HP Vectra Technical Reference Manual page 22

Calling 5TD-8105 Drivers
The following program example demonstrates accessing a typical STD-BIOS driver. The function
sets the position of the cursor on display page 0 to row 20, column 10. The function code (02H)
is passed in register AH. The row position, the column position, and the page number are passed
respectively in DH, DL, and BH.
MOV
MOV
MOV
MOV
INT
AH,02H
DH,14H
DL,OAH
BH,OH
10H
;Function number
;Row number (Row 20)
;Column number (Column 10)
;Page number
;Call Video driver
The STD-BIOS drivers support all industry standard BIOS functions. In addition, many of the
drivers have additional functions that support enhanced features. These functions are referred to
as 'HP extensions' throughout the remainder of this manual. These enhancements are accessed
through function code (06FH) of their respective driver. Most of these extended functions are
further divided into subfunctions. For example, the HP extended function for the Video driver has
six subfunctions which allow access to the enhanced features of the Multimode Video Display
Adapter. The function code (06FH) is placed in the AH register and the subfunction code in AL
for all HP extensions.
The following example uses HP extensions to turn off the cursor control pad on the keyboard.
MOV
MOV
MOV
INT
AH,6FH
AL,07H
BL,02H
16H
,. HP Function
" Switch Keyboard
; Disable CCP: Turn Cursor Control
; Pad Off
; Call Keyboard Driver
2.3.2 EX-BIOS Drivers
The EX-BIOS drivers provide a wide range of functions not found in the STD-BIOS drivers. The EX-
BIOS drivers are accessed through a single software interrupt vector. This interrupt (06FH) will be
referred to as INT HP_ENTRY. Due to the large number of EX-BIOS drivers, it would be
impossible to give each driver its own interrupt vector and still maintain industry standard
compatibility. Therefore, each driver is assigned its own number which is placed in the BP
register. This manual refers to these numbers by the names assigned in Appendix E.
ROM BIOS Overview 13