length := fn(ptr: ^u8): int {
	len := 0
	loop if *ptr == 0 break else {
		len += 1
		ptr += 1
	}
	return len
}

display_int := fn(num: int, p: ^u8): ^u8 {
	i := 0
	if num == 0 {
		set(p, 48)
		return p
	}
	loop {
		if num == 0 break
		set(p + i, num % 10 + 48)
		num /= 10
		i += 1
	}
	reverse(p)
	//null terminate
	set(p + i, 0)
	return p
}

reverse := fn(s: ^u8): void {
	//reverse a string, don't remove digits
	len := 0
	loop {
		if *(s + len) == 0 break
		len += 1
	}
	i := 0
	j := len - 1
	loop {
		if i >= j break
		temp := *(s + i);
		*(s + i) = *(s + j);
		*(s + j) = temp
		i += 1
		j -= 1
	}
	return
}

set := fn(change: ^u8, new: int): void {
	*change = new
	return
}