Intel Extensible Firmware Interface - page 400

Extensible Firmware Interface Specification
382 12/12/00 Version 1.02
Table G-4. !PXE Structure Field Definitions (continued)
Identifier Value Description
S/W UNDI Fields
EntryPoint Varies S/W UNDI API entry point address. This is either a virtual address or an offset
from the start of the !PXE structure. Protocol drivers will push the 64-bit virtual
address of a CDB on the stack and then call the UNDI API entry point. When
control is returned to the protocol driver, the protocol driver must remove the
address of the CDB from the stack.
reserved Zero Reserved for future use.
BusTypeCnt Varies This field is the count of four byte BusType entries in the next field.
BusType Varies This field defines the type of bus S/W UNDI is written to support:
“PCIR”, “PCCR”, “USBR” or “1394”. This field is formatted like the Signature
field. If the S/W UNDI supports more than one BusType there will be more
than one BusType identifier in this field.