Cruise ships calling at Istanbul usually dock on the European side of the Bosphorus, just north of the Golden Horn.
I'm not persuaded that it's the same airport. Istanbul has a new airport now.
I hope that you will have time to visit some of Istanbul's attractions. If you have only half a day, take the walking tour of "Imperial Istanbul" that includes the Hippodrome, Haggia Sophia, the Blue Mosque, and Topkapi Palace. The art and architecture at these sites are beyond belief.
Have a great cruise!