[org 0x7E00]
[bits 16]

jmp stage2
gdt_start:
CODE_SEG equ code - gdt_start
DATA_SEG equ data - gdt_start
null: dq 0x0000000000000000 ;null
code: dq 0x00CF9A000000FFFF ;code
data: dq 0x00CF92000000FFFF ;data

gdtr:
    dw gdtr - gdt_start - 1
    dd gdt_start
stage2:
    ;gdt & protected mode
    cli
    lgdt [gdtr]
    mov eax, cr0
    or eax, 0x01
    mov cr0, eax
    jmp CODE_SEG:_start
    jmp $
[bits 32]
_start:
    ;Segment reload
    mov ax, DATA_SEG
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax
a20:
    ;a20 line
    in al, 0x92
    or al, 0x02
    out 0x92, al

    mov ebp, 0x90000
    mov esp, ebp

    mov eax, [0xC0000]
    mov ebx, $
    mov [eax], ebx
    jmp CODE_SEG:kernel
label:
    mov ecx, 0xB8000
    mov byte [ecx], 'E'
    jmp $
build:
    times 256-($-$$) db 0
kernel: