[haiku-commits] r42104 - in haiku/trunk: build/jam src/add-ons/kernel/partitioning_systems/intel src/apps/aboutsystem src/bin/writembr
- From: anevilyak@xxxxxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Sat, 11 Jun 2011 21:14:50 +0200 (CEST)
Author: anevilyak
Date: 2011-06-11 21:14:49 +0200 (Sat, 11 Jun 2011)
New Revision: 42104
Changeset: https://dev.haiku-os.org/changeset/42104
Ticket: https://dev.haiku-os.org/ticket/3441
Modified:
haiku/trunk/build/jam/AnybootImage
haiku/trunk/src/add-ons/kernel/partitioning_systems/intel/PartitionMapWriter.cpp
haiku/trunk/src/apps/aboutsystem/AboutSystem.cpp
haiku/trunk/src/bin/writembr/mbr.S
Log:
Applied patch by Jean-Lo?\195?\175c Charroud that reworks the anyboot MBR to
fix boot
problems on various systems. Resolves #3441. Thanks!
+alpha3
Modified: haiku/trunk/build/jam/AnybootImage
===================================================================
--- haiku/trunk/build/jam/AnybootImage 2011-06-11 18:38:15 UTC (rev 42103)
+++ haiku/trunk/build/jam/AnybootImage 2011-06-11 19:14:49 UTC (rev 42104)
@@ -14,7 +14,7 @@
actions BuildAnybootMBR1 {
$(RM) $(1)
- $(TARGET_CC) $(MBR_SOURCE) -o $(1) -nostdlib -Xlinker --oformat=binary
-Xlinker -S -Xlinker -N -Xlinker "-e start" -Xlinker "-Ttext=0x600"
+ $(HAIKU_YASM) -f bin $(MBR_SOURCE) -O5 -o $(1)
}
rule BuildAnybootImage anybootImage : mbrPart : isoPart : imageFile {
Modified:
haiku/trunk/src/add-ons/kernel/partitioning_systems/intel/PartitionMapWriter.cpp
===================================================================
---
haiku/trunk/src/add-ons/kernel/partitioning_systems/intel/PartitionMapWriter.cpp
2011-06-11 18:38:15 UTC (rev 42103)
+++
haiku/trunk/src/add-ons/kernel/partitioning_systems/intel/PartitionMapWriter.cpp
2011-06-11 19:14:49 UTC (rev 42104)
@@ -37,44 +37,34 @@
#endif
-// compiled form of hybrid FreeBSD pmbr and mbr loader done by André Braga
+// compiled mbr boot loader code
static const uint8 kBootCode[] = {
- 0xfc, 0xe8, 0x05, 0x01, 0xbc, 0x00, 0x0e, 0xbe, 0x15, 0x7c, 0xbf, 0x15,
- 0x06, 0xb9, 0xeb, 0x01, 0xf3, 0xa4, 0xe9, 0x00, 0x8a, 0xe8, 0xfc, 0x00,
- 0xbb, 0x00, 0x0e, 0xbe, 0xb0, 0x07, 0xb9, 0x01, 0x00, 0xe8, 0x03, 0x01,
- 0x66, 0x81, 0x3e, 0x00, 0x0e, 0x45, 0x46, 0x49, 0x20, 0x75, 0x5c, 0x66,
- 0x81, 0x3e, 0x04, 0x0e, 0x50, 0x41, 0x52, 0x54, 0x75, 0x51, 0xbe, 0x48,
- 0x0e, 0xbb, 0x00, 0x10, 0xb9, 0x01, 0x00, 0xe8, 0xe1, 0x00, 0x89, 0xde,
