Light pen driver
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;; Dissassembled and commented from MCPEN.BIN
org 09c40h
sub_9c40h:
call 0bd19h ;; mc wait flyback
di
ld bc,0f40eh ;; we want to select AY register 14
out (c),c
ld b,0f6h
in a,(c)
and 030h
ld c,a
or 0c0h ;; AY control select register.
out (c),a
out (c),a ;; BUG. Should be out (c),c to be compatible with Plus.
inc b
ld a,092h
out (c),a
push bc
ld bc,0f649h ;; AY control read from register and select keyboard line 9 (joystick)
out (c),c
out (c),c ;; BUG? No need to do this twice.
ld b,0f4h
;; loop reading joystick until input seen or timeout
ld hl,0fa66h ;; timeout is 0-FA66 because it counts up from this starting point.
;; timeout is 59A loops.
l9c68:
in a,(c)
cp 0fdh ;; 11111101. Bits are '1' if 'no press', but '0' if pressed. checking joy 0 down.
jr z,l9c79
inc l
jr nz,l9c68
inc h
jr nz,l9c68
;; timeout. not detected
ld hl,0ffffh
jr l9cbdh
l9c79:
;; detected.
ld de,00420h
add hl,de
l9cbd:
ld (0a410h),hl ;; detected 'position' or 'ffff' for not detected
pop bc
ld a,082h
out (c),a
dec b
out (c),c ;; Set AY control inactive.
ei
ret
sub_9c8ah:
call sub_9da6h ;; screen to buffer
call sub_9ce4h
call sub_9db2h ;; buffer to screen
ret
;; HL = HL/DE
sub_9c94:
ld a,h
ld c,l
ld b,010h ;; 16 bits.
ld hl,00000h
l9cdbh:
rl c
rla
adc hl,hl
sbc hl,de
jr nc,l9ce5h
add hl,de
l9ce5h:
ccf
djnz l9cdbh
rl c
rla
ld h,a
ld l,c
ret
;; HL = HL * DE
sub_9caeh:
ld a,l
ld c,h
ld b,010h ;; 16 bits
ld hl,00000h
l9cf5h:
srl c
rra
jr nc,l9cfbh
add hl,de
l9cfbh:
ex de,hl
add hl,hl
ex de,hl
djnz l9cf5h
ret
sub_9cc1h:
call sub_9c40h ;; detect
ld a,0ffh
cp h
ret z
;; detected.
ld de,00002h
call sub_9c94h ;; HL = HL/DE
ld de,00064h
call sub_9caeh ;; HL = HL*DE
ld de,00084h
call sub_9c94h ;; HL = HL/DE
ex de,hl
ld hl,0018fh
sbc hl,de
ld (0a410h),hl
ret
sub_9ce4:
ld a,000h
ld bc,01a1ah
call 0bc32h ;; scr set ink
call 0bc14h ;; scr clear
ld a,001h
call 0bbdeh ;; gra set pen
call sub_9cc1h ;; get position
ld a,0ffh
cp h
ret z
ld de,0000ah
and a
sbc hl,de
;; BUG? This is jumping just after 0x021 of LD HL and then executing two nops before LD DE,0000h
;;jr nc,$+2
jr nc,l9d06
ld hl,00000h
l9d06:
ld de,00000h
call 0bbc0h ;; gra move absolute
ld a,001h
ld bc,01a1ah
call 0bc32h ;; scr set ink
ld a,000h
ld bc,00000h
call 0bc32h ;; scr set ink
ld b,00ah
l9d1e:
call 0bd19h ;; mc wait flyback
;; BUG? this is jumping back to the 0x0a in LD B,0ah
;; djnz $-4
djnz l9d1e
ld b,020h ;; number of lines
l9d65h:
push bc
call sub_9d35h ;; draw lines
call sub_9c40h ;;detect
pop bc
ld a,0ffh
cp h
jr nz,l9d91h
djnz l9d65h
ret
sub_9d35h:
ld bc,(0a418h)
l9d79h:
push bc
ld de,00000h
ld hl,00014h
call 0bbf9h ;; gra line relative
ld de,(0a416h)
ld hl,0ffech
call 0bbc3h ;; gra move relative
pop bc
djnz l9d79h
ret
l9d91h:
ld de,0ffech ;; -20
ld hl,00000h
call 0bbc3h ;; gra move relative
l9d9ah:
ld a,000h
call 0bbdeh ;; gra set pen
call sub_09d35h ;; lines
ld a,001h
call 0bbdeh ;; gra set pen
ld de,0ffech ;; -20
ld hl,00000h
call 0bbc3h ;; gra move relative
ld bc,(0a420h)
l9db4h:
push bc
call sub_9cc1h ;; get position
ld a,0ffh
cp h
jr nz,sub_9d9ah
ld de,00000h
ld hl,00014h
call 0bbf9h ;; gra line relative
ld de,(0a416h)
ld hl,0ffech ;; -20
call 0bbc3h ;; gra move relative
pop bc
djnz l9db4h
ld hl,0ffffh
ld (0a410h),hl
ret
sub_9d9ah:
pop bc
ld (0a410h),hl
call 0bbc6h ;; gra ask cursor
ld (0a412h),de
ret
;; screen to buffer
;; c000->5bfe length 3fd0
sub_9da6h:
ld bc,03fd0h
ld hl,0c000h
ld de,05bfeh
ldir
ret
;; buffer to screen
;; 5bfe->c000 length 3fd0
sub_9db2h:
ld bc,03fd0h
ld hl,05bfeh
ld de,0c000h
ldir
ret
sub_9dbeh:
push hl
push de
call sub_09e08h
ld (0a414h),hl
ld de,05398h
ld b,004h
l9e0bh:
push bc
ld hl,(0a414h)
ld c,b
ld b,000h
inc hl
and a
sbc hl,bc
ld b,00bh
l9e18h:
ld a,(hl)
ld (de),a
inc de
call 0bc29h ;; scr prev line
djnz l9e18h
pop bc
djnz l9e0bh
pop de
pop hl
ret
sub_9de6h:
push hl
push de
ld de,05398h
ld b,004h
l9e2dh:
push bc
ld hl,(0a414h)
ld c,b
ld b,000h
inc hl
and a
sbc hl,bc
ld b,00bh
l9e3ah:
ld a,(de)
ld (hl),a
inc de
call 0bc29h ;; scr prev line
djnz l9e3ah
pop bc
djnz l9e2dh
pop de
pop hl
ret
sub_9e08h:
push de
ld de,00002h
call sub_9c94h ;; HL = HL/DE
pop de
push hl
ex de,hl
ld de,(0a416h)
call sub_9c94h ;; HL = HL/DE
ex de,hl
pop hl
call 0bc1dh ;; scr dot position
ret
sub_9e1fh:
call sub_9c8ah
ld hl,(0a418h)
ld (0a420h),hl
ld hl,(0a410h)
ld a,0ffh
cp h
ret z
ld (0a41ch),hl
ld de,(0a412h)
ld (0a41ah),de
l9e7ah:
ld de,0000ah
and a
sbc hl,de
jr nc,l9e85h
ld hl,00000h
l9e85h:
push hl
ld hl,(0a412h)
add hl,de
ex de,hl
pop hl
call sub_09dbeh
call 0bbc0h ;; gra move absolute
sub_9e52h:
call sub_09ed2h
call sub_09de6h
ld hl,(0a410h)
ld a,0ffh
cp h
jr nz,l9ea9h
ld a,02fh
call 0bb1eh ;; km test key
ret z
jp sub_9e52h
l9ea9h:
call sub_09eb7h
ld a,02fh
call 0bb1eh ;; km test key
ret z
ld hl,(0a41ch)
ld de,(0a41ah)
call 0bbc0h ;; gra move absolute
ld hl,(0a410h)
ld de,(0a412h)
ld a,(0a41eh)
call 0bbdeh ;; gra set pen
ld (0a41ch),hl
ld (0a41ah),de
call 0bbf6h ;; gra line absolute
ld hl,(0a410h)
jr l9e7ah
sub_09e98h:
ld de,0ffech
ld hl,00000h
call 0bbc3h ;; gra move relative
ld a,001h
call 0bbdeh ;; gra set pen
call sub_09d35h
ld a,000h
call 0bbdeh ;; gra set pen
call sub_9cc1h ;; get position
ld a,0ffh
cp h
ret nz
pop de
ret
sub_9eb7h:
ld hl,(0a41ah)
ld de,(0a412h)
and a
sbc hl,de
ret z
jp p,l9ecbh
ld hl,l9f15h
jp l09eceh
l9ecbh:
ld hl,sub_9ed2h
l9eceh:
ld (l9e52h+1),hl
ret
sub_9ed2h:
call sub_9e98h
ld de,0ffech
ld hl,00000h
call 0bbc3h ;; gra move relative
ld bc,(0a420h)
push bc
ld de,00000h
ld hl,00014h
call 0bbf9h ;; gra line relative
call sub_9cc1h
ld a,0ffh
cp h
jp nz,sub_9efeh
sub_9ef5h:
ld hl,(0a422h)
ld (0a410h),hl
jp sub_9d9ah
sub_9efeh:
ld (0a422h),hl
ld de,(0a416h)
ld hl,0ffech
call 0bbc3h ;; gra move relative
pop bc
djnz l9f22h
ld hl,0ffffh
ld (0a410h),hl
ret
sub_9f82h:
call sub_9e98h
ld bc,(0a420h)
l9f5ch:
push bc
ld de,00000h
ld hl,00014h
call 0bbf9h ;; gra line relative
call sub_9cc1h
ld a,0ffh
cp h
jp z,sub_9ef5h
ld (0a422h),hl
ld de,(0a416h)
ld hl,00000h
and a
sbc hl,de
push hl
pop de
ld hl,0ffech
call 0bbc3h ;; gra move relative
pop bc
djnz l9f5ch
ld hl,00000h
ld de,00014h
call 0bbc3h ;; gra move relative
jp l9f0eh
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
;; screen dump to printer.
sub_0a028h:
ld a,013h
ld (0a124h),a
ld a,00eh
ld (0a0e2h),a
ld a,(0a133h)
bit 1,a
jr z,la083h
ld a,000h
ld (0a124h),a
ld a,007h
ld (0a0e2h),a
la083h:
call 0bd28h ;; mc reset printer
ld de,00000h
ld hl,00000h
ld (0a12dh),de
sub_a050h:
ld a,000h
ld (0a12ch),a ;; accumulated pixels.
ld de,(0a12dh)
call sub_a10dh ;; store current graphics position
call 0bbf0h ;; gra test absolute
ld de,00001h
call sub_a11dh ;; get pixel
ld de,00002h
call sub_a11dh ;; get pixel
ld de,00004h
call sub_a11dh ;; get pixel
ld de,00008h
call sub_a11dh ;; get pixel
ld de,00010h
call sub_a11dh ;; get pixel
ld de,00020h
call sub_a11dh ;; get pixel
ld de,00040h
call sub_a0ffh ;; get pixel
la0c9h:
call 0bd2eh ;; mc busy printer
jr c,la0c9h
call 0bd28h ;; mc reset printer
ld a,01bh ;; ESC
call 0bd2bh ;; mc print char
ld a,04bh ;; K
call 0bd2bh ;; mc print char
ld a,000h ;; number of columns low byte
call 0bd2bh ;; mc print char
ld a,(0a133h)
bit 0,a
jr z,la0b4h
ld a,002h ;; number of columns high byte?
call 0bd2bh ;; mc print char
ld a,(0a12ch) ;; pixel data
call 0bd2bh ;; mc print char
jr la0f9h
la0b4h:
ld a,001h ;; number of columns high byte?
call 0bd2bh ;; mc print char
la0f9h:
ld a,(0a12ch) ;; pixel data
call 0bd2bh ;; mc print char
call sub_a115h
inc hl
inc hl
call sub_a10dh
ld a,h
cp 001h
jp nz,sub_a050h
ld a,l
cp 090h
jp nz,sub_a050h
ld a,00ah ;; next line
call 0bd2bh ;; mc print char
ld a,02fh ;; 47 - space
call 0bb1eh ;; km test key
ret nz
ld hl,(0a12dh)
ld de,0000eh
add hl,de
ld (0a12dh),hl
ld hl,00000h
call sub_a10dh
ld de,(0a12dh)
ld a,d
cp 002h
jp nz,sub_a050h
ld a,e
cp 084h
jp nz,sub_a050h
ret
;; accumulate pixels
sub_a0ffh:
ld b,a
call 0bb99h ;; txt get paper
cp b ;; was the colour read the same as the paper?
ret z
;; any pixel which is not the same as the paper will be considered foreground
;; and the printer will draw a dot. Any pixel the same as the paper will
;; be considered background and no dot is drawn by the printer.
