pxe: clean up C code; reimplement "Plan C"; share PXE API definitions

Minor cleanups to the C code.
Reimplement "Plan C" for finding the entry point.
Share the PXE API definitions between com32 and the core.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

5 files changed, 695 insertions, 755 deletions

diff --git a/com32/include/syslinux/pxe.h b/com32/include/syslinux/pxe.h
index 037642bc..041e0ae1 100644
--- a/com32/include/syslinux/pxe.h
+++ b/com32/include/syslinux/pxe.h
@@ -34,493 +34,10 @@
 #ifndef _SYSLINUX_PXE_H
 #define _SYSLINUX_PXE_H
 
-#include <stdint.h>
-#include <netinet/in.h>
-#include <klibc/compiler.h>
-
-/* PXE spec structures and definitions.  These mostly follow the PXE
-   spec, except when the PXE spec is unnecessarily stupid.  Of course,
-   that is most of the time. */
-
-/* Basic types; use Unix-like _t convention instead of SCREAMING; also
-   re-use types we already have, like in_addr_t. */
-
-typedef uint16_t pxenv_status_t;
-
-#define MAC_ADDR_LEN	16
-typedef uint8_t mac_addr_t[MAC_ADDR_LEN];
-
-/* "Protected mode segment descriptor" according to PXE... */
-typedef struct {
-    uint16_t segaddr;
-    uint32_t physaddr;
-    uint16_t segsize;
-} __packed pxe_segdesc_t;
-
-typedef struct {
-    uint16_t offs;
-    uint16_t seg;
-} segoff16_t;
-
-typedef struct {
-    uint8_t opcode;
-#define BOOTP_REQ 1
-#define BOOTP_REP 2
-    uint8_t Hardware;
-    uint8_t Hardlen;
-    uint8_t Gatehops;
-    uint32_t ident;
-    uint16_t seconds;
-    uint16_t Flags;
-#define BOOTP_BCAST 0x8000
-    in_addr_t cip;		/* Client IP address */
-    in_addr_t yip;		/* You IP address */
-    in_addr_t sip;		/* next server IP address */
-    in_addr_t gip;		/*relay agent IP address */
-    mac_addr_t CAddr;
-    uint8_t Sname[64];
-    uint8_t bootfile[128];
-    union {
-#define BOOTP_DHCPVEND 1024
-	uint8_t d[BOOTP_DHCPVEND];
-	struct {
-	    uint8_t magic[4];
-#define VM_RFC1048 0x63825363L
-	    uint32_t flags;
-	    uint8_t pad[56];
-	} v;
-    } vendor;
-} __packed pxe_bootp_t;
-
-/* Function calling structures and constants */
-
-typedef struct s_PXENV_GET_CACHED_INFO {
-    pxenv_status_t Status;
-    uint16_t PacketType;
-#define PXENV_PACKET_TYPE_DHCP_DISCOVER 1
-#define PXENV_PACKET_TYPE_DHCP_ACK 2
-#define PXENV_PACKET_TYPE_CACHED_REPLY 3
-    uint16_t BufferSize;
-    segoff16_t Buffer;
-    uint16_t BufferLimit;
-} __packed t_PXENV_GET_CACHED_INFO;
-
-typedef struct s_PXENV_START_UNDI {
-    pxenv_status_t Status;
-    uint16_t AX;
-    uint16_t BX;
-    uint16_t DX;
-    uint16_t DI;
-    uint16_t ES;
-} __packed t_PXENV_START_UNDI;
-
-typedef struct s_PXENV_STOP_UNDI {
-    pxenv_status_t Status;
-} __packed t_PXENV_STOP_UNDI;
-
-typedef struct s_PXENV_START_BASE {
-    pxenv_status_t Status;
-} __packed t_PXENV_START_BASE;
-
-typedef struct s_PXENV_STOP_BASE {
-    pxenv_status_t Status;
-} __packed t_PXENV_STOP_BASE;
-
-typedef struct s_PXENV_TFTP_OPEN {
-    pxenv_status_t Status;
-    in_addr_t ServerIPAddress;
-    in_addr_t GatewayIPAddress;
-    uint8_t FileName[128];
-    in_port_t TFTPPort;
-    uint16_t PacketSize;
-} __packed t_PXENV_TFTP_OPEN;
-
-typedef struct s_PXENV_TFTP_CLOSE {
-    pxenv_status_t Status;
-} __packed t_PXENV_TFTP_CLOSE;
-
-typedef struct s_PXENV_TFTP_READ {
-    pxenv_status_t Status;
-    uint16_t PacketNumber;
-    uint16_t BufferSize;
-    segoff16_t Buffer;
-} __packed t_PXENV_TFTP_READ;
-
-typedef struct s_PXENV_TFTP_READ_FILE {
-    pxenv_status_t Status;
-    uint8_t FileName[128];
-    uint32_t BufferSize;
-    void *Buffer;
-    in_addr_t ServerIPAddress;
-    in_addr_t GatewayIPAddress;
-    in_addr_t McastIPAddress;
-    in_port_t TFTPClntPort;
-    in_port_t TFTPSrvPort;
-    uint16_t TFTPOpenTimeOut;
-    uint16_t TFTPReopenDelay;
-} __packed t_PXENV_TFTP_READ_FILE;
-
-typedef struct s_PXENV_TFTP_GET_FSIZE {
-    pxenv_status_t Status;
-    in_addr_t ServerIPAddress;
-    in_addr_t GatewayIPAddress;
-    uint8_t FileName[128];
-    uint32_t FileSize;
-} __packed t_PXENV_TFTP_GET_FSIZE;
-
-typedef struct s_PXENV_UDP_OPEN {
-    pxenv_status_t status;
-    in_addr_t src_ip;
-} __packed t_PXENV_UDP_OPEN;
-
-typedef struct s_PXENV_UDP_CLOSE {
-    pxenv_status_t status;
-} __packed t_PXENV_UDP_CLOSE;
-
-typedef struct s_PXENV_UDP_WRITE {
-    pxenv_status_t status;
-    in_addr_t ip;
-    in_addr_t gw;
-    in_port_t src_port;
-    in_port_t dst_port;
-    uint16_t buffer_size;
-    segoff16_t buffer;
-} __packed t_PXENV_UDP_WRITE;
-
-typedef struct s_PXENV_UDP_READ {
-    pxenv_status_t status;
-    in_addr_t src_ip;
-    in_addr_t dest_ip;
-    in_port_t s_port;
-    in_port_t d_port;
-    uint16_t buffer_size;
-    segoff16_t buffer;
-} __packed t_PXENV_UDP_READ;
-
-typedef struct s_PXENV_UNDI_STARTUP {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_STARTUP;
-
-typedef struct s_PXENV_UNDI_CLEANUP {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_CLEANUP;
-
-typedef struct s_PXENV_UNDI_INITIALIZE {
-    pxenv_status_t Status;
-    void *ProtocolIni;
-    uint8_t reserved[8];
-} __packed t_PXENV_UNDI_INITIALIZE;
-
-#define MAXNUM_MCADDR 8
-typedef struct s_PXENV_UNDI_MCAST_ADDRESS {
-    uint16_t MCastAddrCount;
-    mac_addr_t McastAddr[MAXNUM_MCADDR];
-} __packed t_PXENV_UNDI_MCAST_ADDRESS;
-
-typedef struct s_PXENV_UNDI_RESET {
-    pxenv_status_t Status;
-    t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
-} __packed t_PXENV_UNDI_RESET;
-
-typedef struct s_PXENV_UNDI_SHUTDOWN {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_SHUTDOWN;
-
-typedef struct s_PXENV_UNDI_OPEN {
-    pxenv_status_t Status;
-    uint16_t OpenFlag;
-    uint16_t PktFilter;
-#define FLTR_DIRECTED 0x0001
-#define FLTR_BRDCST 0x0002
-#define FLTR_PRMSCS 0x0004
-#define FLTR_SRC_RTG 0x0008
-     t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
-} __packed t_PXENV_UNDI_OPEN;
-
-typedef struct s_PXENV_UNDI_CLOSE {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_CLOSE;
-
-typedef struct s_PXENV_UNDI_TRANSMIT {
-    pxenv_status_t Status;
-    uint8_t Protocol;
-#define P_UNKNOWN 0
-#define P_IP 1
-#define P_ARP 2
-#define P_RARP 3
-    uint8_t XmitFlag;
-#define XMT_DESTADDR 0x0000
-#define XMT_BROADCAST 0x0001
-    segoff16_t DestAddr;
-    segoff16_t TBD;
-    uint32_t Reserved[2];
-} __packed t_PXENV_UNDI_TRANSMIT;
-#define MAX_DATA_BLKS 8
-typedef struct s_PXENV_UNDI_TBD {
-    uint16_t ImmedLength;
-    segoff16_t Xmit;
-    uint16_t DataBlkCount;
-    struct DataBlk {
-	uint8_t TDPtrType;
-	uint8_t TDRsvdByte;
-	uint16_t TDDataLen;
-	segoff16_t TDDataPtr;
-    } DataBlock[MAX_DATA_BLKS];
-} __packed t_PXENV_UNDI_TBD;
-
-typedef struct s_PXENV_UNDI_SET_MCAST_ADDRESS {
-    pxenv_status_t Status;
-     t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
-} __packed t_PXENV_UNDI_SET_MCAST_ADDR;
-
-typedef struct s_PXENV_UNDI_SET_STATION_ADDRESS {
-    pxenv_status_t Status;
-    mac_addr_t StationAddress;
-} __packed t_PXENV_UNDI_SET_STATION_ADDR;
-
-typedef struct s_PXENV_UNDI_SET_PACKET_FILTER {
-    pxenv_status_t Status;
-    uint8_t filter;
-} __packed t_PXENV_UNDI_SET_PACKET_FILTER;
-
-typedef struct s_PXENV_UNDI_GET_INFORMATION {
-    pxenv_status_t Status;
-    uint16_t BaseIo;
-    uint16_t IntNumber;
-    uint16_t MaxTranUnit;
-    uint16_t HwType;
-#define ETHER_TYPE 1
-#define EXP_ETHER_TYPE 2
-#define IEEE_TYPE 6
-#define ARCNET_TYPE 7
-    uint16_t HwAddrLen;
-    mac_addr_t CurrentNodeAddress;
-    mac_addr_t PermNodeAddress;
-    uint16_t ROMAddress;
-    uint16_t RxBufCt;
-    uint16_t TxBufCt;
-} __packed t_PXENV_UNDI_GET_INFORMATION;
-
-typedef struct s_PXENV_UNDI_GET_STATISTICS {
-    pxenv_status_t Status;