- 0xbf, 0xa0, 0x07, 0xb1, 0x10, 0xf3, 0xa6, 0x75, 0x1b, 0x89, 0xdf, 0x8d,
- 0x75, 0x20, 0xbb, 0xc0, 0x07, 0x8e, 0xc3, 0x31, 0xdb, 0x56, 0x8a, 0x0e,
- 0x9f, 0x07, 0xe8, 0xc2, 0x00, 0x31, 0xc0, 0x8e, 0xc0, 0xe9, 0x94, 0x75,
- 0x66, 0xff, 0x0e, 0x50, 0x0e, 0x74, 0x18, 0xa1, 0x54, 0x0e, 0x01, 0xc3,
- 0x81, 0xfb, 0x00, 0x12, 0x72, 0xc8, 0x66, 0xff, 0x06, 0x48, 0x0e, 0x66,
- 0x83, 0x16, 0x4c, 0x0e, 0x00, 0xeb, 0xaf, 0xe8, 0x7b, 0x00, 0xbc, 0x00,
- 0x7c, 0x31, 0xf6, 0xbb, 0xbe, 0x07, 0xb1, 0x04, 0x38, 0x2f, 0x74, 0x0c,
- 0x0f, 0x8f, 0xa2, 0x00, 0x85, 0xf6, 0x0f, 0x85, 0x9c, 0x00, 0x89, 0xde,
- 0x80, 0xc3, 0x10, 0xe2, 0xeb, 0x85, 0xf6, 0x75, 0x02, 0xcd, 0x18, 0xe8,
- 0x5e, 0x00, 0x89, 0xe7, 0x8a, 0x74, 0x01, 0x8b, 0x4c, 0x02, 0xbb, 0x00,
- 0x7c, 0xf6, 0x06, 0x9e, 0x07, 0x80, 0x74, 0x2d, 0x51, 0x53, 0xbb, 0xaa,
- 0x55, 0xb4, 0x41, 0xcd, 0x13, 0x72, 0x20, 0x81, 0xfb, 0x55, 0xaa, 0x75,
- 0x1a, 0xf6, 0xc1, 0x01, 0x74, 0x15, 0x5b, 0x66, 0x6a, 0x00, 0x66, 0xff,
- 0x74, 0x08, 0x06, 0x53, 0x6a, 0x01, 0x6a, 0x10, 0x89, 0xe6, 0xb8, 0x00,
- 0x42, 0xeb, 0x05, 0x5b, 0x59, 0xb8, 0x01, 0x02, 0xcd, 0x13, 0x89, 0xfc,
- 0x72, 0x49, 0x81, 0xbf, 0xfe, 0x01, 0x55, 0xaa, 0x75, 0x46, 0xe9, 0x5c,
- 0xff, 0x31, 0xc9, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8, 0x8e, 0xd0, 0xc3,
- 0x80, 0xfa, 0x80, 0x72, 0x0b, 0x8a, 0x36, 0x75, 0x04, 0x80, 0xc6, 0x80,
- 0x38, 0xf2, 0x72, 0x02, 0xb2, 0x80, 0xc3, 0x66, 0xff, 0x74, 0x04, 0x66,
- 0xff, 0x34, 0x06, 0x53, 0x51, 0x6a, 0x10, 0x89, 0xe6, 0xb8, 0x00, 0x42,
- 0xcd, 0x13, 0x83, 0xc4, 0x10, 0x0f, 0x82, 0x4a, 0xff, 0xc3, 0xbe, 0x60,
- 0x07, 0xeb, 0x11, 0xbe, 0x74, 0x07, 0xeb, 0x0c, 0xbe, 0x7d, 0x07, 0xeb,
- 0x07, 0xbb, 0x07, 0x00, 0xb4, 0x0e, 0xcd, 0x10, 0xac, 0x84, 0xc0, 0x75,
- 0xf4, 0xf4, 0xeb, 0xfd, 0x42, 0x61, 0x64, 0x20, 0x50, 0x61, 0x72, 0x74,
- 0x69, 0x74, 0x69, 0x6f, 0x6e, 0x20, 0x54, 0x61, 0x62, 0x6c, 0x65, 0x00,
- 0x49, 0x4f, 0x20, 0x45, 0x72, 0x72, 0x6f, 0x72, 0x00, 0x4d, 0x69, 0x73,
- 0x73, 0x69, 0x6e, 0x67, 0x20, 0x53, 0x79, 0x73, 0x74, 0x65, 0x6d, 0x20,
- 0x42, 0x6f, 0x6f, 0x74, 0x6c, 0x6f, 0x61, 0x64, 0x65, 0x72, 0x00, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x02, 0x31, 0x53, 0x46, 0x42,
- 0xa3, 0x3b, 0xf1, 0x10, 0x80, 0x2a, 0x48, 0x61, 0x69, 0x6b, 0x75, 0x21
+ // compiled form of //haiku/trunk/src/bin/writembr/mbr.S
+ // yasm -f bin -O5 -o mbrcode.bin mbr.S -dMBR_CODE_ONLY=1
+ // bin2h <mbrcode.bin 12
+ 0xfa, 0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8, 0x8e, 0xd0, 0xbc, 0x00,
