2008-04-17 07:48:13 +02:00
|
|
|
;------------------------------------------------------------------------------
|
|
|
|
|
;*
|
2010-04-28 14:39:50 +02:00
|
|
|
;* Copyright (c) 2006 - 2007, Intel Corporation. All rights reserved.<BR>
|
|
|
|
|
;* This program and the accompanying materials
|
2008-04-17 07:48:13 +02:00
|
|
|
;* are licensed and made available under the terms and conditions of the BSD License
|
|
|
|
|
;* which accompanies this distribution. The full text of the license may be found at
|
|
|
|
|
;* http://opensource.org/licenses/bsd-license.php
|
|
|
|
|
;*
|
|
|
|
|
;* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
|
|
|
|
|
;* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
|
|
|
|
|
;*
|
|
|
|
|
;* Mbr.asm
|
|
|
|
|
;*
|
|
|
|
|
;* Abstract:
|
|
|
|
|
;*
|
|
|
|
|
;------------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
.model small
|
|
|
|
|
; .dosseg
|
|
|
|
|
.stack
|
|
|
|
|
.486p
|
|
|
|
|
.code
|
|
|
|
|
|
|
|
|
|
BLOCK_SIZE EQU 0200h
|
|
|
|
|
BLOCK_MASK EQU 01ffh
|
|
|
|
|
BLOCK_SHIFT EQU 9
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Code loaded by BIOS at 0x0000:0x7C00
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
org 0h
|
|
|
|
|
Start:
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Start Print
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
mov ax,0b800h
|
|
|
|
|
mov es,ax
|
|
|
|
|
mov ax, 07c0h
|
|
|
|
|
mov ds, ax
|
|
|
|
|
lea si, cs:[StartString]
|
|
|
|
|
mov cx, 10
|
|
|
|
|
mov di, 160
|
|
|
|
|
rep movsw
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Print over
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
xor ax, ax ; AX = 0x0000
|
|
|
|
|
mov bx, 07c00h ; BX = 0x7C00
|
|
|
|
|
mov bp, 0600h ; BP = 0x0600
|
|
|
|
|
mov si, OFFSET RelocatedStart ; SI = Offset(RelocatedStart)
|
|
|
|
|
mov cx, 0200h ; CX = 0x0200
|
|
|
|
|
sub cx, si ; CS = 0x0200 - Offset(RelocatedStart)
|
|
|
|
|
lea di, [bp+si] ; DI = 0x0600 + Offset(RelocatedStart)
|
|
|
|
|
lea si, [bx+si] ; BX = 0x7C00 + Offset(RelocatedStart)
|
|
|
|
|
mov ss, ax ; SS = 0x0000
|
|
|
|
|
mov sp, bx ; SP = 0x7C00
|
|
|
|
|
mov es,ax ; ES = 0x0000
|
|
|
|
|
mov ds,ax ; DS = 0x0000
|
|
|
|
|
push ax ; PUSH 0x0000
|
|
|
|
|
push di ; PUSH 0x0600 + Offset(RelocatedStart)
|
|
|
|
|
cld ; Clear the direction flag
|
|
|
|
|
rep movsb ; Copy 0x0200 bytes from 0x7C00 to 0x0600
|
|
|
|
|
retf ; JMP 0x0000:0x0600 + Offset(RelocatedStart)
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Code relocated to 0x0000:0x0600
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
RelocatedStart:
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Get Driver Parameters to 0x0000:0x7BFC
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
xor ax,ax ; AX = 0
|
|
|
|
|
mov ss,ax ; SS = 0
|
|
|
|
|
add ax,1000h
|
|
|
|
|
mov ds,ax
|
|
|
|
|
|
|
|
|
|
mov sp,07c00h ; SP = 0x7c00
|
|
|
|
|
mov bp,sp ; BP = 0x7c00
|
|
|
|
|
|
|
|
|
|
mov ah,8 ; AH = 8 - Get Drive Parameters Function
|
|
|
|
|
mov byte ptr [bp+PhysicalDrive],dl ; BBS defines that BIOS would pass the booting driver number to the loader through DL
|
|
|
|
|
int 13h ; Get Drive Parameters
|
|
|
|
|
xor ax,ax ; AX = 0
|
|
|
|
|
mov al,dh ; AL = DH
|
|
|
|
|
inc al ; MaxHead = AL + 1
|
|
|
|
|
push ax ; 0000:7bfe = MaxHead
|
|
|
|
|
mov al,cl ; AL = CL
|
|
|
|
|
and al,03fh ; MaxSector = AL & 0x3f
|
|
|
|
|
push ax ; 0000:7bfc = MaxSector
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Read Target DBR from hard disk to 0x0000:0x7C00
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
xor ax, ax
|
|
|
|
|
mov al, byte ptr [bp+MbrPartitionIndicator] ; AX = MbrPartitionIndex
|
|
|
|
|
cmp al, 0ffh ; 0xFF means do legacy MBR boot
|
|
|
|
|
jnz EfiDbr
|
|
|
|
|
LegacyMbr:
|
|
|
|
|
mov eax, 00000600h ; Assume LegacyMBR is backuped in Sector 6
|
|
|
|
|
jmp StartReadTo7C00 ; EAX = Header/Sector/Tracker/Zero
|
|
|
|
|
|
|
|
|
|
EfiDbr:
|
|
|
|
|
cmp al, 4 ; MbrPartitionIndex should < 4
|
|
|
|
|
jae BadDbr
|
|
|
|
|
shl ax, 4 ; AX = MBREntrySize * Index
|
|
|
|
|
add ax, 1beh ; AX = MBREntryOffset
|
|
|
|
|
mov di, ax ; DI = MBREntryOffset
|
|
|
|
|
|
|
|
|
|