-    uint32_t XmtGoodFrames;
-    uint32_t RcvGoodFrames;
-    uint32_t RcvCRCErrors;
-    uint32_t RcvResourceErrors;
-} __packed t_PXENV_UNDI_GET_STATISTICS;
-
-typedef struct s_PXENV_UNDI_CLEAR_STATISTICS {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_CLEAR_STATISTICS;
-
-typedef struct s_PXENV_UNDI_INITIATE_DIAGS {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_INITIATE_DIAGS;
-
-typedef struct s_PXENV_UNDI_FORCE_INTERRUPT {
-    pxenv_status_t Status;
-} __packed t_PXENV_UNDI_FORCE_INTERRUPT;
-
-typedef struct s_PXENV_UNDI_GET_MCAST_ADDRESS {
-    pxenv_status_t Status;
-    in_addr_t InetAddr;
-    mac_addr_t MediaAddr;
-} __packed t_PXENV_UNDI_GET_MCAST_ADDR;
-
-typedef struct s_PXENV_UNDI_GET_NIC_TYPE {
-    pxenv_status_t Status;
-    uint8_t NicType;
-#define PCI_NIC 2
-#define PnP_NIC 3
-#define CardBus_NIC 4
-    union {
-	struct {
-	    uint16_t Vendor_ID;
-	    uint16_t Dev_ID;
-	    uint8_t Base_Class;
-	    uint8_t Sub_Class;
-	    uint8_t Prog_Intf;
-	    uint8_t Rev;
-	    uint16_t BusDevFunc;
-	    uint16_t SubVendor_ID;
-	    uint16_t SubDevice_ID;
-	} pci, cardbus;
-	struct {
-	    uint32_t EISA_Dev_ID;
-	    uint8_t Base_Class;
-	    uint8_t Sub_Class;
-	    uint8_t Prog_Intf;
-	    uint16_t CardSelNum;
-	} __packed pnp;
-    } __packed info;
-} __packed t_PXENV_UNDI_GET_NIC_TYPE;
-
-typedef struct s_PXENV_UNDI_GET_IFACE_INFO {
-    pxenv_status_t Status;
-    uint8_t IfaceType[16];
-    uint32_t LinkSpeed;
-    uint32_t ServiceFlags;
-    uint32_t Reserved[4];
-} __packed t_PXENV_UNDI_GET_NDIS_INFO;
-
-typedef struct s_PXENV_UNDI_GET_STATE {
-#define PXE_UNDI_GET_STATE_STARTED 1
-#define PXE_UNDI_GET_STATE_INITIALIZED 2
-#define PXE_UNDI_GET_STATE_OPENED 3
-    pxenv_status_t Status;
-    uint8_t UNDIstate;
-} __packed t_PXENV_UNDI_GET_STATE;
-
-typedef struct s_PXENV_UNDI_ISR {
-    pxenv_status_t Status;
-    uint16_t FuncFlag;
-    uint16_t BufferLength;
-    uint16_t FrameLength;
-    uint16_t FrameHeaderLength;
-    segoff16_t Frame;
-    uint8_t ProtType;
-    uint8_t PktType;
-} __packed t_PXENV_UNDI_ISR;
-#define PXENV_UNDI_ISR_IN_START 1
-#define PXENV_UNDI_ISR_IN_PROCESS 2
-#define PXENV_UNDI_ISR_IN_GET_NEXT 3
-/* One of these will be returned for
-   PXENV_UNDI_ISR_IN_START */
-#define PXENV_UNDI_ISR_OUT_OURS 0
-#define PXENV_UNDI_USR_OUT_NOT_OURS 1
-/* One of these will be returned for
-   PXENV_UNDI_ISR_IN_PROCESS and
-   PXENV_UNDI_ISR_IN_GET_NEXT */
-#define PXENV_UNDI_ISR_OUT_DONE 0
-#define PXENV_UNDI_ISR_OUT_TRANSMIT 2
-#define PXENV_UNDI_ISR_OUT_RECEIVE 3
-#define PXENV_UNDI_ISR_OUT_BUSY 4
-
-/* Function numbers and error codes */
-
-#define PXENV_TFTP_OPEN			0x0020
-#define PXENV_TFTP_CLOSE		0x0021
-#define PXENV_TFTP_READ			0x0022
-#define PXENV_TFTP_READ_FILE		0x0023
-#define PXENV_TFTP_READ_FILE_PMODE	0x0024
-#define PXENV_TFTP_GET_FSIZE		0x0025
-
-#define PXENV_UDP_OPEN			0x0030
-#define PXENV_UDP_CLOSE			0x0031
-#define PXENV_UDP_READ			0x0032
-#define PXENV_UDP_WRITE			0x0033
-
-#define PXENV_START_UNDI		0x0000
-#define PXENV_UNDI_STARTUP		0x0001
-#define PXENV_UNDI_CLEANUP		0x0002
-#define PXENV_UNDI_INITIALIZE		0x0003
-#define PXENV_UNDI_RESET_NIC		0x0004
-#define PXENV_UNDI_SHUTDOWN		0x0005
-#define PXENV_UNDI_OPEN			0x0006
-#define PXENV_UNDI_CLOSE		0x0007
-#define PXENV_UNDI_TRANSMIT		0x0008
-#define PXENV_UNDI_SET_MCAST_ADDR	0x0009
-#define PXENV_UNDI_SET_STATION_ADDR	0x000A
-#define PXENV_UNDI_SET_PACKET_FILTER	0x000B
-#define PXENV_UNDI_GET_INFORMATION	0x000C
-#define PXENV_UNDI_GET_STATISTICS	0x000D
-#define PXENV_UNDI_CLEAR_STATISTICS	0x000E
-#define PXENV_UNDI_INITIATE_DIAGS	0x000F
-#define PXENV_UNDI_FORCE_INTERRUPT	0x0010
-#define PXENV_UNDI_GET_MCAST_ADDR	0x0011
-#define PXENV_UNDI_GET_NIC_TYPE		0x0012
-#define PXENV_UNDI_GET_IFACE_INFO	0x0013
-#define PXENV_UNDI_ISR			0x0014
-#define	PXENV_STOP_UNDI			0x0015	/* Overlap...? */
-#define PXENV_UNDI_GET_STATE		0x0015	/* Overlap...? */
-
-#define PXENV_UNLOAD_STACK		0x0070
-#define PXENV_GET_CACHED_INFO		0x0071
-#define PXENV_RESTART_DHCP		0x0072
-#define PXENV_RESTART_TFTP		0x0073
-#define PXENV_MODE_SWITCH		0x0074
-#define PXENV_START_BASE		0x0075
-#define PXENV_STOP_BASE			0x0076
-
-#define PXENV_EXIT_SUCCESS 0x0000
-#define PXENV_EXIT_FAILURE 0x0001
-
-#define PXENV_STATUS_SUCCESS 0x00
-#define PXENV_STATUS_FAILURE 0x01
-#define PXENV_STATUS_BAD_FUNC 0x02
-#define PXENV_STATUS_UNSUPPORTED 0x03
-#define PXENV_STATUS_KEEP_UNDI 0x04
-#define PXENV_STATUS_KEEP_ALL 0x05
-#define PXENV_STATUS_OUT_OF_RESOURCES 0x06
-#define PXENV_STATUS_ARP_TIMEOUT 0x11
-#define PXENV_STATUS_UDP_CLOSED 0x18
-#define PXENV_STATUS_UDP_OPEN 0x19
-#define PXENV_STATUS_TFTP_CLOSED 0x1A
-#define PXENV_STATUS_TFTP_OPEN 0x1B
-#define PXENV_STATUS_MCOPY_PROBLEM 0x20
-#define PXENV_STATUS_BIS_INTEGRITY_FAILURE 0x21
-#define PXENV_STATUS_BIS_VALIDATE_FAILURE 0x22
-#define PXENV_STATUS_BIS_INIT_FAILURE 0x23
-#define PXENV_STATUS_BIS_SHUTDOWN_FAILURE 0x24
-#define PXENV_STATUS_BIS_GBOA_FAILURE 0x25
-#define PXENV_STATUS_BIS_FREE_FAILURE 0x26
-#define PXENV_STATUS_BIS_GSI_FAILURE 0x27
-#define PXENV_STATUS_BIS_BAD_CKSUM 0x28
-#define PXENV_STATUS_TFTP_CANNOT_ARP_ADDRESS 0x30
-#define PXENV_STATUS_TFTP_OPEN_TIMEOUT 0x32
-
-#define PXENV_STATUS_TFTP_UNKNOWN_OPCODE 0x33
-#define PXENV_STATUS_TFTP_READ_TIMEOUT 0x35
-#define PXENV_STATUS_TFTP_ERROR_OPCODE 0x36
-#define PXENV_STATUS_TFTP_CANNOT_OPEN_CONNECTION 0x38
-#define PXENV_STATUS_TFTP_CANNOT_READ_FROM_CONNECTION 0x39
-#define PXENV_STATUS_TFTP_TOO_MANY_PACKAGES 0x3A
-#define PXENV_STATUS_TFTP_FILE_NOT_FOUND 0x3B
-#define PXENV_STATUS_TFTP_ACCESS_VIOLATION 0x3C
-#define PXENV_STATUS_TFTP_NO_MCAST_ADDRESS 0x3D
-#define PXENV_STATUS_TFTP_NO_FILESIZE 0x3E
-#define PXENV_STATUS_TFTP_INVALID_PACKET_SIZE 0x3F
-#define PXENV_STATUS_DHCP_TIMEOUT 0x51
-#define PXENV_STATUS_DHCP_NO_IP_ADDRESS 0x52
-#define PXENV_STATUS_DHCP_NO_BOOTFILE_NAME 0x53
-#define PXENV_STATUS_DHCP_BAD_IP_ADDRESS 0x54
-#define PXENV_STATUS_UNDI_INVALID_FUNCTION 0x60
-#define PXENV_STATUS_UNDI_MEDIATEST_FAILED 0x61
-#define PXENV_STATUS_UNDI_CANNOT_INIT_NIC_FOR_MCAST 0x62
-#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_NIC 0x63
-#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_PHY 0x64
-#define PXENV_STATUS_UNDI_CANNOT_READ_CONFIG_DATA 0x65
-#define PXENV_STATUS_UNDI_CANNOT_READ_INIT_DATA 0x66
-#define PXENV_STATUS_UNDI_BAD_MAC_ADDRESS 0x67
-#define PXENV_STATUS_UNDI_BAD_EEPROM_CHECKSUM 0x68
-#define PXENV_STATUS_UNDI_ERROR_SETTING_ISR 0x69
-#define PXENV_STATUS_UNDI_INVALID_STATE 0x6A
-#define PXENV_STATUS_UNDI_TRANSMIT_ERROR 0x6B
-#define PXENV_STATUS_UNDI_INVALID_PARAMETER 0x6C
-#define PXENV_STATUS_BSTRAP_PROMPT_MENU 0x74
-#define PXENV_STATUS_BSTRAP_MCAST_ADDR 0x76
-#define PXENV_STATUS_BSTRAP_MISSING_LIST 0x77
-#define PXENV_STATUS_BSTRAP_NO_RESPONSE 0x78
-#define PXENV_STATUS_BSTRAP_FILE_TOO_BIG 0x79
-#define PXENV_STATUS_BINL_CANCELED_BY_KEYSTROKE 0xA0
-#define PXENV_STATUS_BINL_NO_PXE_SERVER 0xA1
-#define PXENV_STATUS_NOT_AVAILABLE_IN_PMODE 0xA2
-#define PXENV_STATUS_NOT_AVAILABLE_IN_RMODE 0xA3
-#define PXENV_STATUS_BUSD_DEVICE_NOT_SUPPORTED 0xB0
-#define PXENV_STATUS_LOADER_NO_FREE_BASE_MEMORY 0xC0
-#define PXENV_STATUS_LOADER_NO_BC_ROMID 0xC1
-#define PXENV_STATUS_LOADER_BAD_BC_ROMID 0xC2
-#define PXENV_STATUS_LOADER_BAD_BC_RUNTIME_IMAGE 0xC3
-#define PXENV_STATUS_LOADER_NO_UNDI_ROMID 0xC4
-#define PXENV_STATUS_LOADER_BAD_UNDI_ROMID 0xC5
-#define PXENV_STATUS_LOADER_BAD_UNDI_DRIVER_IMAGE 0xC6
-#define PXENV_STATUS_LOADER_NO_PXE_STRUCT 0xC8
-#define PXENV_STATUS_LOADER_NO_PXENV_STRUCT 0xC9
-#define PXENV_STATUS_LOADER_UNDI_START 0xCA
-#define PXENV_STATUS_LOADER_BC_START 0xCB
+#include <syslinux/pxe_api.h>
 
