mirror of https://github.com/acidanthera/audk.git
Port Intel .asm to GNU .S
These .S files now is not for compiler but for us to control the version. git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7548 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
jji4
parent
3c5a8c113e
commit
32f9b796d3
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@ -20,8 +20,10 @@
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bs16.asm | MSFT
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bs16.asm | MSFT
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bs32.asm | INTEL
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bs32.asm | INTEL
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bs32.asm | MSFT
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bs32.asm | MSFT
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# bs32.S | GCC ## It can not be compiled. It is added just for version control.
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Gpt.asm | INTEL
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Gpt.asm | INTEL
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Gpt.asm | MSFT
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Gpt.asm | MSFT
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# Gpt.S | GCC ## It can not be compiled. It is added just for version control.
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Mbr.asm | INTEL
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Mbr.asm | INTEL
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Mbr.asm | MSFT
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Mbr.asm | MSFT
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start.asm | INTEL
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start.asm | INTEL
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@ -0,0 +1,297 @@
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#------------------------------------------------------------------------------
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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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@ -0,0 +1,310 @@
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#------------------------------------------------------------------------------
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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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||||||
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#* http://opensource.org/licenses/bsd-license.php
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#*
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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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||||||
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#* bs32.asm
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||||||
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#*
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||||||
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#* Abstract:
|
||||||
|
#*
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||||||
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#------------------------------------------------------------------------------
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||||||
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#.MODEL small
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.stack:
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.486p:
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.code:
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.equ FAT_DIRECTORY_ENTRY_SIZE, 0x0020
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.equ FAT_DIRECTORY_ENTRY_SHIFT, 5
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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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# "EFILDR_____"
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.equ LOADER_FILENAME_PART1, 0x4c494645 # "EFIL"
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.equ LOADER_FILENAME_PART2, 0x30325244 # "DR20"
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.equ LOADER_FILENAME_PART3, 0x20202030 # "0___"
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.org 0x00
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Ia32Jump:
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jmp BootSectorEntryPoint # JMP inst - 3 bytes
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nop
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OemId: .ascii "INTEL " # OemId - 8 bytes
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# BPB data below will be fixed by tool
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SectorSize: .word 0 # Sector Size - 16 bits
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SectorsPerCluster: .byte 0 # Sector Per Cluster - 8 bits
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ReservedSectors: .word 0 # Reserved Sectors - 16 bits
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NoFats: .byte 0 # Number of FATs - 8 bits
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||||||
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RootEntries: .word 0 # Root Entries - 16 bits
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Sectors: .word 0 # Number of Sectors - 16 bits
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Media: .byte 0 # Media - 8 bits - ignored
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SectorsPerFat: .word 0 # Sectors Per FAT - 16 bits
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SectorsPerTrack: .word 0 # Sectors Per Track - 16 bits - ignored
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Heads: .word 0 # Heads - 16 bits - ignored
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HiddenSectors: .long 0 # Hidden Sectors - 32 bits - ignored
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LargeSectors: .long 0 # Large Sectors - 32 bits
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||||||
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#******************************************************************************
|
||||||
|
#
|
||||||
|
#The structure for FAT32 starting at offset 36 of the boot sector. (At this point,
|
||||||
|
#the BPB/boot sector for FAT12 and FAT16 differs from the BPB/boot sector for FAT32.)
