megademo: hook up improved vapor lock

still issues :(
This commit is contained in:
Vince Weaver 2018-09-21 00:33:51 -04:00
parent b43e50f7c1
commit 3029d4220b
5 changed files with 217 additions and 28 deletions

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@ -21,7 +21,7 @@ MEGADEMO: megademo.o
megademo.o: megademo.s \
zp.inc hardware.inc \
gr_hline.s gr_offsets.s vapor_lock.s \
gr_hline.s gr_offsets.s vapor_lock.s delay_a.s \
c64_opener.s c64.img.lz4 \
falling_apple.s apple_40_96.inc
ca65 -o megademo.o megademo.s -l megademo.lst

25
megademo/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

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@ -73,23 +73,29 @@ falling_apple:
; setup graphics for vapor lock
;==============================
jsr vapor_lock ; 6?
jsr vapor_lock ; 6
; 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 = 889
; Fudge factor (unknown) -24 = 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
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

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@ -38,4 +38,4 @@ loop_forever:
.include "gr_offsets.s"
.include "gr_hline.s"
.include "vapor_lock.s"
.include "delay_a.s"

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@ -1,3 +1,40 @@
; 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
;==============================
@ -6,20 +43,39 @@ vapor_lock:
; Clear Page0
lda #$0
sta DRAW_PAGE
lda #$44
lda #$ee ; full screen white $ff
jsr clear_gr
; Make screen half green
lda #$11
lda #$dd
ldy #40
jsr clear_page_loop ; make top half grey2 $aa
lda #$aa
ldy #24
jsr clear_page_loop
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
; we look for $55 (which is the grey line)
;=====================================================
; See:
; Have an Apple Split by Bob Bishop
@ -33,26 +89,128 @@ vapor_lock:
; 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 zeroes
LDA #$11
vapor_lock_loop:
; first make sure we have a full line of $aa
lda #$aa ; 2
zxloop:
LDX #$04
ldx #$04 ; 2
wiloop:
CMP $C051
BNE zxloop
DEX
BNE 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
LDA #$44 ; now look for our border color (4 times)
; if we get here we read 4 proper pixels, 11 apart (2+4+2+2+3)
; 0 11 22 33, clock at 34
; 1 12 23 34, clock at 35
; 2 13 24 35, clock at 36
; 3 14 25 36, clock at 37
; 4 15 26 37, clock at 38
; 5 16 27 38, clock at 39
; 6 17 28 39, clock at 40
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; X X X X
; 0123456789012345678901234 0123456789012345678901234567890123456789
; 1 2 1 2 3
; hsync pixels
; XXXXXXXXXXXXXXXXXXXXXXXXX 4444444444444444444444444444440123456789
; now look for the color change that
; happens at line 13*8 = 104
lda #$dd ; 2
zloop:
LDX #$04
ldx #$04 ; 2
qloop:
CMP $C051
BNE zloop
DEX
BNE qloop
cmp $C051 ; read floating bus ; 4
bne zloop ; 2/3
dex ; 2
bne qloop ; 3/2
;============
; 11
rts
; 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