2023-03-04 21:17:19 +02:00

105 lines
2.2 KiB
NASM

; https://wiki.osdev.org/Higher_Half_x86_Bare_Bones
; https://wiki.osdev.org/Higher_Half_x86_Bare_Bones_(Backup)
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_INFO_REQUEST_TAG_START:
dw 1
dw 0
dd MB2_INFO_REQUEST_TAG_END - MB2_INFO_REQUEST_TAG_START
dd 1 ; Command Line
dd 2 ; Boot Loader Name
dd 3 ; Module
dd 4 ; Basic Memory Information
dd 5 ; BIOS Boot Device
dd 6 ; Memory Map
dd 7 ; VBE
dd 8 ; Framebuffer
dd 9 ; ELF Sections
dd 10 ; APM Table
dd 11 ; EFI 32-bit System Table Pointer
dd 12 ; EFI 64-bit System Table Pointer
; dd 13 ; SMBIOS
dd 14 ; ACPI Old
dd 15 ; ACPI New
dd 16 ; Network
dd 17 ; EFI Memory Map
dd 18 ; EFI Boot Services Notifier
dd 19 ; EFI 32-bit Image Handle Pointer
dd 20 ; EFI 64-bit Image Handle Pointer
dd 21 ; Load Base Address
MB2_INFO_REQUEST_TAG_END:
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 x32Multiboot2Entry
global _start
section .data
align 0x1000
BootPageTable:
dd 0x00000083
dd 0x00000083
times (KERNEL_PAGE_NUMBER - 2) dd 0
dd 0x00000083
dd 0x00000083
times (1024 - KERNEL_PAGE_NUMBER - 2) dd 0
section .text
_start:
mov word [0xb8F00], 0x072E ; .
mov ecx, (BootPageTable - KERNEL_VIRTUAL_BASE)
mov cr3, ecx
mov word [0xb8F02], 0x072E ; .
mov ecx, cr4
or ecx, 0x00000010 ; Set PSE in CR4
mov cr4, ecx
mov word [0xb8F04], 0x072E ; .
mov ecx, cr0
or ecx, 0x80000000 ; Set PG in CR0
mov cr0, ecx
mov word [0xb8F06], 0x072E ; .
lea ecx, [HigherHalfStart]
jmp ecx
HigherHalfStart:
mov word [0xb8F08], 0x072E ; .
mov dword [BootPageTable], 0
invlpg [0]
mov esp, KernelStack + KERNEL_STACK_SIZE
push eax ; Multiboot2 Magic
add ebx, KERNEL_VIRTUAL_BASE
push ebx ; Multiboot2 Header
call x32Multiboot2Entry
Loop:
hlt
jmp Loop
section .bss
align 16
KernelStack :
resb KERNEL_STACK_SIZE