gdt_null_segment: dq 0x0 gdt_code_segment: dw 0xffff dw 0x0 db 0x0 db 10011010b db 11001111b db 0x0 gdt_data_segment: dw 0xffff dw 0x0 db 0x0 db 10010010b db 11001111b db 0x0 gdt_end: gdt: dw gdt_end - gdt_null_segment - 1 dd gdt_null_segment