#include <sys/types.h>
#include <machine/cpufunc.h>

static void puts(const char *c);
static void sio_putc(char c);

extern char _start[];
extern char _end[];

extern uint64_t pdpt[];
extern uint64_t ptd[];
extern uint64_t ptp[];

int
main(void)
{
	uint32_t start, end, n;
	uint32_t i, r;

	puts("hello from protected mode...\r\n");

	start = (uint32_t)_start & ~(4096 - 1);
	end = ((uint32_t)_end + 4096) & ~(4096 - 1);
	n = (end - start) / 4096;
	for (i = 0; i < 4; i++)
		pdpt[i] = ((uint32_t)ptd + (i * 4096)) | 1;
	ptd[0] = (uint32_t)ptp | 3;
	for (i = 0; i < n; i++) {
		ptp[((start >> 12) & ((1 << 9) - 1)) + i] =
		    (start + (i * 4096)) | 3;
	}
	asm volatile(
	    " movl %1, %%cr3 ; "
	    " movl %%cr4, %0 ; "
	    " orl %2, %0 ; "
	    " movl %0, %%cr4 ; "
	    " movl %%cr0, %0 ; "
	    " orl %3, %0 ; "
	    " movl %0, %%cr0 ; "
	    " jmp 1f ; "
	    " 1: "
	    : "=r" (r)
	    : "r" (pdpt), "i" (1U << 5), "i" (1U << 31));

	puts("hello from pae...\r\n");
}

static void
puts(const char *s)
{
	while (*s != '\0')
		sio_putc(*s++);
}

static void
sio_putc(char c)
{
	while ((inb(0x3f8 + 5) & 0x20) == 0)
		;
	outb(0x3f8, c);
}