gdt64_start:
    ; Null
    dq 0

    ; Code (0x8)
    dw 0x0000                   ; Limit lower
    dw 0x0000                   ; Base  lower
    db 0x00                     ; Base middle
    db 10011010b                ; Access..

    ; NOTE: The AMD Volume 2, page 88 says that the segment limit fields
    ;   are actually ignored in long mode. The OSDev long mode page, however,
    ;   says that the CPU will make one last limit check when jumping into long mode
    ;   (tested by them in Bochs) and that's why I also set the higher bits
    ;   of the limit to 1111. However, I also tested with 0000 and it works.
    ;   Maybe it was a bug in Bochs that lead to checking the limit when
    ;   jumping to long mode?
    db 10101111b                ; Granularity & Limit
    db 0x00                     ; Base higher


    ; Data (0x8)
    dw 0x0000                   ; Limit lower
    dw 0x0000                   ; Base  lower
    db 0x00                     ; Base middle
    db 10010010b                ; Access..
    db 00000000b                ; Granularity & Limit
    db 0x00                     ; Base higher
gdt64_end:

gdt64_pointer:
    dw gdt64_end - gdt64_start - 1
    dq gdt64_start