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.extern bringelle
.extern gdt_memcpy
.globl _start
.text
.set MB_MAGIC, 0x1BADB002
.set MB_FLAGS, 0x00010000
.set MB_CHECKSUM, -(MB_MAGIC+MB_FLAGS)
.set MB_HEADER_ADDR, mb_header
.set MB_LOAD_ADDR, mb_header
.set MB_LOAD_END_ADDR, 0x0
.set MB_BSS_END_ADDR, 0x0
.set MB_ENTRY_ADDR, _start
mb_header:
.align 4
.long MB_MAGIC
.long MB_FLAGS
.long MB_CHECKSUM
.long MB_HEADER_ADDR
.long MB_LOAD_ADDR
.long MB_LOAD_END_ADDR
.long MB_BSS_END_ADDR
.long MB_ENTRY_ADDR
_start:
# Copy GDT into memory then load its register
call gdt_memcpy
lgdtl (GDTR)
# Update all segments register
# with the new GDT offset
movw $0x10, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
# Update code segment
ljmp $0x08, $cs_new
cs_new:
# Update stack segment
movw $0x18, %ax
movw %ax, %ss
movl $0x20000,%esp
# Start kernel main function
call bringelle
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