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[BITS 32]
global start
start:
mov esp, _sys_stack ; Points stack to stack area
jmp stublet
; Align with 4 Bytes
ALIGN 4
mboot:
; Multiboot macros
MULTIBOOT_PAGE_ALIGN equ 1<<0
MULTIBOOT_MEMORY_INFO equ 1<<1
MULTIBOOT_AOUT_KLUDGE equ 1<<16
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE
MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
EXTERN code, bss, end
; GRUB Multiboot header
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd MULTIBOOT_CHECKSUM
; AOUT kludge
dd mboot
dd code
dd bss
dd end
dd start
; Endless loop
stublet:
extern kernel_main
call kernel_main
jmp $
; GDT flush function
global gdt_flush
extern gp
gdt_flush:
lgdt [gp]
mov ax, 0x10 ; Data segment offset of GDT
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
jmp 0x08:flush2 ; Code segment offset
flush2:
ret ; Returns to C code
; IDT loader
global idt_load
extern idtp
idt_load:
lidt [idtp]
ret
; Store the stack
SECTION .bss
resb 8192 ; Reserve 8KiB
_sys_stack:
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