|
||||||
|
#
|
||||||
|
#******************************************************************************
|
||||||
|
|
||||||
|
SectorsPerFat32: .long 0 # Sectors Per FAT for FAT32 - 4 bytes
|
||||||
|
ExtFlags: .word 0 # Mirror Flag - 2 bytes
|
||||||
|
FSVersion: .word 0 # File System Version - 2 bytes
|
||||||
|
RootCluster: .long 0 # 1st Cluster Number of Root Dir - 4 bytes
|
||||||
|
FSInfo: .word 0 # Sector Number of FSINFO - 2 bytes
|
||||||
|
BkBootSector: .word 0 # Sector Number of Bk BootSector - 2 bytes
|
||||||
|
Reserved: .fill 12, 1, 0 # Reserved Field - 12 bytes
|
||||||
|
PhysicalDrive: .byte 0 # Physical Drive Number - 1 byte
|
||||||
|
Reserved1: .byte 0 # Reserved Field - 1 byte
|
||||||
|
Signature: .byte 0 # Extended Boot Signature - 1 byte
|
||||||
|
VolId: .ascii " " # Volume Serial Number - 4 bytes
|
||||||
|
FatLabel: .ascii " " # Volume Label - 11 bytes
|
||||||
|
FileSystemType: .ascii "FAT32 " # File System Type - 8 bytes
|
||||||
|
BootSectorEntryPoint:
|
||||||
|
#ASSUME ds:@code
|
||||||
|
#ASSUME ss:@code
|
||||||
|
|
||||||
|
# ****************************************************************************
|
||||||
|
# Start Print
|
||||||
|
# ****************************************************************************
|
||||||
|
leaw %cs:StartString, %si
|
||||||
|
call PrintString
|
||||||
|
|
||||||
|
# ****************************************************************************
|
||||||
|
# Print over
|
||||||
|
# ****************************************************************************
|
||||||
|
|
||||||
|
movw %cs, %ax # ax = 0
|
||||||
|
movw %ax, %ss # ss = 0
|
||||||
|
addw $0x1000, %ax
|
||||||
|
movw %ax, %ds
|
||||||
|
|
||||||
|
movw $0x7c00, %sp # sp = 0x7c00
|
||||||
|
movw %sp, %bp # bp = 0x7c00
|
||||||
|
|
||||||
|
movb $8, %ah # ah = 8 - Get Drive Parameters Function
|
||||||
|
movb %dl, PhysicalDrive(%bp) # BBS defines that BIOS would pass the booting driver number to the loader through DL
|
||||||
|
int $0x13 # Get Drive Parameters
|
||||||
|
xorw %ax, %ax # ax = 0
|
||||||
|
movb %dh, %al # al = dh
|
||||||
|
incb %al # MaxHead = al + 1
|
||||||
|
pushw %ax # 0000:7bfe = MaxHead
|
||||||
|
movb %cl, %al # al = cl
|
||||||
|
andb $0x3f, %al # MaxSector = al & 0x3f
|
||||||
|
pushw %ax # 0000:7bfc = MaxSector
|
||||||
|
|
||||||
|
cmpw $0xaa55, SectorSignature(%bp) # Verify Boot Sector Signature
|
||||||
|
jne BadBootSector
|
||||||
|
movw RootEntries(%bp), %cx # cx = RootEntries
|
||||||
|
shlw $FAT_DIRECTORY_ENTRY_SHIFT, %cx # cx = cx * 32 = cx * sizeof(FAT_DIRECTORY_ENTRY) = Size of Root Directory in bytes
|
||||||
|
movw %cx, %bx # bx = size of the Root Directory in bytes
|
||||||
|
andw $BLOCK_MASK, %bx # See if it is an even number of sectors long
|
||||||
|
jne BadBootSector # If is isn't, then the boot sector is bad.
|
||||||
|
movw %cx, %bx # bx = size of the Root Directory in bytes
|
||||||
|
shrw $BLOCK_SHIFT, %bx # bx = size of Root Directory in sectors
|
||||||
|
movb NoFats(%bp), %al # al = NoFats
|
||||||
|
xorb %ah, %ah # ah = 0 ==> ax = NoFats
|
||||||
|
mulw SectorsPerFat32(%bp) # ax = NoFats * SectorsPerFat
|
||||||
|
addw ReservedSectors(%bp), %ax # ax = NoFats * SectorsPerFat + ReservedSectors = RootLBA
|
||||||
|
addw %bx, %ax # ax = NoFats * SectorsPerFat + ReservedSectors + RootDirSectors = FirstClusterLBA
|
||||||
|
movw %ax, (%bp) # Save FirstClusterLBA for later use
|
||||||
|
|
||||||
|
movw RootCluster(%bp), %ax # ax = StartCluster of Root Directory
|
||||||
|
subw $2, %ax # ax = StartCluster - 2
|
||||||
|
xorb %bh, %bh
|
||||||
