Stuff

/* real.S - real mode code */

#define ASM	1
#include <mem.h>

        .code16
	.data
	.globl gdtdesc, _gdtdesc
gdtdesc:
        .word 0
	.long gdt
gdt:
/* Allocate some bytes here, set them in protected mode code */
        .quad 0
        .quad 0
        .quad 0
        .quad 0
        .quad 0
        .quad 0
	.text
	.globl	enter_protmode, _enter_protmode
enter_protmode:
_enter_protmode:
        movl $gdt, %eax
	lgdt (%eax)
        movl %cr0, %eax
	orl  $(CR0_PE),%eax
	movl %eax,%cr0
	xorw %ax,%ax
	movw %ax,%gs
	movw %ax,%fs
	movw %ax,%es
        movw $(SEG_KERN_DATA),%ax
	movw %ax,%ds
        movw $(SEG_KERN_CODE),%ax
	shlw $4,%ax
	addl $protmode_entry, %eax
        ljmpl   *(%eax)
     
	.code32
	.text
	.extern multiboot_entry
protmode_entry:
_protmode_entry:
       jmp     multiboot_entry