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; gdt.asm
; GDT is defined here
gdt_start:
gdt_null: ; Null segment
dd 0x0
dd 0x0
gdt_kcode: ; Kernel code segment. Kernel has seperate segment from users for ring level
; flag and access byte description on osdev wiki
dw 0xffff ; low limit
dw 0x0 ;low base
db 0x0 ; mid base
db 10011010b ; order (reversed): ac, rw, dc, ex, s, privl, pr
db 11001111b ; flags then limit. order (reversed): 0, 0, size bit, granularity bit
db 0x0 ; high limit
gdt_kdata: ; same as gdt_kcode but for the data segment
dw 0xffff ;low limit
dw 0x0 ;low base
db 0x0 ;mid base
db 10010010b ; order: same as code seg. changed for data seg
db 11001111b ; same as kcode
db 0x0 ; high limit
gdt_end:
gdt_descriptor: ; describes the gdt to the lgdt register
dw gdt_end - gdt_start - 1
dd gdt_start
CODE_SEG equ gdt_kcode - gdt_start
DATA_SEG equ gdt_kdata - gdt_start
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