+ 0x7c, 0xbf, 0x00, 0x08, 0xb9, 0x18, 0x00, 0xf3, 0xaa, 0xbe, 0x00, 0x7c,
+ 0x89, 0x36, 0x0c, 0x08, 0xc6, 0x06, 0x08, 0x08, 0x10, 0xc6, 0x06, 0x0a,
+ 0x08, 0x01, 0xbf, 0x00, 0x06, 0xb5, 0x01, 0xf3, 0xa5, 0xea, 0x32, 0x06,
+ 0x00, 0x00, 0xfb, 0xbe, 0xbe, 0x07, 0xb0, 0x04, 0x80, 0x3c, 0x80, 0x74,
+ 0x09, 0x83, 0xc6, 0x10, 0xfe, 0xc8, 0x75, 0xf4, 0xeb, 0x6d, 0x89, 0x36,
+ 0x04, 0x08, 0x66, 0x8b, 0x44, 0x08, 0x66, 0xa3, 0x10, 0x08, 0x66, 0x85,
+ 0xc0, 0x74, 0x27, 0xb4, 0x41, 0xbb, 0xaa, 0x55, 0xcd, 0x13, 0x72, 0x1e,
+ 0xbe, 0x08, 0x08, 0xb4, 0x42, 0xcd, 0x13, 0x72, 0x15, 0x81, 0x3e, 0xfe,
+ 0x7d, 0x55, 0xaa, 0x75, 0x42, 0xbe, 0xfb, 0x06, 0xe8, 0x52, 0x00, 0x8b,
+ 0x36, 0x04, 0x08, 0xe9, 0x82, 0x75, 0x8b, 0x36, 0x04, 0x08, 0x8a, 0x74,
+ 0x01, 0x8b, 0x4c, 0x02, 0x88, 0xc8, 0x24, 0x3f, 0x84, 0xc0, 0x74, 0x23,
+ 0x3c, 0x3f, 0x75, 0x14, 0x89, 0xc8, 0xc0, 0xec, 0x06, 0x3d, 0xff, 0x03,
+ 0x75, 0x0a, 0x80, 0xfe, 0xff, 0x75, 0x05, 0x80, 0xfe, 0xfe, 0x74, 0x0b,
+ 0xbb, 0x00, 0x7c, 0xb0, 0x01, 0xb4, 0x02, 0xcd, 0x13, 0x73, 0xb6, 0xbe,
+ 0xdf, 0x06, 0xe8, 0x10, 0x00, 0xe8, 0x08, 0x00, 0xbe, 0xd5, 0x06, 0xe8,
+ 0x07, 0x00, 0xcd, 0x18, 0xb4, 0x00, 0xcd, 0x16, 0xc3, 0x31, 0xdb, 0xac,
+ 0xb4, 0x0e, 0xcd, 0x10, 0x08, 0xc0, 0x75, 0xf7, 0xc3, 0x52, 0x4f, 0x4d,
+ 0x20, 0x42, 0x41, 0x53, 0x49, 0x43, 0x00, 0x4e, 0x6f, 0x20, 0x62, 0x6f,
+ 0x6f, 0x74, 0x61, 0x62, 0x6c, 0x65, 0x20, 0x61, 0x63, 0x74, 0x69, 0x76,
+ 0x65, 0x20, 0x76, 0x6f, 0x6c, 0x75, 0x6d, 0x65, 0x0d, 0x0a, 0x00, 0x4c,
+ 0x6f, 0x61, 0x64, 0x69, 0x6e, 0x67, 0x20, 0x73, 0x79, 0x73, 0x74, 0x65,
+ 0x6d, 0x0a, 0x0d, 0x00
};
Modified: haiku/trunk/src/apps/aboutsystem/AboutSystem.cpp
===================================================================
--- haiku/trunk/src/apps/aboutsystem/AboutSystem.cpp 2011-06-11 18:38:15 UTC
(rev 42103)
+++ haiku/trunk/src/apps/aboutsystem/AboutSystem.cpp 2011-06-11 19:14:49 UTC
(rev 42104)
@@ -1051,6 +1051,7 @@
"Andre Braga\n"
"Michael Bulash\n"
"Bruce Cameron\n"
+ "Jean-Loïc Charroud\n"
"Greg Crain\n"
"Michael Davidson\n"
"David Dengg\n"
Modified: haiku/trunk/src/bin/writembr/mbr.S
===================================================================
--- haiku/trunk/src/bin/writembr/mbr.S 2011-06-11 18:38:15 UTC (rev 42103)
+++ haiku/trunk/src/bin/writembr/mbr.S 2011-06-11 19:14:49 UTC (rev 42104)
@@ -1,164 +1,399 @@
-/*
-** Copyright (c) 1999 Robert Nordier
-** All rights reserved.