;; pixel is set to foreground. accumulate it into the pixel data so far
ld hl,(0a12ch)
add hl,de
ld (0a12ch),hl
ret
sub_a10dh:
ld (0a12fh),hl
ld (0a131h),de
ret
sub_a115h:
ld hl,(0a12fh)
ld de,(0a131h)
ret
sub_a11dh:
call sub_a0ffh ;; accumulate a pixel for printing.
call sub_a115h ;; get current X/Y graphics position
inc de ;; increment X to next pixel accross screen.
inc de
call sub_a10dh ;; set current X/Y graphics position
call 0bbf0h ;; gra test absolute
ret
db 00h,84h,02h,00h,00h,0eh,00h,00h,00h
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
sub_a154h:
call 0bc11h ;; scr get mode
cp 000h
jr nz,la19dh
ld b,004h
la19dh:
cp 001h
jr nz,la1a3h
ld b,002h
la1a3h:
cp 002h
jr nz,la1a9h
ld b,001h
la1a9h:
ld a,b
la1aah:
ld (data_a254),a
call 0bbc6h ;; gra ask cursor
ld (data_a250),hl
ld (data_a250+2),de
la1b7h:
call 0bb99h ;; txt get paper
ld (0a1f9h),a
ld bc,00000h
ld (data_a24c),bc
ld (data_a24e),bc
call sub_a210
ld a,02fh ;; 47 - space
call 0bb1eh ;; km test key
ret nz
ld hl,(data_a24e)
inc hl
inc hl
ld a,004h
cp h
jr nz,la1deh
ld hl,00000h
la1deh:
ld (data_a24e),hl
ld bc,05398h
add hl,bc
ld (0a1aah),hl
ld de,(055e0h)
ld hl,(data_a24e)
sub_a1efh:
ld bc,057e4h
add hl,bc
ld (0a1b7h),hl
ld hl,(05a2ch)
la1f9h:
ld (la257h),hl
ld (data_a255),de
ld bc,00000h
ld a,(data_a254)
ld c,a
ex de,hl
add hl,bc
ex de,hl
call sub_a1efh
and a
ex de,hl
sbc hl,bc
ex de,hl
call sub_a1efh
inc hl
inc hl
call sub_a1efh
dec hl
dec hl
call sub_a1efh
ld hl,(data_a24e)
ld de,(data_a24c)
inc hl
inc hl
and a
sbc hl,de
ret z
jp la18bh
sub_a1efh:
push de
push hl
push bc
call 0bbf0h ;; gra test absolute
pop bc
pop hl
pop de
cp 000h
jr nz,la248h
ld (data_a250),hl
ld (data_a250+2),de
push bc
call sub_0a210h
pop bc
la248h:
ld hl,(data_a257)
ld de,(data_a255)
ret
sub_a210:
ld hl,(data_a250)
ld de,(data_a250+2)
call 0bbeah ;; gra plot absolute
ld hl,(data_a24c)
inc hl
inc hl
ld a,004h
cp h
jr nz,la267h
ld hl,00000h
la267h:
ld (data_a24c),hl
ld bc,05398h
add hl,bc
ld de,(data_a250+2)
ld (0a237h),hl
ld (05648h),de
ld hl,(data_a24c)
ld bc,057e4h
add hl,bc
ld de,(data_a250)
ld (0a249),hl
ld (05a94h),de
ret
;;Data area
data_a24c:
defw 02b0h
data_a24e:
defw 0248h
data_a250:
defw 0beh
data_a252:
defw 0120h
data_a254:
defb 04h
data_a255:
defw 0120h
data_a257:
defw 0bch
end
