HP Vectra Technical Reference Manual page 439

Programmers may write drivers that implement functions and subfunctions that are not defined.
However, two guidelines should be observed when defining additional functions or subfunctions.
First, whenever possible, newly defined function or subfunction numbers should not conflict with
existing numbers. Secondly, function and subfunction numbers should be consistent between
drivers of the same class.
Table
G.2
EX-BIOS Driver Function Code
Summary
Function
Register
Subfunction
AH
AL
Definition
F_ISR
00
Responds to a logical Interrupt Service
Request (ISR).
F_SYSTEM
Executes one of several standard
subfunctions.
SF_INIT*
02
00
Starts the initialization of a driver.
SF_START
* 02 02
Completes the initialization process of the
driver.
SF_REPORT_STATE
02 04
Reports the state of the driver.
SF_VERSION_DESC*
02 06
Reports the revision number and datecode
of the driver.
SF_DEF--ATTR
02
08
Reports the default configuration of the
driver.
SF_GET--ATTR
02
OA
Reports the current configuration of the
driver.
SF_SET--ATTR
02
OC
Overrides the current configuration of the
driver.
SF__OPEN
02
OE
Reserves the driver for exclusive access.
Requests any resources required by the
driver.
SF_CLOSE
02 10
Releases the driver from exclusive access.
SF_TIMEOUT
02 12
Reports to the driver that a requested
timeout has occurred.
SF_INTERVAL
02 14
Reports to the driver that a requested 60 Hz
interval has expired.
SF_TEST
02
16
Periorms a hardware test.
430 Driver Writer's Guide