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MBALIGN equ 1<<0 ; Align loaded modules on page boundries */
MBMEMINFO equ 1<<1 ; Provide memory map*/
MBFLAGS equ MBALIGN | MBMEMINFO ; Multiboot flag field*/
MAGIC equ 0x1BADB002 ;Lets bootloader find header*/
CHECKSUM equ -(MAGIC + MBFLAGS) ; Proves we are multiboot via checksum*/
CODESEG equ 0x08
DATASEG equ 0x10
section .multiboot
align 4
dd MAGIC
dd MBFLAGS
dd CHECKSUM
section .bss
align 16
stack_bottom:
resb 16384
stack_top:
section .text
global gdtr
gdtr:
dw 0
dd 0
global _start:function (_start.end - _start)
_start:
mov esp, stack_top
extern get_gdtr
call get_gdtr
cli
lgdt [gdtr]
mov eax, cr0
or al, 1
mov cr0, eax
call reloadSegments
[bits 32]
extern kernel_main
call kernel_main
cli
.hang: hlt
jmp .hang
.end:
reloadSegments:
JMP CODESEG:.reload_CS ; should def define a CODESEG
.reload_CS:
MOV AX, DATASEG
MOV DS, AX
MOV ES, AX ; TODO: Setup proper extra segment
MOV FS, AX ; TODO: Setup proper General purpose segments
MOV GS, AX ; ...
MOV SS, AX ; TODO: Setup proper stack segment
RET
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