Difference between revisions of "Light pen driver"

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Line 63: Line 63:
 
         ret
 
         ret
  
 +
;; HL = HL/DE
 
sub_9c94:
 
sub_9c94:
 
         ld a,h
 
         ld a,h
Line 84: Line 85:
 
         ret
 
         ret
  
 +
;; HL = HL * DE
 
sub_9caeh:
 
sub_9caeh:
 
         ld a,l
 
         ld a,l
Line 109: Line 111:
 
         ;; detected.
 
         ;; detected.
 
         ld de,00002h
 
         ld de,00002h
         call sub_9c94h
+
         call sub_9c94h ;; HL = HL/DE
 
         ld de,00064h
 
         ld de,00064h
         call sub_9caeh
+
         call sub_9caeh ;; HL = HL*DE
 
         ld de,00084h
 
         ld de,00084h
         call sub_9c94h
+
         call sub_9c94h ;; HL = HL/DE
 
         ex de,hl
 
         ex de,hl
 
         ld hl,0018fh
 
         ld hl,0018fh
Line 296: Line 298:
 
         push de
 
         push de
 
         ld de,00002h
 
         ld de,00002h
         call sub_9c94h
+
         call sub_9c94h ;; HL = HL/DE
 
         pop de
 
         pop de
 
         push hl
 
         push hl
 
         ex de,hl
 
         ex de,hl
 
         ld de,(0a416h)
 
         ld de,(0a416h)
         call sub_9c94h
+
         call sub_9c94h ;; HL = HL/DE
 
         ex de,hl
 
         ex de,hl
 
         pop hl
 
         pop hl
Line 454: Line 456:
 
         call 0bbc3h ;; gra move relative
 
         call 0bbc3h ;; gra move relative
 
         jp l9f0eh
 
         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
Line 480: Line 483:
 
         ld de,00000h
 
         ld de,00000h
 
         ld hl,00000h
 
         ld hl,00000h
         ld (0a12dh),de
+
         ld (data_a12d),de
 
sub_a050h:
 
sub_a050h:
 
         ld a,000h
 
         ld a,000h
         ld (0a12ch),a ;; accumulated pixels.
+
         ld (data_a12c),a ;; accumulated pixels.
  
         ld de,(0a12dh)
+
         ld de,(data_a12d)
 
         call sub_a10dh ;; store current graphics position
 
         call sub_a10dh ;; store current graphics position
  
Line 519: Line 522:
 
         call 0bd2bh ;; mc print char
 
         call 0bd2bh ;; mc print char
  
         ld a,(0a12ch) ;; pixel data
+
         ld a,(data_a12c) ;; pixel data
 
         call 0bd2bh ;; mc print char
 
         call 0bd2bh ;; mc print char
 
         jr la0f9h
 
         jr la0f9h
Line 526: Line 529:
 
         call 0bd2bh ;; mc print char
 
         call 0bd2bh ;; mc print char
 
la0f9h:
 
la0f9h:
         ld a,(0a12ch) ;; pixel data
+
         ld a,(data_a12c) ;; pixel data
 
         call 0bd2bh ;; mc print char
 
         call 0bd2bh ;; mc print char
  
Line 545: Line 548:
 
         call 0bb1eh ;; km test key
 
         call 0bb1eh ;; km test key
 
         ret nz
 
         ret nz
         ld hl,(0a12dh)
+
         ld hl,(data_a12d)
 
         ld de,0000eh
 
         ld de,0000eh
 
         add hl,de
 
         add hl,de
         ld (0a12dh),hl
+
         ld (data_a12d),hl
 
         ld hl,00000h
 
         ld hl,00000h
 
         call sub_a10dh
 
         call sub_a10dh
         ld de,(0a12dh)
+
         ld de,(data_a12d)
 
         ld a,d
 
         ld a,d
 
         cp 002h
 
         cp 002h
Line 573: Line 576:
  