-**
-** Redistribution and use in source and binary forms are freely
-** permitted provided that the above copyright notice and this
-** paragraph and the following disclaimer are duplicated in all
-** such forms.
-**
-** This software is provided "AS IS" and without any express or
-** implied warranties, including, without limitation, the implied
-** warranties of merchantability and fitness for a particular
-** purpose.
-/*
+; Copyright 2011, Jean-Loïc Charroud, jcharroud@xxxxxxx
+; Distributed under the terms of the MIT License or LGPL v3
+;
+; Haiku (C) Copyright Haiku 2011
+; MBR Boot code
+;
+; assemble the Master boot record with:
+; yasm -f bin -O5 -o mbr.bin mbr.S
+;
+; assemble the MBR's code (does not contain the partiton table
+; nor the MAGIC code) with:
+; yasm -f bin -O5 -o mbrcode.bin mbr.S -dMBR_CODE_ONLY=1
-/* A 512 byte MBR boot manager that simply boots the active partition. */
- .set LOAD, 0x7c00 // Load address
- .set EXEC, 0x600 // Execution
address
- .set PT_OFF, 0x1be // Partition
table
- .set MAGIC, 0xaa55 // Magic:
bootable
+;%define DEBUG 1
+;%define MBR_CODE_ONLY 1
- .set NUM_HARD_DRIVES, 0x475 // Number of hard drives
- .globl start // Entry point
- .code16
+;CONST
+ %assign DISKSIG 440 ; Disk
signature offset
+ %assign PT_OFF 0x1be ; Partition
table offset
+ %assign MAGIC_OFF 0x1fe ; Magic offset
+ %assign MAGIC 0xaa55 ; Magic
bootable signature
+ %assign SECSIZE 0x200 ; Size of a
single disk sector
+ %assign FLG_ACTIVE 0x80 ; active
partition flag
+ %assign SECTOR_COUNT 0x01 ; Number of record to
load from
+
; the ctive partition
-/*
- * Setup the segment registers for flat addressing and setup the stack.
- */
-start: cld //
String ops inc
- xorw %ax, %ax // Zero
- movw %ax, %es // Address
- movw %ax, %ds // data
- movw %ax, %ss // Set up stack
- movw $LOAD, %sp //
-/*
- * Relocate ourself to a lower address so that we are out of the way when
- * we load in the bootstrap from the partition to boot.
- */
- movw $main-EXEC+LOAD, %si // Source
- movw $main, %di // Destination
- movw $0x200-(main-start), %cx // Byte count
- rep
// Relocate code
- movsb //
-/*
- * Jump to the relocated code.
- */
- jmp main-LOAD+EXEC // Jump to
relocated code
+ %assign LOAD 0x7c00 ; Load address
+ %assign EXEC 0x600 ; Execution
address
+ %assign HEAP EXEC+SECSIZE ; Execution address
-/*
- * Scan the partition table looking for an active entry. Note that %ch is
- * zero from the repeated string instruction above. We save the offset of
- * the active partition in %si and scan the entire table to ensure that only
- * one partition is marked active.
- */
+;BIOS calls
+ %assign BIOS_VIDEO_SERVICES 0x10; ah - function
+ %assign BIOS_DISK_SERVICES 0x13
+ %assign BIOS_KEYBOARD_SERVICES 0X16
+ %assign BIOS_BASIC 0X18
+ %assign BIOS_REBOOT 0X19
-main: xorw %si, %si // No active partition
- movw $partition_table, %bx // Partition table
- movb $0x4, %cl // Number of
entries
-main.1: cmpb %ch, (%bx) // Null entry?
