mirror of https://github.com/acidanthera/audk.git
298 lines
13 KiB
ArmAsm
298 lines
13 KiB
ArmAsm
#------------------------------------------------------------------------------
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#*
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#* Copyright 2006 - 2007, Intel Corporation
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#* All rights reserved. This program and the accompanying materials
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#* are licensed and made available under the terms and conditions of the BSD License
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#* which accompanies this distribution. The full text of the license may be found at
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#* http://opensource.org/licenses/bsd-license.php
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#*
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#* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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#* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#*
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#* gpt.asm
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#*
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#* Abstract:
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#*
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#------------------------------------------------------------------------------
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#.MODEL small
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# .dosseg
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.stack:
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.486p:
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.code:
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.equ BLOCK_SIZE, 0x0200
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.equ BLOCK_MASK, 0x01ff
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.equ BLOCK_SHIFT, 9
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# ****************************************************************************
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# Code loaded by BIOS at 0x0000:0x7C00
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# ****************************************************************************
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.org 0x00
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Start:
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# ****************************************************************************
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# Start Print
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# ****************************************************************************
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movw $0xb800, %ax
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movw %ax, %es
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movw $0x7c0, %ax
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movw %ax, %ds
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leaw %cs:StartString, %si
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movw $10, %cx
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movw $160, %di
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rep
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movsw
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# ****************************************************************************
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# Print over
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# ****************************************************************************
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# ****************************************************************************
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# Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600
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# ****************************************************************************
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xorw %ax, %ax # AX = 0x0000
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movw $0x7c00, %bx # BX = 0x7C00
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movw $0x600, %bp # BP = 0x0600
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movw RelocatedStart, %si # SI = Offset(RelocatedStart)
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movw $0x200, %cx # CX = 0x0200
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subw %si, %cx # CS = 0x0200 - Offset(RelocatedStart)
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leaw (%bp,%si,), %di # DI = 0x0600 + Offset(RelocatedStart)
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leaw (%bx,%si,), %si # BX = 0x7C00 + Offset(RelocatedStart)
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movw %ax, %ss # SS = 0x0000
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movw %bx, %sp # SP = 0x7C00
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movw %ax, %es # ES = 0x0000
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movw %ax, %ds # DS = 0x0000
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pushw %ax # PUSH 0x0000
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pushw %di # PUSH 0x0600 + Offset(RelocatedStart)
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cld # Clear the direction flag
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rep
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movsb # Copy 0x0200 bytes from 0x7C00 to 0x0600
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retl # JMP 0x0000:0x0600 + Offset(RelocatedStart)
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# ****************************************************************************
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# Code relocated to 0x0000:0x0600
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# ****************************************************************************
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RelocatedStart:
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# ****************************************************************************
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# Get Driver Parameters to 0x0000:0x7BFC
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# ****************************************************************************
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xorw %ax, %ax # ax = 0
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movw %ax, %ss # ss = 0
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addw $0x1000, %ax
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movw %ax, %ds
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movw $0x7c00, %sp # sp = 0x7c00
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movw %sp, %bp # bp = 0x7c00
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movb $8, %ah # ah = 8 - Get Drive Parameters Function
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movb %dl, PhysicalDrive(%bp) # BBS defines that BIOS would pass the booting driver number to the loader through DL
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int $0x13 # Get Drive Parameters
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xorw %ax, %ax # ax = 0
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movb %dh, %al # al = dh
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incb %al # MaxHead = al + 1
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pushw %ax # 0000:7bfe = MaxHead
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movb %cl, %al # al = cl
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andb $0x3f, %al # MaxSector = al & 0x3f
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pushw %ax # 0000:7bfc = MaxSector
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# ****************************************************************************
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# Read GPT Header from hard disk to 0x0000:0x0800
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# ****************************************************************************
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xorw %ax, %ax
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movw %ax, %es # Read to 0x0000:0x0800
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movw $0x800, %di # Read to 0x0000:0x0800
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movl $1, %eax # Read LBA #1
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movl $0, %edx # Read LBA #1
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movw $1, %bx # Read 1 Block
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pushw %es
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call ReadBlocks
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popw %es
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# ****************************************************************************
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# Read Target GPT Entry from hard disk to 0x0000:0x0A00
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# ****************************************************************************
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cmpl $0x20494645, %es:(%di) # Check for "EFI "
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jne BadGpt
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cmpl $0x54524150, %es:4(%di) # Check for "PART"
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jne BadGpt
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cmpl $0x00010000, %es:8(%di) # Check Revision - 0x10000
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jne BadGpt
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movl %es:84(%di), %eax # EAX = SizeOfPartitionEntry
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mulb GptPartitionIndicator(%bp) # EAX = SizeOfPartitionEntry * GptPartitionIndicator
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movl %eax, %edx # EDX = SizeOfPartitionEntry * GptPartitionIndicator
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shrl $BLOCK_SHIFT, %eax # EAX = (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE
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andl $BLOCK_MASK, %edx # EDX = Targer PartitionEntryLBA Offset
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# = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE
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pushl %edx
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movl %es:72(%di), %ecx # ECX = PartitionEntryLBA (Low)
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movl %es:76(%di), %ebx # EBX = PartitionEntryLBA (High)
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addl %ecx, %eax # EAX = Target PartitionEntryLBA (Low)
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# = (PartitionEntryLBA +
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# (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE)
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adcl %ebx, %edx # EDX = Target PartitionEntryLBA (High)
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movw $0xA00, %di # Read to 0x0000:0x0A00
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movw $1, %bx # Read 1 Block
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pushw %es
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call ReadBlocks
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popw %es
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# ****************************************************************************
