dos33fsprogs/mode7/scroll_demo.s
2017-12-14 15:59:54 -05:00

452 lines
6.6 KiB
ArmAsm

.include "zp.inc"
scroll_row1 EQU $8A00
scroll_row2 EQU $8B00
scroll_row3 EQU $8C00
scroll_row4 EQU $8D00
SCROLL_LENGTH EQU $E6
;================================
; Clear screen and setup graphics
;================================
jsr clear_screens ; clear top/bottom of page 0/1
jsr set_gr_page0
;===============
; Init Variables
;===============
lda #0
sta DISP_PAGE
sta ANGLE
;=======================
; decompress scroll text
;=======================
lda #>deater_scroll
sta INH
lda #<deater_scroll
sta INL
jsr decompress_scroll
scroll_loop:
ldx #0
ldy ANGLE
lda DISP_PAGE
beq draw_page2
lda #4
sta sm1+2
sta sm2+2
lda #5
sta sm3+2
sta sm4+2
jmp draw_done
draw_page2:
lda #8
sta sm1+2
sta sm2+2
lda #9
sta sm3+2
sta sm4+2
draw_done:
draw_loop:
lda scroll_row1,Y
sm1:
sta $400,X
lda scroll_row2,Y
sm2:
sta $480,X
lda scroll_row3,Y
sm3:
sta $500,X
lda scroll_row4,Y
sm4:
sta $580,X
iny
inx
cpx #40
bne draw_loop
;==================
; flip pages
;==================
jsr page_flip ; 6
;==================
; delay
;==================
lda #125
jsr WAIT
;==================
; loop forever
;==================
clc
lda ANGLE
adc #40
cmp SCROLL_LENGTH
bne blah
lda #0
sta ANGLE
jmp scroll_loop
blah:
inc ANGLE
jmp scroll_loop ; 3
;=======================
; decompress scroll
;=======================
decompress_scroll:
ldy #0
jsr load_and_increment
sta SCROLL_LENGTH
lda #<scroll_row1
sta OUTL
lda #>scroll_row1
sta OUTH
decompress_scroll_loop:
jsr load_and_increment ; load compressed value
cmp #$A1 ; EOF marker
beq done_decompress_scroll ; if EOF, exit
pha ; save
and #$f0 ; mask
cmp #$a0 ; see if special AX
beq decompress_special
pla ; note, PLA sets flags!
ldx #$1 ; only want to print 1
bne decompress_run
decompress_special:
pla
and #$0f ; check if was A0
bne decompress_color ; if A0 need to read run, color
decompress_large:
jsr load_and_increment ; get run length
decompress_color:
tax ; put runlen into X
jsr load_and_increment ; get color
decompress_run:
sta (OUTL),Y
pha
clc ; increment 16-bit pointer
lda OUTL
adc #$1
sta OUTL
lda OUTH
adc #$0
sta OUTH
pla
dex ; repeat for X times
bne decompress_run
beq decompress_scroll_loop ; get next run
done_decompress_scroll:
rts
load_and_increment:
lda (INL),Y ; load and increment 16-bit pointer
pha
clc
lda INL
adc #$1
sta INL
lda INH
adc #$0
sta INH
pla
rts
;===============================================
; Variables
;===============================================
.include "deater_scroll.inc"
;=====================================================================
;= ROUTINES
;=====================================================================
clear_screens:
;===================================
; Clear top/bottom of page 0
;===================================
lda #$0
sta DRAW_PAGE
jsr clear_top
jsr clear_bottom
;===================================
; Clear top/bottom of page 1
;===================================
lda #$4
sta DRAW_PAGE
jsr clear_top
jsr clear_bottom
rts
;==========
