Updated boot.asm

[org 0x7c00]
KERNEL_LOCATION equ 0x1000

xor ax, ax
mov ds, ax
mov es, ax
mov ss, ax
mov sp, 0x8000
mov [BOOT_DISK], dl

;Get video mode info
mov ax, 4f01h
mov cx, 105h
mov di, modeInfo
int 10h

mov eax, modeInfo
mov bx, KERNEL_LOCATION
mov dh, 32

mov ah, 0x02
mov al, dh
mov ch, 0x00
mov dh, 0x00
mov cl, 0x02
mov dl, [BOOT_DISK]
int 0x13


mov ax, 0x4F02   ; set VBE mode
mov bx, 0x4118   ; VBE mode number
int 0x10         ; call VBE BIOS
cmp ax, 0x004F   ; test for error
jne error

CODE_SEG equ GDT_code - GDT_start
DATA_SEG equ GDT_data - GDT_start

cli
lgdt [GDT_descriptor]
mov eax, cr0
or eax, 1
mov cr0, eax
jmp CODE_SEG:start_protected_mode

jmp $

modeInfo    TIMES 256 db 0

error:
   stc
   ret

BOOT_DISK: db 0

GDT_start:
    GDT_null:
        dd 0x0
        dd 0x0

    GDT_code:
        dw 0xffff
        dw 0x0
        db 0x0
        db 0b10011010
        db 0b11001111
        db 0x0

    GDT_data:
        dw 0xffff
        dw 0x0
        db 0x0
        db 0b10010010
        db 0b11001111
        db 0x0

GDT_end:

GDT_descriptor:
    dw GDT_end - GDT_start - 1
    dd GDT_start


[bits 32]
start_protected_mode:
    mov ax, DATA_SEG
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax
    mov esp, 0x00090000     ; 32 bit stack base pointer
    mov ebp, esp            ; Only if you need this!

    jmp KERNEL_LOCATION



times 510-($-$$) db 0
dw 0xaa55