- je main.2 // Yes
- jg err_partition_table // If 0x1..0x7f
- testw %si, %si // Active
already found?
- jnz err_partition_table // Yes
- movw %bx, %si // Point to
active
-main.2: addb $0x10, %bl // Till
- loop main.1 // done
- testw %si, %si // Active found?
- jnz main.3 // Yes
- int $0x18 //
BIOS: Diskless boot
-/*
- * Ok, we've found a possible active partition. Check to see that the drive
- * is a valid hard drive number.
- */
-main.3: cmpb $0x80, %dl // Drive valid?
- jb main.4 // No
- movb NUM_HARD_DRIVES, %dh // Calculate the highest
- addb $0x80, %dh // drive
number available
- cmpb %dh, %dl // Within range?
- jb main.5 // Yes
-main.4: movb (%si), %dl // Load drive
-/*
- * Ok, now that we have a valid drive and partition entry, load the CHS from
- * the partition entry and read the sector from the disk.
- */
-main.5: movw %sp, %di // Save stack
pointer
- movb 0x1(%si), %dh // Load head
- movw 0x2(%si), %cx // Load
cylinder:sector
- movw $LOAD, %bx // Transfer
buffer
- cmpb $0xff, %dh // Might we
need to use LBA?
- jnz main.7 // No.
- cmpw $0xffff, %cx // Do we need
to use LBA?
- jnz main.7 // No.
- pushw %cx // Save
%cx
- pushw %bx // Save
%bx
- movw $0x55aa, %bx // Reversed
Magic
- movb $0x41, %ah // BIOS:
EDD extensions present?
- int $0x13 //
- jc main.6 // No.
- cmpw $MAGIC, %bx // Magic ok?
- jne main.6 // No.
- testb $0x1, %cl // Packet mode
present?
- jz main.6 // No.
- popw %bx //
Restore %bx
- pushl $0x0 // Set
the LBA
- pushl 0x8(%si) // address
- pushw %es // Set
the address of
- pushw %bx // the
transfer buffer
- pushw $0x1 // Read
1 sector
- pushw $0x10 //
Packet length
- movw %sp, %si // Packet
pointer
- movw $0x4200, %ax // BIOS:
LBA Read from disk
- jmp main.8 // Skip
the CHS setup
-main.6: popw %bx //
Restore %bx
- popw %cx //
Restore %cx
-main.7: movw $0x201, %ax // BIOS: Read
from disk
-main.8: int $0x13 // Call
the BIOS
- movw %di,%sp // Restore stack
- jc err_loading_os // If error
-/*
- * Now that we've loaded the bootstrap, check for the magic 0xaa55 signature.
- * If it is present, execute the bootstrap we just loaded.
- */
- cmpw $MAGIC, 0x1fe(%bx) // Bootable?
- jne err_missing_os // No
- jmp *%bx //
Invoke bootstrap
-/*
- * Various error message entry points.
- */
-err_partition_table:
- movw $msg_partition_table, %si // "Invalid partition table"
- jmp putString //
+ ;BIOS calls parameters
+ ; video services
+ %assign WRITE_CHAR 0x0e; al - char
+
; bh - page?
-err_loading_os:
- movw $msg_loading_os, %si // "Error loading
operating system"
- jmp putString //
+ ; disk services
+ %assign READ_DISK_SECTORS 0x02; dl - drive
+
; es:bx - buffer
+
; dh - head
+
; ch7:0 - track7:0
+
; cl7:6 - track9:8
+
; 5:0 - sector
+
; al - sector count
+
; -> al - sectors read
+ %assign READ_DRV_PARAMETERS 0x08; dl - drive
+
; -> cl - max cylinder 9:8
+
; - sectors per track
+
; ch - max cylinder 7:0
+
; dh - max head
+
; dl - number of drives (?)
+ %assign CHK_DISK_EXTENTIONS 0x41; bx - 0x55aa
+
; dl - drive
+
; -> success: carry clear
+
; ah - extension version
+
; bx - 0xaa55
+
; cx - support bit mask
+
; 1 - Device Access using the
+
; packet structure
+
; 2 - Drive Locking and
+
; Ejecting
+
; 4 - Enhanced Disk Drive
+
; Support (EDD)
+
; -> error: carry set
+ %assign EXTENDED_READ 0x42; dl - drive
+
; ds:si - address packet
+
; -> success: carry clear
+
; -> error: carry set
-err_missing_os:
- movw $msg_missing_os, %si // "Missing operating
system"
- jmp putString //
-/*
- * Output an ASCIZ string to the console via the BIOS.
