mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-08-14 10:29:46 +00:00
1234 lines
20 KiB
ArmAsm
1234 lines
20 KiB
ArmAsm
; Lo-res cycle-counting water transparency hack
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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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MASK = $2E
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COLOR = $30
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FRAME = $60
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MB_VALUE = $91
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BIRD_STATE = $E0
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BIRD_DIR = $E1
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DRAW_PAGE = $EE
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LASTKEY = $F1
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PADDLE_STATUS = $F2
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XPOS = $F3
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OLD_XPOS = $F4
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TEMP = $FA
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TEMPY = $FB
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INL = $FC
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INH = $FD
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OUTL = $FE
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OUTH = $FF
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; Soft Switches
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KEYPRESS= $C000
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KEYRESET= $C010
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SET_GR = $C050 ; Enable graphics
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FULLGR = $C052 ; Full screen, no text
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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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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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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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; location we don't care about
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DUMMY = $300
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waterfall_demo:
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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 PAGE0
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;===================
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; init vars
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lda #0
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sta BIRD_DIR
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sta BIRD_STATE
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sta FRAME
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sta OLD_XPOS
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lda #4
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sta DRAW_PAGE
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sta XPOS
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;===================
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; Mockingboard
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jsr mockingboard_init
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; Enable channel A tone+noise
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ldx #7 ; 2
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lda #$36 ; 2
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sta MB_VALUE ; 3
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jsr write_ay_both ; 6+65
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; enable white noise
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ldx #6 ; 2
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lda #1 ; 2
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sta MB_VALUE ; 3
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jsr write_ay_both ; 6+65
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;===============
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; 78
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;=============================
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; Load foreground to graphic page1 (apple page2)
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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 #<waterfall_page1
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sta GBASL
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lda #>waterfall_page1
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sta GBASH
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jsr load_rle_gr
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jsr gr_copy_to_current ; copy to page1
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;=============================
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; Load bg to memory
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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 #<waterfall_page2
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sta GBASL
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lda #>waterfall_page2
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sta GBASH
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jsr load_rle_gr
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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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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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wfloopA:ldx #9 ; 2
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wfloopB:dex ; 2
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bne wfloopB ; 2nt/3
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dey ; 2
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bne wfloopA ; 2nt/3
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jmp display_loop
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jump_table:
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.word (display_even-1)
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.word (display_odd-1)
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.word (display_three-1)
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.word (display_four-1)
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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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; jump_table
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; 38 + display_odd
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; we have 3 (the jmp back)
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; = 3 cycles that need to be eaten by the vblank
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display_loop:
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inc FRAME ; 5
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lda FRAME ; 3
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and #$30 ; 2
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; 0011 0000, so more or less div by 16, 3.75Hz
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lsr ; 2
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lsr ; 2
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lsr ; 2
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tay ; 2 ; 18
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lda jump_table+1,y ; 4
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pha ; 3
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lda jump_table,y ; 4
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pha ; 3
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rts ; 6 ; 38
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display_loop_return:
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vblank:
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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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; do_nothing should be 4550