|
movb SectorsPerCluster(%bp), %bl # bx = SectorsPerCluster
|
||||||
|
mulw %bx # ax = (StartCluster - 2) * SectorsPerCluster
|
||||||
|
addw (%bp), %ax # ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
|
||||||
|
pushw %ds
|
||||||
|
popw %es
|
||||||
|
xorw %di, %di # Store directory in es:di = 1000:0000
|
||||||
|
call ReadBlocks # Read StartCluster of Root Directory
|
||||||
|
|
||||||
|
# dx - variable storage (initial value is 0)
|
||||||
|
# bx - loader (initial value is 0)
|
||||||
|
xorw %dx, %dx
|
||||||
|
xorw %bx, %bx
|
||||||
|
|
||||||
|
FindEFILDR:
|
||||||
|
cmpl $LOADER_FILENAME_PART1, (%di)
|
||||||
|
jne FindVARSTORE
|
||||||
|
cmpl $LOADER_FILENAME_PART2, 4(%di)
|
||||||
|
jne FindVARSTORE
|
||||||
|
cmpl $LOADER_FILENAME_PART3, 7(%di)
|
||||||
|
jne FindVARSTORE
|
||||||
|
movw 26(%di), %bx # bx = Start Cluster for EFILDR <----------------------------------
|
||||||
|
testw %dx, %dx
|
||||||
|
je FindNext # Efivar.bin is not loaded
|
||||||
|
jmp FoundAll
|
||||||
|
|
||||||
|
FindVARSTORE:
|
||||||
|
# if the file is not loader file, see if it's "EFIVAR BIN"
|
||||||
|
cmpl $0x56494645, (%di) # Compare to "EFIV"
|
||||||
|
jne FindNext
|
||||||
|
cmpl $0x20205241, 4(%di) # Compare to "AR "
|
||||||
|
jne FindNext
|
||||||
|
cmpl $0x4e494220, 7(%di) # Compare to " BIN"
|
||||||
|
jne FindNext
|
||||||
|
movw %di, %dx # dx = Offset of Start Cluster for Efivar.bin <---------------------
|
||||||
|
addw $26, %dx
|
||||||
|
testw %bx, %bx
|
||||||
|
je FindNext # Efildr is not loaded
|
||||||
|
jmp FoundAll
|
||||||
|
|
||||||
|
FindNext:
|
||||||
|
# go to next find
|
||||||
|
addw $FAT_DIRECTORY_ENTRY_SIZE, %di # Increment di
|
||||||
|
subw $FAT_DIRECTORY_ENTRY_SIZE, %cx # Decrement cx
|
||||||
|
# TODO: jump to FindVarStore if ...
|
||||||
|
jne FindEFILDR
|
||||||
|
jmp NotFoundAll
|
||||||
|
|
||||||
|
FoundAll:
|
||||||
|
FoundEFILDR:
|
||||||
|
movw %bx, %cx # cx = Start Cluster for EFILDR <----------------------------------
|
||||||
|
movw %cs, %ax # Destination = 2000:0000
|
||||||
|
addw $0x2000, %ax
|
||||||
|
movw %ax, %es
|
||||||
|
xorw %di, %di
|
||||||
|
ReadFirstClusterOfEFILDR:
|
||||||
|
movw %cx, %ax # ax = StartCluster
|
||||||
|
subw $2, %ax # ax = StartCluster - 2
|
||||||
|
xorb %bh, %bh
|
||||||
|
movb SectorsPerCluster(%bp), %bl # bx = SectorsPerCluster
|
||||||
|
pushw %dx
|
||||||
|
mulw %bx
|
||||||
|
popw %dx # ax = (StartCluster - 2) * SectorsPerCluster
|
||||||
|
addw (%bp), %ax # ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
|
||||||
|
xorb %bh, %bh
|
||||||
|
movb SectorsPerCluster(%bp), %bl # bx = Number of Sectors in a cluster
|
||||||
|
pushw %es
|
||||||
|
call ReadBlocks
|
||||||
|
popw %ax
|
||||||
|
JumpIntoFirstSectorOfEFILDR:
|
||||||
|
movw %ax, JumpSegment(%bp)
|
||||||
|
JumpFarInstruction:
|
||||||
|
.byte 0xea
|
||||||
|
JumpOffset:
|
||||||
|
.word 0x000
|
||||||
|
JumpSegment:
|
||||||
|
.word 0x2000
|
||||||
|
|
||||||
|
|
||||||
|
PrintString:
|
||||||
|
movw $0xb800, %ax
|
||||||
|
movw %ax, %es
|
||||||
|
movw $0x7c0, %ax
|
||||||
|
movw %ax, %ds
|
||||||
|
movw $7, %cx
|
||||||
|
movw $160, %di
|
||||||
|
rep
|
||||||
|
movsw
|
||||||
|
ret
|
||||||
|
# ****************************************************************************
|
||||||
|
# ReadBlocks - Reads a set of blocks from a block device
|
||||||
|
#
|
||||||
|
# AX = Start LBA
|
||||||
|
# BX = Number of Blocks to Read
|
||||||
|
# ES:DI = Buffer to store sectors read from disk
|
||||||
|
# ****************************************************************************
|
