98 lines
2.2 KiB
ArmAsm
98 lines
2.2 KiB
ArmAsm
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
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*
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* GRUB 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 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <grub/symbol.h>
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#include <grub/machine/memory.h>
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#include <grub/machine/kernel.h>
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.text
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.code32
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.globl _start
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_start:
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jmp codestart
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. = _start + GRUB_KERNEL_MACHINE_CORE_ENTRY_ADDR
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VARIABLE(grub_core_entry_addr)
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.long 0
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VARIABLE(grub_kernel_image_size)
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.long 0
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VARIABLE(grub_prefix)
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/* to be filled by grub-mkimage */
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/*
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* Leave some breathing room for the prefix.
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*/
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. = _start + GRUB_KERNEL_MACHINE_DATA_END
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codestart:
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/* Relocate to low memory. First we figure out our location.
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We will derive the rom start address from it. */
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call 1f
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1: popl %esi
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/* Rom size is a multiple of 64 kiB. With this we get the
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value of `grub_core_entry_addr' in %esi. */
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xorw %si, %si
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/* ... which allows us to access `grub_kernel_image_size'
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before relocation. */
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movl (grub_kernel_image_size - _start)(%esi), %ecx
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movl $_start, %edi
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cld
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rep
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movsb
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ljmp $GRUB_MEMORY_MACHINE_PROT_MODE_CSEG, $1f
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1:
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#ifdef APPLE_CC
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/* clean out the bss */
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bss_start_abs = ABS (bss_start)
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bss_end_abs = ABS (bss_end)
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movl bss_start_abs, %edi
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/* compute the bss length */
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movl bss_end_abs, %ecx
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subl %edi, %ecx
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#else
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/* clean out the bss */
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movl $BSS_START_SYMBOL, %edi
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/* compute the bss length */
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movl $END_SYMBOL, %ecx
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subl %edi, %ecx
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#endif
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/* clean out */
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xorl %eax, %eax
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cld
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rep
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stosb
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/*
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* Call the start of main body of C code.
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*/
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call EXT_C(grub_main)
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/* This should never happen. */
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jmp EXT_C(grub_stop)
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