dos33fsprogs/megademo/c64_opener.s
2018-10-13 16:55:14 -04:00

389 lines
7.6 KiB
ArmAsm

; C64 Opener
; all good demos start with the C64 boot screen, right?
; Apple II has a lot of trouble making clear text with bluish background
; it looks a lot cleaner in black+white
; Zero page addresses
TOP = $F0
BOTTOM = $F1
c64_opener:
;===================
; init vars
;===================
lda #0
sta TOP
sta BOTTOM
;===================
; setup graphics
;===================
; We assume that the c64 image was put in $2000 by the loader
bit PAGE0 ; first graphics page
bit FULLGR ; full screen graphics
bit HIRES ; hires mode !!!
bit SET_GR ; graphics mode
jsr wait_until_keypress
;==============================
; setup graphics for vapor lock
;==============================
jsr vapor_lock ; 6
bit PAGE0 ; first graphics page ; 4
bit FULLGR ; full screen graphics ; 4
bit HIRES ; hires mode !!! ; 4
bit SET_GR ; graphics mode ; 4
; vapor lock returns with us at beginning of hsync in line
; 114 (7410 cycles), so with 5070 + 4550 lines to go (9620)
; - 16 = 9604, -3 for jmp = 9601
; Try X=18 Y=100 cycles=9601
ldy #100 ; 2
loopcoA:ldx #18 ; 2
loopcoB:dex ; 2
bne loopcoB ; 2nt/3
dey ; 2
bne loopcoA ; 2nt/3
beq c64_split
;.align $100
;================================================
; c64_split
;================================================
; We want to:
; Wait 3s, just flashing cursor@1Hz
; Then slowly open to text page0
; Count to 480?
; Width = 0 - 40, 10 steps
c64_split:
;=========================
; Top third
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnNnNnNnTtttGgggNnNnNnNnNnNnNnNn 16= 4W
ldx #64 ; 2
jmp c64_loop_1_five_in ; 3
c64_loop_1:
lda $0 ; 3
nop ; 2
c64_loop_1_five_in:
lda $0 ; 3
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
;=============
; 25
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
;============
; 16
bit SET_TEXT ; 4
bit SET_GR ; 4
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
;============
; 16
c64_loop_1_end:
dex ; 2
bne c64_loop_1 ; 3
;============
; 5
;=========================
; Middle third
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnNnNnTtttNnNnNnNnNnGgggNnNnNnNnLll 11=14W
; 5-1=4
ldx #64 ; 2
jmp c64_loop_2_four_in ; 3
c64_loop_2:
nop ; 2
nop ; 2
c64_loop_2_four_in:
nop ; 2
lda $0 ; 3
lda $0 ; 3
nop ; 2
nop ; 2
nop ; 2
lda $0
;=============
; 20
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
bit SET_TEXT ; 4
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
bit SET_GR ; 4
nop ; 2
nop ; 2
nop ; 2
nop ; 2
lda $0
c64_loop_2_end:
dex ; 2
bne c64_loop_2 ; 3
;============
; 5
;=========================
; Bottom third
; DdBbbNnNnNnNnNnNnNnNnNnNn NnTtttNnNnNnNnNnNnNnNnNnNnNnNnNnNnGgggNn 2=32W
; 5-1=4
ldx #64 ; 2
jmp c64_loop_3_four_in ; 3
c64_loop_3:
nop ; 2
nop ; 2
c64_loop_3_four_in:
nop ; 2
lda $0 ; 3
lda $0 ; 3
nop ; 2
nop ; 2
nop ; 2
nop ; 2
;=============
; 20
nop ; 2
bit SET_TEXT ; 4
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
;============
; 16
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
nop ; 2
bit SET_GR ; 4
nop ; 2
;============
; 16
c64_loop_3_end:
dex ; 2
bne c64_loop_3 ; 3
;============
; 5
; -1
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; do_nothing should be 4550
; -10 keyboard handling
; +1 leftover from main screen
; -15
; -12
; -46
; = 4468
; run the 2Hz counter, overflow at 30 60Hz frames
clc ; 2
lda BOTTOM ; 3
adc #1 ; 2
sta BOTTOM ; 3
cmp #30 ; 2
bne not_thirty ; 3
;===========
; 15
thirty:
; -1
lda #0 ; 2
sta BOTTOM ; 3
inc TOP ; 5
jmp done_thirty ; 3
;===========
; 12
not_thirty:
lda TOP ; 3
lda TOP ; 3
lda TOP ; 3
lda TOP ; 3
;===========
; 12
done_thirty:
; handle the cursor
; FIXME: not aligned well. Do we care?