- */
-putString.0:
- movw $0x7, %bx //
Page:attribute
- movb $0xe, %ah // BIOS:
Display character
- int $0x10 //
-putString:
- lodsb // Get
character
- testb %al,%al // End of
string?
- jnz putString.0 // No
-putString.1:
- jmp putString.1 // Await reset
+ %assign FIXED_DSK_SUPPORT 0x1 ; flag
indicating fixed disk
+
; extension command subset
-msg_partition_table: .asciz "Invalid partition table"
-msg_loading_os: .asciz "Error loading operating system"
-msg_missing_os: .asciz "Missing operating system"
+ ; keyboard services
+ %assign READ_CHAR 0x00; -> al -
ASCII char
- .org PT_OFF
+;MACRO
+ ; nicer way to get the size of a structure
+ %define sizeof(s) s %+ _size
-partition_table:
- .fill 0x10,0x4,0x0 // Partition
table
- .word MAGIC //
Magic number
+ ; using a structure in a another structure definition
+ %macro nstruc 1-2 1
+ resb sizeof(%1) * %2
+ %endmacro
+
+ ; nicer way to access GlobalVariables
+ %macro declare_var 1
+ %define %1 HEAP + GlobalVariables. %+ %1
+ %endmacro
+
+ %macro puts 1
+ mov si, %1
+ call _puts
+ %endmacro
+
+ %macro error 1
+ mov si, %1
+ jmp _error
+ %endmacro
+
+;TYPEDEFS
+ ; 64 bit value
+ struc quadword
+ .lower resd 1
+ .upper resd 1
+ endstruc
+
+ struc CHS_addr
+ .head resb 1
+ .sector resb 1
+ .cylindre resb 1
+ endstruc
+
+ struc PartitionEntry
+ .status resb 1
+ .CHS_first nstruc CHS_addr
+ .type resb 1
+ .CHS_last nstruc CHS_addr
+ .LBA_start resd 1
+ .LBA_size resd 1
+ endstruc
+
+ ; address packet as required by the EXTENDED_READ BIOS call
+ struc AddressPacket
+ .packet_size resb 1
+ .reserved resb 1
+ .block_count resw 1
+ .buffer resd 1
+ .sector nstruc quadword
+ ;.long_buffer nstruc quadword
+ ; We don't need the 64 bit buffer pointer. The 32 bit
.buffer is more
+ ; than sufficient.
+ endstruc
+
+ ; Structure containing the variables that don't need pre-initialization.
+ ; this structure will be allocated onto our "heap".
+ struc GlobalVariables
+ .boot_drive_id resd 1
+ .boot_partition resd 1
+ .address_packet nstruc AddressPacket
+ endstruc
+
+;alias for easy access to our global variables
+ declare_var boot_drive_id
+ declare_var boot_partition
+ declare_var address_packet
+
+;/////////////////////////////////////////////////////////////////////////
+;// A 512 byte MBR boot manager that simply boots the active partition. //
+;/////////////////////////////////////////////////////////////////////////
+; 16 bit code
+SECTION .text
+BITS 16
+ORG EXEC ; MBR is loaded at
0x7c00 but relocated at 0x600
+start: ; we run the LOADed code
+ cli ; disable
interrupts
+ cld ; clear
direction flag (for string operations)
+ init:
+ xor ax, ax ; Zero
+ mov es, ax ; Set up extra
segment
+ mov ds, ax ; Set up data
segment
+ mov ss, ax ; Set up stack
segment
+ mov sp, LOAD ; Set up stack pointer
+
+ ;init our heap allocated variables with zeros
+ mov di, HEAP ;start adress
+ mov cx, sizeof(GlobalVariables) ;size
+ rep ; while(cx--)
+ stosb ; es[di++]:=al;
+
+ ; Relocate ourself to a lower address so that we are out of the way
+ ; when we load in the bootstrap from the partition to boot.
