waterfall: use new vapor lock code

This commit is contained in:
Vince Weaver 2018-09-20 12:56:17 -04:00
parent 76da5568c6
commit b43e50f7c1
5 changed files with 450 additions and 123 deletions

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@ -16,8 +16,8 @@ waterfall.dsk: WATERFALL
WATERFALL: waterfall.o
ld65 -o WATERFALL waterfall.o -C ../linker_scripts/apple2_1000.inc
waterfall.o: waterfall.s gr_copy.s gr_unrolled_copy.s \
put_sprite.s \
waterfall.o: waterfall.s gr_copy.s gr_unrolled_copy.s vapor_lock.s \
put_sprite.s delay_a.s \
waterfall_page1.inc waterfall_page2.inc tfv_sprites.inc
ca65 -o waterfall.o waterfall.s -l waterfall.lst

25
waterfall/delay_a.s Normal file
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@ -0,0 +1,25 @@
; From http://6502org.wikidot.com/software-delay
; 25+A cycles (including JSR), 19 bytes (excluding JSR)
;
; The branches must not cross page boundaries!
;
; Cycles Accumulator Carry flag
; 0 1 2 3 4 5 6 (hex) 0 1 2 3 4 5 6
; jsr delay_a ; 6 6 6 6 6 6 6 00 01 02 03 04 05 06
dly0: sbc #7
delay_a:cmp #7 ; 2 2 2 2 2 2 2 00 01 02 03 04 05 06 0 0 0 0 0 0 0
bcs dly0 ; 2 2 2 2 2 2 2 00 01 02 03 04 05 06 0 0 0 0 0 0 0
lsr ; 2 2 2 2 2 2 2 00 00 01 01 02 02 03 0 1 0 1 0 1 0
bcs dly1 ; 2 3 2 3 2 3 2 00 00 01 01 02 02 03 0 1 0 1 0 1 0
dly1: beq dly2 ; 3 3 2 2 2 2 2 00 00 01 01 02 02 03 0 1 0 1 0 1 0
lsr ; 2 2 2 2 2 00 00 01 01 01 1 1 0 0 1
beq dly3 ; 3 3 2 2 2 00 00 01 01 01 1 1 0 0 1
bcc dly3 ; 3 3 2 01 01 01 0 0 1
dly2: bne dly3 ; 2 2 3 00 00 01 0 1 0
dly3: rts ; 6 6 6 6 6 6 6 00 00 00 00 01 01 01 0 1 1 1 0 0 1
;
; Total cycles: 25 26 27 28 29 30 31

