dos33fsprogs/vaporlock/iie/double.s
2023-04-26 11:03:58 -04:00

317 lines
4.3 KiB
ArmAsm

; Test mid-screen mode switch on Apple IIe double modes
; TODO: detect iic/iigs and vblank properly there
; by Vince `deater` Weaver
; zero page
GBASL = $26
GBASH = $27
V2 = $2D
HGRPAGE = $E6
YPOS = $FE
TCOLOR = $FF
; soft-switches
; yes, I know these aren't necessary the "official" names
EIGHTYSTORE = $C001
CLR80COL = $C00C
SET80COL = $C00D
SET_GR = $C050
SET_TEXT= $C051
FULLGR = $C052
TEXTGR = $C053
PAGE1 = $C054
PAGE2 = $C055
LORES = $C056
HIRES = $C057
CLRAN3 = $C05E
SETAN3 = $C05F
VBLANK = $C019 ; *not* RDVBL (VBL signal low)
; ROM routines
SETCOL = $F864 ; COLOR=A*17
SETGR = $FB40
VLINE = $F828 ; VLINE A,$2D at Y
HGR = $F3E2
HPOSN = $F411
HPLOT0 = $F457 ; plot at (Y,X), (A)
HGLIN = $F53A ; line to (X,A),(Y)
;================================
; Clear screen and setup graphics
;================================
double:
jsr SETGR ; set lo-res 40x40 mode
; set 80-store mode
sta EIGHTYSTORE ; PAGE2 selects AUX memory
bit PAGE1
;===================
; draw lo-res lines
ldx #39
draw_lores_lines:
txa
tay
jsr SETCOL
lda #47
sta V2
lda #0
jsr VLINE ; VLINE A,$2D at Y
dex
bpl draw_lores_lines
; copy to 800 temporarily
; yes this is a bit of a hack
ldy #0
cp_loop:
lda $400,Y
sta $800,Y
lda $500,Y
sta $900,Y
lda $600,Y
sta $A00,Y
lda $700,Y
sta $B00,Y
iny
bne cp_loop
bit PAGE1
; copy to $400 in AUX
bit PAGE2 ; $400 now maps to AUX:$400
ldy #0
cp2_loop:
lda $800,Y
eor #$FF
sta $400,Y
lda $900,Y
eor #$FF
sta $500,Y
lda $A00,Y
eor #$FF
sta $600,Y
lda $B00,Y
eor #$FF
sta $700,Y
iny
bne cp2_loop
bit PAGE1
;===================
; draw hi-res lines
jsr HGR
bit FULLGR ; make it 40x48
lda #$FF
sta $E4 ; HCOLOR
ldx #0
ldy #0
lda #96
jsr HPLOT0 ; plot at (Y,X), (A)
ldx #0
lda #140
ldy #191
jsr HGLIN ; line to (X,A),(Y)
ldx #1
lda #23
ldy #96
jsr HGLIN ; line to (X,A),(Y)
; draw double-hires lines
lda #$20 ; draw to page0 (MAIN?)
sta HGRPAGE
lda #150 ; start at 150
sta YPOS
color_loop:
lda YPOS
and #$f
sta TCOLOR
asl
asl
asl
asl
ora TCOLOR
sta TCOLOR ; update color
lda YPOS
jsr draw_line_color
inc YPOS
lda YPOS
cmp #192
bne color_loop
; wait for vblank on IIe
; positive? during vblank
wait_vblank_iie:
lda VBLANK
bmi wait_vblank_iie ; wait for positive (in vblank)
wait_vblank_done_iie:
lda VBLANK ; wait for negative (vlank done)
bpl wait_vblank_done_iie
;
double_loop:
;===========================
; text mode first 6*4 (24) lines
; each line 65 cycles (25 hblank+40 bytes)
; 3 LINES 80-COL AN3
sta SET80COL ; 4
bit SET_TEXT ; 4
; wait 6*4=24 lines
; (24*65)-8 = 1560-8 = 1552
jsr delay_1552
; 3 LINES 40-COL AN3
sta CLR80COL ; 4
bit SET_TEXT ; 4
jsr delay_1552
; 3 LINES 40-col LORES AN3
lda LORES ; 4
bit SET_GR ; 4
jsr delay_1552
; 3 LINES 80-col DLORES AN3
sta SET80COL ; 4
sta CLRAN3 ; 4
jsr delay_1552
; 3 lines 40-col LORES
sta CLR80COL ; 4
sta SETAN3 ; 4 ; doublehiresoff
jsr delay_1552
; 3 lines HIRES
sta HIRES ; 4
sta CLRAN3 ; 4
jsr delay_1552
; 3 lines HIRES
sta HIRES ; 4
sta SETAN3 ; 4
jsr delay_1552
; 3 line Double-HIRES
sta SET80COL ; 4
sta CLRAN3 ; 4
jsr delay_1552
;==================================
; vblank = 4550 cycles
; Try X=226 Y=4 cycles=4545
skip_vblank:
nop
ldy #4 ; 2
loop3: ldx #226 ; 2
loop4: dex ; 2
bne loop4 ; 2nt/3
dey ; 2
bne loop3 ; 2nt/3
jmp double_loop ; 3
;=======================================================
; need to align because if we straddle a page boundary
; the time counts end up off
.align $100
; actually want 1552-12 (6 each for jsr/rts)
; 1540
; Try X=15 Y=19 cycles=1540
delay_1552:
ldy #19 ; 2
loop5: ldx #15 ; 2
loop6: dex ; 2
bne loop6 ; 2nt/3
dey ; 2
bne loop5 ; 2nt/3
rts
;==========================
; draw horizontal DHGR line
;==========================
; color is in TCOLOR
; Y position is in A
;=========================
draw_line_color:
ldx #0
ldy #0
jsr HPOSN ; setup GBASL/GBASH with Y position
ldy #0
line_loop_it:
; set page2
sta PAGE2
lda TCOLOR
sta (GBASL),Y
cmp #$80
rol TCOLOR
; set page1
sta PAGE1
lda TCOLOR
sta (GBASL),Y
cmp #$80
rol TCOLOR
iny
cpy #40
bne line_loop_it
rts