; Here we don't use the C/H/S information provided by Partition table
|
|
|
|
|
; but calculate C/H/S from LBA ourselves
|
|
|
|
|
; Ci: Cylinder number
|
|
|
|
|
; Hi: Header number
|
|
|
|
|
; Si: Sector number
|
|
|
|
|
mov eax, dword ptr es:[bp + di + 8] ; Start LBA
|
|
|
|
|
mov edx, eax
|
|
|
|
|
shr edx, 16 ; DX:AX = Start LBA
|
|
|
|
|
; = Ci * (H * S) + Hi * S + (Si - 1)
|
|
|
|
|
|
|
|
|
|
; Calculate C/H/S according to LBA
|
|
|
|
|
mov bp, 7bfah
|
|
|
|
|
div word ptr [bp+2] ; AX = Hi + H*Ci
|
|
|
|
|
; DX = Si - 1
|
|
|
|
|
inc dx ; DX = Si
|
|
|
|
|
push dx ; 0000:7bfa = Si <----
|
|
|
|
|
xor dx, dx ; DX:AX = Hi + H*Ci
|
|
|
|
|
div word ptr [bp+4] ; AX = Ci <----
|
|
|
|
|
; DX = Hi <----
|
|
|
|
|
|
|
|
|
|
StartReadTo7C00:
|
|
|
|
|
|
|
|
|
|
mov cl, byte ptr [bp] ; Si
|
|
|
|
|
mov ch, al ; Ci[0-7]
|
|
|
|
|
or cl, ah ; Ci[8,9]
|
|
|
|
|
mov bx, 7c00h ; ES:BX = 0000:7C00h
|
|
|
|
|
mov ah, 2h ; Function 02h
|
|
|
|
|
mov al, 1 ; 1 Sector
|
|
|
|
|
mov dh, dl ; Hi
|
|
|
|
|
mov bp, 0600h
|
|
|
|
|
mov dl, byte ptr [bp + PhysicalDrive] ; Drive number
|
|
|
|
|
int 13h
|
|
|
|
|
jc BadDbr
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Transfer control to BootSector - Jump to 0x0000:0x7C00
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
xor ax, ax
|
|
|
|
|
push ax ; PUSH 0x0000 - Segment
|
|
|
|
|
mov di, 07c00h
|
|
|
|
|
push di ; PUSH 0x7C00 - Offset
|
|
|
|
|
retf ; JMP 0x0000:0x7C00
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; ERROR Condition:
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
BadDbr:
|
|
|
|
|
push ax
|
|
|
|
|
mov ax, 0b800h
|
|
|
|
|
mov es, ax
|
|
|
|
|
mov ax, 060h
|
|
|
|
|
mov ds, ax
|
|
|
|
|
lea si, cs:[ErrorString]
|
|
|
|
|
mov di, 320
|
|
|
|
|
pop ax
|
|
|
|
|
call A2C
|
|
|
|
|
mov [si+16], ah
|
|
|
|
|
mov [si+18], al
|
|
|
|
|
mov cx, 10
|
|
|
|
|
rep movsw
|
|
|
|
|
Halt:
|
|
|
|
|
jmp Halt
|
|
|
|
|
|
|
|
|
|
StartString:
|
|
|
|
|
db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'S', 0ch, 't', 0ch, 'a', 0ch, 'r', 0ch, 't', 0ch, '!', 0ch
|
|
|
|
|
ErrorString:
|
|
|
|
|
db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'E', 0ch, 'r', 0ch, 'r', 0ch, ':', 0ch, '?', 0ch, '?', 0ch
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; A2C - convert Ascii code stored in AH to character stored in AX
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
A2C:
|
|
|
|
|
mov al, ah
|
|
|
|
|
shr ah, 4
|
|
|
|
|
and al, 0Fh
|
|
|
|
|
add ah, '0'
|
|
|
|
|
add al, '0'
|
|
|
|
|
|
|
|
|
|
cmp ah, '9'
|
|
|
|
|
jle @f
|
|
|
|
|
add ah, 7
|
|
|
|
|
@@:
|
|
|
|
|
|
|
|
|
|
cmp al, '9'
|
|
|
|
|
jle @f
|
|
|
|
|
add al, 7
|
|
|
|
|
@@:
|
|
|
|
|
ret
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; PhysicalDrive - Used to indicate which disk to be boot
|
|
|
|
|
; Can be patched by tool
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
org 01B6h
|
|
|
|
|
PhysicalDrive db 80h
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; MbrPartitionIndicator - Used to indicate which MBR partition to be boot
|
|
|
|
|
; Can be patched by tool
|
|
|
|
|
; OxFF means boot to legacy MBR. (LBA OFFSET 6)
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
org 01B7h
|
|
|
|
|
MbrPartitionIndicator db 0
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Unique MBR signature
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
org 01B8h
|
|
|
|
|
db 'DUET'
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Unknown
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
org 01BCh
|
|
|
|
|
dw 0
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; MBR Entry - To be patched
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
org 01BEh
|
|
|
|
|
dd 0, 0, 0, 0
|
|
|
|
|
org 01CEh
|
|
|
|
|
dd 0, 0, 0, 0
|
|
|
|
|
org 01DEh
|
|
|
|
|
dd 0, 0, 0, 0
|
|
|
|
|
org 01EEh
|
|
|
|
|
dd 0, 0, 0, 0
|
|
|
|
|
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
; Sector Signature
|
|
|
|
|
; ****************************************************************************
|
|
|
|
|
|
|
|
|
|
org 01FEh
|
|
|
|
|
SectorSignature:
|
|
|
|
|
dw 0aa55h ; Boot Sector Signature
|
|
|
|
|
|
|
|
|
|
end
|
|
|
|
|
|
