GCD_CMPL

In the following C++ function, let n >= m.

int gcd(int n, int m) {
  if (n%m ==0) return m;
  if (n < m) swap(n, m);
  while (m > 0) {
    n = n%m;
    swap(n, m);
  }
  return n;
}

What is the time complexity of the above function assuming n > m?.
Θ symbol represents theta notation and Ω symbol represents omega notation.