HP Vectra Technical Reference Manual page 243

On Entry: AH
=
F17_INIT (01 H)
DX
=
Port number (0, 1, 2, 3)
On Exit: AH
=
Printer port status (see table 7.8)
Registers Altered: AH
Example:
MOV AH, F17_INIT
INT INT_PRINTER
TEST AH,
0000001
a
F17_STATUS (AH
=
02H)
,. (AH
=
01H)
" Call printer driver (lNT 17H)
,. Test for error
This function returns the status of the specified parallel printer port.
On Entry: AH
=
F17_STATUS (02H)
DX
=
Port number (0, 1, 2, 3)
On Exit: AH
=
Printer port status (see table 7.8)
Registers Altered: AH
F17_INQUIRE (AX
=
6FOOH)
This subfunction determines whether arnot the extended EX-BIOS functions are available. If the
EX-BIOS functions are available, the BX register will be set to 4850H (which are the ASCII
characters 'HP').
On Entry: AX
=
F17_INQUIRE (6FOOH)
BX
=
Any value except 4850H ('HP')
On Exit: BX
=
'HP'
Registers Altered: AX, BX
Example:
MOV AX, F17_INQUIRE ; (AH
=
6FOOH)
XOR aX,ax ,. Clear out ax
INT INT_PRINTER ,. Call printer driver (lNT 17H)
CMP ax, 'HP' ,. Check?
JNE short
ERROR~O_EXTENDED_FUNCTIONS
234 Serial and Parrallel I/O