 
         ;; pixel is set to foreground. accumulate it into the pixel data so far
 
         ;; pixel is set to foreground. accumulate it into the pixel data so far
         ld hl,(0a12ch)
+
         ld hl,(data_a12c)
 
         add hl,de
 
         add hl,de
         ld (0a12ch),hl
+
         ld (data_a12c),hl
 
         ret
 
         ret
  
 
sub_a10dh:
 
sub_a10dh:
         ld (0a12fh),hl
+
         ld (data_a12f),hl
         ld (0a131h),de
+
         ld (data_a131),de
 
         ret
 
         ret
  
 
sub_a115h:
 
sub_a115h:
         ld hl,(0a12fh)
+
         ld hl,(data_a12f)
         ld de,(0a131h)
+
         ld de,(data_a131)
 
         ret
 
         ret
  
Line 596: Line 599:
 
         call 0bbf0h ;; gra test absolute
 
         call 0bbf0h ;; gra test absolute
 
         ret
 
         ret
 +
data_a12c:
 +
        db 00h
 +
data_a12d:
 +
        db 84h,02h
 +
data_a12f:
 +
        db 00h,00h
 +
data_a131:
 +
        db 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
  
la10ch:
 
        nop
 
        add a,h
 
        ld (bc),a
 
        nop
 
        nop
 
        ld c,000h
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
        nop
 
 
sub_a154h:
 
sub_a154h:
 
         call 0bc11h ;; scr get mode
 
         call 0bc11h ;; scr get mode
Line 653: Line 625:
 
         ld a,b
 
         ld a,b
 
la1aah:
 
la1aah:
         ld (0a254h),a
+
         ld (data_a254),a
 
         call 0bbc6h ;; gra ask cursor
 
         call 0bbc6h ;; gra ask cursor
         ld (0a250h),hl
+
         ld (data_a250),hl
         ld (0a250h+2),de
+
         ld (data_a250+2),de
 
la1b7h:
 
la1b7h:
 
         call 0bb99h ;; txt get paper
 
         call 0bb99h ;; txt get paper
         ld (0a1f9h),a
+
         ld (pen_cmp+1),a
 
         ld bc,00000h
 
         ld bc,00000h
         ld (0a24ch),bc
+
         ld (data_a24c),bc
         ld (0a24eh),bc
+
         ld (data_a24e),bc
 
         call sub_a210
 
         call sub_a210
 +
la18bh:
 
         ld a,02fh  ;; 47 - space
 
         ld a,02fh  ;; 47 - space
 
         call 0bb1eh ;; km test key
 
         call 0bb1eh ;; km test key
 
         ret nz
 
         ret nz
         ld hl,(0a24eh)
+
         ld hl,(data_a24e)
 
         inc hl
 
         inc hl
 
         inc hl
 
         inc hl
Line 675: Line 648:
 
         ld hl,00000h
 
         ld hl,00000h
 
la1deh:
 
la1deh:
         ld (0a24eh),hl
+
         ld (data_a24e),hl
 
         ld bc,05398h
 
         ld bc,05398h
 
         add hl,bc
 
         add hl,bc
         ld (0a1aah),hl
+
         ld (buffer_addr3+2),hl ;; +2 to skip ED,53
 +
buffer_addr3:
 
         ld de,(055e0h)
 
         ld de,(055e0h)
         ld hl,(0a24eh)
+
         ld hl,(data_a24e)
 
sub_a1efh:
 
sub_a1efh:
 
         ld bc,057e4h
 
         ld bc,057e4h
 
         add hl,bc
 
         add hl,bc
         ld (0a1b7h),hl
+
         ld (buffer_addr4+1),hl ;; +1 to skip 22
 +
buffer_addr4:
 
         ld hl,(05a2ch)
 
         ld hl,(05a2ch)
la1f9h:
+
         ld (data_a257),hl
         ld (la257h),hl
+
         ld (data_a255),de
         ld (0a255h),de
+
 
         ld bc,00000h
 
         ld bc,00000h
         ld a,(0a254h)
+
         ld a,(data_a254)
 
         ld c,a
 
         ld c,a
 
         ex de,hl
 
         ex de,hl
Line 707: Line 681:
 
         dec hl
 
         dec hl
 
         call sub_a1efh
 
         call sub_a1efh
         ld hl,(0a24eh)
+
         ld hl,(data_a24e)
         ld de,(0a24ch)
+
         ld de,(data_a24c)
 
         inc hl
 
         inc hl
 
         inc hl
 
         inc hl
Line 715: Line 689:
 
         ret z
 
         ret z
 
         jp la18bh
 
         jp la18bh
 +
 
sub_a1efh:
 
sub_a1efh:
 
         push de
 
         push de
Line 723: Line 698:
 
         pop hl
 
         pop hl
 
         pop de
 
         pop de
 +
pen_cmp:
 
         cp 000h
 
         cp 000h
 
         jr nz,la248h
 
         jr nz,la248h
         ld (0a250h),hl
+
         ld (data_a250),hl
         ld (0a250h+2),de
+
         ld (data_a252),de
 
         push bc
 
         push bc
 
         call sub_0a210h
 
         call sub_0a210h
 
         pop bc
 
         pop bc
 
la248h:
 
la248h:
         ld hl,(0a257h)
+
         ld hl,(data_a257)
         ld de,(0a255h)
+
         ld de,(data_a255)
 
         ret
 
         ret
 
sub_a210:
 
sub_a210:
         ld hl,(0a250h)
+
         ld hl,(data_a250)
         ld de,(0a250h+2)
+
         ld de,(data_a252)
 
         call 0bbeah ;; gra plot absolute
 
         call 0bbeah ;; gra plot absolute
         ld hl,(0a24ch)
+
         ld hl,(data_a24c)
 
         inc hl
 
         inc hl
 
         inc hl
 
         inc hl
Line 746: Line 722:
 
         ld hl,00000h
 
         ld hl,00000h
 
la267h:
 
la267h:
         ld (0a24ch),hl
+
         ld (data_a24c),hl
 
         ld bc,05398h
 
         ld bc,05398h
 
         add hl,bc
 
         add hl,bc
         ld de,(0a250h+2)
+
         ld de,(data_a252)
         ld (0a237h),hl
+
         ld (buffer_addr1+2),hl ;; +2 to skip ED, 53
 +
buffer_addr1:
 
         ld (05648h),de
 
         ld (05648h),de
         ld hl,(0a24ch)
+
         ld hl,(data_a24c)
 
         ld bc,057e4h
 
         ld bc,057e4h
 
         add hl,bc
 
         add hl,bc
         ld de,(0a250h)
+
         ld de,(data_a250)
         ld (0a249),hl
+
         ld (buffer_addr+2),hl ;; +2 to skip ED, 53
 +
buffer_addr2:
 
         ld (05a94h),de
 
         ld (05a94h),de
 
         ret
 
         ret
la24ch:
+
 
         or b
+
;;Data area
        ld (bc),a
+
data_a24c:
         ld c,b
+
         defw 02b0h
        ld (bc),a
+
data_a24e:
         cp (hl)
+
         defw 0248h
        nop
+
data_a250:
         jr nz,la295h
+
         defw 0beh
         inc b
+
data_a252:
         jr nz,$+3
+
         defw 0120h
         cp h
+
data_a254:
 +
         defb 04h
 +
data_a255:
 +
         defw 0120h
 +
data_a257:
 +
         defw 0bch
  
 
         end
 
         end

Latest revision as of 02:52, 18 July 2025

;; 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 (data_a12d),de
sub_a050h:
        ld a,000h
        ld (data_a12c),a ;; accumulated pixels.

        ld de,(data_a12d)
        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,(data_a12c) ;; 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,(data_a12c) ;; 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,(data_a12d)
        ld de,0000eh
        add hl,de
        ld (data_a12d),hl
        ld hl,00000h
        call sub_a10dh
        ld de,(data_a12d)
        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,(data_a12c)
        add hl,de
        ld (data_a12c),hl
        ret

sub_a10dh:
        ld (data_a12f),hl
        ld (data_a131),de
        ret

sub_a115h:
        ld hl,(data_a12f)
        ld de,(data_a131)
        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
data_a12c:
        db 00h
data_a12d:
        db 84h,02h
data_a12f:
        db 00h,00h
data_a131:
        db 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 (pen_cmp+1),a
        ld bc,00000h
        ld (data_a24c),bc
        ld (data_a24e),bc
        call sub_a210
la18bh:
        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 (buffer_addr3+2),hl ;; +2 to skip ED,53
buffer_addr3:
        ld de,(055e0h)
        ld hl,(data_a24e)
sub_a1efh:
        ld bc,057e4h
        add hl,bc
        ld (buffer_addr4+1),hl ;; +1 to skip 22
buffer_addr4:
        ld hl,(05a2ch)
        ld (data_a257),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
pen_cmp:
        cp 000h
        jr nz,la248h
        ld (data_a250),hl
        ld (data_a252),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_a252)
        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_a252)
        ld (buffer_addr1+2),hl ;; +2 to skip ED, 53
buffer_addr1:
        ld (05648h),de
        ld hl,(data_a24c)
        ld bc,057e4h
        add hl,bc
        ld de,(data_a250)
        ld (buffer_addr+2),hl ;; +2 to skip ED, 53
buffer_addr2:
        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