s_PXE Struct Reference
[PXE entry points]

The !PXE structure. More...

#include <pxe_api.h>

Data Fields
UINT8_t	Signature [4]
	Signature.
UINT8_t	StructLength
	Length of this structure.
UINT8_t	StructCksum
	Checksum.
UINT8_t	StructRev
	Revision of this structure.
UINT8_t	reserved_1
	Must be zero.
SEGOFF16_t	UNDIROMID
	Address of the UNDI ROM ID structure.
SEGOFF16_t	BaseROMID
	Address of the Base Code ROM ID structure.
SEGOFF16_t	EntryPointSP
	16-bit !PXE entry point
SEGOFF16_t	EntryPointESP
	32-bit !PXE entry point
SEGOFF16_t	StatusCallout
	Status call-out function.
UINT8_t	reserved_2
	Must be zero.
UINT8_t	SegDescCnt
	Number of segment descriptors.
SEGSEL_t	FirstSelector
	First protected-mode selector.
SEGDESC_t	Stack
	Stack segment descriptor.
SEGDESC_t	UNDIData
	UNDI data segment descriptor.
SEGDESC_t	UNDICode
	UNDI code segment descriptor.
SEGDESC_t	UNDICodeWrite
	UNDI writable code segment descriptor.
SEGDESC_t	BC_Data
	Base-code data segment descriptor.
SEGDESC_t	BC_Code
	Base-code code segment descriptor.
SEGDESC_t	BC_CodeWrite
	Base-code writable code segment descriptor.

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Detailed Description

The !PXE structure.

Definition at line 124 of file pxe_api.h.

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Field Documentation

UINT8_t s_PXE::Signature[4]

Signature.

Contains the bytes '!', 'P', 'X', 'E'.

Definition at line 129 of file pxe_api.h.

UINT8_t s_PXE::StructLength

Length of this structure.

Definition at line 130 of file pxe_api.h.

UINT8_t s_PXE::StructCksum

Checksum.

The byte checksum of this structure (using the length in StructLength) must be zero.

Definition at line 136 of file pxe_api.h.

UINT8_t s_PXE::StructRev

Revision of this structure.

For PXE version 2.1, this field must be zero.

Definition at line 141 of file pxe_api.h.

UINT8_t s_PXE::reserved_1

Must be zero.

Definition at line 142 of file pxe_api.h.

SEGOFF16_t s_PXE::UNDIROMID

Address of the UNDI ROM ID structure.

This is a pointer to a struct s_UNDI_ROM_ID.

Definition at line 147 of file pxe_api.h.

SEGOFF16_t s_PXE::BaseROMID

Address of the Base Code ROM ID structure.

This is a pointer to a struct s_BC_ROM_ID.

Definition at line 152 of file pxe_api.h.

SEGOFF16_t s_PXE::EntryPointSP

16-bit !PXE entry point

This is the entry point for either real mode, or protected mode with a 16-bit stack segment.

Definition at line 158 of file pxe_api.h.

Referenced by undi_load().

SEGOFF16_t s_PXE::EntryPointESP

32-bit !PXE entry point

This is the entry point for protected mode with a 32-bit stack segment.

Definition at line 164 of file pxe_api.h.

SEGOFF16_t s_PXE::StatusCallout

Status call-out function.

Parameters:

	0	(if in a time-out loop)
	n	Number of a received TFTP packet

Return values:

	0	Continue operation
	1	Cancel operation

This function will be called whenever the PXE stack is in protected mode, is waiting for an event (e.g. a DHCP reply) and wishes to allow the user to cancel the operation. Parameters are passed in register ax; the return value must also be placed in register ax. All other registers and flags must be preserved.

In real mode, an internal function (that checks for a keypress) will be used.

If this field is set to -1, no status call-out function will be used and consequently the user will not be allowed to interrupt operations.

Note:

The PXE specification version 2.1 defines the StatusCallout field, mentions it 11 times, but nowhere defines what it actually does or how it gets called. Fortunately, the WfM specification version 1.1a deigns to inform us of such petty details.

Definition at line 192 of file pxe_api.h.

UINT8_t s_PXE::reserved_2

Must be zero.

Definition at line 193 of file pxe_api.h.

UINT8_t s_PXE::SegDescCnt

Number of segment descriptors.

If this number is greater than 7, the remaining descriptors follow immediately after BC_CodeWrite.

Definition at line 199 of file pxe_api.h.

SEGSEL_t s_PXE::FirstSelector

First protected-mode selector.

This is the segment selector value for the first segment assigned to PXE. Protected-mode selectors must be consecutive, according to the PXE 2.1 specification, though no reason is given. Each SEGDESC_t includes a field for the segment selector, so this information is entirely redundant.

Definition at line 209 of file pxe_api.h.

SEGDESC_t s_PXE::Stack

Stack segment descriptor.

Definition at line 211 of file pxe_api.h.

SEGDESC_t s_PXE::UNDIData

UNDI data segment descriptor.

Definition at line 213 of file pxe_api.h.

SEGDESC_t s_PXE::UNDICode

UNDI code segment descriptor.

Definition at line 215 of file pxe_api.h.

SEGDESC_t s_PXE::UNDICodeWrite

UNDI writable code segment descriptor.

Definition at line 217 of file pxe_api.h.

SEGDESC_t s_PXE::BC_Data

Base-code data segment descriptor.

Definition at line 219 of file pxe_api.h.

SEGDESC_t s_PXE::BC_Code

Base-code code segment descriptor.

Definition at line 221 of file pxe_api.h.

SEGDESC_t s_PXE::BC_CodeWrite

Base-code writable code segment descriptor.

Definition at line 223 of file pxe_api.h.

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The documentation for this struct was generated from the following file:

• arch/i386/include/pxe_api.h