Multiboot2 Specification version 2.0

not

             +-------------------+
+     u16     | type              |
+     u16     | flags             |
+     u32     | size              |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 1          |
+     u16     | flags             |
+     u32     | size              |
+     u32[n]  | mbi_tag_types     |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 2          |
+     u16     | flags             |
+     u32     | size              |
+     u32     | header_addr       |
+     u32     | load_addr         |
+     u32     | load_end_addr     |
+     u32     | bss_end_addr      |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 3          |
+     u16     | flags             |
+     u32     | size              |
+     u32     | entry_addr        |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 8          |
+     u16     | flags             |
+     u32     | size              |
+     u32     | entry_addr        |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 9          |
+     u16     | flags             |
+     u32     | size              |
+     u32     | entry_addr        |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 4          |
+     u16     | flags             |
+     u32     | size = 12         |
+     u32     | console_flags     |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 5          |
+     u16     | flags             |
+     u32     | size = 20         |
+     u32     | width             |
+     u32     | height            |
+     u32     | depth             |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 6          |
+     u16     | flags             |
+     u32     | size = 8          |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 7          |
+     u16     | flags             |
+     u32     | size = 8          |
+             +-------------------+
+
             +-------------------+
+     u16     | type = 10         |
+     u16     | flags             |
+     u32     | size = 24         |
+     u32     | min_addr          |
+     u32     | max_addr          |
+     u32     | align             |
+     u32     | preference        |
+             +-------------------+
+
             +-------------------+
+     u32     | total_size        |
+     u32     | reserved          |
+             +-------------------+
+
             +-------------------+
+     u32     | type              |
+     u32     | size              |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 4          |
+     u32     | size = 16         |
+     u32     | mem_lower         |
+     u32     | mem_upper         |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 5          |
+     u32     | size = 20         |
+     u32     | biosdev           |
+     u32     | partition         |
+     u32     | sub_parition      |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 1          |
+     u32     | size              |
+     u8[n]   | string            |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 3          |
+     u32     | size              |
+     u32     | mod_start         |
+     u32     | mod_end           |
+     u8[n]   | string            |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 9          |
+     u32     | size              |
+     u16     | num               |
+     u16     | entsize           |
+     u16     | shndx             |
+     u16     | reserved          |
+     varies  | section headers   |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 6          |
+     u32     | size              |
+     u32     | entry_size        |
+     u32     | entry_version     |
+     varies  | entries           |
+             +-------------------+
+
             +-------------------+
+     u64     | base_addr         |
+     u64     | length            |
+     u32     | type              |
+     u32     | reserved          |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 2          |
+     u32     | size              |
+     u8[n]   | string            |
+             +-------------------+
+
             +----------------------+
+     u32     | type = 10            |
+     u32     | size = 28            |
+     u16     | version              |
+     u16     | cseg                 |
+     u32     | offset               |
+     u16     | cseg_16              |
+     u16     | dseg                 |
+     u16     | flags                |
+     u16     | cseg_len             |
+     u16     | cseg_16_len          |
+     u16     | dseg_len             |
+             +----------------------+
+
             +-------------------+