+ reloc:
+ mov si, LOAD ; Source
+ ; init AddressPacket.buffer now since LOAD is in 'si'
+ mov [address_packet+AddressPacket.buffer],si
+ mov
byte[address_packet+AddressPacket.packet_size],sizeof(AddressPacket)
+ mov byte[address_packet+AddressPacket.block_count],SECTOR_COUNT
+
+ mov di, EXEC ; Destination
+ mov ch, 1 ; count cx:=256
(cl cleared by precedent rep call)
+ rep ; while(cx--)
+ movsw ; es[di++]:=ds[si++]
+ ; //di and si
are incremented by sizeof(word)
+ jmp word 0x0000:continue; FAR jump to the relocated "continue"
(some
+ ; BIOSes
initialise CS to 0x07c0 so we must set
+ ; CS correctly)
+
+continue: ; Now we run EXEC_based
relocated code
+ sti ; enable
interrupts
+ %ifdef DEBUG
+ puts kMsgStart
+ %endif
+
+search_active_partition:
+ mov si,EXEC+PT_OFF ; point
to first table entry
+ mov al,04
; there are 4 table entries
+ .loop:
; SEARCH FOR AN ACTIVE ENTRY
+ cmp byte[si],FLG_ACTIVE ; is
this the active entry?
+ je found_active ; yes
+ add si, sizeof(PartitionEntry) ; next
PartitionEntry
+ dec al
; decrease remaining entry count
+ jnz .loop
; loop if entry count > 0
+ jmp no_bootable_active_partition; last partition
reached
+
+found_active: ;
active partition (pointed by si)
+ mov [boot_partition],si ; Save
active partition pointer
+
+ .get_read_sector: ;
initialise address_packet:
+ mov eax,[si + PartitionEntry.LBA_start]
+ mov [address_packet+AddressPacket.sector],eax
+
+ ; if LBA_adress equals 0 then it's not a valid PBR (it is the
MBR)
+ ; this can append when we only have a CHS adress in the
partition entry
+ test eax, eax ;if (
LBA_adress == 0 )
+ jz no_disk_extentions ;then
no_disk_extentions()
+
+check_disk_extensions:
+ ; Note: this test may be unnecessary since EXTENDED_READ also
+ ; set the carry flag when extended calls are not supported
+ %ifdef DEBUG
+ puts kMsgCheckEx
+ %endif
+
+ mov ah, CHK_DISK_EXTENTIONS ; set command
+ mov bx, 0x55aa
; set parameter : hton(MAGIC)
+ ; dl has not changed yet, still contains the drive ID
+ int BIOS_DISK_SERVICES ; if(
do_command() <> OK )
+ jc no_disk_extentions ; then
use simple read operation
+
; else use extended read
+disk_extentions:
+ %ifdef DEBUG
+ puts kMsgRead_Ex
+ %endif
+
+ ; load first bloc active partition
+ ; dl has not changed yet, still contains the drive ID
+ mov si, address_packet ; set
command parameters
+ mov ah, EXTENDED_READ ; set
command
+ .read_PBR:
+ int BIOS_DISK_SERVICES ; if (
do_command() <> OK )
+ jc no_disk_extentions ; then
try CHS_read();
+
+check_for_bootable_partition:
+ cmp word[LOAD+MAGIC_OFF],MAGIC ; if ( !
