dos33fsprogs/demosplash/book.s
2019-11-02 11:44:11 -04:00

161 lines
2.7 KiB
ArmAsm

; Display a 40x48d lo-res image
; Uses the 40x48d page1/page2 every-1-scanline pageflip mode
; by deater (Vince Weaver) <vince@deater.net>
end_book:
;===================
; init screen
jsr TEXT
jsr HOME
bit KEYRESET
;===================
; init vars
lda #0
sta DRAW_PAGE
;===================
; setup grahics
jsr create_update_type1
;=============================
; Load graphic page0
lda #<book_low
sta GBASL
lda #>book_low
sta GBASH
lda #$c ; load image to $c00
jsr load_rle_gr
lda #4
sta DRAW_PAGE
jsr gr_copy_to_current ; copy to page1
; GR part
bit PAGE1
bit LORES ; 4
bit SET_GR ; 4
bit FULLGR ; 4
;=============================
; Load graphic page1
lda #<book_high
sta GBASL
lda #>book_high
sta GBASH
lda #$c ; load image to $c00
jsr load_rle_gr
lda #0
sta DRAW_PAGE
jsr gr_copy_to_current
; GR part
bit PAGE0
;==============================
; 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
; now we have 322 left
; 322 - 12 = 310
; - 3 for jmp
; 307
; Try X=9 Y=6 cycles=307
ldy #6 ; 2
loopQ: ldx #9 ; 2
loopR: dex ; 2
bne loopR ; 2nt/3
dey ; 2
bne loopQ ; 2nt/3
jmp book_loop ; 3
.align $100
;================================================
; Display Loop
;================================================
; We want to alternate between page1 and page2 every 65 cycles
; vblank = 4550 cycles to do scrolling
book_loop:
jsr $9000 ; cycle-counted page0/page1 flip code
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; do_nothing should be
; 4550
; -12 -- enter/leave flip code
; -10 -- keypress code
; =======
; 4528 cycles
;=================================
; do nothing
;=================================
; and take 4528
book_do_nothing:
; Try X=4 Y=174 cycles=4525 R3
lda TEMP ; 3
ldy #174 ; 2
bloop1:
ldx #4 ; 2
bloop2:
dex ; 2
bne bloop2 ; 2nt/3
dey ; 2
bne bloop1 ; 2nt/3
lda KEYPRESS ; 4
bpl book_no_keypress ; 3
rts ; 6
book_no_keypress:
jmp book_loop ; 3
.include "book_40_48d.inc"