+++ /dev/null
-#------------------------------------------------------------------------------\r
-#*\r
-#* Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>\r
-#* This program and the accompanying materials\r
-#* are licensed and made available under the terms and conditions of the BSD License\r
-#* which accompanies this distribution. The full text of the license may be found at\r
-#* http://opensource.org/licenses/bsd-license.php\r
-#*\r
-#* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
-#* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
-#*\r
-#* Mbr.asm\r
-#*\r
-#* Abstract:\r
-#*\r
-#------------------------------------------------------------------------------\r
-\r
- .code16 \r
-\r
-.equ BLOCK_SIZE, 0x0200\r
-.equ BLOCK_MASK, 0x01ff\r
-.equ BLOCK_SHIFT, 9\r
-\r
-# ****************************************************************************\r
-# Code loaded by BIOS at 0x0000:0x7C00\r
-# ****************************************************************************\r
-\r
-.org 0x0\r
-\r
-.global _start\r
-_start:\r
-\r
-# ****************************************************************************\r
-# Start Print\r
-# ****************************************************************************\r
-\r
- movw $0xb800, %ax\r
- movw %ax, %es\r
- movw $0x7c0, %ax\r
- movw %ax, %ds\r
- leaw %cs:StartString, %si\r
- movw $10, %cx\r
- movw $160, %di\r
- rep \r
- movsw\r
-\r
-# ****************************************************************************\r
-# Print over\r
-# ****************************************************************************\r
-\r
-# ****************************************************************************\r
-# Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600\r
-# ****************************************************************************\r
- xorw %ax, %ax # AX = 0x0000\r
- movw $0x7c00, %bx # BX = 0x7C00\r
- movw $0x600, %bp # BP = 0x0600\r
- movw $RelocatedStart, %si # SI = Offset(RelocatedStart)\r
- movw $0x200, %cx # CX = 0x0200\r
- subw %si, %cx # CS = 0x0200 - Offset(RelocatedStart)\r
- leaw (%bp,%si,), %di # DI = 0x0600 + Offset(RelocatedStart)\r
- leaw (%bx,%si,), %si # BX = 0x7C00 + Offset(RelocatedStart)\r
- movw %ax, %ss # SS = 0x0000\r
- movw %bx, %sp # SP = 0x7C00\r
- movw %ax, %es # ES = 0x0000\r
- movw %ax, %ds # DS = 0x0000\r
- pushw %ax # PUSH 0x0000\r
- pushw %di # PUSH 0x0600 + Offset(RelocatedStart)\r
- cld # Clear the direction flag\r
- rep\r
- movsb # Copy 0x0200 bytes from 0x7C00 to 0x0600\r
- retl # JMP 0x0000:0x0600 + Offset(RelocatedStart)\r
-\r
-# ****************************************************************************\r
-# Code relocated to 0x0000:0x0600\r
-# ****************************************************************************\r
-\r
-RelocatedStart: \r
-# ****************************************************************************\r
-# Get Driver Parameters to 0x0000:0x7BFC\r
-# ****************************************************************************\r
-\r
- xorw %ax, %ax # AX = 0\r
- movw %ax, %ss # SS = 0\r
- addw $0x1000, %ax\r
- movw %ax, %ds\r
-\r
- movw $0x7c00, %sp # SP = 0x7c00\r
- movw %sp, %bp # BP = 0x7c00\r
-\r
- movb $8, %ah # AH = 8 - Get Drive Parameters Function\r
- movb %dl, PhysicalDrive(%bp) # BBS defines that BIOS would pass the booting driver number to the loader through DL\r
- int $0x13 # Get Drive Parameters\r
- xorw %ax, %ax # AX = 0\r
- movb %dh, %al # AL = DH\r
- incb %al # MaxHead = AL + 1\r
- pushw %ax # 0000:7bfe = MaxHead\r
- movb %cl, %al # AL = CL\r
- andb $0x3f, %al # MaxSector = AL & 0x3f\r
- pushw %ax # 0000:7bfc = MaxSector\r
-\r
-# ****************************************************************************\r
-# Read Target DBR from hard disk to 0x0000:0x7C00\r
-# ****************************************************************************\r
-\r
- xorw %ax, %ax\r
- movb MbrPartitionIndicator(%bp), %al # AX = MbrPartitionIndex\r
- cmpb $0xff, %al # 0xFF means do legacy MBR boot\r
- jnz EfiDbr\r
-LegacyMbr: \r
- movl $0x0000600, %eax # Assume LegacyMBR is backuped in Sector 6\r
- jmp StartReadTo7C00 # EAX = Header/Sector/Tracker/Zero\r
-\r
-EfiDbr: \r
- cmpb $4, %al # MbrPartitionIndex should < 4\r
- jae BadDbr\r
- shlw $4, %ax # AX = MBREntrySize * Index\r
- addw $0x1be, %ax # AX = MBREntryOffset\r
- movw %ax, %di # DI = MBREntryOffset\r
