-#------------------------------------------------------------------------------
-#*
-#* 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.
-#*
-#* Mbr.asm
-#*
-#* Abstract:
-#*
-#------------------------------------------------------------------------------
-
-.equ BLOCK_SIZE, 0x0200
-.equ BLOCK_MASK, 0x01ff
-.equ BLOCK_SHIFT, 9
-
-# ****************************************************************************
-# Code loaded by BIOS at 0x0000:0x7C00
-# ****************************************************************************
-
-.org 0x0
-
+#------------------------------------------------------------------------------\r
+#*\r
+#* Copyright 2006 - 2007, Intel Corporation \r
+#* All rights reserved. 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
+.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:
-
-# ****************************************************************************
-# 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 Target DBR from hard disk to 0x0000:0x7C00
-# ****************************************************************************
-
- xorw %ax, %ax
- movb MbrPartitionIndicator(%bp), %al # AX = MbrPartitionIndex
- cmpb $0xff, %al # 0xFF means do legacy MBR boot
- jnz EfiDbr
-LegacyMbr:
- movl $0x0000600, %eax # Assume LegacyMBR is backuped in Sector 6
- jmp StartReadTo7C00 # EAX = Header/Sector/Tracker/Zero
-
-EfiDbr:
- cmpb $4, %al # MbrPartitionIndex should < 4
- jae BadDbr
- shlw $4, %ax # AX = MBREntrySize * Index
- addw $0x1be, %ax # AX = MBREntryOffset
- movw %ax, %di # 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
- movl %es:8(%bp,%di,), %eax # Start LBA
- movl %eax, %edx
- shrl $16, %edx # DX:AX = Start LBA
- # = Ci * (H * S) + Hi * S + (Si - 1)
-
- # Calculate C/H/S according to LBA
- movw $0x7bfa, %bp
- divw 2(%bp) # AX = Hi + H*Ci
- # DX = Si - 1
- incw %dx # DX = Si
- pushw %dx # 0000:7bfa = Si <----
- xorw %dx, %dx # DX:AX = Hi + H*Ci
- divw 4(%bp) # AX = Ci <----
- # DX = Hi <----
-
-StartReadTo7C00:
-
- movb (%bp), %cl # Si
- movb %al, %ch # Ci[0-7]
- orb %ah, %cl # Ci[8,9]
- movw $0x7c00, %bx # ES:BX = 0000:7C00h
- movb $0x2, %ah # Function 02h
- movb $1, %al # 1 Sector
- movb %dl, %dh # Hi
- movw $0x600, %bp
- movb PhysicalDrive(%bp), %dl # Drive number
- int $0x13
- jc BadDbr
-
-
-
-# ****************************************************************************
-# Transfer control to BootSector - Jump to 0x0000:0x7C00
-# ****************************************************************************
- xorw %ax, %ax
- pushw %ax # PUSH 0x0000 - Segment
- movw $0x7c00, %di
- pushw %di # PUSH 0x7C00 - Offset
- retl # JMP 0x0000:0x7C00
-
-# ****************************************************************************
-# ERROR Condition:
-# ****************************************************************************
-
-BadDbr:
- pushw %ax
- movw $0xb800, %ax
- movw %ax, %es
- movw $0x60, %ax
- movw %ax, %ds
- leaw %cs:ErrorString, %si
- movw $320, %di
- popw %ax
- call A2C
- movb %ah, 16(%si)
- movb %al, 18(%si)
- movw $10, %cx
- rep
- movsw
-Halt:
- jmp Halt
-
-StartString:
-.byte 'M', 0x0c, 'B', 0x0c, 'R', 0x0c, ' ', 0x0c, 'S', 0x0c, 't', 0x0c, 'a', 0x0c, 'r', 0x0c, 't', 0x0c, '!', 0x0c
-ErrorString:
-.byte 'M', 0x0c, 'B', 0x0c, 'R', 0x0c, ' ', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, ':', 0x0c, '?', 0x0c, '?', 0x0c
-
-# ****************************************************************************
-# A2C - convert Ascii code stored in AH to character stored in AX
-# ****************************************************************************
-A2C:
- movb %ah, %al
- shrb $4, %ah
- andb $0xF, %al
- addb '0', %ah
- addb '0', %al
-
- cmpb '9', %ah
- jle A2C_L1
- addb $7, %ah
-A2C_L1:
-
- cmpb '9', %al
- jle A2C_L2
- addb $7, %al
-A2C_L2:
- ret
-
-
-# ****************************************************************************
-# PhysicalDrive - Used to indicate which disk to be boot
-# Can be patched by tool
-# ****************************************************************************
-.org 0x01B6
-PhysicalDrive: .byte 0x80
-
-# ****************************************************************************
-# 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 0x01B7
-MbrPartitionIndicator: .byte 0
-
-# ****************************************************************************
-# Unique MBR signature
-# ****************************************************************************
-.org 0x01B8
- .ascii "DUET"
-
-# ****************************************************************************
-# Unknown
-# ****************************************************************************
-.org 0x01BC
- .word 0
-
-# ****************************************************************************
-# MBR Entry - To be patched
-# ****************************************************************************
-.org 0x01BE
- .long 0,0,0,0
-.org 0x01CE
- .long 0,0,0,0
-.org 0x01DE
- .long 0,0,0,0
-.org 0x01EE
- .long 0,0,0,0
-
-# ****************************************************************************
-# Sector Signature
-# ****************************************************************************
-
-.org 0x01FE
-SectorSignature:
- .word 0xaa55 # Boot Sector Signature
-
-
-
+_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