diff options
Diffstat (limited to 'grub-core/kern/i386/qemu/startup.S')
| -rw-r--r-- | grub-core/kern/i386/qemu/startup.S | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/grub-core/kern/i386/qemu/startup.S b/grub-core/kern/i386/qemu/startup.S new file mode 100644 index 0000000..7834d1d --- /dev/null +++ b/grub-core/kern/i386/qemu/startup.S @@ -0,0 +1,104 @@ +/* + * 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 <http://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <grub/symbol.h> + +#include <grub/i386/pc/memory.h> +#include <grub/machine/memory.h> +#include <grub/machine/kernel.h> + + .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_PREFIX_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" |