+     u32     | type = 7          |
+     u32     | size = 784        |
+     u16     | vbe_mode          |
+     u16     | vbe_interface_seg |
+     u16     | vbe_interface_off |
+     u16     | vbe_interface_len |
+     u8[512] | vbe_control_info  |
+     u8[256] | vbe_mode_info     |
+             +-------------------+
+
             +--------------------+
+     u32     | type = 8           |
+     u32     | size               |
+     u64     | framebuffer_addr   |
+     u32     | framebuffer_pitch  |
+     u32     | framebuffer_width  |
+     u32     | framebuffer_height |
+     u8      | framebuffer_bpp    |
+     u8      | framebuffer_type   |
+     u8      | reserved           |
+     varies  | color_info         |
+             +--------------------+
+
             +----------------------------------+
+     u32     | framebuffer_palette_num_colors   |
+     varies  | framebuffer_palette              |
+             +----------------------------------+
+
             +-------------+
+     u8      | red_value   |
+     u8      | green_value |
+     u8      | blue_value  |
+             +-------------+
+
            +----------------------------------+
+     u8     | framebuffer_red_field_position   |
+     u8     | framebuffer_red_mask_size        |
+     u8     | framebuffer_green_field_position |
+     u8     | framebuffer_green_mask_size      |
+     u8     | framebuffer_blue_field_position  |
+     u8     | framebuffer_blue_mask_size       |
+            +----------------------------------+
+
             +-------------------+
+     u32     | type = 11         |
+     u32     | size = 12         |
+     u32     | pointer           |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 12         |
+     u32     | size = 16         |
+     u64     | pointer           |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 13         |
+     u32     | size              |
+     u8      | major             |
+     u8      | minor             |
+     u8[6]   | reserved          |
+             | smbios tables     |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 14         |
+     u32     | size              |
+             | copy of RSDPv1    |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 15         |
+     u32     | size              |
+             | copy of RSDPv2    |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 16         |
+     u32     | size              |
+             | DHCP ACK          |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 17         |
+     u32     | size              |
+     u32     | descriptor size   |
+     u32     | descriptor version|
+             | EFI memory map    |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 18         |
+     u32     | size = 8          |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 19         |
+     u32     | size = 12         |
+     u32     | pointer           |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 20         |
+     u32     | size = 16         |
+     u64     | pointer           |
+             +-------------------+
+
             +-------------------+
+     u32     | type = 21         |
+     u32     | size = 12         |
+     u32     | load_base_addr    |
+             +-------------------+
+
     /*   multiboot2.h - Multiboot 2 header file. */
+     /*   Copyright (C) 1999,2003,2007,2008,2009,2010  Free Software Foundation, Inc.
+      *
+      *  Permission is hereby granted, free of charge, to any person obtaining a copy
+      *  of this software and associated documentation files (the "Software"), to
+      *  deal in the Software without restriction, including without limitation the
+      *  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+      *  sell copies of the Software, and to permit persons to whom the Software is
+      *  furnished to do so, subject to the following conditions:
+      *
+      *  The above copyright notice and this permission notice shall be included in
+      *  all copies or substantial portions of the Software.
+      *
+      *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+      *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+      *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL ANY
+      *  DEVELOPER OR DISTRIBUTOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+      *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+      *  IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+      */
+     
+     #ifndef MULTIBOOT_HEADER
+     #define MULTIBOOT_HEADER 1
+     
+     /*  How many bytes from the start of the file we search for the header. */
+     #define MULTIBOOT_SEARCH                        32768
+     #define MULTIBOOT_HEADER_ALIGN                  8
+     
+     /*  The magic field should contain this. */
+     #define MULTIBOOT2_HEADER_MAGIC                 0xe85250d6
+     
+     /*  This should be in %eax. */
+     #define MULTIBOOT2_BOOTLOADER_MAGIC             0x36d76289
+     
+     /*  Alignment of multiboot modules. */
+     #define MULTIBOOT_MOD_ALIGN                     0x00001000
+     
+     /*  Alignment of the multiboot info structure. */
+     #define MULTIBOOT_INFO_ALIGN                    0x00000008
+     
+     /*  Flags set in the 'flags' member of the multiboot header. */
+     
+     #define MULTIBOOT_TAG_ALIGN                  8
+     #define MULTIBOOT_TAG_TYPE_END               0
+     #define MULTIBOOT_TAG_TYPE_CMDLINE           1
+     #define MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME  2
+     #define MULTIBOOT_TAG_TYPE_MODULE            3
+     #define MULTIBOOT_TAG_TYPE_BASIC_MEMINFO     4
+     #define MULTIBOOT_TAG_TYPE_BOOTDEV           5
+     #define MULTIBOOT_TAG_TYPE_MMAP              6
+     #define MULTIBOOT_TAG_TYPE_VBE               7
+     #define MULTIBOOT_TAG_TYPE_FRAMEBUFFER       8
+     #define MULTIBOOT_TAG_TYPE_ELF_SECTIONS      9
+     #define MULTIBOOT_TAG_TYPE_APM               10
+     #define MULTIBOOT_TAG_TYPE_EFI32             11
+     #define MULTIBOOT_TAG_TYPE_EFI64             12
+     #define MULTIBOOT_TAG_TYPE_SMBIOS            13
+     #define MULTIBOOT_TAG_TYPE_ACPI_OLD          14
+     #define MULTIBOOT_TAG_TYPE_ACPI_NEW          15
+     #define MULTIBOOT_TAG_TYPE_NETWORK           16
+     #define MULTIBOOT_TAG_TYPE_EFI_MMAP          17
+     #define MULTIBOOT_TAG_TYPE_EFI_BS            18
+     #define MULTIBOOT_TAG_TYPE_EFI32_IH          19
+     #define MULTIBOOT_TAG_TYPE_EFI64_IH          20
+     #define MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR    21
+     
+     #define MULTIBOOT_HEADER_TAG_END  0
+     #define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST  1
+     #define MULTIBOOT_HEADER_TAG_ADDRESS  2
+     #define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS  3
+     #define MULTIBOOT_HEADER_TAG_CONSOLE_FLAGS  4
+     #define MULTIBOOT_HEADER_TAG_FRAMEBUFFER  5
+     #define MULTIBOOT_HEADER_TAG_MODULE_ALIGN  6
+     #define MULTIBOOT_HEADER_TAG_EFI_BS        7
+     #define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI32  8
+     #define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64  9
+     #define MULTIBOOT_HEADER_TAG_RELOCATABLE  10
+     
+     #define MULTIBOOT_ARCHITECTURE_I386  0
+     #define MULTIBOOT_ARCHITECTURE_MIPS32  4
+     #define MULTIBOOT_HEADER_TAG_OPTIONAL 1
+     
+     #define MULTIBOOT_LOAD_PREFERENCE_NONE 0
+     #define MULTIBOOT_LOAD_PREFERENCE_LOW 1
+     #define MULTIBOOT_LOAD_PREFERENCE_HIGH 2
+     
+     #define MULTIBOOT_CONSOLE_FLAGS_CONSOLE_REQUIRED 1
+     #define MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED 2
+     
+     #ifndef ASM_FILE
+     
+     typedef unsigned char           multiboot_uint8_t;
+     typedef unsigned short          multiboot_uint16_t;
+     typedef unsigned int            multiboot_uint32_t;
+     typedef unsigned long long      multiboot_uint64_t;
+     
+     struct multiboot_header
+     {
+       /*  Must be MULTIBOOT_MAGIC - see above. */
+       multiboot_uint32_t magic;
+     
+       /*  ISA */
+       multiboot_uint32_t architecture;
+     
+       /*  Total header length. */
+       multiboot_uint32_t header_length;
+     
+       /*  The above fields plus this one must equal 0 mod 2^32. */
+       multiboot_uint32_t checksum;
+     };
+     
+     struct multiboot_header_tag
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+     };
+     
+     struct multiboot_header_tag_information_request
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t requests[0];
+     };
+     
+     struct multiboot_header_tag_address
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t header_addr;
+       multiboot_uint32_t load_addr;
+       multiboot_uint32_t load_end_addr;
+       multiboot_uint32_t bss_end_addr;
+     };
+     
+     struct multiboot_header_tag_entry_address
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t entry_addr;
+     };
+     
+     struct multiboot_header_tag_console_flags
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t console_flags;
+     };
+     
+     struct multiboot_header_tag_framebuffer
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t width;
+       multiboot_uint32_t height;
+       multiboot_uint32_t depth;
+     };
+     
+     struct multiboot_header_tag_module_align
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+     };
+     
+     struct multiboot_header_tag_relocatable
+     {
+       multiboot_uint16_t type;
+       multiboot_uint16_t flags;
+       multiboot_uint32_t size;
+       multiboot_uint32_t min_addr;
+       multiboot_uint32_t max_addr;
+       multiboot_uint32_t align;
+       multiboot_uint32_t preference;
+     };
+     
+     struct multiboot_color
+     {
+       multiboot_uint8_t red;
+       multiboot_uint8_t green;
+       multiboot_uint8_t blue;
+     };
+     
+     struct multiboot_mmap_entry
+     {
+       multiboot_uint64_t addr;
+       multiboot_uint64_t len;
+     #define MULTIBOOT_MEMORY_AVAILABLE              1
+     #define MULTIBOOT_MEMORY_RESERVED               2
+     #define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE       3
+     #define MULTIBOOT_MEMORY_NVS                    4
+     #define MULTIBOOT_MEMORY_BADRAM                 5
+       multiboot_uint32_t type;
+       multiboot_uint32_t zero;
+     };
+     typedef struct multiboot_mmap_entry multiboot_memory_map_t;
+     
+     struct multiboot_tag
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+     };
+     
+     struct multiboot_tag_string
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       char string[0];
+     };
+     
+     struct multiboot_tag_module
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t mod_start;
+       multiboot_uint32_t mod_end;
+       char cmdline[0];
+     };
+     
+     struct multiboot_tag_basic_meminfo
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t mem_lower;
+       multiboot_uint32_t mem_upper;
+     };
+     
+     struct multiboot_tag_bootdev
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t biosdev;
+       multiboot_uint32_t slice;
+       multiboot_uint32_t part;
+     };
+     
+     struct multiboot_tag_mmap
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t entry_size;
+       multiboot_uint32_t entry_version;
+       struct multiboot_mmap_entry entries[0];
+     };
+     
+     struct multiboot_vbe_info_block
+     {
+       multiboot_uint8_t external_specification[512];
+     };
+     
+     struct multiboot_vbe_mode_info_block
+     {
+       multiboot_uint8_t external_specification[256];
+     };
+     
+     struct multiboot_tag_vbe
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+     
+       multiboot_uint16_t vbe_mode;
+       multiboot_uint16_t vbe_interface_seg;
+       multiboot_uint16_t vbe_interface_off;
+       multiboot_uint16_t vbe_interface_len;
+     
+       struct multiboot_vbe_info_block vbe_control_info;
+       struct multiboot_vbe_mode_info_block vbe_mode_info;
+     };
+     
+     struct multiboot_tag_framebuffer_common
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+     
+       multiboot_uint64_t framebuffer_addr;
+       multiboot_uint32_t framebuffer_pitch;
+       multiboot_uint32_t framebuffer_width;
+       multiboot_uint32_t framebuffer_height;
+       multiboot_uint8_t framebuffer_bpp;
+     #define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+     #define MULTIBOOT_FRAMEBUFFER_TYPE_RGB     1
+     #define MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT     2
+       multiboot_uint8_t framebuffer_type;
+       multiboot_uint16_t reserved;
+     };
+     
+     struct multiboot_tag_framebuffer
+     {
+       struct multiboot_tag_framebuffer_common common;
+     
+       union
+       {
+         struct
+         {
+           multiboot_uint16_t framebuffer_palette_num_colors;
+           struct multiboot_color framebuffer_palette[0];
+         };
+         struct
+         {
+           multiboot_uint8_t framebuffer_red_field_position;
+           multiboot_uint8_t framebuffer_red_mask_size;
+           multiboot_uint8_t framebuffer_green_field_position;
+           multiboot_uint8_t framebuffer_green_mask_size;
+           multiboot_uint8_t framebuffer_blue_field_position;
+           multiboot_uint8_t framebuffer_blue_mask_size;
+         };
+       };
+     };
+     
+     struct multiboot_tag_elf_sections
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t num;
+       multiboot_uint32_t entsize;
+       multiboot_uint32_t shndx;
+       char sections[0];
+     };
+     
+     struct multiboot_tag_apm
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint16_t version;
+       multiboot_uint16_t cseg;
+       multiboot_uint32_t offset;
+       multiboot_uint16_t cseg_16;
+       multiboot_uint16_t dseg;
+       multiboot_uint16_t flags;
+       multiboot_uint16_t cseg_len;
+       multiboot_uint16_t cseg_16_len;
+       multiboot_uint16_t dseg_len;
+     };
+     
+     struct multiboot_tag_efi32
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t pointer;
+     };
+     
+     struct multiboot_tag_efi64
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint64_t pointer;
+     };
+     
+     struct multiboot_tag_smbios
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint8_t major;
+       multiboot_uint8_t minor;
+       multiboot_uint8_t reserved[6];
+       multiboot_uint8_t tables[0];
+     };
+     
+     struct multiboot_tag_old_acpi
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint8_t rsdp[0];
+     };
+     
+     struct multiboot_tag_new_acpi
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint8_t rsdp[0];
+     };
+     
+     struct multiboot_tag_network
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint8_t dhcpack[0];
+     };
+     
+     struct multiboot_tag_efi_mmap
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t descr_size;
+       multiboot_uint32_t descr_vers;
+       multiboot_uint8_t efi_mmap[0];
+     };
+     
+     struct multiboot_tag_efi32_ih
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t pointer;
+     };
+     
+     struct multiboot_tag_efi64_ih
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint64_t pointer;
+     };
+     
+     struct multiboot_tag_load_base_addr
+     {
+       multiboot_uint32_t type;
+       multiboot_uint32_t size;
+       multiboot_uint32_t load_base_addr;
+     };
+     
+     #endif /*  ! ASM_FILE */
+     
+     #endif /*  ! MULTIBOOT_HEADER */
+
     /*  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))
+     #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
+
     /*  kernel.c - the C part of the kernel */
+     /*  Copyright (C) 1999, 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/>.
+      */
+     
+     #include "multiboot2.h"
+     
+     /*  Macros. */
+     
+     /*  Some screen stuff. */
+     /*  The number of columns. */
+     #define COLUMNS                 80
+     /*  The number of lines. */
+     #define LINES                   24
+     /*  The attribute of an character. */
+     #define ATTRIBUTE               7
+     /*  The video memory address. */
+     #define VIDEO                   0xB8000
+     
+     /*  Variables. */
+     /*  Save the X position. */
+     static int xpos;
+     /*  Save the Y position. */
+     static int ypos;
+     /*  Point to the video memory. */
+     static volatile unsigned char *video;
+     
+     /*  Forward declarations. */
+     void cmain (unsigned long magic, unsigned long addr);
+     static void cls (void);
+     static void itoa (char *buf, int base, int d);
+     static void putchar (int c);
+     void printf (const char *format, ...);
+     
+     /*  Check if MAGIC is valid and print the Multiboot information structure
+        pointed by ADDR. */
+     void
+     cmain (unsigned long magic, unsigned long addr)
+     {
+       struct multiboot_tag *tag;
+       unsigned size;
+     
+       /*  Clear the screen. */
+       cls ();
+     
+       /*  Am I booted by a Multiboot-compliant boot loader? */
+       if (magic != MULTIBOOT2_BOOTLOADER_MAGIC)
+         {
+           printf ("Invalid magic number: 0x%x\n", (unsigned) magic);
+           return;
+         }
+     
+       if (addr & 7)
+         {
+           printf ("Unaligned mbi: 0x%x\n", addr);
+           return;
+         }
+     
+       size = *(unsigned *) addr;
+       printf ("Announced mbi size 0x%x\n", size);
+       for (tag = (struct multiboot_tag *) (addr + 8);
+            tag->type != MULTIBOOT_TAG_TYPE_END;
+            tag = (struct multiboot_tag *) ((multiboot_uint8_t *) tag
+                                            + ((tag->size + 7) & ~7)))
+         {
+           printf ("Tag 0x%x, Size 0x%x\n", tag->type, tag->size);
+           switch (tag->type)
+             {
+             case MULTIBOOT_TAG_TYPE_CMDLINE:
+               printf ("Command line = %s\n",
+                       ((struct multiboot_tag_string *) tag)->string);
+               break;
+             case MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME:
+               printf ("Boot loader name = %s\n",
+                       ((struct multiboot_tag_string *) tag)->string);
+               break;
+             case MULTIBOOT_TAG_TYPE_MODULE:
+               printf ("Module at 0x%x-0x%x. Command line %s\n",
+                       ((struct multiboot_tag_module *) tag)->mod_start,
+                       ((struct multiboot_tag_module *) tag)->mod_end,
+                       ((struct multiboot_tag_module *) tag)->cmdline);
+               break;
+             case MULTIBOOT_TAG_TYPE_BASIC_MEMINFO:
+               printf ("mem_lower = %uKB, mem_upper = %uKB\n",
+                       ((struct multiboot_tag_basic_meminfo *) tag)->mem_lower,
+                       ((struct multiboot_tag_basic_meminfo *) tag)->mem_upper);
+               break;
+             case MULTIBOOT_TAG_TYPE_BOOTDEV:
+               printf ("Boot device 0x%x,%u,%u\n",
+                       ((struct multiboot_tag_bootdev *) tag)->biosdev,
+                       ((struct multiboot_tag_bootdev *) tag)->slice,
+                       ((struct multiboot_tag_bootdev *) tag)->part);
+               break;
+             case MULTIBOOT_TAG_TYPE_MMAP:
+               {
+                 multiboot_memory_map_t *mmap;
+     
+                 printf ("mmap\n");
+     
+                 for (mmap = ((struct multiboot_tag_mmap *) tag)->entries;
+                      (multiboot_uint8_t *) mmap
+                        < (multiboot_uint8_t *) tag + tag->size;
+                      mmap = (multiboot_memory_map_t *)
+                        ((unsigned long) mmap
+                         + ((struct multiboot_tag_mmap *) tag)->entry_size))
+                   printf (" base_addr = 0x%x%x,"
+                           " length = 0x%x%x, type = 0x%x\n",
+                           (unsigned) (mmap->addr >> 32),
+                           (unsigned) (mmap->addr & 0xffffffff),
+                           (unsigned) (mmap->len >> 32),
+                           (unsigned) (mmap->len & 0xffffffff),
+                           (unsigned) mmap->type);
+               }
+               break;
+             case MULTIBOOT_TAG_TYPE_FRAMEBUFFER:
+               {
+                 multiboot_uint32_t color;
+                 unsigned i;
+                 struct multiboot_tag_framebuffer *tagfb
+                   = (struct multiboot_tag_framebuffer *) tag;
+                 void *fb = (void *) (unsigned long) tagfb->common.framebuffer_addr;
+     
+                 switch (tagfb->common.framebuffer_type)
+                   {
+                   case MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED:
+                     {
+                       unsigned best_distance, distance;
+                       struct multiboot_color *palette;
+     
+                       palette = tagfb->framebuffer_palette;
+     
+                       color = 0;
+                       best_distance = 4*256*256;
+     
+                       for (i = 0; i < tagfb->framebuffer_palette_num_colors; i++)
+                         {
+                           distance = (0xff - palette[i].blue)
+                             * (0xff - palette[i].blue)
+                             + palette[i].red * palette[i].red
+                             + palette[i].green * palette[i].green;
+                           if (distance < best_distance)
+                             {
+                               color = i;
+                               best_distance = distance;
+                             }
+                         }
+                     }
+                     break;
+     
+                   case MULTIBOOT_FRAMEBUFFER_TYPE_RGB:
+                     color = ((1 << tagfb->framebuffer_blue_mask_size) - 1)
+                       << tagfb->framebuffer_blue_field_position;
+                     break;
+     
+                   case MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT:
+                     color = '\\' | 0x0100;
+                     break;
+     
+                   default:
+                     color = 0xffffffff;
+                     break;
+                   }
+     
+                 for (i = 0; i < tagfb->common.framebuffer_width
+                        && i < tagfb->common.framebuffer_height; i++)
+                   {
+                     switch (tagfb->common.framebuffer_bpp)
+                       {
+                       case 8:
+                         {
+                           multiboot_uint8_t *pixel = fb
+                             + tagfb->common.framebuffer_pitch * i + i;
+                           *pixel = color;
+                         }
+                         break;
+                       case 15:
+                       case 16:
+                         {
+                           multiboot_uint16_t *pixel
+                             = fb + tagfb->common.framebuffer_pitch * i + 2 * i;
+                           *pixel = color;
+                         }
+                         break;
+                       case 24:
+                         {
+                           multiboot_uint32_t *pixel
+                             = fb + tagfb->common.framebuffer_pitch * i + 3 * i;
+                           *pixel = (color & 0xffffff) | (*pixel & 0xff000000);
+                         }
+                         break;
+     
+                       case 32:
+                         {
+                           multiboot_uint32_t *pixel
+                             = fb + tagfb->common.framebuffer_pitch * i + 4 * i;
+                           *pixel = color;
+                         }
+                         break;
+                       }
+                   }
+                 break;
+               }
+     
+             }
+         }
+       tag = (struct multiboot_tag *) ((multiboot_uint8_t *) tag
+                                       + ((tag->size + 7) & ~7));
+       printf ("Total mbi size 0x%x\n", (unsigned) tag - addr);
+     }
+     
+     /*  Clear the screen and initialize VIDEO, XPOS and YPOS. */
+     static void
+     cls (void)
+     {
+       int i;
+     
+       video = (unsigned char *) VIDEO;
+     
+       for (i = 0; i < COLUMNS * LINES * 2; i++)
+         *(video + i) = 0;
+     
+       xpos = 0;
+       ypos = 0;
+     }
+     
+     /*  Convert the integer D to a string and save the string in BUF. If
+        BASE is equal to 'd', interpret that D is decimal, and if BASE is
+        equal to 'x', interpret that D is hexadecimal. */
+     static void
+     itoa (char *buf, int base, int d)
+     {
+       char *p = buf;
+       char *p1, *p2;
+       unsigned long ud = d;
+       int divisor = 10;
+     
+       /*  If %d is specified and D is minus, put `-' in the head. */
+       if (base == 'd' && d < 0)
+         {
+           *p++ = '-';
+           buf++;
+           ud = -d;
+         }
+       else if (base == 'x')
+         divisor = 16;
+     
+       /*  Divide UD by DIVISOR until UD == 0. */
+       do
+         {
+           int remainder = ud % divisor;
+     
+           *p++ = (remainder < 10) ? remainder + '0' : remainder + 'a' - 10;
+         }
+       while (ud /= divisor);
+     
+       /*  Terminate BUF. */
+       *p = 0;
+     
+       /*  Reverse BUF. */
+       p1 = buf;
+       p2 = p - 1;
+       while (p1 < p2)
+         {
+           char tmp = *p1;
+           *p1 = *p2;
+           *p2 = tmp;
+           p1++;
+           p2--;
+         }
+     }
+     
+     /*  Put the character C on the screen. */
+     static void
+     putchar (int c)
+     {
+       if (c == '\n' || c == '\r')
+         {
+         newline:
+           xpos = 0;
+           ypos++;
+           if (ypos >= LINES)
+             ypos = 0;
+           return;
+         }
+     
+       *(video + (xpos + ypos * COLUMNS) * 2) = c & 0xFF;
+       *(video + (xpos + ypos * COLUMNS) * 2 + 1) = ATTRIBUTE;
+     
+       xpos++;
+       if (xpos >= COLUMNS)
+         goto newline;
+     }
+     
+     /*  Format a string and print it on the screen, just like the libc
+        function printf. */
+     void
+     printf (const char *format, ...)
+     {
+       char **arg = (char **) &format;
+       int c;
+       char buf[20];
+     
+       arg++;
+     
+       while ((c = *format++) != 0)
+         {
+           if (c != '%')
+             putchar (c);
+           else
+             {
+               char *p, *p2;
+               int pad0 = 0, pad = 0;
+     
+               c = *format++;
+               if (c == '0')
+                 {
+                   pad0 = 1;
+                   c = *format++;
+                 }
+     
+               if (c >= '0' && c <= '9')
+                 {
+                   pad = c - '0';
+                   c = *format++;
+                 }
+     
+               switch (c)
+                 {
+                 case 'd':
+                 case 'u':
+                 case 'x':
+                   itoa (buf, c, *((int *) arg++));
+                   p = buf;
+                   goto string;
+                   break;
+     
+                 case 's':
+                   p = *arg++;
+                   if (! p)
+                     p = "(null)";
+     
+                 string:
+                   for (p2 = p; *p2; p2++);
+                   for (; p2 < p + pad; p2++)
+                     putchar (pad0 ? '0' : ' ');
+                   while (*p)
+                     putchar (*p++);
+                   break;
+     
+                 default:
+                   putchar (*((int *) arg++));
+                   break;
+                 }
+             }
+         }
+     }
+

