dos33fsprogs/demosplash/missing.s
Vince Weaver 3ef490be2d ds: move things off of $9000 so everything fits
BLURGH lots of hard-coded $9000s everywhere
2019-11-07 11:44:05 -05:00

186 lines
3.0 KiB
ArmAsm

; Missing scene
; Uses the 40x48d page1/page2 every-1-scanline pageflip mode
; by deater (Vince Weaver) <vince@deater.net>
missing_intro:
;===================
; init screen
; jsr TEXT
; jsr HOME
bit KEYRESET
;===================
; init vars
lda #0
sta DRAW_PAGE
;=============================
; setup graphics code
jsr create_update_type1
;=============================
; Load graphic page0
lda #<k_low
sta GBASL
lda #>k_low
sta GBASH
lda #$c ; load to $c00
jsr load_rle_gr
lda #4
sta DRAW_PAGE
jsr gr_copy_to_current ; copy to page1
; GR part
bit PAGE1
bit LORES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
; jsr wait_until_keypressed
;=============================
; Load graphic page1
lda #<k_high
sta GBASL
lda #>k_high
sta GBASH
lda #$c
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
; vapor lock returns with us at beginning of hsync in line
; 114 (7410 cycles), so with 5070 lines to go
; GR part
bit LORES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
jsr gr_copy_to_current ; 6+ 9292
; 5070 + 4550 = 9620
; 9292
; 12
; 6
; ====
; 310
; - 3 for jmp
; 307
; Try X=9 Y=6 cycles=307
ldy #6 ; 2
mloopA: ldx #9 ; 2
mloopB: dex ; 2
bne mloopB ; 2nt/3
dey ; 2
bne mloopA ; 2nt/3
jmp missing_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
; want colors 01234567
; line 0: $X0 to $800
; line 1: $X1 to $400
; line 2: $X2
; line 3: $X3
; line 4: $4X
; line 5: $5X
; line 6: $6X
; line 7: $7X
missing_display_loop:
jsr $9800 ; update_type1
;.include "missing_screen_update.s"
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; do_nothing should be
; 4550
; -12 jsr/ret to update_type1
; - 7 check keypress
; - 3 jmp loop
;=============
; 4528
; blah, current code the tight loops are right at a page boundary
do_nothing_missing:
; want 4528
; Try X=4 Y=174 cycles=4525 R3
lda TEMP ; nop 3
ldy #174 ; 2
gloop1: ldx #4 ; 2
gloop2: dex ; 2
bne gloop2 ; 2nt/3
dey ; 2
bne gloop1 ; 2nt/3
lda KEYPRESS ; 4
bpl missing_no_keypress ; 3
rts
missing_no_keypress:
jmp missing_display_loop ; 3
.align $100
.include "k_40_48d.inc"