realmode.S

.globl go_realmode
.org 0

ivt:
	.skip 1024, 0

ivt_ptr:
	.hword 1023
	.int ivt

go_realmode:
	cli

	mov $0x10, %eax /* 16-bit code descriptor in GDT */
	mov %eax, %ds
	mov %eax, %es
	mov %eax, %fs
	mov %eax, %gs
	mov %eax, %ss

	mov %cr0, %eax
	and $0x7FFFFFFe, %eax
	mov %eax, %cr0

	ljmp $0, $realmode

realmode:

	mov $0, %ax
	mov %ax, %ds
	mov %ax, %es
	mov %ax, %fs
	mov %ax, %gs

	lidt ivt_ptr

	sti
	ret