| #------------------------------------------------------------------------------ | |
| #* | |
| #* Copyright 2006 - 2007, Intel Corporation | |
| #* All rights reserved. This program and the accompanying materials | |
| #* 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. | |
| #* | |
| #* gpt.asm | |
| #* | |
| #* Abstract: | |
| #* | |
| #------------------------------------------------------------------------------ | |
| #.MODEL small | |
| # .dosseg | |
| .stack: | |
| .486p: | |
| .code: | |
| .equ BLOCK_SIZE, 0x0200 | |
| .equ BLOCK_MASK, 0x01ff | |
| .equ BLOCK_SHIFT, 9 | |
| # **************************************************************************** | |
| # Code loaded by BIOS at 0x0000:0x7C00 | |
| # **************************************************************************** | |
| .org 0x00 | |
| Start: | |
| # **************************************************************************** | |
| # Start Print | |
| # **************************************************************************** | |
| movw $0xb800, %ax | |
| movw %ax, %es | |
| movw $0x7c0, %ax | |
| movw %ax, %ds | |
| leaw %cs:StartString, %si | |
| movw $10, %cx | |
| movw $160, %di | |
| rep | |
| movsw | |
| # **************************************************************************** | |
| # Print over | |
| # **************************************************************************** | |
| # **************************************************************************** | |
| # Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600 | |
| # **************************************************************************** | |
| xorw %ax, %ax # AX = 0x0000 | |
| movw $0x7c00, %bx # BX = 0x7C00 | |
| movw $0x600, %bp # BP = 0x0600 | |
| movw RelocatedStart, %si # SI = Offset(RelocatedStart) | |
| movw $0x200, %cx # CX = 0x0200 | |
| subw %si, %cx # CS = 0x0200 - Offset(RelocatedStart) | |
| leaw (%bp,%si,), %di # DI = 0x0600 + Offset(RelocatedStart) | |
| leaw (%bx,%si,), %si # BX = 0x7C00 + Offset(RelocatedStart) | |
| movw %ax, %ss # SS = 0x0000 | |
| movw %bx, %sp # SP = 0x7C00 | |
| movw %ax, %es # ES = 0x0000 | |
| movw %ax, %ds # DS = 0x0000 | |
| pushw %ax # PUSH 0x0000 | |
| pushw %di # PUSH 0x0600 + Offset(RelocatedStart) | |
| cld # Clear the direction flag | |
| rep | |
| movsb # Copy 0x0200 bytes from 0x7C00 to 0x0600 | |
| retl # JMP 0x0000:0x0600 + Offset(RelocatedStart) | |
| # **************************************************************************** | |
| # Code relocated to 0x0000:0x0600 | |
| # **************************************************************************** | |
| RelocatedStart: | |
| # **************************************************************************** | |
| # Get Driver Parameters to 0x0000:0x7BFC | |
| # **************************************************************************** | |
| xorw %ax, %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 | |
| # **************************************************************************** | |
| # Read GPT Header from hard disk to 0x0000:0x0800 | |
| # **************************************************************************** | |
| xorw %ax, %ax | |
| movw %ax, %es # Read to 0x0000:0x0800 | |
| movw $0x800, %di # Read to 0x0000:0x0800 | |
| movl $1, %eax # Read LBA #1 | |
| movl $0, %edx # Read LBA #1 | |
| movw $1, %bx # Read 1 Block | |
| pushw %es | |
| call ReadBlocks | |
| popw %es | |
| # **************************************************************************** | |
| # Read Target GPT Entry from hard disk to 0x0000:0x0A00 | |
| # **************************************************************************** | |
| cmpl $0x20494645, %es:(%di) # Check for "EFI " | |
| jne BadGpt | |
| cmpl $0x54524150, %es:4(%di) # Check for "PART" | |
| jne BadGpt | |
| cmpl $0x00010000, %es:8(%di) # Check Revision - 0x10000 | |
| jne BadGpt | |
| movl %es:84(%di), %eax # EAX = SizeOfPartitionEntry | |
| mulb GptPartitionIndicator(%bp) # EAX = SizeOfPartitionEntry * GptPartitionIndicator | |
| movl %eax, %edx # EDX = SizeOfPartitionEntry * GptPartitionIndicator | |
| shrl $BLOCK_SHIFT, %eax # EAX = (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE | |
| andl $BLOCK_MASK, %edx # EDX = Targer PartitionEntryLBA Offset | |
| # = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE | |
| pushl %edx | |
| movl %es:72(%di), %ecx # ECX = PartitionEntryLBA (Low) | |
| movl %es:76(%di), %ebx # EBX = PartitionEntryLBA (High) | |
| addl %ecx, %eax # EAX = Target PartitionEntryLBA (Low) | |
| # = (PartitionEntryLBA + | |
| # (SizeOfPartitionEntry * GptPartitionIndicator) / BLOCK_SIZE) | |
| adcl %ebx, %edx # EDX = Target PartitionEntryLBA (High) | |
| movw $0xA00, %di # Read to 0x0000:0x0A00 | |
| movw $1, %bx # Read 1 Block | |
| pushw %es | |
| call ReadBlocks | |
| popw %es | |
| # **************************************************************************** | |
| # Read Target DBR from hard disk to 0x0000:0x7C00 | |
| # **************************************************************************** | |
| popl %edx # EDX = (SizeOfPartitionEntry * GptPartitionIndicator) % BLOCK_SIZE | |
| addw %dx, %di # DI = Targer PartitionEntryLBA Offset | |
| cmpl $0xC12A7328, %es:(%di) # Check for EFI System Partition "C12A7328-F81F-11d2-BA4B-00A0C93EC93B" | |
| jne BadGpt | |
| cmpl $0x11d2F81F, %es:4(%di) # | |