 /* SYSLINUX-defined PXE utility functions */
-int pxe_get_cached_info(int level, void **buf, size_t * len);
+int pxe_get_cached_info(int level, void **buf, size_t *len);
 int pxe_get_nic_type(t_PXENV_UNDI_GET_NIC_TYPE * gnt);
 
 #endif /* _SYSLINUX_PXE_H */
diff --git a/com32/include/syslinux/pxe_api.h b/com32/include/syslinux/pxe_api.h
new file mode 100644
index 00000000..5fd102ef
--- /dev/null
+++ b/com32/include/syslinux/pxe_api.h
@@ -0,0 +1,531 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux/pxe_api.h
+ *
+ * PXE type and constant definitions for SYSLINUX
+ */
+
+#ifndef _SYSLINUX_PXE_API_H
+#define _SYSLINUX_PXE_API_H
+
+#include <stdint.h>
+#include <netinet/in.h>
+#include <klibc/compiler.h>
+#include <com32.h>
+
+/* PXE spec structures and definitions.  These mostly follow the PXE
+   spec, except when the PXE spec is unnecessarily stupid.  Of course,
+   that is most of the time. */
+
+/* Basic types; use Unix-like _t convention instead of SCREAMING; also
+   re-use types we already have, like in_addr_t. */
+
+typedef uint16_t pxenv_status_t;
+
+#define MAC_ADDR_LEN	16
+typedef uint8_t mac_addr_t[MAC_ADDR_LEN];
+
+/* "Protected mode segment descriptor" according to PXE... */
+typedef struct {
+    uint16_t sel;
+    uint32_t base;
+    uint16_t size;
+} __packed pxe_segdesc_t;
+
+typedef far_ptr_t segoff16_t;
+
+typedef struct {
+    uint8_t opcode;
+#define BOOTP_REQ 1
+#define BOOTP_REP 2
+    uint8_t Hardware;
+    uint8_t Hardlen;
+    uint8_t Gatehops;
+    uint32_t ident;
+    uint16_t seconds;
+    uint16_t Flags;
+#define BOOTP_BCAST 0x8000
+    in_addr_t cip;		/* Client IP address */
+    in_addr_t yip;		/* You IP address */
+    in_addr_t sip;		/* next server IP address */
+    in_addr_t gip;		/*relay agent IP address */
+    mac_addr_t CAddr;
+    uint8_t Sname[64];
+    uint8_t bootfile[128];
+    union {
+#define BOOTP_DHCPVEND 1024
+	uint8_t d[BOOTP_DHCPVEND];
+	struct {
+	    uint8_t magic[4];
+#define VM_RFC1048 0x63825363L
+	    uint32_t flags;
+	    uint8_t pad[56];
+	} v;
+    } vendor;
+} __packed pxe_bootp_t;
+
+/* Function calling structures and constants */
+
+typedef struct s_PXENV_GET_CACHED_INFO {
+    pxenv_status_t Status;
+    uint16_t PacketType;
+#define PXENV_PACKET_TYPE_DHCP_DISCOVER 1
+#define PXENV_PACKET_TYPE_DHCP_ACK 2
+#define PXENV_PACKET_TYPE_CACHED_REPLY 3
+    uint16_t BufferSize;
+    segoff16_t Buffer;
+    uint16_t BufferLimit;
+} __packed t_PXENV_GET_CACHED_INFO;
+
+typedef struct s_PXENV_START_UNDI {
+    pxenv_status_t Status;
+    uint16_t AX;
+    uint16_t BX;
+    uint16_t DX;
+    uint16_t DI;
+    uint16_t ES;
+} __packed t_PXENV_START_UNDI;
+
+typedef struct s_PXENV_STOP_UNDI {
+    pxenv_status_t Status;
+} __packed t_PXENV_STOP_UNDI;
+
+typedef struct s_PXENV_START_BASE {
+    pxenv_status_t Status;
+} __packed t_PXENV_START_BASE;
+
+typedef struct s_PXENV_STOP_BASE {
+    pxenv_status_t Status;
+} __packed t_PXENV_STOP_BASE;
+
+typedef struct s_PXENV_TFTP_OPEN {
+    pxenv_status_t Status;
+    in_addr_t ServerIPAddress;
+    in_addr_t GatewayIPAddress;
+    uint8_t FileName[128];
+    in_port_t TFTPPort;
+    uint16_t PacketSize;
+} __packed t_PXENV_TFTP_OPEN;
+
+typedef struct s_PXENV_TFTP_CLOSE {
+    pxenv_status_t Status;
+} __packed t_PXENV_TFTP_CLOSE;
+
+typedef struct s_PXENV_TFTP_READ {
+    pxenv_status_t Status;
+    uint16_t PacketNumber;
+    uint16_t BufferSize;
+    segoff16_t Buffer;
+} __packed t_PXENV_TFTP_READ;
+
+typedef struct s_PXENV_TFTP_READ_FILE {
+    pxenv_status_t Status;
+    uint8_t FileName[128];
+    uint32_t BufferSize;
+    void *Buffer;
+    in_addr_t ServerIPAddress;
+    in_addr_t GatewayIPAddress;
+    in_addr_t McastIPAddress;
+    in_port_t TFTPClntPort;
+    in_port_t TFTPSrvPort;
+    uint16_t TFTPOpenTimeOut;
+    uint16_t TFTPReopenDelay;
+} __packed t_PXENV_TFTP_READ_FILE;
+
+typedef struct s_PXENV_TFTP_GET_FSIZE {
+    pxenv_status_t Status;
+    in_addr_t ServerIPAddress;
+    in_addr_t GatewayIPAddress;
+    uint8_t FileName[128];
+    uint32_t FileSize;
+} __packed t_PXENV_TFTP_GET_FSIZE;
+
+typedef struct s_PXENV_UDP_OPEN {
+    pxenv_status_t status;
+    in_addr_t src_ip;
+} __packed t_PXENV_UDP_OPEN;
+
+typedef struct s_PXENV_UDP_CLOSE {
+    pxenv_status_t status;
+} __packed t_PXENV_UDP_CLOSE;
+
+typedef struct s_PXENV_UDP_WRITE {
+    pxenv_status_t status;
+    in_addr_t ip;
+    in_addr_t gw;
+    in_port_t src_port;
+    in_port_t dst_port;
+    uint16_t buffer_size;
+    segoff16_t buffer;
+} __packed t_PXENV_UDP_WRITE;
+
+typedef struct s_PXENV_UDP_READ {
+    pxenv_status_t status;
+    in_addr_t src_ip;
+    in_addr_t dest_ip;
+    in_port_t s_port;
+    in_port_t d_port;
+    uint16_t buffer_size;
+    segoff16_t buffer;
+} __packed t_PXENV_UDP_READ;
+
+typedef struct s_PXENV_UNDI_STARTUP {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_STARTUP;
+
+typedef struct s_PXENV_UNDI_CLEANUP {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_CLEANUP;
+
+typedef struct s_PXENV_UNDI_INITIALIZE {
+    pxenv_status_t Status;
+    void *ProtocolIni;
+    uint8_t reserved[8];
+} __packed t_PXENV_UNDI_INITIALIZE;
+
+#define MAXNUM_MCADDR 8
+typedef struct s_PXENV_UNDI_MCAST_ADDRESS {
+    uint16_t MCastAddrCount;
+    mac_addr_t McastAddr[MAXNUM_MCADDR];
+} __packed t_PXENV_UNDI_MCAST_ADDRESS;
+
+typedef struct s_PXENV_UNDI_RESET {
