:ASM textmode
  MOV AX 0x03 #
  INT 0x10 #
  NEXT

0 VAR, textpageid
0 VAR, textpage
:t page! dup textpageid ! 12 << textpage ! ;

:ASM showpage
  POP AX
  MOV AH 0x05 #
  INT 0x10 #
  NEXT

:ASM movecursor ( xy -- )
  MOV BH textpageid @+
  MOV AH 0x02 #
  POP DX
  INT 0x10 #
  NEXT

:ASM cursorshape! ( shape -- )
  POP CX
  MOV AH 0x01 #
  INT 0x10 #
  NEXT

:t hidecursor 0x2607 cursorshape! ;
:t showcursor 0x0607 cursorshape! ;

0x0f VAR, textpen

80 CONST pagew
25 CONST pageh

0xb800 CONST TEXTMEM
: PREP-TEXTCOPY
  MOV ES t& TEXTMEM @+
  MOV AH textpen @+
  MOV DI textpage @+ ;

:ASM fill-page ( char -- )
  INT 3 #
  POP AX
  PREP-TEXTCOPY
  MOV CX pagew pageh * #
  REPZ STOSW
  NEXT

0 VAR, textpos
:t textx textpos @ 1 >> pagew % ;
:t texty textpos @ 1 >> pagew / ;
:t textx! texty pagew 1 << * + textpos ! ;
:t texty! pagew 1 << * textx + textpos ! ;
:t nextline texty 1+ pagew 1 << * textpos ! ;

: PREP-TEXTCOPY-XY
  PREP-TEXTCOPY
  ADD DI textpos @+ ;

:ASM draw-text ( s -- )
  MOV BX SI
  POP SI
  PREP-TEXTCOPY-XY
L: draw-next-char
  LODSB
  OR AL AL
  JZ 0 @>
  STOSW
  JMP draw-next-char
0 <:
  SUB DI textpage @+
  MOV textpos @+ DI
  MOV SI BX
  NEXT