luxos/Kernel/hal/cpu/gdt-asm.asm

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NASM
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; GLOBAL DESCRIPTOR TABLE
;
;
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bits 32
; !!! GDT !!!
; This will set up our new segment registers. We need to do
; something special in order to set CS. We do what is called a
; far jump. A jump that includes a segment as well as an offset.
global GdtFlush ; Allows the C code to link to this
extern gp ; Says that 'gp' is in another file
GdtFlush:
lgdt [gp] ; Load the GDT with our 'gp' which is a special pointer
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mov ax, 0x10 ; 0x10 is the offset in the GDT to our data segment
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
jmp 0x08:flush2 ; 0x08 is the offset to our code segment: Far jump!
flush2:
ret ; Returns back to the C code!