Hello I am trying to get multiboot information from grub for creating physical memory manager.
this is my multiboot code:
part of loader.asm:
Code:
MBOOT_PAGE_ALIGN equ 1<<0 ; Load kernel and modules on a page boundary
MBOOT_MEM_INFO equ 1<<1 ; Provide your kernel with memory info
MBOOT_HEADER_MAGIC equ 0x1BADB002 ; Multiboot Magic value
MBOOT_HEADER_FLAGS equ MBOOT_PAGE_ALIGN | MBOOT_MEM_INFO
MBOOT_CHECKSUM equ -(MBOOT_HEADER_MAGIC + MBOOT_HEADER_FLAGS)
[BITS 32]
global start
start:
mov esp, _sys_stack
mov ebx, mboot
push ebx
jmp stublet
ALIGN 4 ; Ensure proper alignment for the Multiboot header
global mboot
extern code
extern bss
extern end
mboot:
dd MBOOT_HEADER_MAGIC ; GRUB will search for this value on each
; 4-byte boundary in your kernel file
dd MBOOT_HEADER_FLAGS ; How GRUB should load your file / settings
dd MBOOT_CHECKSUM ; To ensure that the above values are correct
dd mboot ; Location of this descriptor
dd code ; Start of kernel '.text' (code) section.
dd bss ; End of kernel '.data' section.
dd end ; End of kernel.
dd start ; Kernel entry point (initial EIP).
extern kernel_main
stublet:
call kernel_main
jmp $
multiboot.h:
Code:
#ifndef _MULTIBOOT_H
#define _MULTIBOOT_H
#define MULTIBOOT_FLAG_MEM 0x001
#define MULTIBOOT_FLAG_DEVICE 0x002
#define MULTIBOOT_FLAG_CMDLINE 0x004
#define MULTIBOOT_FLAG_MODS 0x008
#define MULTIBOOT_FLAG_AOUT 0x010
#define MULTIBOOT_FLAG_ELF 0x020
#define MULTIBOOT_FLAG_MMAP 0x040
#define MULTIBOOT_FLAG_CONFIG 0x080
#define MULTIBOOT_FLAG_LOADER 0x100
#define MULTIBOOT_FLAG_APM 0x200
#define MULTIBOOT_FLAG_VBE 0x400
#include <stdint.h>
typedef struct multiboot_info_t {
uint32_t flags;
uint32_t mem_lower;
uint32_t mem_upper;
uint32_t boot_device;
uint32_t cmdline;
uint32_t mods_count;
uint32_t mods_addr;
uint32_t num;
uint32_t size;
uint32_t addr;
uint32_t shndx;
uint32_t mmap_length;
uint32_t mmap_addr;
uint32_t drives_length;
uint32_t drives_addr;
uint32_t config_table;
uint32_t boot_loader_name;
uint32_t apm_table;
uint32_t vbe_control_info;
uint32_t vbe_mode_info;
uint32_t vbe_mode;
uint32_t vbe_interface_seg;
uint32_t vbe_interface_off;
uint32_t vbe_interface_len;
} __attribute__((packed)) multiboot_info_t;
#endif
kernel.c:
Code:
#include "../include/kernel.h"
void kernel_main(multiboot_info_t *mbi)
{
terminal_init();
qemu_init_debug();
gdt_init();
idt_init();
timer_init(50);
keyboard_init();
get_cpu_info();
uint32_t mbi_flags = mbi->flags;
uint32_t mbi_lower = mbi->mem_lower;
uint32_t mbi_upper = mbi->mem_upper;
printf("flags: 0x%x\n", mbi_flags);
printf("lower memory: 0x%u kb\n",
mbi_lower); // Use %u for unsigned integers
printf("upper memory: %u kb\n",
mbi_upper); // Use %u for unsigned integers
printf("mmap_length: %u\n", mbi->mmap_length);
printf("mmap_addr: %u\n", mbi->mmap_addr);
// set_mode(320, 200, 8);
// clear_screen_withcolor(0x04);
}
and this is my multiboot information:
Attachment:
mbi_ss.png [ 8.9 KiB | Viewed 4327 times ]
The flag is correct but the memory details are not i guess. I dont understand which part is wrong. Thank you for any help.
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