+    pxenv_status_t Status;
+    t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
+} __packed t_PXENV_UNDI_RESET;
+
+typedef struct s_PXENV_UNDI_SHUTDOWN {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_SHUTDOWN;
+
+typedef struct s_PXENV_UNDI_OPEN {
+    pxenv_status_t Status;
+    uint16_t OpenFlag;
+    uint16_t PktFilter;
+#define FLTR_DIRECTED 0x0001
+#define FLTR_BRDCST 0x0002
+#define FLTR_PRMSCS 0x0004
+#define FLTR_SRC_RTG 0x0008
+     t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
+} __packed t_PXENV_UNDI_OPEN;
+
+typedef struct s_PXENV_UNDI_CLOSE {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_CLOSE;
+
+typedef struct s_PXENV_UNDI_TRANSMIT {
+    pxenv_status_t Status;
+    uint8_t Protocol;
+#define P_UNKNOWN 0
+#define P_IP 1
+#define P_ARP 2
+#define P_RARP 3
+    uint8_t XmitFlag;
+#define XMT_DESTADDR 0x0000
+#define XMT_BROADCAST 0x0001
+    segoff16_t DestAddr;
+    segoff16_t TBD;
+    uint32_t Reserved[2];
+} __packed t_PXENV_UNDI_TRANSMIT;
+#define MAX_DATA_BLKS 8
+typedef struct s_PXENV_UNDI_TBD {
+    uint16_t ImmedLength;
+    segoff16_t Xmit;
+    uint16_t DataBlkCount;
+    struct DataBlk {
+	uint8_t TDPtrType;
+	uint8_t TDRsvdByte;
+	uint16_t TDDataLen;
+	segoff16_t TDDataPtr;
+    } DataBlock[MAX_DATA_BLKS];
+} __packed t_PXENV_UNDI_TBD;
+
+typedef struct s_PXENV_UNDI_SET_MCAST_ADDRESS {
+    pxenv_status_t Status;
+     t_PXENV_UNDI_MCAST_ADDRESS R_Mcast_Buf;
+} __packed t_PXENV_UNDI_SET_MCAST_ADDR;
+
+typedef struct s_PXENV_UNDI_SET_STATION_ADDRESS {
+    pxenv_status_t Status;
+    mac_addr_t StationAddress;
+} __packed t_PXENV_UNDI_SET_STATION_ADDR;
+
+typedef struct s_PXENV_UNDI_SET_PACKET_FILTER {
+    pxenv_status_t Status;
+    uint8_t filter;
+} __packed t_PXENV_UNDI_SET_PACKET_FILTER;
+
+typedef struct s_PXENV_UNDI_GET_INFORMATION {
+    pxenv_status_t Status;
+    uint16_t BaseIo;
+    uint16_t IntNumber;
+    uint16_t MaxTranUnit;
+    uint16_t HwType;
+#define ETHER_TYPE 1
+#define EXP_ETHER_TYPE 2
+#define IEEE_TYPE 6
+#define ARCNET_TYPE 7
+    uint16_t HwAddrLen;
+    mac_addr_t CurrentNodeAddress;
+    mac_addr_t PermNodeAddress;
+    uint16_t ROMAddress;
+    uint16_t RxBufCt;
+    uint16_t TxBufCt;
+} __packed t_PXENV_UNDI_GET_INFORMATION;
+
+typedef struct s_PXENV_UNDI_GET_STATISTICS {
+    pxenv_status_t Status;
+    uint32_t XmtGoodFrames;
+    uint32_t RcvGoodFrames;
+    uint32_t RcvCRCErrors;
+    uint32_t RcvResourceErrors;
+} __packed t_PXENV_UNDI_GET_STATISTICS;
+
+typedef struct s_PXENV_UNDI_CLEAR_STATISTICS {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_CLEAR_STATISTICS;
+
+typedef struct s_PXENV_UNDI_INITIATE_DIAGS {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_INITIATE_DIAGS;
+
+typedef struct s_PXENV_UNDI_FORCE_INTERRUPT {
+    pxenv_status_t Status;
+} __packed t_PXENV_UNDI_FORCE_INTERRUPT;
+
+typedef struct s_PXENV_UNDI_GET_MCAST_ADDRESS {
+    pxenv_status_t Status;
+    in_addr_t InetAddr;
+    mac_addr_t MediaAddr;
+} __packed t_PXENV_UNDI_GET_MCAST_ADDR;
+
+typedef struct s_PXENV_UNDI_GET_NIC_TYPE {
+    pxenv_status_t Status;
+    uint8_t NicType;
+#define PCI_NIC 2
+#define PnP_NIC 3
+#define CardBus_NIC 4
+    union {
+	struct {
+	    uint16_t Vendor_ID;
+	    uint16_t Dev_ID;
+	    uint8_t Base_Class;
+	    uint8_t Sub_Class;
+	    uint8_t Prog_Intf;
+	    uint8_t Rev;
+	    uint16_t BusDevFunc;
+	    uint16_t SubVendor_ID;
+	    uint16_t SubDevice_ID;
+	} pci, cardbus;
+	struct {
+	    uint32_t EISA_Dev_ID;
+	    uint8_t Base_Class;
+	    uint8_t Sub_Class;
+	    uint8_t Prog_Intf;
+	    uint16_t CardSelNum;
+	} __packed pnp;
+    } __packed info;
+} __packed t_PXENV_UNDI_GET_NIC_TYPE;
+
+typedef struct s_PXENV_UNDI_GET_IFACE_INFO {
+    pxenv_status_t Status;
+    uint8_t IfaceType[16];
+    uint32_t LinkSpeed;
+    uint32_t ServiceFlags;
+    uint32_t Reserved[4];
+} __packed t_PXENV_UNDI_GET_NDIS_INFO;
+
+typedef struct s_PXENV_UNDI_GET_STATE {
+#define PXE_UNDI_GET_STATE_STARTED 1
+#define PXE_UNDI_GET_STATE_INITIALIZED 2
+#define PXE_UNDI_GET_STATE_OPENED 3
+    pxenv_status_t Status;
+    uint8_t UNDIstate;
+} __packed t_PXENV_UNDI_GET_STATE;
+
+typedef struct s_PXENV_UNDI_ISR {
+    pxenv_status_t Status;
+    uint16_t FuncFlag;
+    uint16_t BufferLength;
+    uint16_t FrameLength;
+    uint16_t FrameHeaderLength;
+    segoff16_t Frame;
+    uint8_t ProtType;
+    uint8_t PktType;
+} __packed t_PXENV_UNDI_ISR;
+#define PXENV_UNDI_ISR_IN_START 1
+#define PXENV_UNDI_ISR_IN_PROCESS 2
+#define PXENV_UNDI_ISR_IN_GET_NEXT 3
+/* One of these will be returned for
+   PXENV_UNDI_ISR_IN_START */
+#define PXENV_UNDI_ISR_OUT_OURS 0
+#define PXENV_UNDI_USR_OUT_NOT_OURS 1
+/* One of these will be returned for
+   PXENV_UNDI_ISR_IN_PROCESS and
+   PXENV_UNDI_ISR_IN_GET_NEXT */
+#define PXENV_UNDI_ISR_OUT_DONE 0
+#define PXENV_UNDI_ISR_OUT_TRANSMIT 2
+#define PXENV_UNDI_ISR_OUT_RECEIVE 3
+#define PXENV_UNDI_ISR_OUT_BUSY 4
+
+/* Function numbers and error codes */
+
+#define PXENV_TFTP_OPEN			0x0020
+#define PXENV_TFTP_CLOSE		0x0021
+#define PXENV_TFTP_READ			0x0022
+#define PXENV_TFTP_READ_FILE		0x0023
+#define PXENV_TFTP_READ_FILE_PMODE	0x0024
+#define PXENV_TFTP_GET_FSIZE		0x0025
+
+#define PXENV_UDP_OPEN			0x0030
+#define PXENV_UDP_CLOSE			0x0031
+#define PXENV_UDP_READ			0x0032
+#define PXENV_UDP_WRITE			0x0033
+
+#define PXENV_START_UNDI		0x0000
