.set ALIGN,    1<<0
.set MEMINFO,  1<<1
.set FLAGS,    ALIGN | MEMINFO
.set MAGIC,    0x1BADB002
.set CHECKSUM, -(MAGIC + FLAGS)

.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM

# C stack startup
.section .bss
.align 16
stack_bottom:
	.skip 16384
stack_top:

# start function - calls kernel_main
.section .text
.global _start
.type _start, @function

_start:
	movl $stack_top, %esp
	
	call _init
	
	call kernel_main
	
	cli
1:  hlt
	jmp 1b
	
.size _start, . - _start


# GDT segment register setup
.global gdt_flush
.extern gp
gdt_flush:
	lgdt (gp)    #load the GDT with the special pointer
	mov %eax,0x10  #offset from GDT to data segment
	mov %eax, %ds 
	mov %eax, %es
	mov %eax, %fs
	mov %eax, %gs
	mov %eax, %ss
	
	pushl 12(%esp)
	push $flush2
	ljmp *(%esp) #long jump
flush2:
	ret           #return to c code
	
.global idt_load
.extern idtp
idt_load:
	lidt (idtp)
	ret