Plug and Play BIOS Specification

Plug and Play BIOS Specification 1.0A Page 19
Reg On Entry Description
AX Provides an indication as to which vectors should be hooked by specifying the
type of boot device this device has been selected as.
Bit 7..3 Reserved(0)
Bit 2 1=Connect as IPL (INT 13h)
Bit 1 1=Connect as primary Video (INT 10h)
Bit 0 1=Connect as primary Input (INT 09h)
ES:DI Pointer to System BIOS PnP Installation Check Structure (See section 4.4)
BX CSN for this card, ISA PnP devices only. If not an ISA PnP device then this
parameter will be set to FFFFh.
DX Read Data Port, (ISA PnP devices only. If no ISA PnP devices then this
parameter will be set to FFFFh.
Disconnect Vector (Real/Protected mode) - This vector is used to perform a cleanup from an unsuccessful
boot attempt on an IPL device. The system ROM will execute a FAR CALL to this location on IPL
failure.
Bootstrap Entry Vector (Real/Protected mode) - This vector is used primarily for RPL (Remote Program
Load) support. To RPL (bootstrap), the System ROM will execute a FAR CALL to this location. The
System ROM will call the Real/Protected Mode Bootstrap Entry Vector instead of INT 19h if:
a) The device indicates that it may function as an IPL device,
b) The device indicates that it does not support the INT 13h Block Mode interface,
c) The device has a non-null Bootstrap Entry Vector,
d) The Real/Protected Mode Boot Connection Vector is null.
The method for supporting RPL is beyond the scope of this specification. A separate specification should
define the explicit requirements for supporting RPL devices.
Reserved - Reserved for Expansion
Static Resource Information Vector - This vector may be used by non-Plug and Play devices to report
static resource configuration information. Plug and Play devices should not support the Static Resource
Information Vector for reporting their configuration information. This vector should be callable both
before and/or after the option ROM has been initialized. The call interface for the Static Resource
Information Vector is as follows:
Entry: ES:DI Pointer to memory buffer to hold the device's static resource configuration information.
The buffer should be a minimum of 1024 bytes. This information should follow the
System Device Node data structure, except that the Device node number field should
always be set to 0, and the information returned should only specify the currently
allocated resources (Allocated resource configuration descriptor block) and not the
block of possible resources (Possible resource configuration descriptor block). The
Possible resource configuration descriptor block should only contain the END_TAG
resource descriptor to indicate that there are no alternative resource configuration
settings for this device because the resource configuration for this device is static. Refer
to the Plug and Play ISA Specification under the section labeled Plug and Play
Resources for more information about the resource descriptors. This data structure has
the following format: