HP Vectra Technical Reference Manual page 440

Function Register
Subfunction AH
AL
Definition
F_IO_CONTROL Executes the following subfunctions and any
driver dependant subfunctions.
SF_LOCK
04
00
Reserves the sub-address device specified for
exclusive access.
SF_UNLOCK
()4
02
Releases the sub-address specified from the
exclusive access.
F_PUT_BYTE
06
Writes a byte of data.
F_GET_BYTE ()8 Reads a byte of data.
F_PUT_BUFFER
OA
Writes a variable length buffer of data
(supported by character devices).
F_PUT_BLOCK
OA
Writes a fixed length buffer of data
(supported by block devices).
F_GET_BUFFER
DC
Reads a variable length buffer of data
(supported by character devices).
F_GET_BLOCK
OC
Reads a fixed length block of data
(supported by block devices).
F_PUT_WORD
DE
Writes a word of data.
F_GET_WORD
10
Reads a word of data.
Note: Functions marked with an asterisk (*) should be supported by all drivers. These functions
may perform no useful function. However, they should return a status code of RS_DONE or
RS_SUCCESSFUL as opposed to HS_UNSUPPORTED.
The following is a list of predefined driver function codes and a brief description of their purpose
and parameters:
EX-BIOS Driver Function Definitions
F_ISR (AH
=
OOH)
This function processes either a logical or a physical interrupt event. It reports whether or not it
handled the event through its Return Status Code (see table G.2). The driver may require the
service of its parent driver to handle the interrupt.
Driver Writer's Guide 431