Intel Extensible Firmware Interface, Specification

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32/64-bit UNDI Specification
Version 1.02 12/12/00 419
G.4.2.1 Issuing the Command
To issue a Get State command, create a CDB and fill it in as shows in the table below:
CDB Field How to initialize the CDB structure for a Get State command
OpCode PXE_OPCODE_GET_STATE
OpFlags PXE_OPFLAGS_NOT_USED
CPBsize PXE_CPBSIZE_NOT_USED
DBsize
PXE_DBSIZE_NOT_USED
CPBaddr PXE_CPBADDR_NOT_USED
DBaddr PXE_DBADDR_NOT_USED
StatCode PXE_STATCODE_INITIALIZE
StatFlags PXE_STATFLAGS_INITIALIZE
IFnum
A valid interface number from zero to
!PXE.IFcnt
.
Control Set as needed.
G.4.2.2 Waiting for the Command to Execute
Monitor the upper two bits (14 & 15) in the
CDB.StatFlags
field. Until these bits change to
report
PXE_STATFLAGS_COMMAND_COMPLETE
or
PXE_STATFLAGS_COMMAND_FAILED
,
the command has not been executed by the UNDI.
StatFlags Reason
COMMAND_COMPLETE Command completed successfully. StatFlags contain operational state.
COMMAND_FAILED Command failed. StatCode field contains error code.
COMMAND_QUEUED Command has been queued. All other fields are unchanged.
INITIALIZE Command has not been executed or queued.
G.4.2.3 Checking Command Execution Results
After command execution completes, either successfully or not, the
CDB.StatCode
field
contains the result of the command execution.
StatCode Reason
SUCCESS Command completed successfully. StatFlags contain operational state.
INVALID_CDB One of the CDB fields was not set correctly.
BUSY UNDI is already processing commands. Try again later.
QUEUE_FULL Command queue is full. Try again later.
If the command completes successfully, use
PXE_STATFLAGS_GET_STATE_MASK
to check the
state of the UNDI.
StatFlags Reason
STOPPED The UNDI is stopped.
STARTED The UNDI is started, but not initialized.
INITIALIZED The UNDI is initialized.