/* * GRUB -- GRand Unified Bootloader * Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009 Free Software Foundation, Inc. * * GRUB 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 3 of the License, or * (at your option) any later version. * * GRUB 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 GRUB. If not, see . */ #include #include #include #include .text .code32 .globl _start _start: jmp codestart . = _start + GRUB_KERNEL_I386_QEMU_CORE_ENTRY_ADDR VARIABLE(grub_core_entry_addr) .long 0 VARIABLE(grub_kernel_image_size) .long 0 VARIABLE(grub_prefix) /* to be filled by grub-mkimage */ /* * Leave some breathing room for the prefix. */ . = _start + GRUB_KERNEL_MACHINE_DATA_END codestart: /* Relocate to low memory. First we figure out our location. We will derive the rom start address from it. */ call 1f 1: popl %esi /* Rom size is a multiple of 64 kiB. With this we get the value of `grub_core_entry_addr' in %esi. */ xorw %si, %si /* ... which allows us to access `grub_kernel_image_size' before relocation. */ movl (grub_kernel_image_size - _start)(%esi), %ecx movl $_start, %edi cld rep movsb ljmp $GRUB_MEMORY_MACHINE_PROT_MODE_CSEG, $1f 1: #ifdef APPLE_CC /* clean out the bss */ bss_start_abs = ABS (bss_start) bss_end_abs = ABS (bss_end) movl bss_start_abs, %edi /* compute the bss length */ movl bss_end_abs, %ecx subl %edi, %ecx #else /* clean out the bss */ movl $BSS_START_SYMBOL, %edi /* compute the bss length */ movl $END_SYMBOL, %ecx subl %edi, %ecx #endif /* clean out */ xorl %eax, %eax cld rep stosb /* * Call the start of main body of C code. */ call EXT_C(grub_main) /* This should never happen. */ cli 1: hlt jmp 1b #include "../realmode.S"