||||||
|
|
||||||
|
# cx = Blocks
|
||||||
|
# bx = NumberOfBlocks
|
||||||
|
# si = StartLBA
|
||||||
|
|
||||||
|
ReadBlocks:
|
||||||
|
pusha
|
||||||
|
addl LBAOffsetForBootSector(%bp), %eax # Add LBAOffsetForBootSector to Start LBA
|
||||||
|
addl HiddenSectors(%bp), %eax # Add HiddenSectors to Start LBA
|
||||||
|
movl %eax, %esi # esi = Start LBA
|
||||||
|
movw %bx, %cx # cx = Number of blocks to read
|
||||||
|
ReadCylinderLoop:
|
||||||
|
movw $0x7bfc, %bp # bp = 0x7bfc
|
||||||
|
movl %esi, %eax # eax = Start LBA
|
||||||
|
xorl %edx, %edx # edx = 0
|
||||||
|
movzwl (%bp), %ebx # bx = MaxSector
|
||||||
|
divl %ebx # ax = StartLBA / MaxSector
|
||||||
|
incw %dx # dx = (StartLBA % MaxSector) + 1
|
||||||
|
subw %dx, %bx # bx = MaxSector - Sector
|
||||||
|
incw %bx # bx = MaxSector - Sector + 1
|
||||||
|
cmpw %bx, %cx # Compare (Blocks) to (MaxSector - Sector + 1)
|
||||||
|
jg LimitTransfer
|
||||||
|
movw %cx, %bx # bx = Blocks
|
||||||
|
LimitTransfer:
|
||||||
|
pushw %cx
|
||||||
|
movb %dl, %cl # cl = (StartLBA % MaxSector) + 1 = Sector
|
||||||
|
xorw %dx, %dx # dx = 0
|
||||||
|
divw 2(%bp) # ax = ax / (MaxHead + 1) = Cylinder
|
||||||
|
# dx = ax % (MaxHead + 1) = Head
|
||||||
|
|
||||||
|
pushw %bx # Save number of blocks to transfer
|
||||||
|
movb %dl, %dh # dh = Head
|
||||||
|
movw $0x7c00, %bp # bp = 0x7c00
|
||||||
|
movb PhysicalDrive(%bp), %dl # dl = Drive Number
|
||||||
|
movb %al, %ch # ch = Cylinder
|
||||||
|
movb %bl, %al # al = Blocks
|
||||||
|
movb $2, %ah # ah = Function 2
|
||||||
|
movw %di, %bx # es:bx = Buffer address
|
||||||
|
int $0x13
|
||||||
|
jc DiskError
|
||||||
|
popw %bx
|
||||||
|
popw %cx
|
||||||
|
movzwl %bx, %ebx
|
||||||
|
addl %ebx, %esi # StartLBA = StartLBA + NumberOfBlocks
|
||||||
|
subw %bx, %cx # Blocks = Blocks - NumberOfBlocks
|
||||||
|
movw %es, %ax
|
||||||
|
shlw $(BLOCK_SHIFT-4), %bx
|
||||||
|
addw %bx, %ax
|
||||||
|
movw %ax, %es # es:di = es:di + NumberOfBlocks*BLOCK_SIZE
|
||||||
|
cmpw $0, %cx
|
||||||
|
jne ReadCylinderLoop
|
||||||
|
popa
|
||||||
|
ret
|
||||||
|
|
||||||
|
# ****************************************************************************
|
||||||
|
# ERROR Condition:
|
||||||
|
# ****************************************************************************
|
||||||
|
NotFoundAll:
|
||||||
|
# if we found EFILDR, continue
|
||||||
|
testw %bx, %bx
|
||||||
|
jne FoundEFILDR
|
||||||
|
BadBootSector:
|
||||||
|
DiskError:
|
||||||
|
leaw %cs:ErrorString, %si
|
||||||
|
call PrintString
|
||||||
|
Halt:
|
||||||
|
jmp Halt
|
||||||
|
|
||||||
|
StartString:
|
||||||
|
.byte 'B', 0x0c, 'S', 0x0c, 't', 0x0c, 'a', 0x0c, 'r', 0x0c, 't', 0x0c, '!', 0x0c
|
||||||
|
ErrorString:
|
||||||
|
.byte 'B', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!', 0x0c
|
||||||
|
|
||||||
|
# ****************************************************************************
|
||||||
|
# LBA Offset for BootSector, need patched by tool for HD boot.
|
||||||
|
# ****************************************************************************
|
||||||
|
|
||||||
|
.org 0x01fa
|
||||||
|
LBAOffsetForBootSector:
|
||||||
|
.long 0x0
|
||||||
|
|
||||||
|
# ****************************************************************************
|
||||||
|
# Sector Signature
|
||||||
|
# ****************************************************************************
|
||||||
|
|
||||||
|
.org 0x01fe
|
||||||
|
SectorSignature:
|
||||||
|
.word 0xaa55 # Boot Sector Signature
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
Loading…
Reference in New Issue