Offset	Type	Field Name	Note +
0	u32	magic	required +
4	u32	architecture	required +
8	u32	header_length	required +
12	u32	checksum	required +
16-XX		tags	required +

Multiboot2 Specification version 2.0

Multiboot2 Specification

1 Introduction to Multiboot2 Specification

1.1 The background of Multiboot2 Specification

1.2 The target architecture

1.3 The target operating systems

1.4 Boot sources

1.5 Configure an operating system at boot-time

1.6 How to make OS development easier

1.7 Boot modules

2 The definitions of terms used through the specification

3 The exact definitions of Multiboot2 Specification

3.1 OS image format

3.1.1 The layout of Multiboot2 header

3.1.2 The magic fields of Multiboot2 header

3.1.3 General tag structure

3.1.4 Multiboot2 information request

3.1.5 The address tag of Multiboot2 header

3.1.6 The entry address tag of Multiboot2 header

3.1.7 EFI i386 entry address tag of Multiboot2 header

3.1.8 EFI amd64 entry address tag of Multiboot2 header

3.1.9 Flags tag

3.1.10 The framebuffer tag of Multiboot2 header

3.1.11 Module alignment tag

3.1.12 EFI boot services tag

3.1.13 Relocatable header tag

3.2 MIPS machine state

3.3 I386 machine state

3.4 EFI i386 machine state with boot services enabled

3.5 EFI amd64 machine state with boot services enabled

3.6 Boot information

3.6.1 Boot information format

3.6.2 Basic tags structure

3.6.3 Basic memory information

3.6.4 BIOS Boot device

3.6.5 Boot command line

3.6.6 Modules

3.6.7 ELF-Symbols

3.6.8 Memory map

3.6.9 Boot loader name

3.6.10 APM table

3.6.11 VBE info

3.6.12 Framebuffer info

3.6.13 EFI 32-bit system table pointer

3.6.14 EFI 64-bit system table pointer

3.6.15 SMBIOS tables

3.6.16 ACPI old RSDP

3.6.17 ACPI new RSDP

3.6.18 Networking information

3.6.19 EFI memory map

3.6.20 EFI boot services not terminated

3.6.21 EFI 32-bit image handle pointer

3.6.22 EFI 64-bit image handle pointer

3.6.23 Image load base physical address

4 Examples

4.1 C structure members alignment and padding consideration

4.2 Notes on PC

4.3 BIOS device mapping techniques

4.3.1 Data comparison technique

4.3.2 I/O restriction technique

4.4 Example OS code

4.4.1 multiboot2.h

4.4.2 boot.S

4.4.3 kernel.c

4.4.4 Other Multiboot2 kernels

4.5 Example boot loader code

5 The change log of this specification

Index

Table of Contents