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Diffstat (limited to 'stage2/start_eltorito.S')
| -rw-r--r-- | stage2/start_eltorito.S | 326 |
1 files changed, 0 insertions, 326 deletions
diff --git a/stage2/start_eltorito.S b/stage2/start_eltorito.S deleted file mode 100644 index 99a7109..0000000 --- a/stage2/start_eltorito.S +++ /dev/null @@ -1,326 +0,0 @@ -/* - * GRUB -- GRand Unified Bootloader - * Copyright (C) 1994-2002 H. Peter Anvin - * Copyright (C) 1999,2000,2001,2004 Free Software Foundation, Inc. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - * - */ - -/* - Most of this file was originally "isolinux.asm" from SYSLINUX package. - It has been very heavily modified. -*/ - -#define ASM_FILE -#include "stage1.h" -#include "shared.h" -#include "iso9660.h" - -#ifndef STAGE1_5 -#include "stage2_size.h" -#endif - - - /* Absolute addresses - This makes the assembler generate the address without support - from the linker. (ELF can't relocate 16-bit addresses!) */ -#define ABS(x) (x-_start+BOOTSEC_LOCATION) - -#ifdef STAGE1_5 -# define STAGE_ADDR 0x2000 -#else -# define STAGE_ADDR 0x8000 -#endif /* STAGE1_5 */ - - /* Print message string */ -#define MSG(x) mov $ABS(x), %si; call message; - - .file "start_eltorito.S" - - .text - - /* Tell GAS to generate 16-bit instructions so that this code works - in real mode. */ - .code16 - - .globl start, _start - -/* - * Primary entry point. Because BIOSes are buggy, we only load the first - * CD-ROM sector (2K) of the file, so the number one priority is actually - * loading the rest. - */ -start: -_start: - cli - ljmp $0, $ABS(real_start) - - . = _start + 8 /* Pad to file offset 8 */ - - /* This table gets filled in by mkisofs using the - -boot-info-table option */ -bi_pvd: .long 0xDEADBEEF /* LBA of primary volume descript */ -bi_file: .long 0xDEADBEEF /* LBA of boot file */ -bi_length: .long 0xDEADBEEF /* Length of boot file */ -bi_csum: .long 0xDEADBEEF /* Checksum of boot file */ -bi_reserved: .space (10*4) /* Reserved */ - -real_start: - xor %ax, %ax - mov %ax, %ss - mov %ax, %ds - mov %ax, %es - mov %ax, %fs - mov %ax, %gs - mov $STAGE1_STACKSEG, %sp /* set up the REAL stack */ - sti - cld - - /* save drive reference first thing! */ - mov %dl, ABS(BootDrive) - - /* print a notification message on the screen */ - MSG(notification_string) - -load_image: - /* Set up boot file sector, size, load address */ - mov ABS(bi_length), %eax - add $(ISO_SECTOR_SIZE-1), %eax - shr $ISO_SECTOR_BITS, %eax /* dwords->sectors */ - mov %ax, %bp /* boot file sectors */ - mov $(STAGE_ADDR >> 4), %bx - mov %bx, %es - xor %bx, %bx - mov ABS(bi_file), %eax - call getlinsec - mov %ds, %ax - mov %ax, %es - - MSG(notification_done) -bootit: - /* save the sector number of the second sector in %ebp */ - mov $ABS(firstlist - BOOTSEC_LISTSIZE), %si - mov (%si), %ebp - mov ABS(BootDrive), %dl /* this makes sure %dl is our "boot" drive */ - ljmp $0, $(STAGE_ADDR+SECTOR_SIZE) /* jump to main() in asm.S */ - -/* go here when you need to stop the machine hard after an error condition */ -stop: jmp stop - - -/* - * Get linear sectors - EBIOS LBA addressing, 2048-byte sectors. - * - * Note that we can't always do this as a single request, because at least - * Phoenix BIOSes has a 127-sector limit. To be on the safe side, stick - * to 16 sectors (32K) per request. - * - * Input: - * EAX - Linear sector number - * ES:BX - Target buffer - * BP - Sector count - */ -getlinsec: - mov $ABS(dapa), %si /* Load up the DAPA */ - mov %bx, 4(%si) - mov %es, %bx - mov %bx, 6(%si) - mov %eax, 8(%si) -1: - push %bp - push %si - cmp ABS(MaxTransfer), %bp - jbe 2f - mov ABS(MaxTransfer), %bp -2: - mov %bp, 2(%si) - mov ABS(BootDrive), %dl - mov $0x42, %ah /* Extended Read */ - call xint13 - pop %si - pop %bp - movzwl 2(%si), %eax /* Sectors we read */ - add %eax, 8(%si) /* Advance sector pointer */ - sub %ax, %bp /* Sectors left */ - shl $(ISO_SECTOR_BITS-4), %ax /* 2048-byte sectors -> segment */ - add %ax, 6(%si) /* Advance buffer pointer */ - - pushal - MSG(notification_step) - popal - cmp $0, %bp - ja 1b - mov 8(%si), %eax /* Return next sector */ - ret - -/* - * INT 13h with retry - */ -xint13: - movb $6, ABS(RetryCount) - pushal -.try: - int $0x13 - jc 1f - add $(8*4), %sp /* Clean up stack */ - ret -1: - mov %ah, %dl /* Save error code */ - decb ABS(RetryCount) - jz .real_error - mov ABS(RetryCount), %al - mov ABS(dapa+2), %ah /* Sector transfer count */ - cmp $2, %al /* Only 2 attempts left */ - ja 2f - mov $1, %ah /* Drop transfer size to 1 */ - jmp .setmaxtr -2: - cmp $3, %al - ja 3f /* First time, just try again */ - shr $1, %ah /* Otherwise, try to reduce */ - adc $0, %ah /* the max transfer size, but not */ -.setmaxtr: - mov %ah, ABS(MaxTransfer) - mov %ah, ABS(dapa+2) -3: - popal - jmp .try - -.real_error: - MSG(read_error_string) - mov %dl, %al - call printhex2 - popal - jmp stop - - - -/* - * message: write the string pointed to by %si - * - * WARNING: trashes %si, %ax, and %bx - */ - - /* - * Use BIOS "int 10H Function 0Eh" to write character in teletype mode - * %ah = 0xe %al = character - * %bh = page %bl = foreground color (graphics modes) - */ -1: - mov $0x0001, %bx - mov $0x0E, %ah - int $0x10 /* display a byte */ - -message: - lodsb - or %al, %al - jne 1b /* if not end of string, jmp to display */ - ret - -/* - * printhex[248]: Write a hex number in (AL, AX, EAX) to the console - */ -printhex2: - pushal - rol $24, %eax - mov $2, %cx - jmp 1f -printhex4: - pushal - rol $16, %eax - mov $4, %cx - jmp 1f -printhex8: - pushal - mov $8, %cx -1: - rol $4, %eax - push %eax - and $0x0F, %al - cmp $10, %al - jae .high -.low: add $('0'), %al - jmp 2f -.high: add $('A'-10), %al -2: - mov $0x0001, %bx - mov $0x0E, %ah - int $0x10 /* display a char */ - pop %eax - loop 1b - popal - ret - -/**************************************************************************/ -#ifdef STAGE1_5 -notification_string: .string "Loading stage1.5 " -#else -notification_string: .string "Loading stage2 " -#endif - -notification_step: .string "." -notification_done: .string "\r\n" - -read_error_string: .string "Read error 0x" - -/* - * EBIOS disk address packet - */ - .align 8 -dapa: .byte 16 /* Packet size */ - .byte 0 /* reserved */ - .word 0 /* +2 Block count */ - .word 0 /* +4 Offset of buffer */ - .word 0 /* +6 Segment of buffer */ - .long 0 /* +8 LBA (LSW) */ - .long 0 /* +C LBA (MSW) */ - -VARIABLE(BootDrive) - .byte 0xFF -VARIABLE(MaxTransfer) - .word 16 /* Max sectors per transfer (32Kb) */ -VARIABLE(RetryCount) - .byte 0 - - -/* - * This area is an empty space between the main body of code below which - * grows up (fixed after compilation, but between releases it may change - * in size easily), and the lists of sectors to read, which grows down - * from a fixed top location. - */ - - .word 0 - .word 0 - - . = _start + SECTOR_SIZE - BOOTSEC_LISTSIZE - - /* fill the first data listing with the default */ -blocklist_default_start:/* this is the sector start parameter, in logical - sectors from the start of the disk, sector 0 */ - .long 0 - -blocklist_default_len: /* this is the number of sectors to read */ -#ifdef STAGE1_5 - .word 0 -#else - .word (STAGE2_SIZE + ISO_SECTOR_SIZE - 1) >> ISO_SECTOR_BITS -#endif -blocklist_default_seg: /* this is the segment of the starting address - to load the data into */ - .word (STAGE_ADDR + SECTOR_SIZE) >> 4 - -firstlist: /* this label has to be after the list data!!! */ |