+#define PXENV_UNDI_STARTUP		0x0001
+#define PXENV_UNDI_CLEANUP		0x0002
+#define PXENV_UNDI_INITIALIZE		0x0003
+#define PXENV_UNDI_RESET_NIC		0x0004
+#define PXENV_UNDI_SHUTDOWN		0x0005
+#define PXENV_UNDI_OPEN			0x0006
+#define PXENV_UNDI_CLOSE		0x0007
+#define PXENV_UNDI_TRANSMIT		0x0008
+#define PXENV_UNDI_SET_MCAST_ADDR	0x0009
+#define PXENV_UNDI_SET_STATION_ADDR	0x000A
+#define PXENV_UNDI_SET_PACKET_FILTER	0x000B
+#define PXENV_UNDI_GET_INFORMATION	0x000C
+#define PXENV_UNDI_GET_STATISTICS	0x000D
+#define PXENV_UNDI_CLEAR_STATISTICS	0x000E
+#define PXENV_UNDI_INITIATE_DIAGS	0x000F
+#define PXENV_UNDI_FORCE_INTERRUPT	0x0010
+#define PXENV_UNDI_GET_MCAST_ADDR	0x0011
+#define PXENV_UNDI_GET_NIC_TYPE		0x0012
+#define PXENV_UNDI_GET_IFACE_INFO	0x0013
+#define PXENV_UNDI_ISR			0x0014
+#define	PXENV_STOP_UNDI			0x0015	/* Overlap...? */
+#define PXENV_UNDI_GET_STATE		0x0015	/* Overlap...? */
+
+#define PXENV_UNLOAD_STACK		0x0070
+#define PXENV_GET_CACHED_INFO		0x0071
+#define PXENV_RESTART_DHCP		0x0072
+#define PXENV_RESTART_TFTP		0x0073
+#define PXENV_MODE_SWITCH		0x0074
+#define PXENV_START_BASE		0x0075
+#define PXENV_STOP_BASE			0x0076
+
+/* gPXE extensions... */
+#define PXENV_FILE_OPEN			0x00e0
+#define PXENV_FILE_CLOSE		0x00e1
+#define PXENV_FILE_SELECT		0x00e2
+#define PXENV_FILE_READ			0x00e3
+#define PXENV_GET_FILE_SIZE		0x00e4
+#define PXENV_FILE_EXEC			0x00e5
+#define PXENV_FILE_API_CHECK		0x00e6
+
+/* Exit codes */
+#define PXENV_EXIT_SUCCESS				 0x0000
+#define PXENV_EXIT_FAILURE				 0x0001
+
+/* Status codes */
+#define PXENV_STATUS_SUCCESS				 0x00
+#define PXENV_STATUS_FAILURE				 0x01
+#define PXENV_STATUS_BAD_FUNC				 0x02
+#define PXENV_STATUS_UNSUPPORTED			 0x03
+#define PXENV_STATUS_KEEP_UNDI				 0x04
+#define PXENV_STATUS_KEEP_ALL				 0x05
+#define PXENV_STATUS_OUT_OF_RESOURCES			 0x06
+#define PXENV_STATUS_ARP_TIMEOUT			 0x11
+#define PXENV_STATUS_UDP_CLOSED				 0x18
+#define PXENV_STATUS_UDP_OPEN				 0x19
+#define PXENV_STATUS_TFTP_CLOSED			 0x1a
+#define PXENV_STATUS_TFTP_OPEN				 0x1b
+#define PXENV_STATUS_MCOPY_PROBLEM			 0x20
+#define PXENV_STATUS_BIS_INTEGRITY_FAILURE		 0x21
+#define PXENV_STATUS_BIS_VALIDATE_FAILURE		 0x22
+#define PXENV_STATUS_BIS_INIT_FAILURE			 0x23
+#define PXENV_STATUS_BIS_SHUTDOWN_FAILURE		 0x24
+#define PXENV_STATUS_BIS_GBOA_FAILURE			 0x25
+#define PXENV_STATUS_BIS_FREE_FAILURE			 0x26
+#define PXENV_STATUS_BIS_GSI_FAILURE			 0x27
+#define PXENV_STATUS_BIS_BAD_CKSUM			 0x28
+#define PXENV_STATUS_TFTP_CANNOT_ARP_ADDRESS		 0x30
+#define PXENV_STATUS_TFTP_OPEN_TIMEOUT			 0x32
+
+#define PXENV_STATUS_TFTP_UNKNOWN_OPCODE		 0x33
+#define PXENV_STATUS_TFTP_READ_TIMEOUT			 0x35
+#define PXENV_STATUS_TFTP_ERROR_OPCODE			 0x36
+#define PXENV_STATUS_TFTP_CANNOT_OPEN_CONNECTION	 0x38
+#define PXENV_STATUS_TFTP_CANNOT_READ_FROM_CONNECTION	 0x39
+#define PXENV_STATUS_TFTP_TOO_MANY_PACKAGES		 0x3a
+#define PXENV_STATUS_TFTP_FILE_NOT_FOUND		 0x3b
+#define PXENV_STATUS_TFTP_ACCESS_VIOLATION		 0x3c
+#define PXENV_STATUS_TFTP_NO_MCAST_ADDRESS		 0x3d
+#define PXENV_STATUS_TFTP_NO_FILESIZE			 0x3e
+#define PXENV_STATUS_TFTP_INVALID_PACKET_SIZE		 0x3f
+#define PXENV_STATUS_DHCP_TIMEOUT			 0x51
+#define PXENV_STATUS_DHCP_NO_IP_ADDRESS			 0x52
+#define PXENV_STATUS_DHCP_NO_BOOTFILE_NAME		 0x53
+#define PXENV_STATUS_DHCP_BAD_IP_ADDRESS		 0x54
+#define PXENV_STATUS_UNDI_INVALID_FUNCTION		 0x60
+#define PXENV_STATUS_UNDI_MEDIATEST_FAILED		 0x61
+#define PXENV_STATUS_UNDI_CANNOT_INIT_NIC_FOR_MCAST	 0x62
+#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_NIC		 0x63
+#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_PHY		 0x64
+#define PXENV_STATUS_UNDI_CANNOT_READ_CONFIG_DATA	 0x65
+#define PXENV_STATUS_UNDI_CANNOT_READ_INIT_DATA		 0x66
+#define PXENV_STATUS_UNDI_BAD_MAC_ADDRESS		 0x67
+#define PXENV_STATUS_UNDI_BAD_EEPROM_CHECKSUM		 0x68
+#define PXENV_STATUS_UNDI_ERROR_SETTING_ISR		 0x69
+#define PXENV_STATUS_UNDI_INVALID_STATE			 0x6a
+#define PXENV_STATUS_UNDI_TRANSMIT_ERROR		 0x6b
+#define PXENV_STATUS_UNDI_INVALID_PARAMETER		 0x6c
+#define PXENV_STATUS_BSTRAP_PROMPT_MENU			 0x74
+#define PXENV_STATUS_BSTRAP_MCAST_ADDR			 0x76
+#define PXENV_STATUS_BSTRAP_MISSING_LIST		 0x77
+#define PXENV_STATUS_BSTRAP_NO_RESPONSE			 0x78
+#define PXENV_STATUS_BSTRAP_FILE_TOO_BIG		 0x79
+#define PXENV_STATUS_BINL_CANCELED_BY_KEYSTROKE		 0xa0
+#define PXENV_STATUS_BINL_NO_PXE_SERVER			 0xa1
+#define PXENV_STATUS_NOT_AVAILABLE_IN_PMODE		 0xa2
+#define PXENV_STATUS_NOT_AVAILABLE_IN_RMODE		 0xa3
+#define PXENV_STATUS_BUSD_DEVICE_NOT_SUPPORTED		 0xb0
+#define PXENV_STATUS_LOADER_NO_FREE_BASE_MEMORY		 0xc0
+#define PXENV_STATUS_LOADER_NO_BC_ROMID			 0xc1
+#define PXENV_STATUS_LOADER_BAD_BC_ROMID		 0xc2
+#define PXENV_STATUS_LOADER_BAD_BC_RUNTIME_IMAGE	 0xc3
+#define PXENV_STATUS_LOADER_NO_UNDI_ROMID		 0xc4
+#define PXENV_STATUS_LOADER_BAD_UNDI_ROMID		 0xc5
+#define PXENV_STATUS_LOADER_BAD_UNDI_DRIVER_IMAGE	 0xc6
+#define PXENV_STATUS_LOADER_NO_PXE_STRUCT		 0xc8
+#define PXENV_STATUS_LOADER_NO_PXENV_STRUCT		 0xc9
+#define PXENV_STATUS_LOADER_UNDI_START			 0xca
+#define PXENV_STATUS_LOADER_BC_START			 0xcb
+
+#endif /* _SYSLINUX_PXE_API_H */
diff --git a/core/include/pxe.h b/core/include/pxe.h
index 06cea0a3..1f66032e 100644
--- a/core/include/pxe.h
+++ b/core/include/pxe.h
@@ -1,164 +1,28 @@
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
 
