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Legacy-Sync/gdt.s
Jenny Curle f6ba6aa117 Legacy OS files. Have an i686-elf-gcc & -ld in your PATH,
and the Makefile will take care of the rest.
2019-04-01 01:38:50 +01:00

29 lines
918 B
ArmAsm

;
; Gdt.s -- contains global descriptor table and interrupt descriptor table
; setup code.
; Based on code from Bran's kernel development tutorials.
; Rewritten for JamesM's kernel development tutorials.
[GLOBAL gdt_flush] ; Allows the C code to call gdt_flush().
gdt_flush:
mov eax, [esp+4] ; Get the pointer to the GDT, passed as a parameter.
lgdt [eax] ; Load the new GDT pointer
mov ax, 0x10 ; 0x10 is the offset in the GDT to our data segment
mov ds, ax ; Load all data segment selectors
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
jmp 0x08:.flush ; 0x08 is the offset to our code segment: Far jump!
.flush:
ret
[GLOBAL idt_flush] ; Allows the C code to call idt_flush().
idt_flush:
mov eax, [esp+4] ; Get the pointer to the IDT, passed as a parameter.
lidt [eax] ; Load the IDT pointer.
ret