void *
sbrk(
	uintptr_t increment
    ) {
	ASSERT(increment % 0x1000 == 0);
	ASSERT(heap_end % 0x1000 == 0);
	uintptr_t address = heap_end;
	heap_end += increment;
	uintptr_t i;
	for (i = address; i < heap_end; i += 0x1000) {
		get_page(i, 1, kernel_directory);
		alloc_frame(get_page(i, 1, kernel_directory), 0, 1);
	}
	return (void *)address;
}