2022-10-18 00:19:44 +03:00

61 lines
1.2 KiB
NASM

; Inspired From: https://github.com/MQuy/mos/blob/master/src/kernel/boot.asm
section .multiboot2
align 4096
HEADER_START:
dd 0xE85250D6
dd 0
dd (HEADER_END - HEADER_START)
dd 0x100000000 - (HEADER_END - HEADER_START) - 0 - 0xE85250D6
align 8
MB2_TAG_START:
dw 0
dw 0
dd MB2_TAG_END - MB2_TAG_START
MB2_TAG_END:
HEADER_END:
KERNEL_VIRTUAL_BASE equ 0xC0000000 ; 3GB
KERNEL_PAGE_NUMBER equ (KERNEL_VIRTUAL_BASE >> 22) ; 768
KERNEL_STACK_SIZE equ 0x4000 ; 16KB
extern x32Entry
global _start
section .data
align 0x1000
BootPageTable:
dd 0x00000083
times (KERNEL_PAGE_NUMBER - 1) dd 0
dd 0x00000083
times (1024 - KERNEL_PAGE_NUMBER - 1) dd 0
section .text
_start:
mov ecx, (BootPageTable - KERNEL_VIRTUAL_BASE)
mov cr3, ecx
mov ecx, cr4
or ecx, 0x00000010 ; Set PSE in CR4
mov cr4, ecx
mov ecx, cr0
or ecx, 0x80000000 ; Set PG in CR0
mov cr0, ecx
lea ecx, [HigherHalfStart]
jmp ecx
HigherHalfStart:
mov esp, KernelStack + KERNEL_STACK_SIZE
push eax ; Multiboot2 Magic
add ebx, KERNEL_VIRTUAL_BASE
push ebx ; Multiboot2 Header
call x32Entry
Loop:
hlt
jmp Loop
section .bss
align 16
KernelStack :
resb KERNEL_STACK_SIZE