64-bit bootloader from scratch in AT&T assembly, Part-1

Basic info

I will make multiple parts of it

BIOS bootloaders must be 512 Bytes and end with 55AA bytes to be considered as bootloaders

So

.code16
.org 0

.text
.global _start

_start:
    # Segment setup
    xor %ax, %ax
    mov %ax, %ds
    mov %ax, %es
    mov %ax, %ss

    # Stack setup
    mov $0x9c00, %bp
    mov %bp, %sp

    # If you don't want kernel, don't do this section from here to disable_int label
    # Load Kernel from Disk
    mov $0x1000, %ax     # Segment 0x1000
    mov %ax, %es         # ES now points to 0x1000
    xor %bx, %bx         # Offset 0
    # Destination is ES:BX -> (0x1000 * 16) + 0 = 0x10000
    mov $2, %ah              # BIOS read sector function
    mov $8, %al              # Number of sectors to read (adjust as needed)
    xor %ch, %ch             # Cylinder 0
    mov $2, %cl              # Sector 2 (Sector 1 is the bootloader)
    xor %dh, %dh             # Head 0
    int $0x13
jc disk_error
    jmp disable_int

disk_error:
    mov $disk_err_msg, %dx
    call print
    call println

disable_int:


.fill 510-(.-_start), 1, 0   # if any space remains, fill with 0
.word 0xAA55