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; -3 letfover from HBLANK code
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; ** -9
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; -49 check for keypress
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; -2252 copy screen
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; -2231 draw sprite
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; =============
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; 15 cycles
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; 15 cycles
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inc YPOS ; 5
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nop ; 2
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nop ; 2
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lda YPOS ; 3
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lda YPOS ; 3
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;=========================
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; Clear background
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;=========================
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jsr gr_copy_row22 ; 6+ 2246
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;=========
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; 2252
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;==========================
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; draw bird sprite
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;==========================
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; 8 prefix
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; bird_walk_right= 14 + 2175 2206 (need 17)
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; bird_stand_right= 13 + 2190 2206 (need 3)
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; bird_walk_left= 15 + 2175 2206 (need 16)
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; bird_stand_left= 14 + 2190 2206 (need 2)
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; call to sprite 17 postfix
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;====================================================
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; 2231
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lda BIRD_STATE ; 3
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and #1 ; 2
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ldx BIRD_DIR ; 3
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bne bird_left
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bird_right:
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; 2
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cmp #1 ; 2
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beq bird_walk_right
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; 2
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bird_stand_right:
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ldx #>bird_rider_stand_right ; 2
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ldy #<bird_rider_stand_right ; 2
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lda YPOS ; nop=3
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jmp draw_bird ; 3
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bird_walk_right:
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; 3
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ldx #>bird_rider_walk_right ; 2
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ldy #<bird_rider_walk_right ; 2
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jmp kill_less_time ; 3
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bird_left:
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; 3
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cmp #1 ; 2
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beq bird_walk_left
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bird_stand_left:
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; 2
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ldx #>bird_rider_stand_left ; 2
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ldy #<bird_rider_stand_left ; 2
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nop ; nop=2
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jmp draw_bird ; 3
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bird_walk_left:
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; 3
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ldx #>bird_rider_walk_left ; 2
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ldy #<bird_rider_walk_left ; 2
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kill_time:
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nop ; 2 ; need to kill 16
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kill_less_time:
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lda YPOS ; nop=3 ; need to kill 14
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lda YPOS ; nop=3
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lda YPOS ; nop=3
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lda YPOS ; nop=3
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nop ; 2
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jmp draw_bird ; 3
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draw_bird:
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stx INH ; 3
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sty INL ; 3
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lda #22 ; 2
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sta YPOS ; 3
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jsr put_sprite ; 6
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;=========
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; 17 + 2190
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;====================
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; Handle keypresses
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; if no keypress, 9
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; if keypress, 6+43 = 49
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lda KEYPRESS ; 4
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bmi keypress
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; 2
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no_keypress:
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; kill 40 cycles
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ldx #0 ; 2
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inc YPOS,X ; 6
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inc YPOS,X ; 6
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inc YPOS,X ; 6
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inc YPOS,X ; 6
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inc YPOS,X ; 6
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inc YPOS,X ; 6
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nop ; 2
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jmp display_loop ; 3
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;===================================================
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; key was pressed handling takes 12 + 20 + 11 = 43
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keypress:
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; 1
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bit KEYRESET ; 4
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inc BIRD_STATE ; 5
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and #$5f ; mask keypress ; 2
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is_it_right:
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cmp #$15 ; right arrow ; 2
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bne is_it_left
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; 2
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inc XPOS ; 5