-/**
-* -----------------------------------------------------------------------
-*
-*   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
-*
-*   This program is free software; you can redistribute it and/or modify
-*   it under the terms of the GNU General Public License as published by
-*   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
-*   Boston MA 02111-1307, USA; either version 2 of the License, or
-*   (at your option) any later version; incorporated herein by reference.
-*
-* -----------------------------------------------------------------------
-
-*
-* pxe.inc
-*
-* PXE opcodes
-*
-*/
+/*
+ * pxe.h
+ *
+ * PXE opcodes
+ *
+ */
 #ifndef PXE_H
 #define PXE_H
 
-
-#define PXENV_TFTP_OPEN					 0x0020
-#define PXENV_TFTP_CLOSE				 0x0021
-#define PXENV_TFTP_READ					 0x0022
-#define PXENV_TFTP_READ_FILE				 0x0023
-#define PXENV_TFTP_READ_FILE_PMODE			 0x0024
-#define PXENV_TFTP_GET_FSIZE				 0x0025
-
-#define PXENV_UDP_OPEN					 0x0030
-#define PXENV_UDP_CLOSE					 0x0031
-#define PXENV_UDP_READ					 0x0032
-#define PXENV_UDP_WRITE					 0x0033
-
-#define PXENV_START_UNDI				 0x0000
-#define PXENV_UNDI_STARTUP				 0x0001
-#define PXENV_UNDI_CLEANUP				 0x0002
-#define PXENV_UNDI_INITIALIZE				 0x0003
-#define PXENV_UNDI_RESET_NIC				 0x0004
-#define PXENV_UNDI_SHUTDOWN				 0x0005
-#define PXENV_UNDI_OPEN					 0x0006
-#define PXENV_UNDI_CLOSE				 0x0007
-#define PXENV_UNDI_TRANSMIT				 0x0008
-#define PXENV_UNDI_SET_MCAST_ADDR			 0x0009
-#define PXENV_UNDI_SET_STATION_ADDR			 0x000A
-#define PXENV_UNDI_SET_PACKET_FILTER			 0x000B
-#define PXENV_UNDI_GET_INFORMATION			 0x000C
-#define PXENV_UNDI_GET_STATISTICS			 0x000D
-#define PXENV_UNDI_CLEAR_STATISTICS			 0x000E
-#define PXENV_UNDI_INITIATE_DIAGS			 0x000F
-#define PXENV_UNDI_FORCE_INTERRUPT			 0x0010
-#define PXENV_UNDI_GET_MCAST_ADDR			 0x0011
-#define PXENV_UNDI_GET_NIC_TYPE				 0x0012
-#define PXENV_UNDI_GET_IFACE_INFO			 0x0013
-#define PXENV_UNDI_ISR					 0x0014
-#define PXENV_STOP_UNDI					 0x0015
-#define PXENV_UNDI_GET_STATE				 0x0015
-
-#define PXENV_UNLOAD_STACK				 0x0070
-#define PXENV_GET_CACHED_INFO				 0x0071
-#define PXENV_RESTART_DHCP				 0x0072
-#define PXENV_RESTART_TFTP				 0x0073
-#define PXENV_MODE_SWITCH				 0x0074
-#define PXENV_START_BASE				 0x0075
-#define PXENV_STOP_BASE					 0x0076
-
-/* gPXE extensions... */
-#define PXENV_FILE_OPEN					 0x00e0
-#define PXENV_FILE_CLOSE				 0x00e1
-#define PXENV_FILE_SELECT				 0x00e2
-#define PXENV_FILE_READ					 0x00e3
-#define PXENV_GET_FILE_SIZE				 0x00e4
-#define PXENV_FILE_EXEC					 0x00e5
-#define PXENV_FILE_API_CHECK				 0x00e6
-
-/* Exit codes */
-#define PXENV_EXIT_SUCCESS				 0x0000
-#define PXENV_EXIT_FAILURE				 0x0001
-
-/* Status codes */
-#define PXENV_STATUS_SUCCESS				 0x00
-#define PXENV_STATUS_FAILURE				 0x01
-#define PXENV_STATUS_BAD_FUNC				 0x02
-#define PXENV_STATUS_UNSUPPORTED			 0x03
-#define PXENV_STATUS_KEEP_UNDI				 0x04
-#define PXENV_STATUS_KEEP_ALL				 0x05
-#define PXENV_STATUS_OUT_OF_RESOURCES			 0x06
-#define PXENV_STATUS_ARP_TIMEOUT			 0x11
-#define PXENV_STATUS_UDP_CLOSED				 0x18
-#define PXENV_STATUS_UDP_OPEN				 0x19
-#define PXENV_STATUS_TFTP_CLOSED			 0x1a
-#define PXENV_STATUS_TFTP_OPEN				 0x1b
-#define PXENV_STATUS_MCOPY_PROBLEM			 0x20
-#define PXENV_STATUS_BIS_INTEGRITY_FAILURE		 0x21
-#define PXENV_STATUS_BIS_VALIDATE_FAILURE		 0x22
-#define PXENV_STATUS_BIS_INIT_FAILURE			 0x23
-#define PXENV_STATUS_BIS_SHUTDOWN_FAILURE		 0x24
-#define PXENV_STATUS_BIS_GBOA_FAILURE			 0x25
-#define PXENV_STATUS_BIS_FREE_FAILURE			 0x26
-#define PXENV_STATUS_BIS_GSI_FAILURE			 0x27
-#define PXENV_STATUS_BIS_BAD_CKSUM			 0x28
-#define PXENV_STATUS_TFTP_CANNOT_ARP_ADDRESS		 0x30
-#define PXENV_STATUS_TFTP_OPEN_TIMEOUT			 0x32
-
-#define PXENV_STATUS_TFTP_UNKNOWN_OPCODE		 0x33
-#define PXENV_STATUS_TFTP_READ_TIMEOUT			 0x35
-#define PXENV_STATUS_TFTP_ERROR_OPCODE			 0x36
-#define PXENV_STATUS_TFTP_CANNOT_OPEN_CONNECTION	 0x38
-#define PXENV_STATUS_TFTP_CANNOT_READ_FROM_CONNECTION	 0x39
-#define PXENV_STATUS_TFTP_TOO_MANY_PACKAGES		 0x3a
-#define PXENV_STATUS_TFTP_FILE_NOT_FOUND		 0x3b
-#define PXENV_STATUS_TFTP_ACCESS_VIOLATION		 0x3c
-#define PXENV_STATUS_TFTP_NO_MCAST_ADDRESS		 0x3d
-#define PXENV_STATUS_TFTP_NO_FILESIZE			 0x3e
-#define PXENV_STATUS_TFTP_INVALID_PACKET_SIZE		 0x3f
-#define PXENV_STATUS_DHCP_TIMEOUT			 0x51
-#define PXENV_STATUS_DHCP_NO_IP_ADDRESS			 0x52
-#define PXENV_STATUS_DHCP_NO_BOOTFILE_NAME		 0x53
-#define PXENV_STATUS_DHCP_BAD_IP_ADDRESS		 0x54
-#define PXENV_STATUS_UNDI_INVALID_FUNCTION		 0x60
-#define PXENV_STATUS_UNDI_MEDIATEST_FAILED		 0x61
-#define PXENV_STATUS_UNDI_CANNOT_INIT_NIC_FOR_MCAST	 0x62
-#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_NIC		 0x63
-#define PXENV_STATUS_UNDI_CANNOT_INITIALIZE_PHY		 0x64
-#define PXENV_STATUS_UNDI_CANNOT_READ_CONFIG_DATA	 0x65
-#define PXENV_STATUS_UNDI_CANNOT_READ_INIT_DATA		 0x66
-#define PXENV_STATUS_UNDI_BAD_MAC_ADDRESS		 0x67
-#define PXENV_STATUS_UNDI_BAD_EEPROM_CHECKSUM		 0x68
-#define PXENV_STATUS_UNDI_ERROR_SETTING_ISR		 0x69
-#define PXENV_STATUS_UNDI_INVALID_STATE			 0x6a
-#define PXENV_STATUS_UNDI_TRANSMIT_ERROR		 0x6b
-#define PXENV_STATUS_UNDI_INVALID_PARAMETER		 0x6c
-#define PXENV_STATUS_BSTRAP_PROMPT_MENU			 0x74
-#define PXENV_STATUS_BSTRAP_MCAST_ADDR			 0x76
-#define PXENV_STATUS_BSTRAP_MISSING_LIST		 0x77
-#define PXENV_STATUS_BSTRAP_NO_RESPONSE			 0x78
-#define PXENV_STATUS_BSTRAP_FILE_TOO_BIG		 0x79
-#define PXENV_STATUS_BINL_CANCELED_BY_KEYSTROKE		 0xa0
-#define PXENV_STATUS_BINL_NO_PXE_SERVER			 0xa1
-#define PXENV_STATUS_NOT_AVAILABLE_IN_PMODE		 0xa2
-#define PXENV_STATUS_NOT_AVAILABLE_IN_RMODE		 0xa3
-#define PXENV_STATUS_BUSD_DEVICE_NOT_SUPPORTED		 0xb0
-#define PXENV_STATUS_LOADER_NO_FREE_BASE_MEMORY		 0xc0
-#define PXENV_STATUS_LOADER_NO_BC_ROMID			 0xc1
-#define PXENV_STATUS_LOADER_BAD_BC_ROMID		 0xc2
-#define PXENV_STATUS_LOADER_BAD_BC_RUNTIME_IMAGE	 0xc3
-#define PXENV_STATUS_LOADER_NO_UNDI_ROMID		 0xc4
-#define PXENV_STATUS_LOADER_BAD_UNDI_ROMID		 0xc5
-#define PXENV_STATUS_LOADER_BAD_UNDI_DRIVER_IMAGE	 0xc6
-#define PXENV_STATUS_LOADER_NO_PXE_STRUCT		 0xc8
-#define PXENV_STATUS_LOADER_NO_PXENV_STRUCT		 0xc9
-#define PXENV_STATUS_LOADER_UNDI_START			 0xca
-#define PXENV_STATUS_LOADER_BC_START			 0xcb
-
-
-
+#include <syslinux/pxe_api.h>
 