216
waterfall/vapor_lock.s Normal file
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@ -0,0 +1,216 @@
; This took a while to track down
; On Apple II/II+ the horiz blanking addr are $1000 higher than on IIe
; So on II+ were outside video area, so unlikely to be our set value
; (unless I foolishly use $ff which some uninitialized mem is set to)
; Lots of this color fiddling is to make sure you don't accidentally
; get runs of colors on IIe due to the horiz blank
; 0-5 aqua 6-12 = grey, 13 - 20 = yellow, 21-23 = aqua rainbow 14
;
;
;16 0 YA
;17 1 YA
;18 2 YA
;19 3 YA
;20 4 YA
;21 5 AA
;22 6 AG
;23 7 AG
;0 8 AG
;1 9 AG
;2 10 AG
;3 11 AG
;4 12 AG
;5 13 AY ****
;6 14 GY RAINBOW
;7 15 GY
;8 16 GY
;9 17 GY
;10 18 GY
;11 19 GY
;12 20 GY
;13 21 YA
;14 22 YA
;15 23 YA
;==============================
; setup graphics for vapor lock
;==============================
vapor_lock:
; Clear Page0
lda #$0
sta DRAW_PAGE
lda #$ee ; full screen white $ff
jsr clear_gr
lda #$dd
ldy #40
jsr clear_page_loop ; make top half grey2 $aa
lda #$aa
ldy #24
jsr clear_page_loop ; make top half grey2 $aa
lda #$ee
ldy #10
jsr clear_page_loop ; make top half grey2 $aa
; set up a rainbow to aid in exact lock
ldy #00
rainbow_loop:
tya
sta $728+20,Y
iny
cpy #20
bne rainbow_loop
;btt:
; jmp btt
;=====================================================
; attempt vapor lock
; by reading the "floating bus" we can see most recently
; written value of the display
;=====================================================
; See:
; Have an Apple Split by Bob Bishop
; Softalk, October 1982
; Challenges: each scan line scans 40 bytes.
; The blanking happens at the *beginning*
; So 65 bytes are scanned, starting at adress of the line - 25
; the scan takes 8 cycles, look for 4 repeats of the value
; to avoid false positive found if the horiz blanking is mirroring
; the line (max 3 repeats in that case)
vapor_lock_loop:
; first make sure we have a full line of $aa
lda #$aa ; 2
zxloop:
ldx #$04 ; 2
wiloop:
cmp $C051 ; read the floating bus ; 4
bne zxloop ; if not, start from scratch ; 2/3
dex ; we were, dec ; 2
bne wiloop ; if not 4 of them, restart ; 3/2
; if we get here we read 4 proper pixels, 11 apart (2+4+2+2+3)
; 0 11 22 33, clock at 34
; 1 12 23 34, clock at 35
; 2 13 24 35, clock at 36
; 3 14 25 36, clock at 37
; 4 15 26 37, clock at 38
; 5 16 27 38, clock at 39
; 6 17 28 39, clock at 40
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; 0123456789012345678901234 0123456789012345678901234567890123456789
; 1 2 1 2 3
; hsync pixels
; XXXXXXXXXXXXXXXXXXXXXXXXX 4444444444444444444444444444440123456789
; now look for the color change that
; happens at line 13*8 = 104
lda #$dd ; 2
zloop:
ldx #$04 ; 2
qloop:
cmp $C051 ; read floating bus ; 4
bne zloop ; 2/3
dex ; 2
bne qloop ; 3/2
;============
; 11
; Found it!
; if we get here we read 4 proper pixels, 11 apart (2+4+2+2+3)
; 0 11 22 33, clock at 34
; 1 12 23 34, clock at 35
; 2 13 24 35, clock at 36
; 3 14 25 36, clock at 37
; 4 15 26 37, clock at 38
; 5 16 27 38, clock at 39
; 6 17 28 39, clock at 40
; In theory near end of line 104
; now skip ahead 8 lines and read from the rainbow pattern we set
; up to find our exact location
; delay 65 * 8 = 520
; we back off a few to make sure we're not in the horiz blank
; try to delay 510
lda #230 ; 2
jsr delay_a ; delay 25+230 = 255
lda #226 ; 2
jsr delay_a ; delay 25+226 = 251
; now near end of line 112
lda $C051 ; 4
;kbb:
; jmp kbb
; we are in theory on line $728 = 14*8 = 112
; so 112*65 = 7280 cycles from start
; we are actualy 25+20+A pixels in
; 7325+A
; Our goal is line 114 at 7410 cycles
; 7410 - 7325 = 85
; so kill 85-A cycles
; -6 to do subtraction
; -6 for rts
; -25 for delay_a overhead
eor #$ff ; 2
sec ; 2
adc #48 ; 2
jsr delay_a ; should total 48 cycles
done_vapor_lock:
rts ; 6
; Some random related work
; Docs:
; Lancaster
; Bishop
; Sather
; Vaguely relevant but no help with the Apple II+ issue
;
; Eamon: Screen display and timing synchronization
; on the Apple IIe and Apple IIgs
;
; Adams: Visually presented verbal stimuli by assembly
; language on the Apple II computer.
; Cavanagh and Anstis: Visual psychophysics on the
; Apple II: Getting started

Binary file not shown.