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lda #0 ; 2
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sta BIRD_DIR ; 3
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lda YPOS ; 3-cycle nop ; 3
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convoluted:
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jmp adjust_xpos ; 3 ; 20 if right
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is_it_left:
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; 5
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cmp #$8 ; left arrow ; 2
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beq is_left
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; 2
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nop ; 2
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lda YPOS ; 3-cycle nop
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jmp convoluted ; 3
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; ------ 20 if neither
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is_left:
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; 3
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dec XPOS ; 5 ; 20 if left
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lda #1 ; 2
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sta BIRD_DIR ; 3
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adjust_xpos:
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lda XPOS ; 3
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and #$1f ; keep in 0-31 range ; 2
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sta XPOS ; 3
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jmp display_loop ; 3
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.include "gr_hline.s"
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.include "../asm_routines/gr_unrle.s"
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.align $100
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.include "../asm_routines/keypress.s"
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.include "gr_copy.s"
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.include "gr_unrolled_copy.s"
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.align $100
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.include "gr_putsprite.s"
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.include "mockingboard.s"
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.include "vapor_lock.s"
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.include "delay_a.s"
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.include "waterfall_page1.inc"
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.include "waterfall_page2.inc"
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.align $100
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.include "tfv_sprites.inc"
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.align $100
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;=================================
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; Display Even
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;=================================
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; we have 65 cycles per line
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; the first 25 are in hblank
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; we come in already 21 cycles into things
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; so the first scanline is a loss (but that's OK)
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; first scanline: 21+ 2 (from ldy) so need to kill 65-23 = 42
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; second scanline, again kill so 65 killed
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display_even:
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even_first_four_lines:
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; we do mockingboard here
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; we have 222 cycles (65*4 = 260 - 38 = 222)
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; 38
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; come in with 38
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; 222 - 100 = 122 to kill
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; kill 122
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ldx #10 ; 2
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dummy_loop:
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asl DUMMY ; 6
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dex ; 2
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bne dummy_loop ; 3
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; -1 exit loop
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; 11 left over
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nop ;2
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lda XPOS ; 3
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lda XPOS ; 3
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lda XPOS ; 3
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; high = 5 + 12+ 3 = 20
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; medium = 5 + 9 + 6 = 20
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; low = 5 + 9 + 6 = 20
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lda XPOS ; 3
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; cmp OLD_XPOS ; 3
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; beq skip_mb ;
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; 2
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; sta OLD_XPOS ; 3
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cmp #23 ; 2
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bmi check_medium
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; 2
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lda #35 ; 2
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sec ; 2
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sbc XPOS ; 3
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sta YPOS ; (nop) ; 3
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was_low:
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jmp write_volume ; 3
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check_medium:
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; 3
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nop ; 2
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nop ; 2
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cmp #12 ; 2
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bmi was_low
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was_medium:
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; 2
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lda #12 ; 2
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nop ; 2
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write_volume:
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; write A/noise volume
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sta MB_VALUE ; 3
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ldx #8 ; 2
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lda #$2 ; 2
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jsr write_ay_both ; 6+65
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;===============
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; 78
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skip_mb:
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; setup loop for next section
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ldy #4 ; 2
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even_twinkle_stars:
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twinkle_loop_even:
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; page1 for 4 lines, 65 - 4 = 61 -2 = 59 - 25 = 34
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; line 0
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bit PAGE1 ; 4
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lda #34 ; 2
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jsr delay_a ; 25+34
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; line 1
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bit PAGE1 ; 4
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lda #34 ; 2
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jsr delay_a ; 25+34
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; line 2
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bit PAGE1 ; 4
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lda #34 ; 2
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jsr delay_a ; 25+34
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; line 3
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bit PAGE1 ; 4
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lda #27 ; 2
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jsr delay_a ; 25+27
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; below: 7 if not zero
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; 7 (including ldy later) if is zero
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dey ; 2
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beq twinkle_loop_even_done ; 3
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;-1
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jmp twinkle_loop_even ; 3
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twinkle_loop_even_done:
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ldy #31 ; 2
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falls_loop_even:
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; === line 0
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bit PAGE0 ; 4
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; delay 31
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lda #4 ; 2
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jsr delay_a ; 25+4
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; delay 11
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bit PAGE0 ; 4
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lda YPOS ; 3
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bit PAGE0 ; 4
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; delay 19
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nop ; 2
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nop ; 2
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asl DUMMY ; 6
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asl DUMMY ; 6
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lda YPOS ; 3
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;=== line 1
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bit PAGE0 ; 4
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; delay 31
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lda #4 ; 2
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jsr delay_a ; 25+4
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; delay 11
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bit PAGE0 ; 4
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lda YPOS ; 3
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bit PAGE0 ; 4
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; delay 19
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nop ; 2
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nop ; 2
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asl DUMMY ; 6
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asl DUMMY ; 6
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lda YPOS ; 3
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;=== line 2
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bit PAGE0 ; 4
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; delay 31
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lda #4 ; 2
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jsr delay_a ; 25+4
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; delay 11
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bit PAGE1 ; 4
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lda YPOS ; 3
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bit PAGE0 ; 4
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; delay 19
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nop ; 2
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nop ; 2
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asl DUMMY ; 6
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asl DUMMY ; 6
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lda YPOS ; 3
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;== line 3
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bit PAGE0 ; 4
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; delay 31
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lda #4 ; 2
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jsr delay_a ; 25+4
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; delay 11
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bit PAGE1 ; 4
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lda YPOS ; 3
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bit PAGE0 ; 4 ; 46
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; delay 21 - 7 from loop
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nop ; 2
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nop ; 2
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asl DUMMY ; 6
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nop ; 2 ; 58
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dey ; 2
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beq falls_loop_even_done ; 3
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; -1
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jmp falls_loop_even ; 3
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falls_loop_even_done:
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ldy #12 ; 2
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ground_loop_even:
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;==== line 0
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bit PAGE0 ; 4
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; delay 61
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lda #34 ; 2
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jsr delay_a ; 25+34
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;==== line 1
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bit PAGE1 ; 4
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; delay 61
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lda #34 ; 2
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jsr delay_a ; 25+34
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;==== line 2
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bit PAGE0 ; 4
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; delay 61
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lda #34 ; 2
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jsr delay_a ; 25+34
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;=== line 3
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bit PAGE1 ; 4
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; delay 54
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lda #27 ; 2
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jsr delay_a ; 25+27
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dey ; 2
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beq ground_loop_even_done ; 3
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; -1
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jmp ground_loop_even ; 3
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ground_loop_even_done:
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nop ; 2
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jmp display_loop_return ; 3
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.align $100
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;=================================
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; Display Odd