| jne BadGpt | |
| cmpl $0xA0004BBA, %es:8(%di) # | |
| jne BadGpt | |
| cmpl $0x3BC93EC9, %es:0xc(%di) # | |
| jne BadGpt | |
| movl %es:32(%di), %eax # EAX = StartingLBA (Low) | |
| movl %es:36(%di), %edx # EDX = StartingLBA (High) | |
| movw $0x7C00, %di # Read to 0x0000:0x7C00 | |
| movw $1, %bx # Read 1 Block | |
| call ReadBlocks | |
| # **************************************************************************** | |
| # Transfer control to BootSector - Jump to 0x0000:0x7C00 | |
| # **************************************************************************** | |
| xorw %ax, %ax | |
| pushw %ax # PUSH 0x0000 | |
| movw $0x7c00, %di | |
| pushw %di # PUSH 0x7C00 | |
| retl # JMP 0x0000:0x7C00 | |
| # **************************************************************************** | |
| # ReadBlocks - Reads a set of blocks from a block device | |
| # | |
| # EDX:EAX = Start LBA | |
| # BX = Number of Blocks to Read (must < 127) | |
| # ES:DI = Buffer to store sectors read from disk | |
| # **************************************************************************** | |
| # si = DiskAddressPacket | |
| ReadBlocks: | |
| pushal | |
| pushw %ds | |
| xorw %cx, %cx | |
| movw %cx, %ds | |
| movw $0x600, %bp # bp = 0x600 | |
| leaw AddressPacket(%bp), %si | |
| movb %bl, %ds:2(%si) # 02 = Number Of Block transfered | |
| movw %di, %ds:4(%si) # 04 = Transfer Buffer Offset | |
| movw %es, %ds:6(%si) # 06 = Transfer Buffer Segment | |
| movl %eax, %ds:8(%si) # 08 = Starting LBA (Low) | |
| movl %edx, %ds:0xc(%si) # 0C = Starting LBA (High) | |
| movb $0x42, %ah # ah = Function 42 | |
| movb PhysicalDrive(%bp), %dl # dl = Drive Number | |
| int $0x13 | |
| jc BadGpt | |
| popw %ds | |
| popal | |
| ret | |
| # **************************************************************************** | |
| # Address Packet used by ReadBlocks | |
| # **************************************************************************** | |
| AddressPacket: | |
| .byte 0x10 # Size of address packet | |
| .byte 0x0 # Reserved. Must be 0 | |
| .byte 0x1 # Read blocks at a time (To be fixed each times) | |
| .byte 0x0 # Reserved. Must be 0 | |
| .word 0x000 # Destination Address offset (To be fixed each times) | |
| .word 0x000 # Destination Address segment (To be fixed each times) | |
| AddressPacketLba: | |
| .long 0x0,0x0 # Start LBA (To be fixed each times) | |
| AddressPacketEnd: | |
| # **************************************************************************** | |
| # ERROR Condition: | |
| # **************************************************************************** | |
| BadGpt: | |
| movw $0xb800, %ax | |
| movw %ax, %es | |
| movw $0x60, %ax | |
| movw %ax, %ds | |
| leaw %cs:ErrorString, %si | |
| movw $10, %cx | |
| movw $320, %di | |
| rep | |
| movsw | |
| Halt: | |
| jmp Halt | |
| StartString: | |
| .byte 'G', 0x0c, 'P', 0x0c, 'T', 0x0c, ' ', 0x0c, 'S', 0x0c, 't', 0x0c, 'a', 0x0c, 'r', 0x0c, 't', 0x0c, '!', 0x0c | |
| ErrorString: | |
| .byte 'G', 0x0c, 'P', 0x0c, 'T', 0x0c, ' ', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!', 0x0c | |
| # **************************************************************************** | |
| # PhysicalDrive - Used to indicate which disk to be boot | |
| # Can be patched by tool | |
| # **************************************************************************** | |
| # .org 0x01B6 # Just for passing build. | |
| PhysicalDrive: .byte 0x80 | |
| # **************************************************************************** | |
| # GptPartitionIndicator - Used to indicate which GPT partition to be boot | |
| # Can be patched by tool | |
| # **************************************************************************** | |
| # .org 0x01B7 # Just for passing build. | |
| GptPartitionIndicator: .byte 0 | |
| # **************************************************************************** | |
| # Unique MBR signature | |
| # **************************************************************************** | |
| # .org 0x01B8 # Just for passing build. | |
| .ascii "DUET" | |
| # **************************************************************************** | |
| # Unknown | |
| # **************************************************************************** | |
| # .org 0x01BC # Just for passing build. | |
| .word 0 | |
| # **************************************************************************** | |
| # PMBR Entry - Can be patched by tool | |
| # **************************************************************************** | |
| # .org 0x01BE # Just for passing build. | |
| .byte 0 # Boot Indicator | |
| .byte 0xff # Start Header | |
| .byte 0xff # Start Sector | |
| .byte 0xff # Start Track | |
| .byte 0xee # OS Type | |
| .byte 0xff # End Header | |
| .byte 0xff # End Sector | |
| .byte 0xff # End Track | |
| .long 1 # Starting LBA | |
| .long 0xFFFFFFFF # End LBA | |
| # .org 0x01CE # Just for passing build. | |
| .long 0,0,0,0 | |
| # .org 0x01DE # Just for passing build. | |
| .long 0,0,0,0 | |
| # .org 0x01EE # Just for passing build. | |
| .long 0,0,0,0 | |
| # **************************************************************************** | |
| # Sector Signature | |
| # **************************************************************************** | |
| # .org 0x01FE # Just for passing build. | |
| SectorSignature: | |
| .word 0xaa55 # Boot Sector Signature | |