 /*
- * some other defines 
+ * Some basic defines...
  */
 #define PKTBUF_SIZE        (65536 / MAX_OPEN)
 
@@ -168,11 +32,6 @@
 #define DNS_MAX_SERVERS    4
 
 #define is_digit(c) (((c) >= '0') && ((c) <= '9'))
-#define htons(x)    ( ( ((x) & 0xff) << 8) + ( ((x) &0xff00) >> 8) )
-#define ntohs(x)    htons(x)
-#define htonl(x)    ( ( ((x) & 0xff) << 24)     + ( ((x) & 0xff00) << 8 ) + \
-                      ( ((x) & 0xff0000) >> 8 ) + ( ((x) & 0xff000000) >> 24) )
-#define ntohl(x)    htonl(x)
 
 /*
  * TFTP operation codes
@@ -200,10 +59,58 @@
 #define BOOTP_OPTION_MAGIC  htonl(0x63825363)
 #define MAC_MAX 32
 
-
 /*
  * structures 
  */
+
+struct pxenv_t {
+    uint8_t    signature[6];	/* PXENV+ */
+    uint16_t   version;
+    uint8_t    length;
+    uint8_t    checksum;
+    segoff16_t rmentry;
+    uint32_t   pmoffset;
+    uint16_t   pmselector;
+    uint16_t   stackseg;
+    uint16_t   stacksize;
+    uint16_t   bc_codeseg;
+    uint16_t   bc_codesize;
+    uint16_t   bc_dataseg;
+    uint16_t   bc_datasize;
+    uint16_t   undidataseg;
+    uint16_t   undidatasize;
+    uint16_t   undicodeseg;
+    uint16_t   undicodesize;
+    segoff16_t pxeptr;
+} __packed;
+
+struct pxe_t {
+    uint8_t    signature[4];	/* !PXE */
+    uint8_t    structlength;
+    uint8_t    structcksum;
+    uint8_t    structrev;
+    uint8_t    _pad1;
+    segoff16_t undiromid;
+    segoff16_t baseromid;
+    segoff16_t entrypointsp;
+    segoff16_t entrypointesp;
+    segoff16_t statuscallout;
+    uint8_t    _pad2;
+    uint8_t    segdesccnt;
+    uint16_t   firstselector;
+    pxe_segdesc_t  seg[7];
+} __packed;
+
+enum pxe_segments {
+    PXE_Seg_Stack         = 0,
+    PXE_Seg_UNDIData      = 1,
+    PXE_Seg_UNDICode      = 2,
+    PXE_Seg_UNDICodeWrite = 3,
+    PXE_Seg_BC_Data       = 4,
+    PXE_Seg_BC_Code       = 5,
+    PXE_Seg_BC_CodeWrite  = 6
+};
+
 struct bootp_t {
     uint8_t  opcode;        /* BOOTP/DHCP "opcode" */
     uint8_t  hardware;      /* ARP hreadware type */
@@ -302,8 +209,6 @@ struct gpxe_file_read {
     uint16_t buffer[2];
 } __attribute__ ((packed));
 
-
-
 /*
  * functions
  */
@@ -311,7 +216,4 @@ int ip_ok(uint32_t);
 void parse_dhcp(int);
 void parse_dhcp_options(void *, int, int);
 
-
-
-
 #endif /* pxe.h */
diff --git a/core/pxe.c b/core/pxe.c
index f4afc087..916bf435 100644
--- a/core/pxe.c
+++ b/core/pxe.c
@@ -336,7 +336,6 @@ static int pxe_get_cached_info(int type)
  */
 static int is_url(char *url)
 {
-    
     while (*url) {
         if(! strncmp(url, "://", 3))
             return 1;
@@ -1251,42 +1250,43 @@ static void ip_init(void)
  * return 1 for success, 0 for failure.
  *
  */
-static int is_pxe(char *buf)
+static int is_pxe(const void *buf)
 {
-    int i = buf[4];
+    const struct pxe_t *pxe = buf;
+    const uint8_t *p = buf;
+    int i = pxe->structlength;
     uint8_t sum = 0;
 
-    if (memcmp(buf, "!PXE", 4) || i < 0x58)
+    if (i < sizeof(struct pxe_t) ||
+	memcmp(pxe->signature, "!PXE", 4))
         return 0;
 
     while (i--)
-        sum += *buf++;
+        sum += *p++;
 
-    if (sum == 0)
-        return 1;
-    else
-        return 0;
+    return sum == 0;
 }
 
 /**
  * Just like is_pxe, it checks PXENV+ structure
  *
  */
-static int is_pxenv(char *buf)
+static int is_pxenv(const void *buf)
 {
-    int i = buf[8];
+    const struct pxenv_t *pxenv = buf;
+    const uint8_t *p = buf;
+    int i = pxenv->length;
     uint8_t sum = 0;
     
-    if (memcmp(buf, "PXENV+", 6) || i < 0x28)
+    /* The pxeptr field isn't present in old versions */
+    if (i < offsetof(struct pxenv_t, pxeptr) ||
+	memcmp(pxenv->signature, "PXENV+", 6))
         return 0;
 
     while (i--)
-        sum += *buf++;
+        sum += *p++;
 
-    if (sum == 0)
-        return 1;
-    else
-        return 0;
+    return sum == 0;
 }
         
 
@@ -1309,29 +1309,29 @@ static int is_pxenv(char *buf)
 ;
  ********************************************************************/
 
-static inline int memory_scan(uint16_t seg, int (*func)(char *))
+static const void *memory_scan(uintptr_t start, int (*func)(const void *))
 {
-    while (seg < 0xA000) {
-        if (func(MK_PTR(seg, 0)))
-            return 1;       /* found it */
-        seg++;
+    const char *ptr;
+
+    /* Scan each 16 bytes of conventional memory before the VGA region */
+    for (ptr = (const char *)start; ptr < (const char *)0xA0000; ptr += 16) {
+        if (func(ptr))
+            return ptr;		/* found it! */
+	ptr += 16;
     }
-    return 0;
+    return NULL;
 }
     
-static int memory_scan_for_pxe_struct(void)
+static const struct pxe_t *memory_scan_for_pxe_struct(void)
 {
     extern uint16_t BIOS_fbm;  /* Starting segment */
-    uint16_t seg = BIOS_fbm << (10 - 4);
 
-    return memory_scan(seg, is_pxe);
+    return memory_scan(BIOS_fbm << 10, is_pxe);
 }
     
