IBM PC CONVERTIBLE Technical Reference page 106

ASCI I TELETYPE ROUTINE FOR OUTPUT
(AH)=OEH WRITE TELETYPE TO ACTIVE PAGE
(AL) = CHAR TO WRITE
(BL) = FOREGROUND COLOR I N GRAPH I CS MODE
NOTE --SCREEN WIDTH IS CTRLLED BY PREVIOUS MODE SET
(AH)=OFH CURRENT VIDEO STATE
RETURNS THE CURRENT VIDEO STATE
ON EXIT:
(AL) = MODE CURRENTLY SET ( SEE AH=O FOR EXPL
(AH) = NUMBER OF CHARACTER COLUMNS ON SCREEN
(BH) = CURRENT ACTIVE DISPLAY PAGE
(AH)=lOH RESERVED - NO OPERATION
(AH) =llH RESERVED - NO OPERATION
(AH)=12H RESERVED - NO OPERATION
(AH)=13H WRITE STRING
(ES:BP) = POINTER TO STRING TO BE WRITTEN
(CX) = LENGTH OF CHARACER STRING TO WRITTEN
IF CX = 0 NO OPERATION
(OX) = CURSOR POSITION FOR STRING TO BE WRITTEN
(BH) = PAGE NUMBER
(AL)
0
WRITE CHARACTER STRING
BL - ATTRIBUTE
STRING IS {CHAR,CHAR, ... ,CHAR}
CURSOR NOT MOV ED
(AL)
=
1
WRITE CHARACTER STRING AND MOVE CURSOR
BL - ATTRI BUTE
STRING IS {CHAR,CHAR, ... ,CHAR}
CURSOR IS MOVED
(AL)
=
2
WRITE CHARACTER AND ATTRI BUTE STRING
STRING IS {CHAR,ATTR,CHAR,ATTR.. ,CHAR,ATTR}
CURSOR IS NOT MOVED
(AL)
=
3
WRITE CHARACTER AND ATTR STRING AND MOVE CURSO
STRING IS {CHAR,ATTR,CHAR,ATTR.. ,CHAR,ATTR}
CURSOR IS MOVED
(AL)
=
4 - 255
NO OP ERA TI ON
NOTE: CARRIAGE RETURN, LINE FEED, BACKSPACE, AND BELL ARE
TREATED AS COMMANDS RATHER THAN PRINTABLE CHARACTERS.
ROM BIOS 2-81