Oil light came on and engine started tapping!!

What is your question?

It was running fine.I pulled away and noticed the oil light came on and turned down the stereo and it was tapping I pulled over right away and shut it off and checked the oil!! It was 1 quart low! Put a quart in and oil light Still on engine still tapping but running smooth!! I revved it up a little and oil light went off but still tapping but running smooth!! It's not knocking on the lower half but tapping from the top half!! Car only has 37,000 miles!!! Thank you for your time!!