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Added DOS compatible Master Boot Record (MBR)

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svn path=/trunk/; revision=4497
This commit is contained in:
Casper Hornstrup 2003-04-05 15:28:45 +00:00
parent 4f133928b7
commit d44d6e392a
4 changed files with 191 additions and 3 deletions
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7
freeldr/bootsect/Makefile
View file

@ -27,12 +27,16 @@ BOOTCD_DIR = ..\..\bootcd
.PHONY : clean bootcd
all: $(BIN2C) fat.bin fat32.bin isoboot.bin ext2.bin
all: $(BIN2C) dosmbr.bin fat.bin fat32.bin isoboot.bin ext2.bin
$(BIN2C) :
@$(MAKE) --no-print-directory -C $(TOOLSDIR)
dosmbr.bin : dosmbr.asm
@echo ===================================================== Assembling dosmbr
@$(NASM_CMD) -o dosmbr.bin -f bin dosmbr.asm
fat.bin : fat.asm $(BIN2C)
@echo ===================================================== Assembling fat
@$(NASM_CMD) -o fat.bin -f bin fat.asm
@ -57,6 +61,7 @@ ext2.bin : ext2.asm
.PHONY : bootcd
bootcd: bootcd_dirs isoboot.bin
$(CP) isoboot.bin $(BOOTCD_DIR)
$(CP) dosmbr.bin $(BOOTCD_DIR)\disk\loader
$(CP) ext2.bin $(BOOTCD_DIR)\disk\loader
$(CP) fat.bin $(BOOTCD_DIR)\disk\loader
$(CP) fat32.bin $(BOOTCD_DIR)\disk\loader

179
freeldr/bootsect/dosmbr.asm Normal file
View file

@ -0,0 +1,179 @@
;
; normal DOS boot sector
;
; Ported to nasm from FreeDOS fdisk 1.2.0 by:
; Casper Hornstrup (chorns@users.sourceforge.net)
;
align 2, db 0
global _bootnormal_code
_bootnormal_code:
;-----------------------------------------------------------------------
; ENTRY (copied from freedos bootsector)
;
; IN: DL = boot drive
;OUT: DL = boot drive
;
;-----------------------------------------------------------------------
real_start: cli
cld
xor ax, ax
mov ss, ax ; initialize stack
mov ds, ax
mov bp, 0x7c00
lea sp, [bp-0x20]
sti
mov ax, 0x1FE0
mov es, ax
mov si, bp
mov di, bp
mov cx, 0x0100
rep movsw
jmp word 0x1FE0:0x7c00+ cont-real_start
cont: mov ds, ax
mov ss, ax
xor ax,ax
mov es,ax
; search for active partition
lea di, [bp+0x1be] ; start of partition table
test_next_for_active:
test byte [di],0x80
jne active_partition_found
add di,0x10 ; next table
cmp di, 07c00h+0x1fe; scanned beyond end of table ??
jb test_next_for_active
;*****************************************************************
call print
db 'no active partition found',0
WAIT_FOR_REBOOT:
jmp $
;*****************************************************************
trouble_reading_drive:
call print
db 'read error while reading drive',0
jmp WAIT_FOR_REBOOT
;*****************************************************************
invalid_partition_code:
call print
db 'partition signature != 55AA',0
jmp WAIT_FOR_REBOOT
;*****************************************************************
active_partition_found:
; call print
; db 'loading active partition',0
call read_boot_sector
jc trouble_reading_drive
cmp word [es:0x7c00+0x1fe],0xaa55
jne invalid_partition_code
jmp word 0x0:0x7c00 ; and jump to boot sector code
;*****************************
; read_boot_sector
;
; IN: DI--> partition info
;OUT:CARRY
;*****************************
read_boot_sector:
; /* check for LBA support */
mov bx,0x55aa
mov ah,0x41
int 0x13
jc StandardBios ; if (regs.b.x != 0xaa55 || (regs.flags & 0x01))
cmp bx,0xaa55 ; goto StandardBios;
jne StandardBios
; /* if DAP cannot be used, don't use LBA */
; if ((regs.c.x & 1) == 0)
; goto StandardBios;
test cl,1
jz StandardBios
jmp short LBABios
_bios_LBA_address_packet:
db 0x10
db 0
db 4 ; read four sectors - why not
db 0
dw 0x7c00 ; fixed boot address for DOS sector
dw 0x0000
_bios_LBA_low dw 0
_bios_LBA_high dw 0
dw 0,0
LBABios:
; copy start address of partition to DAP
mov ax,[di+8]
mov [0x7c00+ (_bios_LBA_low-real_start)],ax
mov ax,[di+8+2]
mov [0x7c00+ (_bios_LBA_high-real_start)],ax
mov ax,0x4200 ; regs.a.x = LBA_READ;
mov si,0x7c00+ (_bios_LBA_address_packet-real_start); regs.si = FP_OFF(&dap);
int 0x13
ret
;*****************************************************************
; read disk, using standard BIOS
;
StandardBios:
mov ax,0x0204 ; regs.a.x = 0x0201;
mov bx,0x7c00 ; regs.b.x = FP_OFF(buffer);
mov cx,[di+2] ; regs.c.x =
; ((chs.Cylinder & 0xff) << 8) + ((chs.Cylinder & 0x300) >> 2) +
; chs.Sector;
; that was easy ;-)
mov dh,[di+1] ; regs.d.b.h = chs.Head;
; regs.es = FP_SEG(buffer);
int 0x13
ret
;****** PRINT
; prints text after call to this function.
print_1char:
xor bx, bx ; video page 0
mov ah, 0x0E ; else print it
int 0x10 ; via TTY mode
print: pop si ; this is the first character
print1: lodsb ; get token
push si ; stack up potential return address
cmp al, 0 ; end of string?
jne print_1char ; until done
ret ; and jump to it
times 0x1fe-$+$$ db 0
db 0x55,0xaa

4
freeldr/freeldr/CHANGELOG
View file

@ -1,3 +1,7 @@
Changes in v1.8.4 (4/5/2003) (chorns)
- Added DOS compatible Master Boot Record (MBR)
Changes in v1.8.3 (3/18/2003) (brianp)
- Added _alloca() function because Mingw32 generates code that needs it

4
freeldr/freeldr/include/version.h
View file

@ -22,7 +22,7 @@
/* just some stuff */
#define VERSION "FreeLoader v1.8.3"
#define VERSION "FreeLoader v1.8.4"
#define COPYRIGHT "Copyright (C) 1998-2003 Brian Palmer <brianp@sginet.com>"
#define AUTHOR_EMAIL "<brianp@sginet.com>"
#define BY_AUTHOR "by Brian Palmer"
@ -36,7 +36,7 @@
//
#define FREELOADER_MAJOR_VERSION 1
#define FREELOADER_MINOR_VERSION 8
#define FREELOADER_PATCH_VERSION 3
#define FREELOADER_PATCH_VERSION 4
PUCHAR GetFreeLoaderVersionString(VOID);