-\r
- # Here we don't use the C/H/S information provided by Partition table\r
- # but calculate C/H/S from LBA ourselves\r
- # Ci: Cylinder number\r
- # Hi: Header number\r
- # Si: Sector number\r
- movl %es:8(%bp,%di,), %eax # Start LBA\r
- movl %eax, %edx\r
- shrl $16, %edx # DX:AX = Start LBA\r
- # = Ci * (H * S) + Hi * S + (Si - 1)\r
-\r
- # Calculate C/H/S according to LBA\r
- movw $0x7bfa, %bp\r
- divw 2(%bp) # AX = Hi + H*Ci\r
- # DX = Si - 1\r
- incw %dx # DX = Si\r
- pushw %dx # 0000:7bfa = Si <----\r
- xorw %dx, %dx # DX:AX = Hi + H*Ci\r
- divw 4(%bp) # AX = Ci <----\r
- # DX = Hi <----\r
-\r
-StartReadTo7C00: \r
-\r
- movb (%bp), %cl # Si\r
- movb %al, %ch # Ci[0-7]\r
- orb %ah, %cl # Ci[8,9]\r
- movw $0x7c00, %bx # ES:BX = 0000:7C00h\r
- movb $0x2, %ah # Function 02h\r
- movb $1, %al # 1 Sector\r
- movb %dl, %dh # Hi\r
- movw $0x600, %bp\r
- movb PhysicalDrive(%bp), %dl # Drive number\r
- int $0x13\r
- jc BadDbr\r
-\r
-\r
-\r
-# ****************************************************************************\r
-# Transfer control to BootSector - Jump to 0x0000:0x7C00\r
-# ****************************************************************************\r
- xorw %ax, %ax\r
- pushw %ax # PUSH 0x0000 - Segment\r
- movw $0x7c00, %di\r
- pushw %di # PUSH 0x7C00 - Offset\r
- retl # JMP 0x0000:0x7C00\r
-\r
-# ****************************************************************************\r
-# ERROR Condition:\r
-# ****************************************************************************\r
-\r
-BadDbr: \r
- pushw %ax\r
- movw $0xb800, %ax\r
- movw %ax, %es\r
- movw $0x60, %ax\r
- movw %ax, %ds\r
- leaw %cs:ErrorString, %si\r
- movw $320, %di\r
- popw %ax\r
- call A2C\r
- movb %ah, 16(%si)\r
- movb %al, 18(%si)\r
- movw $10, %cx\r
- rep\r
- movsw\r
-Halt: \r
- jmp Halt\r
-\r
-StartString: \r
-.byte 'M', 0x0c, 'B', 0x0c, 'R', 0x0c, ' ', 0x0c, 'S', 0x0c, 't', 0x0c, 'a', 0x0c, 'r', 0x0c, 't', 0x0c, '!', 0x0c\r
-ErrorString: \r
-.byte 'M', 0x0c, 'B', 0x0c, 'R', 0x0c, ' ', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, ':', 0x0c, '?', 0x0c, '?', 0x0c\r
-\r
-# ****************************************************************************\r
-# A2C - convert Ascii code stored in AH to character stored in AX\r
-# ****************************************************************************\r
-A2C: \r
- movb %ah, %al\r
- shrb $4, %ah\r
- andb $0xF, %al\r
- addb '0', %ah\r
- addb '0', %al\r
-\r
- cmpb '9', %ah\r
- jle A2C_L1\r
- addb $7, %ah\r
-A2C_L1: \r
-\r
- cmpb '9', %al\r
- jle A2C_L2\r
- addb $7, %al\r
-A2C_L2: \r
- ret\r
-\r
-\r
-# ****************************************************************************\r
-# PhysicalDrive - Used to indicate which disk to be boot\r
-# Can be patched by tool\r
-# ****************************************************************************\r
-.org 0x01B6\r
-PhysicalDrive: .byte 0x80\r
-\r
-# ****************************************************************************\r
-# MbrPartitionIndicator - Used to indicate which MBR partition to be boot\r
-# Can be patched by tool\r
-# OxFF means boot to legacy MBR. (LBA OFFSET 6)\r
-# ****************************************************************************\r
-.org 0x01B7\r
-MbrPartitionIndicator: .byte 0\r
-\r
-# ****************************************************************************\r
-# Unique MBR signature\r
-# ****************************************************************************\r
-.org 0x01B8\r
- .ascii "DUET"\r
-\r
-# ****************************************************************************\r
-# Unknown\r
-# ****************************************************************************\r
-.org 0x01BC\r
- .word 0\r
-\r
-# ****************************************************************************\r
-# MBR Entry - To be patched\r
-# ****************************************************************************\r
-.org 0x01BE\r
- .long 0,0,0,0\r
-.org 0x01CE\r
- .long 0,0,0,0\r
-.org 0x01DE\r
- .long 0,0,0,0\r
-.org 0x01EE\r
- .long 0,0,0,0\r
-\r
-# ****************************************************************************\r
-# Sector Signature\r
-# ****************************************************************************\r
-\r
-.org 0x01FE\r
-SectorSignature: \r
- .word 0xaa55 # Boot Sector Signature\r
-\r
-\r
-\r
projects / mirror_edk2.git / blobdiff