mirror of
https://github.com/reactos/reactos.git
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262 lines
4.9 KiB
ArmAsm
262 lines
4.9 KiB
ArmAsm
/*
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* FreeLoader
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* Copyright (C) 1999, 2000, 2001 Brian Palmer <brianp@sginet.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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.text
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.code16
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#define ASM
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#include "asmcode.h"
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#include "multiboot.h"
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/*
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* Here we assume the kernel is loaded at 1mb
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* This boots the kernel
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*/
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.code32
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EXTERN(_boot_reactos)
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call switch_to_real
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.code16
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/* Save cursor position */
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movw $3,%ax //! Reset video mode
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int $0x10
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movb $10,%bl
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movb $12,%ah
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int $0x10
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movw $0x1112,%ax // Use 8x8 font
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xorb %bl,%bl
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int $0x10
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movw $0x1200,%ax // Use alternate print screen
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movb $0x20,%bl
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int $0x10
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movb $1,%ah // Define cursor (scan lines 6 to 7)
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movw $0x0607,%cx
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int $0x10
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movb $1,%ah
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movw $0x600,%cx
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int $0x10
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movb $6,%ah // Scroll active page up
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movb $0x32,%al // Clear 25 lines
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movw $0,%cx // Upper left of scroll
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movw $0x314F,%dx // Lower right of scroll
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movb $(1*0x10+1),%bh // Use normal attribute on blanked line
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int $0x10 // Video-IO
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movw $0,%dx
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movb $0,%dh
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movb $2,%ah
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movb $0,%bh
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int $0x10
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movw $0,%dx
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movb $0,%dh
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movb $2,%ah
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movb $0,%bh
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int $0x10
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call _multi_boot
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// Should never get here
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cli
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hlt
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/*
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* After you have setup the _mb_header and _mb_info structures
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* then call this routine to transfer control to the kernel.
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* This routine must be entered in 16-bit mode.
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*/
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.code16
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EXTERN(_multi_boot)
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cli
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/*
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* Setup various variables
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*/
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movw %ds,%bx
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movzwl %bx,%eax
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shll $4,%eax
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addl %eax,kernel_gdtbase
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/*
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* Load the absolute address of the multiboot information structure
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*/
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movl $_mb_info,%ebx
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/*
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* load gdt
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*/
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lgdt kernel_gdtptr
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/*
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* Enter pmode and clear prefetch queue
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*/
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movl %cr0,%eax
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orl $0x10001,%eax
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movl %eax,%cr0
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jmp next
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next:
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/*
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* NOTE: This must be position independant (no references to
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* non absolute variables)
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*/
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/*
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* Initalize segment registers
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*/
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movw $KERNEL_DS,%ax
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movw %ax,%ds
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movw %ax,%ss
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movw %ax,%es
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movw %ax,%fs
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movw %ax,%gs
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/*
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* Initalize eflags
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*/
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pushl $0
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popfl
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/*
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* Load the multiboot magic value into eax
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*/
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movl $0x2badb002,%eax
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/*
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* Jump to start of 32 bit code at 0xc0000000 + 0x1000
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*/
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pushl $KERNEL_CS
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pushl _mb_entry_addr
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lretl
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//ljmpl $KERNEL_CS,$(0x0200000+0x1000)
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//ljmpl $KERNEL_CS,(_mb_entry_addr)
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//ljmpl $KERNEL_CS,$(KERNEL_BASE+0x1000)
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.p2align 2 /* force 4-byte alignment */
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kernel_gdt:
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.word 0 // Zero descriptor
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.word 0
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.word 0
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.word 0
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.word 0xffff // Kernel code descriptor
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.word 0x0000 //
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.word 0x9a00 // base 0h limit 4gb
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.word 0x00cf
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.word 0xffff // Kernel data descriptor
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.word 0x0000 //
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.word 0x9200 // base 0h limit 4gb
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.word 0x00cf
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kernel_gdtptr:
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.word (3*8)-1 /* Limit */
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kernel_gdtbase:
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.long kernel_gdt /* Base Address */
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EXTERN(_mb_header)
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_mb_magic:
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.long 0 // unsigned long magic;
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_mb_flags:
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.long 0 // unsigned long flags;
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_mb_checksum:
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.long 0 // unsigned long checksum;
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_mb_header_addr:
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.long 0 // unsigned long header_addr;
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_mb_load_addr:
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.long 0 // unsigned long load_addr;
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_mb_load_end_addr:
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.long 0 // unsigned long load_end_addr;
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_mb_bss_end_addr:
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.long 0 // unsigned long bss_end_addr;
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_mb_entry_addr:
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.long 0 // unsigned long entry_addr;
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//
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// Boot information structure
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//
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EXTERN(_mb_info)
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_multiboot_flags:
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.long 0
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_multiboot_mem_lower:
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.long 0
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_multiboot_mem_upper:
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.long 0
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_multiboot_boot_device:
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.long 0
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_multiboot_cmdline:
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.long 0
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_multiboot_mods_count:
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.long 0
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_multiboot_mods_addr:
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.long 0
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_multiboot_syms:
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.rept 12
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.byte 0
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.endr
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_multiboot_mmap_length:
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.long 0
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_multiboot_mmap_addr:
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.long 0
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_multiboot_drives_count:
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.long 0
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_multiboot_drives_addr:
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.long 0
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_multiboot_config_table:
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.long 0
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_multiboot_boot_loader_name:
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.long 0
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_multiboot_apm_table:
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.long 0
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EXTERN(_multiboot_modules)
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.rept (64 * /*multiboot_module_size*/ 16)
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.byte 0
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.endr
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EXTERN(_multiboot_module_strings)
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.rept (64*256)
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.byte 0
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.endr
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EXTERN(_multiboot_memory_map_descriptor_size)
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.long 0
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EXTERN(_multiboot_memory_map)
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.rept (64 * /*sizeof(memory_map_t)*/24)
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.byte 0
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.endr
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EXTERN(_multiboot_kernel_cmdline)
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.rept 255
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.byte 0
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.endr
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