volume.isBootable() )
+ jne no_bootable_active_partition; then error();
+
+jump_PBR:
+ %ifdef DEBUG
+ puts kMsgBootPBR
+ call _pause
+ %else
+ puts kMsgStart
+ %endif
+
+ ; jump to 0x7c00 with :
+ ; - CS=0
+ ; - DL=drive number
+ ; - DS:SI=pointer to the selected partition table
+ ; entry (required by some PBR)
+
+ ; dl has not changed yet, still contains the drive ID
+ mov si, [boot_partition]
+ jmp LOAD
; jump into partition boot loader
+
+no_disk_extentions:
+ %ifdef DEBUG
+ puts kMsgNoExtentions
+ %endif
+
+ mov si, [boot_partition] ;
Restore active partition pointer
+
+ ;load CHS PBR sector info
+ mov dh, [si+1]
; dh 7:0 = head 7:0 (0 - 255)
+ mov cx, [si+2]
; cl 5:0 = sector 7:0 (1 - 63)
+
; cl 7:6 = cylinder 9:8 (0 - 1023)
+
; ch 7:0 = cylinder 7:0
+ .check_Sector:
+ mov al, cl
+ and al, 0x3F
; extract sector
+ test al, al;
; if (sector==0)
+ jz no_bootable_active_partition; then
error("invalid sector");
+ cmp al, 0x3F
; if( (Sector == 63)
+ jne .CHS_valid
;
+ .check_Cylinder:
+ mov ax, cx
+ shr ah, 6
+ cmp ax, 0x03FF
; and (Cylinder == 1023)
+ jne .CHS_valid
+ .check_Head:
+ cmp dh, 0xFF
; and ( (Head == 255)
+ jne .CHS_valid
+ cmp dh, 0xFE
; or (Head == 254) ) )
+ je no_bootable_active_partition; then
error("invalid CHS_adress");
+
+ .CHS_valid:
+ ; dl has not changed yet, still contains the drive ID
+ mov bx, LOAD
; set buffer
+ mov al, SECTOR_COUNT ; set
Size
+ mov ah, READ_DISK_SECTORS ; set
read command
+ int BIOS_DISK_SERVICES ; if (
do_command() == OK )
+ jnc check_for_bootable_partition; then
resume(normal boot sequence)
+
; else continue;
+
+no_bootable_active_partition:
+ mov si, kMsgNoBootable
+ ;jmp _error
; _error is the next line !
+
+_error:
+ ; display a non-empty null-terminated string on the screen,
+ ; wait for a key pressed and go back to the bios
+ ; IN :
+ ; - si = address of string to display
+ ; OUT :
+ ; DIRTY :
+ ; - ax
+ ; - si
+ call _puts
+ call _pause
+ puts kMsgROMBASIC
+ int BIOS_BASIC
; BIOS_BASIC give the control back
+
; to the BIOS. Doing so, let some
+
; BIOSes try to boot an alternate
+
; device (PXE/CD/HDD : see your
+
; BIOS' boot device order )
+_pause:
+ ; wait for a key pressed
+ ; IN :
+ ; OUT :
+ ; DIRTY :
+ ; - ax
+ mov ah, READ_CHAR
+ int BIOS_KEYBOARD_SERVICES
+ ret
+
+_puts:
+ ; display a non-empty null-terminated string on the screen
+ ; IN :
+ ; - si = address of string to display
+ ; OUT :
+ ; DIRTY :
+ ; - ax
+ ; - bx
+ ; - si
+ xor bx, bx
; bx:=0
+ .loop:
; do {
+ lodsb
; al=[si++];
+ mov ah, WRITE_CHAR
;
+ int BIOS_VIDEO_SERVICES ;
WRITE_CHAR(al)
+ or al, al
; } while (al<>0);
+ jnz .loop
+ ret
+
+data:
+ kMsgROMBASIC db 'ROM BASIC',0
+ kMsgNoBootable db 'No bootable active volume',13,10,0
+ kMsgStart db 'Loading system',10,13,0
+
+ %ifdef DEBUG
+ kMsgBootPBR db 'JMP PBR',13,10,0
+ kMsgRead_Ex db 'Read_ex block',13,10,0
+ kMsgCheckEx db 'CheckEx',13,10,0
+ kMsgNoExtentions db 'Read block',13,10,0
+ kMsgReloc db 'reloc MBR',13,10,0
+ %endif
+
+; check whether the code is small enough to fit in the boot code area
+end:
+ ;use nasm instead of yasm to check the code size
+ ;%if end - start > DISKSIG
+ ; %error "Code exceeds master boot code area!"
+ ;%endif
+
+%ifdef MBR_CODE_ONLY
+ ;just build the code.
+ ;Do not generate the datas
+%else
+ ;use nasm instead of yasm => use %rep instead of times
+ ;%rep start + DISKSIG - end
+ ; db 0 ;fill
the rest of the code area
+ ;%endrep
+ times start + DISKSIG - end db 0
+ kMbrDiskID dd 0 ;Disk signature
+ dw 0 ;reserved
+ PartitionTable times PartitionEntry_size * 4 db 0
+DiskSignature:
+ ;use nasm instead of yasm to check the MAGIC offset
+ ;%if DiskSignature - start <> MAGIC_OFF
+ ; %error "incorrect Disk Signature offset"
+ ;%endif
+ kMbrSignature db 0x55, 0xAA
+%endif
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