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@ -128,90 +128,29 @@ waterfall_demo:
; setup graphics for vapor lock
;==============================
; Clear Page0 to all green
lda #$0
sta DRAW_PAGE
lda #$44
jsr clear_gr
jsr vapor_lock ; 6
; Make top half of screen blue, down to line 26
lda #$11
ldy #24
jsr clear_page_loop
;=====================================================
; attempt vapor lock
; by reading the "floating bus" we can see most recently
; written value of the display
; we look for $55 (which is the grey line)
;=====================================================
; See:
; Have an Apple Split by Bob Bishop
; Softalk, October 1982
; Challenges: each scan line scans 40 bytes.
; The blanking happens at the *beginning*
; So 65 bytes are scanned, starting at adress of the line - 25
; the scan takes 8 cycles, look for 4 repeats of the value
; to avoid false positive found if the horiz blanking is mirroring
; the line (max 3 repeats in that case)
vapor_lock_loop: ; first make sure we have all blue
lda #$11 ; 2
zxloop:
ldx #$04 ; 2
wiloop:
cmp $C051 ; 4
bne zxloop ; 2/3
dex ; 2
bne wiloop ; 2/3
lda #$44 ; now look for our color (4 times) ; 2
zloop:
ldx #$04 ; 2
; what cycle does CMP happen at?
; while matching match = 4+2+2+3 = 11???
; if start at x=0, 0, 11, 22, 33 exit at 43
; if start at x=1, 1, 12, 23, 34 exit at 44
; if start at x=2, 2, 13, 24, 35 exit at 45
; if start at x=3, 3, 14, 25, 36 exit at 46
; if start at x=4, 4, 15, 26, 37 exit at 47
; if start at x=5, 5, 16, 27, 38 exit at 48
; if start at x=6, 6, 17, 28, 39 exit at 49
; if start at x=7, 7, 18, 29, *40 exit at **
; if start at x=8, 8, 19, 30, *41 exit at **
; if not match, 2+4+3 = 9, first match = 8
qloop:
cmp $C051 ; 4
bne zloop ; 2/3
dex ; 2
bne qloop ; 2/3
; found first line of black after green, at up to line 26 on screen
; so we want roughly 22 lines * 4 = 88*65 = 5720 + 4550 = 10270
; - 65 (for the scanline we missed) = 10205 - 12 = 10193
; vapor lock returns with us at beginning of hsync in line
; 114 (7410 cycles), so with 5070 lines to go
jsr gr_copy_to_current ; 6+ 9292
; 10193 - 9298 = 895
; Fudge factor (unknown) -30 = 865
; now we have 322 left
; GR part
bit LORES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
; Try X=88 Y=2 cycles=893 R2
; 322 - 12 = 310
; -3 for jmp
; 307
nop ; 2
ldy #2 ; 2
; Try X=9 Y=6 cycles=307
ldy #6 ; 2
loopA:
ldx #88 ; 2
ldx #9 ; 2
loopB:
dex ; 2
bne loopB ; 2nt/3
@ -535,6 +474,9 @@ gr_offsets:
.include "gr_unrolled_copy.s"
.include "put_sprite.s"
.include "mockingboard.s"
.include "vapor_lock.s"
.include "delay_a.s"
.include "waterfall_page1.inc"
.include "waterfall_page2.inc"
@ -645,13 +587,16 @@ twinkle_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -665,13 +610,16 @@ twinkle_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -685,13 +633,16 @@ twinkle_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -705,13 +656,16 @@ twinkle_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -733,13 +687,16 @@ falls_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -753,13 +710,16 @@ falls_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -773,13 +733,16 @@ falls_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -793,13 +756,16 @@ falls_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -822,13 +788,16 @@ ground_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -842,13 +811,16 @@ ground_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -862,13 +834,16 @@ ground_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -882,13 +857,16 @@ ground_loop_even:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -990,13 +968,16 @@ twinkle_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1010,13 +991,16 @@ twinkle_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1030,13 +1014,16 @@ twinkle_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1050,13 +1037,16 @@ twinkle_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -1078,13 +1068,16 @@ falls_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1098,13 +1091,16 @@ falls_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1118,13 +1114,16 @@ falls_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1138,13 +1137,16 @@ falls_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -1167,13 +1169,16 @@ ground_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1187,13 +1192,16 @@ ground_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1207,13 +1215,16 @@ ground_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1227,13 +1238,16 @@ ground_loop_odd:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -1354,13 +1368,16 @@ twinkle_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1374,13 +1391,16 @@ twinkle_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1394,13 +1414,16 @@ twinkle_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1414,13 +1437,16 @@ twinkle_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
nop ; 2 ; 58
@ -1442,13 +1468,16 @@ falls_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1462,13 +1491,16 @@ falls_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1482,13 +1514,16 @@ falls_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1502,13 +1537,16 @@ falls_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
nop ; 2 ; 58
@ -1531,13 +1569,16 @@ ground_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1551,13 +1592,16 @@ ground_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1571,13 +1615,16 @@ ground_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1591,13 +1638,16 @@ ground_loop_three:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
nop ; 2 ; 58
@ -1702,13 +1752,16 @@ twinkle_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1722,13 +1775,16 @@ twinkle_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1742,13 +1798,16 @@ twinkle_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1762,13 +1821,16 @@ twinkle_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -1790,13 +1852,16 @@ falls_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1810,13 +1875,16 @@ falls_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1830,13 +1898,16 @@ falls_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1850,13 +1921,16 @@ falls_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
nop ; 2 ; 58
@ -1879,13 +1953,16 @@ ground_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; endfalls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1899,13 +1976,16 @@ ground_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4
; end falls
; delay 21
asl DUMMY ; 6
; asl DUMMY ; 6
nop
nop
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1919,13 +1999,16 @@ ground_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE0 ; 4
lda YPOS ; 3
bit PAGE0 ; 4
; end falls
; delay 21
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
asl DUMMY ; 6
lda YPOS ; 3
@ -1939,13 +2022,16 @@ ground_loop_four:
asl DUMMY ; 6
lda YPOS ; 3
nop ; 2
nop
; falls
bit PAGE1 ; 4
lda YPOS ; 3
bit PAGE1 ; 4 ; 44
; end falls
; delay 21 - 7 from loop
asl DUMMY ; 6
nop
nop
; asl DUMMY ; 6
asl DUMMY ; 6
nop ; 2 ; 58