Ring or vibrate?

Design the control logic for a phone's ringer. When a call comes in (ring = 1), the phone either rings or vibrates — never both:

• If vibrate_mode is 1, turn on the vibration motor (motor = 1) and keep the ringer off.
• If vibrate_mode is 0, sound the ringer (ringer = 1) and keep the motor off.
• When there is no incoming call, both outputs are 0.

Think of it as deciding when each output should be on: the motor is on only while a call arrives in vibrate mode; the ringer is on only while a call arrives not in vibrate mode.