr load_rle_gr
; lda #4
; sta DRAW_PAGE
; jsr gr_copy_to_current ; copy to page1
; GR part
; bit PAGE1
; bit LORES ; 4
; bit SET_GR ; 4
; bit FULLGR ; 4
; jsr wait_until_keypressed
;=============================
; Load graphic page1
; lda #$0c
; sta BASH
; lda #$00
; sta BASL ; load image to $c00
; lda #<bg_final_high
; sta GBASL
; lda #>bg_final_high
; sta GBASH
; jsr load_rle_gr
; lda #0
; sta DRAW_PAGE
; jsr gr_copy_to_current
; GR part
; bit PAGE0
; jsr wait_until_keypressed
;==============================
; setup graphics for vapor lock
;==============================
jsr vapor_lock ; 6
; vapor lock returns with us at beginning of hsync in line
; 114 (7410 cycles), so with 5070 lines to go
; so we have 5070 + 4550 = 9620 to kill
jsr gr_copy_to_current ; 6+ 9292
; now we have 322 left
; GR part
bit LORES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
; 322 - 12 = 310
; - 3 for jmp
; 307
; Try X=9 Y=6 cycles=307
ldy #6 ; 2
loopA:
ldx #9 ; 2
loopB:
dex ; 2
bne loopB ; 2nt/3
dey ; 2
bne loopA ; 2nt/3
jmp display_loop ; 3
.align $100
;================================================
; Display Loop
;================================================
; each scan line 65 cycles
; 1 cycle each byte (40cycles) + 25 for horizontal
; Total of 12480 cycles to draw screen
; Vertical blank = 4550 cycles (70 scan lines)
; Total of 17030 cycles to get back to where was
; We want to alternate between page1 and page2 every 65 cycles
; vblank = 4550 cycles to do scrolling
; 2 + 48*( (4+2+25*(2+3)) + (4+2+23*(2+3)+4+5)) + 9)
; 48*[(6+125)-1] + [(6+115+10)-1]
display_loop:
;===================================
; 192 lines, alternate PAGE0/PAGE1 every 2 lines
;===================================
ldy #96 ; *2=192 lines ; 2
; we set PAGE0 (4) then want to NOP (61) for a total of 65
bouter_loop:
bit PAGE0 ; 4
ldx #12 ; 65 cycles with PAGE0 ; 2
bpage0_loop: ; delay 61+bit
dex ; 2
bne bpage0_loop ; 2/3
;=============
; 6+(12*5)-1=65
; we set PAGE1 (4) as well as dey (2) and bne (3) then nop (55)
;
bit PAGE1 ; 4
ldx #11 ; 65 cycles with PAGE1 ; 2
bpage1_loop:
dex ; 2
bne bpage1_loop ; 2/3
;=============
; 6+(11*5)-1=60
dey ; 2
bne bouter_loop ; 2/3
;==============
; 5 to make 65
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; 4550
; +1 fallthrough
; -2 for ldy in previous
; -35 call through jumptable
; -7 keyboard
; -3 jmp
; ========
; 4504
;========================
; each subunit should take 4504 cycles
firework_state_machine:
check_keyboard:
lda KEYPRESS ; 4
bpl no_keypress ; 3
jmp restart
no_keypress:
jmp display_loop ; 3
restart:
jmp setup_background
.include "gr_hline.s"
;.include "../asm_routines/gr_unrle.s"
;.include "../asm_routines/keypress.s"
.include "gr_copy.s"
;.include "random16.s"
.include "vapor_lock.s"
.include "delay_a.s"