lda TOP ; 3
and #$1 ; 2
beq cursor_off ; 3
;============
; 8
cursor_on:
; -1
; it's lSB first
; blue is 6
; 1 1111110
lda #$fE ; blue ; 2
sta $3300 ; 52 ; 4
sta $3B00 ; 54 ; 4
sta $2380 ; 56 ; 4
sta $2B80 ; 58 ; 4
; purple is 2
; 0 1111110
lda #$7E ; purple ; 2
sta $3700 ; 53 ; 4
sta $3F00 ; 55 ; 4
sta $2780 ; 57 ; 4
sta $2F80 ; 59 ; 4
jmp cursor_done ; 3
;============
; 38
cursor_off:
; blue is 6
; 1 1010101
lda #$d5 ; blue ; 2
sta $3300 ; 52 ; 4
sta $3B00 ; 54 ; 4
sta $2380 ; 56 ; 4
sta $2B80 ; 58 ; 4
; purple is 2
; 0 1010101
lda #$55 ; purple ; 2
sta $3700 ; 53 ; 4
sta $3F00 ; 55 ; 4
sta $2780 ; 57 ; 4
sta $2F80 ; 59 ; 4
nop ; 2
;============
; 38
cursor_done:
; Try X=17 Y=49 cycles=4460 R8
nop
lda $0
lda $0
ldy #49 ; 2
loopcoE:ldx #17 ; 2
loopcoF:dex ; 2
bne loopcoF ; 2nt/3
dey ; 2
bne loopcoE ; 2nt/3
lda KEYPRESS ; 4
bpl no_c64_keypress ; 3
jmp done_c64
no_c64_keypress:
jmp c64_split ; 3
done_c64:
rts ; 6
;===================
; c64 graphic, load at $2000-$4000 to start with
;===================
;c64:
;.incbin "c64.img"
;c64_end:
;=========================================================
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNn Nothing
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnNnNnNnTtttGgggNnNnNnNnNnNnNnNn 16= 4W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnNnNnNnNnTtttNnGgggNnNnNnNnNnNnLll 15= 6W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnNnNnTtttNnNnGgggNnNnNnNnNnNnNn 14= 8W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnNnNnNnTtttNnNnNnGgggNnNnNnNnNnLll 13=10W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnNnTtttNnNnNnNnGgggNnNnNnNnNnNn 12=12W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnNnNnTtttNnNnNnNnNnGgggNnNnNnNnLll 11=14W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnNnTtttNnNnNnNnNnNnGgggNnNnNnNnNn 10=16W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnNnTtttNnNnNnNnNnNnNnGgggNnNnNnLll 9=18W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnNnTtttNnNnNnNnNnNnNnNnGgggNnNnNnNn 8=20W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnNnTtttNnNnNnNnNnNnNnNnNnGgggNnNnLll 7=22W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnNnTtttNnNnNnNnNnNnNnNnNnNnGgggNnNnNn 6=24W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnNnTtttNnNnNnNnNnNnNnNnNnNnNnGgggNnLll 5=26W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnNnTtttNnNnNnNnNnNnNnNnNnNnNnNnGgggNnNn 4=28W
; DdBbbNnNnNnNnNnNnNnNnNnLl lNnTtttNnNnNnNnNnNnNnNnNnNnNnNnNnGgggLll 3=30W
; DdBbbNnNnNnNnNnNnNnNnNnNn NnTtttNnNnNnNnNnNnNnNnNnNnNnNnNnNnGgggNn 2=32W
; nLllDdBbbNnNnNnNnNnNnLllN nTtttNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnGgggN NOPE
; DdBbbNnNnNnNnNnNnNnNnNnNn TtttNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnNnGggg 0=36W