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# Read Target DBR from hard disk to 0x0000:0x7C00
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# ****************************************************************************
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popl %edx # EDX = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE
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addw %dx, %di # DI = Targer PartitionEntryLBA Offset
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cmpl $0xC12A7328, %es:(%di) # Check for EFI System Partition "C12A7328-F81F-11d2-BA4B-00A0C93EC93B"
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jne BadGpt
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cmpl $0x11d2F81F, %es:4(%di) #
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jne BadGpt
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cmpl $0xA0004BBA, %es:8(%di) #
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jne BadGpt
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cmpl $0x3BC93EC9, %es:0xc(%di) #
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jne BadGpt
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movl %es:32(%di), %eax # EAX = StartingLBA (Low)
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movl %es:36(%di), %edx # EDX = StartingLBA (High)
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movw $0x7C00, %di # Read to 0x0000:0x7C00
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movw $1, %bx # Read 1 Block
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call ReadBlocks
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# ****************************************************************************
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# Transfer control to BootSector - Jump to 0x0000:0x7C00
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# ****************************************************************************
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xorw %ax, %ax
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pushw %ax # PUSH 0x0000
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movw $0x7c00, %di
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pushw %di # PUSH 0x7C00
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retl # JMP 0x0000:0x7C00
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# ****************************************************************************
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# ReadBlocks - Reads a set of blocks from a block device
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#
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# EDX:EAX = Start LBA
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# BX = Number of Blocks to Read (must < 127)
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# ES:DI = Buffer to store sectors read from disk
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# ****************************************************************************
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# si = DiskAddressPacket
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ReadBlocks:
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pushal
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pushw %ds
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xorw %cx, %cx
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movw %cx, %ds
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movw $0x600, %bp # bp = 0x600
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leaw AddressPacket(%bp), %si
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movb %bl, %ds:2(%si) # 02 = Number Of Block transfered
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movw %di, %ds:4(%si) # 04 = Transfer Buffer Offset
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movw %es, %ds:6(%si) # 06 = Transfer Buffer Segment
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movl %eax, %ds:8(%si) # 08 = Starting LBA (Low)
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movl %edx, %ds:0xc(%si) # 0C = Starting LBA (High)
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movb $0x42, %ah # ah = Function 42
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movb PhysicalDrive(%bp), %dl # dl = Drive Number
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int $0x13
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jc BadGpt
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popw %ds
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popal
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ret
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# ****************************************************************************
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# Address Packet used by ReadBlocks
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# ****************************************************************************
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AddressPacket:
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.byte 0x10 # Size of address packet
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.byte 0x0 # Reserved. Must be 0
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.byte 0x1 # Read blocks at a time (To be fixed each times)
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.byte 0x0 # Reserved. Must be 0
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.word 0x000 # Destination Address offset (To be fixed each times)
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.word 0x000 # Destination Address segment (To be fixed each times)
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AddressPacketLba:
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.long 0x0,0x0 # Start LBA (To be fixed each times)
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AddressPacketEnd:
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# ****************************************************************************
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# ERROR Condition:
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# ****************************************************************************
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BadGpt:
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movw $0xb800, %ax
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movw %ax, %es
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movw $0x60, %ax
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movw %ax, %ds
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leaw %cs:ErrorString, %si
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movw $10, %cx
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movw $320, %di
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rep
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movsw
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Halt:
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jmp Halt
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StartString:
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.byte 'G', 0x0c, 'P', 0x0c, 'T', 0x0c, ' ', 0x0c, 'S', 0x0c, 't', 0x0c, 'a', 0x0c, 'r', 0x0c, 't', 0x0c, '!', 0x0c
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ErrorString:
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.byte 'G', 0x0c, 'P', 0x0c, 'T', 0x0c, ' ', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!', 0x0c
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# ****************************************************************************
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# PhysicalDrive - Used to indicate which disk to be boot
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# Can be patched by tool
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# ****************************************************************************
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.org 0x01B6
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PhysicalDrive: .byte 0x80
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# ****************************************************************************
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# GptPartitionIndicator - Used to indicate which GPT partition to be boot
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# Can be patched by tool
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# ****************************************************************************
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.org 0x01B7
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GptPartitionIndicator: .byte 0
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# ****************************************************************************
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# Unique MBR signature
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# ****************************************************************************
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.org 0x01B8
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.ascii "DUET"
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# ****************************************************************************
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# Unknown
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# ****************************************************************************
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.org 0x01BC
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.word 0
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# ****************************************************************************
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# PMBR Entry - Can be patched by tool
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# ****************************************************************************
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.org 0x01BE
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.byte 0 # Boot Indicator
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.byte 0xff # Start Header
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.byte 0xff # Start Sector
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.byte 0xff # Start Track
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.byte 0xee # OS Type
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.byte 0xff # End Header
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.byte 0xff # End Sector
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.byte 0xff # End Track
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.long 1 # Starting LBA
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.long 0xFFFFFFFF # End LBA
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.org 0x01CE
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.long 0,0,0,0
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.org 0x01DE
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.long 0,0,0,0
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.org 0x01EE
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.long 0,0,0,0
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# ****************************************************************************
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# Sector Signature
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# ****************************************************************************
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.org 0x01FE
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SectorSignature:
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.word 0xaa55 # Boot Sector Signature
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