Code: Select all
multiboot_header:
/* magic */
.long MULTIBOOT2_HEADER_MAGIC
/* ISA: i386 */
.long GRUB_MULTIBOOT_ARCHITECTURE_I386
/* Header length. */
.long multiboot_header_end - multiboot_header
/* checksum */
.long -(MULTIBOOT2_HEADER_MAGIC + GRUB_MULTIBOOT_ARCHITECTURE_I386 + (multiboot_header_end - multiboot_header))
.long 0
.long 8
Code: Select all
/* boot.S - bootstrap the kernel */
/* Copyright (C) 1999, 2001, 2010 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#define ASM_FILE 1
#include "multiboot2.h"
/* C symbol format. HAVE_ASM_USCORE is defined by configure. */
#ifdef HAVE_ASM_USCORE
# define EXT_C(sym) _ ## sym
#else
# define EXT_C(sym) sym
#endif
/* The size of our stack (16KB). */
#define STACK_SIZE 0x4000
/* The flags for the Multiboot header. */
#ifdef __ELF__
# define AOUT_KLUDGE 0
#else
# define AOUT_KLUDGE MULTIBOOT_AOUT_KLUDGE
#endif
.text
.globl start, _start
start:
_start:
jmp multiboot_entry
/* Align 64 bits boundary. */
.align 8
/* Multiboot header. */
multiboot_header:
/* magic */
.long MULTIBOOT2_HEADER_MAGIC
/* ISA: i386 */
.long GRUB_MULTIBOOT_ARCHITECTURE_I386
/* Header length. */
.long multiboot_header_end - multiboot_header
/* checksum */
.long -(MULTIBOOT2_HEADER_MAGIC + GRUB_MULTIBOOT_ARCHITECTURE_I386 + (multiboot_header_end - multiboot_header))
.long 0
.long 8
#ifndef __ELF__
address_tag_start:
.short MULTIBOOT_HEADER_TAG_ADDRESS
.short MULTIBOOT_HEADER_TAG_OPTIONAL
.long address_tag_end - address_tag_start
/* header_addr */
.long multiboot_header
/* load_addr */
.long _start
/* load_end_addr */
.long _edata
/* bss_end_addr */
.long _end
address_tag_end:
entry_address_tag_start:
.short MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS
.short MULTIBOOT_HEADER_TAG_OPTIONAL
.long entry_address_tag_end - entry_address_tag_start
/* entry_addr */
.long multiboot_entry
entry_address_tag_end:
#endif /* __ELF__ */
framebuffer_tag_start:
.short MULTIBOOT_HEADER_TAG_FRAMEBUFFER
.short MULTIBOOT_HEADER_TAG_OPTIONAL
.long framebuffer_tag_end - framebuffer_tag_start
.long 1024
.long 768
.long 32
framebuffer_tag_end:
.short MULTIBOOT_HEADER_TAG_END
.short 0
.long 8
multiboot_header_end:
multiboot_entry:
/* Initialize the stack pointer. */
movl $(stack + STACK_SIZE), %esp
/* Reset EFLAGS. */
pushl $0
popf
/* Push the pointer to the Multiboot information structure. */
pushl %ebx
/* Push the magic value. */
pushl %eax
/* Now enter the C main function... */
call EXT_C(cmain)
/* Halt. */
pushl $halt_message
call EXT_C(printf)
loop: hlt
jmp loop
halt_message:
.asciz "Halted."
/* Our stack area. */
.comm stack, STACK_SIZE