/* At entry, the processor is in 16 bit real mode and the code is being
* executed from an address it was not linked to. Code must be pic and
* 32 bit sensitive until things are fixed up.
*
* Also be very careful as the stack is at the rear end of the interrupt
* table so using a noticeable amount of stack space is a no-no.
*/
.text
.code16
.arch i386
.section ".prefix", "ax", @progbits
.org 0x00
romheader:
.word 0xAA55 /* BIOS extension signature */
.byte _rom_size /* Size in 512-byte blocks */
jmp init_vector /* Initialisation vector */
.org 0x16
.word undiheader
.org 0x18
.word pciheader
.org 0x1a
.word pnpheader
.size romheader, . - romheader
pciheader:
.ascii "PCIR" /* Signature */
.word pci_vendor_id /* Vendor ID */
.word pci_device_id /* Device ID */
.word 0x0000 /* pointer to vital product data */
.word pciheader_len /* PCI data structure length */
.byte 0x00 /* PCI data structure revision */
.byte 0x02 /* Device Base Type code */
.byte 0x00 /* Device Sub-Type code */
.byte 0x00 /* Device Interface Type code */
.word _rom_size /* Image length same as offset 02h */
.word 0x0001 /* revision level of code/data */
.byte 0x00 /* code type */
.byte 0x80 /* Flags (last PCI data structure) */
.word 0x0000 /* reserved */
.equ pciheader_len, . - pciheader
.size pciheader, . - pciheader
pnpheader:
.ascii "$PnP" /* Signature */
.byte 0x01 /* Structure revision */
.byte ( pnpheader_len / 16 ) /* Length (in 16 byte increments) */
.word 0x0000 /* Offset of next header */
.byte 0x00 /* Reserved */
.byte 0x00 /* Checksum */
.long 0x00000000 /* Device identifier */
.word mfgstr /* Manufacturer string */
.word prodstr /* Product name */
.byte 0x02 /* Device base type code */
.byte 0x00 /* Device sub-type code */
.byte 0x00 /* Device interface type code */
.byte 0x54 /* Device indicator */
.word 0x0000 /* Boot connection vector */
.word 0x0000 /* Disconnect vector */
.word exec_vector /* Boot execution vector */
.word 0x0000 /* Reserved */
.word 0x0000 /* Static resource information vector*/
.equ pnpheader_len, . - pnpheader
.size pnpheader, . - pnpheader
mfgstr:
.asciz "http://etherboot.org"
.size mfgstr, . - mfgstr
prodstr:
.asciz "Etherboot"
.size prodstr, . - prodstr
undiheader:
.ascii "UNDI" /* Signature */
.byte undiheader_len /* Length of structure */
.byte 0 /* Checksum */
.byte 0 /* Structure revision */
.byte 0,1,2 /* PXE version: 2.1.0 */
.word undiloader /* Offset to loader routine */
.word _data16_size /* Stack segment size */
.word _data16_size /* Data segment size */
.word _text16_size /* Code segment size */
.equ undiheader_len, . - undiheader
.size undiheader, . - undiheader
/* Initialisation vector
*
* Determine whether or not this is a PnP system via a signature
* check. If it is PnP, return to the PnP BIOS indicating that we are
* a boot-capable device; the BIOS will call our boot execution vector
* if it wants to boot us. If it is not PnP, hook INT 19.
*/
init_vector:
pushw %si
cmpw $'$'+'P'*256, %es:0(%di)
jne notpnp
cmpw $'n'+'P'*256, %es:2(%di)
jne notpnp
ispnp:
movw $ispnp_message, %si
jmp 99f
notpnp:
pushw %ds
pushw $0
popw %ds
pushw %cs
pushw $exec_vector
popl ( 0x19 * 4 )
popw %ds
movw $notpnp_message, %si
99:
call print_message
movw $0x20, %ax
popw %si
lret
.size init_vector, . - init_vector
ispnp_message:
.asciz "Etherboot detected PnP BIOS\r\n"
.size ispnp_message, . - ispnp_message
notpnp_message:
.asciz "Etherboot detected non-PnP BIOS\r\n"
.size notpnp_message, . - notpnp_message
/* Boot execution vector
*
* Called by the PnP BIOS when it wants to boot us, or via the hooked
* INT 19 if we detected a non-PnP BIOS.
*/
exec_vector:
/* Obtain a reasonably-sized stack */
xorw %ax, %ax
movw %ax, %ss
movw $0x7c00, %sp
movw $exec_message, %si
call print_message
call install
/* Set up real-mode stack */
movw %bx, %ss
movw $_estack16, %sp
/* Jump to .text16 segment */
pushw %ax
pushw $1f
lret
.section ".text16", "awx", @progbits
1:
pushl $main
pushw %cs
call prot_call
popl %eax /* discard */
/* Boot next device */
int $0x18
.previous
exec_message:
.asciz "Etherboot starting boot\r\n"
.size exec_message, . - exec_message
/* UNDI loader
*
* Called by an external program to load our PXE stack.
*/
undiloader:
.size undiloader, . - undiloader
/* Utility function: print string
*/
print_message:
pushw %ax
pushw %bx
pushw %bp
movw $0x0007, %bx
1: cs lodsb
testb %al, %al
je 2f
movb $0x0e, %ah /* write char, tty mode */
int $0x10
jmp 1b
2: popw %bp
popw %bx
popw %ax
ret
.size print_message, . - print_message
