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|
;; -----------------------------------------------------------------------
;;
;; Copyright 1994-2008 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.
;;
;; -----------------------------------------------------------------------
;;
;; bootsect.inc
;;
;; Load a boot sector (or other bootstrap program.)
;;
;; Unlike previous versions of this software, this doesn't require that
;; the length is 512 bytes. This allows PXE bootstraps and WinNT
;; "CD boot sectors" to be invoked.
;;
;
; Load a boot sector
;
is_bootsector:
%if IS_SYSLINUX || IS_MDSLINUX
; Transfer zero bytes
mov byte [CopySuper],0
jmp short load_bootsec
is_bss_sector:
; Transfer the superblock
mov byte [CopySuper],superblock_len
%endif
load_bootsec:
xchg dx,ax
shl eax,16
xchg dx,ax ; Now EAX = file length
mov edi, 100000h
mov [trackbuf+4],edi ; Copy from this address
push edi ; Save load address
xor dx,dx ; No padding
mov bx,abort_check ; Don't print dots, but allow abort
call load_high
sub edi,100000h
mov [trackbuf+8],edi ; Save length
mov eax,7C00h ; Entry point
mov [trackbuf],eax ; Copy to this address
mov [EntryPoint],eax ; Jump to this address when done
%if IS_SYSLINUX || IS_MDSLINUX
movzx ecx,byte [CopySuper]
jcxz .not_bss
; For a BSS boot sector we have to patch.
mov esi,superblock
mov edi,100000h+(superblock-bootsec)
call bcopy
.not_bss:
%endif
xor edx,edx
xor esi,esi
%if IS_SYSLINUX || IS_MDSLINUX || IS_EXTLINUX
; Restore original FDC table
mov eax,[OrigFDCTabPtr]
mov [fdctab],eax
mov dl,[DriveNumber]
mov si,PartInfo ; Partition info buffer
mov di,800h-18 ; Put partition info here
push di
mov cx,8 ; 16 bytes
xor ax,ax
rep movsw
pop si ; DS:SI points to partition info
%elif IS_ISOLINUX
mov dl,[DriveNumber]
%elif IS_PXELINUX
mov byte [KeepPXE],1 ; Chainloading another NBP
call reset_pxe
%endif
xor bx,bx
;
; replace_bootstrap for the special case where we have exactly one
; descriptor, and it's the first entry in the trackbuf
;
replace_bootstrap_one:
push word 1 ; Length of descriptor list
push word trackbuf ; Address of descriptor list
; Fall through
;
; Entrypoint for "shut down and replace bootstrap" -- also invoked by
; the COMBOOT API. This routine expects two words on the stack:
; address of the copy list (versus DS) and count. Additionally,
; the values of ESI and EDX are passed on to the new bootstrap;
; the value of BX becomes the new DS.
;
replace_bootstrap:
;
; Prepare for shutting down
;
call vgaclearmode
call cleanup_hardware
;
; Set up initial stack frame (not used by PXE if keeppxe is
; set - we use the PXE stack then.)
; AFTER THIS POINT ONLY .earlybss IS AVAILABLE, NOT .bss
;
xor ax,ax
mov ds,ax
mov es,ax
%if IS_PXELINUX
test byte [KeepPXE],01h
jz .stdstack
les di,[InitStack] ; Reset stack to PXE original
jmp .stackok
%endif
.stdstack:
mov di,7C00h-44
push di
mov cx,22 ; 44 bytes
rep stosw
pop di
.stackok:
mov [es:di+28],edx ; New EDX
mov [es:di+12],esi ; New ESI
mov [es:di+6],bx ; New DS
%if IS_PXELINUX == 0
; DON'T DO THIS FOR PXELINUX...
; For PXE, ES:BX -> PXENV+, and this would corrupt
; that use.
; Restore ES:DI -> $PnP (if we were ourselves called
; that way...)
mov ax,[OrigESDI]
mov bx,[OrigESDI+2]
mov [es:di+8],ax ; New DI
mov [es:di+4],bx ; New ES
%endif
pop bx ; Copy from...
pop ax ; Copy list count
cli
mov cx,es
mov ss,cx
movzx esp,di
jmp shuffle_and_boot
|