; page_flip
;==========
page_flip:
; lda $c019 ; wait for vertical refresh
; bmi page_flip
lda DISP_PAGE ; 3
beq page_flip_show_1 ; 2nt/3
page_flip_show_0:
bit PAGE0 ; 4
lda #4 ; 2
sta DRAW_PAGE ; DRAW_PAGE=1 ; 3
lda #0 ; 2
sta DISP_PAGE ; DISP_PAGE=0 ; 3
rts ; 6
page_flip_show_1:
bit PAGE1 ; 4
sta DRAW_PAGE ; DRAW_PAGE=0 ; 3
lda #1 ; 2
sta DISP_PAGE ; DISP_PAGE=1 ; 3
rts ; 6
;====================
; DISP_PAGE=0 26
; DISP_PAGE=1 24
;==========================================================
; set_gr_page0
;==========================================================
;
set_gr_page0:
;lda #4
;sta GR_PAGE
bit PAGE0 ; set page 0
bit LORES ; Lo-res graphics
bit TEXTGR ; mixed gr/text mode
bit SET_GR ; set graphics
rts
;================================
; hlin_setup
;================================
; put address in GBASL/GBASH
; Ycoord in A, Xcoord in Y
hlin_setup:
sty TEMPY ; 3
tay ; y=A ; 2
lda gr_offsets,Y ; lookup low-res memory address ; 4
clc ; 2
adc TEMPY ; 3
sta GBASL ; 3
iny ; 2
lda gr_offsets,Y ; 4
adc DRAW_PAGE ; add in draw page offset ; 3
sta GBASH ; 3
rts ; 6
;===========
; 35
;================================
; hlin_double:
;================================
; HLIN Y, V2 AT A
; Y, X, A trashed
; start at Y, draw up to and including X
hlin_double:
;int hlin_double(int page, int x1, int x2, int at) {
jsr hlin_setup ; 41
sec ; 2
lda V2 ; 3
sbc TEMPY ; 3
tax ; 2
inx ; 2
;===========
; 53
; fallthrough
;=================================
; hlin_double_continue: width
;=================================
; width in X
hlin_double_continue:
ldy #0 ; 2
lda COLOR ; 3
hlin_double_loop:
sta (GBASL),Y ; 6
inc GBASL ; 5
dex ; 2
bne hlin_double_loop ; 2nt/3
rts ; 6
;=============
; 53+5+X*16+5
;================================
; hlin_single:
;================================
; HLIN Y, V2 AT A
; Y, X, A trashed
hlin_single:
jsr hlin_setup
sec
lda V2
sbc TEMPY
tax
; fallthrough
;=================================
; hlin_single_continue: width
;=================================
; width in X
hlin_single_continue:
hlin_single_top:
lda COLOR
and #$f0
sta COLOR
hlin_single_top_loop:
ldy #0
lda (GBASL),Y
and #$0f
ora COLOR
sta (GBASL),Y
inc GBASL
dex
bne hlin_single_top_loop
rts
hlin_single_bottom:
lda COLOR
and #$0f
sta COLOR
hlin_single_bottom_loop:
ldy #0
lda (GBASL),Y
and #$f0
sta (GBASL),Y
inc GBASL
dex
bne hlin_single_bottom_loop
rts
;=============================
; clear_top
;=============================
clear_top:
lda #$00
;=============================
; clear_top_a
;=============================
clear_top_a:
sta COLOR
; VLIN Y, V2 AT A
lda #40
sta V2
lda #0
clear_top_loop:
ldy #0
pha
jsr hlin_double
pla
clc
adc #$2
cmp #40
bne clear_top_loop
rts
clear_bottom:
lda #$a0 ; NORMAL space
sta COLOR
lda #40
sta V2
clear_bottom_loop:
ldy #0
pha
jsr hlin_double
pla
clc
adc #$2
cmp #48
bne clear_bottom_loop
rts
; move these to zero page for slight speed increase?
gr_offsets:
.word $400,$480,$500,$580,$600,$680,$700,$780
.word $428,$4a8,$528,$5a8,$628,$6a8,$728,$7a8
.word $450,$4d0,$550,$5d0,$650,$6d0,$750,$7d0