-static int memory_scan_for_pxenv_struct(void)
+static const struct pxenv_t *memory_scan_for_pxenv_struct(void)
 {
-    uint16_t seg = 0x1000;
-    
-    return memory_scan(seg, is_pxenv);
+    return memory_scan(0x10000, is_pxenv);
 }
 
 /*
@@ -1349,11 +1349,16 @@ static int memory_scan_for_pxenv_struct(void)
  */
 static void pxe_init(void)
 {
+    extern void pxe_int1a(void);
     char plan = 'A';
     uint16_t seg, off;
     uint16_t code_seg, code_len;
     uint16_t data_seg, data_len;
     char *base = GET_PTR(InitStack);
+    com32sys_t regs;
+    const char *type;
+    const struct pxenv_t *pxenv;
+    const struct pxe_t *pxe;
 
     /* Assume API version 2.1 */
     APIVer = 0x201;
@@ -1361,43 +1366,39 @@ static void pxe_init(void)
     /* Plan A: !PXE structure as SS:[SP + 4] */
     off = *(uint16_t *)(base + 48);
     seg = *(uint16_t *)(base + 50);
-    if (is_pxe(MK_PTR(seg, off))) 
+    pxe = MK_PTR(seg, off);
+    if (is_pxe(pxe)) 
         goto have_pxe;
 
     /* Plan B: PXENV+ structure at [ES:BX] */
     plan++;
     off = *(uint16_t *)(base + 24);  /* Original BX */
     seg = *(uint16_t *)(base + 4);   /* Original ES */
-    if (is_pxenv(MK_PTR(seg, off)))
+    pxenv = MK_PTR(seg, off);
+    if (is_pxenv(pxenv))
         goto have_pxenv;
 
     /* 
      * Plan C: PXENV+ structure via INT 1Ah AX=5650h 
-     * 
-     * for now, we just skip it since it must be run in Real mode 
      */
-    extern void plan_c(void);
     plan++;
-#if 0
-    goto plan_D;               
-    call16(plan_c, regs, regs);
-    if (((regs->eflags.l & EFLAGS_CF) == 0) && (regs->eax.w[0] == 0x564e)) {
-        seg = regs->es;
-        off = regs->ebx.w[0];
-        if (is_pxenv(MK_PTR(seg, off)))
+    memset(&regs, 0, sizeof regs);
+    regs.eax.w[0] = 0x5650;
+    call16(pxe_int1a, &regs, &regs);
+    if (!(regs.eflags.l & EFLAGS_CF) && (regs.eax.w[0] == 0x564e)) {
+	pxenv = MK_PTR(regs.es, regs.ebx.w[0]);
+        if (is_pxenv(pxenv))
             goto have_pxenv;
     }
 
- plan_D:
-#endif
     /* Plan D: !PXE memory scan */
     plan++;
-    if (memory_scan_for_pxe_struct())
+    if ((pxe = memory_scan_for_pxe_struct()))
         goto have_pxe;
     
     /* Plan E: PXENV+ memory scan */
     plan++;
-    if (memory_scan_for_pxenv_struct())
+    if ((pxenv = memory_scan_for_pxenv_struct()))
         goto have_pxenv;
 
     /* Found nothing at all !! */
@@ -1405,59 +1406,51 @@ static void pxe_init(void)
     call16(kaboom, NULL, NULL);
     
  have_pxenv:
-    base = MK_PTR(seg, off);
-    APIVer = *(uint16_t *)(base + 6);
+    APIVer = pxenv->version;
     printf("Found PXENV+ structure\nPXE API version is %04x\n", APIVer);
 
     /* if the API version number is 0x0201 or higher, use the !PXE structure */
     if (APIVer >= 0x201) {
-        if (*(char *)(base + 8) < 0x2c) {          /* Length of PXENV+ structure in bytes */
-            if (memory_scan_for_pxe_struct())
-                goto have_pxe;
-        }
-    
-        off = *(uint16_t *)(base + 0x28);
-        seg = *(uint16_t *)(base + 0x2a);
-        if (is_pxe(MK_PTR(seg, off)))
-            goto have_pxe;    
-        /*
-         * Nope, !PXE structuremissing despite API 2.1+, or at least
-         * the pointer is missing. Do a last-ditch attempt to find it
-         */
-        if (memory_scan_for_pxe_struct())
-            goto have_pxe;
+	if (pxenv->length >= sizeof(struct pxenv_t)) {
+	    pxe = GET_PTR(pxenv->pxeptr);
+	    if (is_pxe(pxe))
+		goto have_pxe;  
+	    /*
+	     * Nope, !PXE structure missing despite API 2.1+, or at least
+	     * the pointer is missing. Do a last-ditch attempt to find it
+	     */
+	    if ((pxe = memory_scan_for_pxe_struct()))
+		goto have_pxe;
+	}
     }
     
     /* Otherwise, no dice, use PXENV+ structure */
-    data_len = *(uint16_t *)(base + 0x22);  /* UNDI data len */
-    data_seg = *(uint16_t *)(base + 0x20);  /* UNDI data seg */
-    code_len = *(uint16_t *)(base + 0x26);  /* UNDI code len */
-    code_seg = *(uint16_t *)(base + 0x24);  /* UNDI code seg */
-    PXEEntry = *(far_ptr_t *)(base + 0x0a);  /* PXENV+ entry point */
-    printf("PXENV+ entry point found (we hope) at ");
+    data_len = pxenv->undidatasize;
+    data_seg = pxenv->undidataseg;
+    code_len = pxenv->undicodesize;
+    code_seg = pxenv->undicodeseg;
+    PXEEntry = pxenv->rmentry;
+    type = "PXENV+";
     goto have_entrypoint;
 
  have_pxe:
-    base = MK_PTR(seg, off);
-    
-    data_len = *(uint16_t *)(base + 0x2e);  /* UNDI data len */
-    data_seg = *(uint16_t *)(base + 0x28);  /* UNDI data seg */
-    code_len = *(uint16_t *)(base + 0x36);  /* UNDI code len */
-    code_seg = *(uint16_t *)(base + 0x30);  /* UNDI code seg */
-    PXEEntry = *(far_ptr_t *)(base + 0x10);  /* !PXE entry point */
-    printf("!PXE entry point found (we hope) at ");
+    data_len = pxe->seg[PXE_Seg_UNDIData].size;
+    data_seg = pxe->seg[PXE_Seg_UNDIData].sel;
+    code_len = pxe->seg[PXE_Seg_UNDICode].size;
+    code_seg = pxe->seg[PXE_Seg_UNDICode].sel;
+    PXEEntry = pxe->entrypointsp;
+    type = "!PXE";
 
  have_entrypoint:
-    printf("%04X:%04X via plan %c\n", PXEEntry.seg, PXEEntry.offs, plan);
+    printf("%s entry point found (we hope) at %04X:%04X via plan %c\n",
+	   type, PXEEntry.seg, PXEEntry.offs, plan);
     printf("UNDI code segment at %04X len %04X\n", code_seg, code_len);
-    code_seg = code_seg + ((code_len + 15) >> 4);
-    
     printf("UNDI data segment at %04X len %04X\n", data_seg, data_len);
+
+    code_seg = code_seg + ((code_len + 15) >> 4);
     data_seg = data_seg + ((data_len + 15) >> 4);
-    
-    
+
     RealBaseMem = MAX(code_seg,data_seg) >> 6; /* Convert to kilobytes */
-    //regs->es = regs->ds;                       /* Restore the es segment */
 }                                  
 
 /*
diff --git a/core/pxelinux.asm b/core/pxelinux.asm
index b8077fd9..06e52061 100644
--- a/core/pxelinux.asm
+++ b/core/pxelinux.asm
@@ -290,29 +290,8 @@ _start1:
                 extern pxe_fs_ops
 	        mov eax,pxe_fs_ops
                 pm_call fs_init
-                jmp next
 
 ;
-; Plan C, because it must be in real mode, we set it here
-;
-                global plan_c
-plan_c:
-                
-		; Plan C: PXENV+ structure via INT 1Ah AX=5650h
-		mov ax, 5650h
-%if USE_PXE_PROVIDED_STACK == 0
-		lss sp,[InitStack]
-%endif
-		int 1Ah			; May trash regs
-%if USE_PXE_PROVIDED_STACK == 0
-		lss esp,[BaseStack]
-%endif
-		sti			; Work around Etherboot bug
-                ret
-
-
-next:
-;
 ; Common initialization code
 ;
 %include "cpuinit.inc"
@@ -483,6 +462,24 @@ PXEEntry	equ pxenv.jump+1
 PXEStatus	resb 2
 
 
+		section .text16
+;
+; Invoke INT 1Ah on the PXE stack.  This is used by the "Plan C" method
+; for finding the PXE entry point.
+;
+                global pxe_int1a
+pxe_int1a:
+%if USE_PXE_PROVIDED_STACK == 0
+		mov [cs:PXEStack],sp
+		mov [cs:PXEStack+2],ss
+		lss sp,[cs:InitStack]
+%endif
+		int 1Ah			; May trash registers
+%if USE_PXE_PROVIDED_STACK == 0
+		lss sp,[cs:PXEStack]
+%endif
+		ret
+
 ;
 ; TimeoutTable: list of timeouts (in 18.2 Hz timer ticks)
 ;