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;=================================
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; we have 65 cycles per line
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; the first 25 are in hblank
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display_odd:
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; first scanline: comes in with 38
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odd_first_four_lines:
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|
|
; line 0-3 = 65*4 = 260
|
|
; -38
|
|
; -2
|
|
; -2
|
|
; -25
|
|
;=========================
|
|
; 193
|
|
|
|
lda #193 ; 2
|
|
jsr delay_a ; 125
|
|
|
|
ldy #4 ; 2
|
|
|
|
odd_twinkle_stars:
|
|
|
|
twinkle_loop_odd:
|
|
|
|
; page1 for 4 lines, 65 - 4 = 61 -2 = 59 - 25 = 34
|
|
|
|
; line 0
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
; line 1
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
; line 2
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
; line 3
|
|
bit PAGE1 ; 4
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
dey ; 2
|
|
beq twinkle_loop_odd_done ; 3
|
|
; -1
|
|
jmp twinkle_loop_odd ; 3
|
|
twinkle_loop_odd_done:
|
|
|
|
ldy #31 ; 2
|
|
falls_loop_odd:
|
|
|
|
;=== line 0
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; falls 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;==== line 1
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; falls 8
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 2
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; falls 8
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;===line 4
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; falls 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4 ; 44
|
|
|
|
; end falls
|
|
; delay 21 - 7 from loop
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
nop ; 2 ; 58
|
|
|
|
dey ; 2
|
|
beq falls_loop_odd_done ; 3
|
|
;-1
|
|
jmp falls_loop_odd ; 3
|
|
falls_loop_odd_done:
|
|
; 3
|
|
ldy #12 ; 2
|
|
|
|
ground_loop_odd:
|
|
|
|
;=== line 0
|
|
bit PAGE1 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 1
|
|
bit PAGE0 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;==== line 2
|
|
bit PAGE1 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;==== line 3
|
|
bit PAGE0 ; 4
|
|
; delay 54
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
dey ; 2
|
|
beq ground_loop_odd_done ; 3
|
|
;-1
|
|
jmp ground_loop_odd ; 3
|
|
ground_loop_odd_done:
|
|
|
|
|
|
; 3
|
|
nop ; 2
|
|
|
|
jmp display_loop_return ; 3
|
|
|
|
rts ; 6
|
|
|
|
|
|
.align $100
|
|
|
|
;=================================
|
|
; Display 3
|
|
;=================================
|
|
; we have 65 cycles per line
|
|
; the first 25 are in hblank
|
|
; we come in already 21 cycles into things
|
|
; so the first scanline is a loss (but that's OK)
|
|
|
|
; first scanline: 21+ 2 (from ldy) so need to kill 65-23 = 42
|
|
; second scanline, again kill so 65 killed
|
|
|
|
display_three:
|
|
|
|
three_first_four_lines:
|
|
|
|
; we do mockingboard here
|
|
; we have 222 cycles (65*4 = 260 - 38 = 222)
|
|
|
|
; 38
|
|
; come in with 38
|
|
; 222 - 100 = 122 to kill
|
|
|
|
; kill 122
|
|
|
|
ldx #10 ; 2
|
|
dummy_loop2:
|
|
asl DUMMY ; 6
|
|
dex ; 2
|
|
bne dummy_loop2 ; 3
|
|
|
|
; -1 exit loop
|
|
|
|
; 11 left over
|
|
nop ;2
|
|
lda XPOS ; 3
|
|
lda XPOS ; 3
|
|
lda XPOS ; 3
|
|
|
|
|
|
; high = 5 + 12+ 3 = 20
|
|
; medium = 5 + 9 + 6 = 20
|
|
; low = 5 + 9 + 6 = 20
|
|
|
|
lda XPOS ; 3
|
|
|
|
; cmp OLD_XPOS ; 3
|
|
; beq skip_mb2 ;
|
|
; 2
|
|
; sta OLD_XPOS ; 3
|
|
|
|
cmp #23 ; 2
|
|
bmi check_medium2
|
|
; 2
|
|
lda #35 ; 2
|
|
sec ; 2
|
|
sbc XPOS ; 3
|
|
sta YPOS ; (nop) ; 3
|
|
was_low2:
|
|
jmp write_volume2 ; 3
|
|
check_medium2:
|
|
; 3
|
|
nop ; 2
|
|
nop ; 2
|
|
cmp #12 ; 2
|
|
bmi was_low2
|
|
was_medium2:
|
|
; 2
|
|
lda #12 ; 2
|
|
nop ; 2
|
|
|
|
write_volume2:
|
|
; write A/noise volume
|
|
sta MB_VALUE ; 3
|
|
ldx #8 ; 2
|
|
lda #$2 ; 2
|
|
jsr write_ay_both ; 6+65
|
|
;===============
|
|
; 78
|
|
|
|
skip_mb2:
|
|
|
|
|
|
; setup loop for next section
|
|
ldy #4 ; 2
|
|
|
|
three_twinkle_stars:
|
|
|
|
twinkle_loop_three:
|
|
|
|
; line 0
|
|
bit PAGE0 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
; line 1
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
; line 2
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
; line 4
|
|
bit PAGE0 ; 4
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
dey ; 2
|
|
beq twinkle_loop_three_done ; 3
|
|
; -1
|
|
jmp twinkle_loop_three ; 3
|
|
|
|
|
|
twinkle_loop_three_done:
|
|
|
|
ldy #31 ; 2
|
|
falls_loop_three:
|
|
|
|
;=== line 0
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 1
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop
|
|
nop
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 2
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 4
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4 ; 44
|
|
|
|
; delay 21 - 7 from loop
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
nop ; 2 ; 58
|
|
|
|
dey ; 2
|
|
beq falls_loop_three_done ; 3
|
|
; -1
|
|
jmp falls_loop_three ; 3
|
|
falls_loop_three_done:
|
|
ldy #12 ; 2
|
|
|
|
ground_loop_three:
|
|
|
|
;=== line 0
|
|
bit PAGE1 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 1
|
|
bit PAGE0 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 2
|
|
bit PAGE1 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 3
|
|
bit PAGE0 ; 4
|
|
; delay 54
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
dey ; 2
|
|
beq ground_loop_three_done ; 3
|
|
; -1
|
|
jmp ground_loop_three ; 3
|
|
ground_loop_three_done:
|
|
|
|
nop ; 2
|
|
|
|
jmp display_loop_return ; 3
|
|
|
|
|
|
.align $100
|
|
|
|
;=================================
|
|
; Display Four
|
|
;=================================
|
|
; we have 65 cycles per line
|
|
; the first 25 are in hblank
|
|
; we come in already 21 cycles into things
|
|
; so the first scanline is a loss (but that's OK)
|
|
|
|
display_four:
|
|
|
|
; first scanline comes in with 38
|
|
|
|
four_first_four_lines:
|
|
; line 0-3 = 65*4 = 260
|
|
; -38
|
|
; -2
|
|
; -2
|
|
; -25
|
|
;=========================
|
|
; 193
|
|
|
|
lda #193 ; 2
|
|
jsr delay_a ; 25+193
|
|
|
|
ldy #4 ; 2
|
|
|
|
four_twinkle_stars:
|
|
|
|
twinkle_loop_four:
|
|
|
|
;=== line 0
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 1
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 2
|
|
bit PAGE1 ; 4
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
|
|
;=== line 3
|
|
bit PAGE1 ; 4
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
|
|
dey ; 2
|
|
beq twinkle_loop_four_done ; 3
|
|
; -1
|
|
jmp twinkle_loop_four ; 3
|
|
twinkle_loop_four_done:
|
|
|
|
ldy #31 ; 2
|
|
falls_loop_four:
|
|
|
|
;=== line 0
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 1
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 2
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE1 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4
|
|
|
|
; delay 19
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
asl DUMMY ; 6
|
|
lda YPOS ; 3
|
|
|
|
;=== line 3
|
|
bit PAGE0 ; 4
|
|
; delay 31
|
|
lda #4 ; 2
|
|
jsr delay_a ; 25+4
|
|
|
|
; delay 11
|
|
bit PAGE0 ; 4
|
|
lda YPOS ; 3
|
|
bit PAGE0 ; 4 ; 44
|
|
|
|
; delay 21 - 7 from loop
|
|
nop ; 2
|
|
nop ; 2
|
|
asl DUMMY ; 6
|
|
nop ; 2 ; 58
|
|
|
|
dey ; 2
|
|
beq falls_loop_four_done ; 3
|
|
; -1
|
|
jmp falls_loop_four ; 3
|
|
falls_loop_four_done:
|
|
ldy #12 ; 2
|
|
|
|
ground_loop_four:
|
|
|
|
;=== line 0
|
|
bit PAGE0 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 1
|
|
bit PAGE1 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
;=== line 2
|
|
bit PAGE0 ; 4
|
|
; delay 61
|
|
lda #34 ; 2
|
|
jsr delay_a ; 25+34
|
|
|
|
|
|
;=== line 3
|
|
bit PAGE1 ; 4
|
|
; delay 54
|
|
lda #27 ; 2
|
|
jsr delay_a ; 25+27
|
|
|
|
dey ; 2
|
|
beq ground_loop_four_done ; 3
|
|
; -1
|
|
jmp ground_loop_four ; 3
|
|
ground_loop_four_done:
|
|
nop ; 2
|
|
|
|
jmp display_loop_return ; 3
|
|
|
|
|