In F-16 the pilot or FLCS , use the rudder to address the adverse yaw effects in direction of roll during an aileron roll? or opposite way?
Adverse yaw from aileron deflection, at roll initiation, is a function of wing span: a longer wing span creates more adverse yaw. And a long wing span is not what an F-16 possesses.

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Its main problem at lower airspeed is creating a roll rate at all with such short wings. Deflecting the rudder may help increasing the roll rate - for a left roll, it would be deflected Trailing Edge Right, creating adverse yaw. Which might or might be compensated by asymmetric aileron deflection, depending on the priorities posed upon the manoeuvres of a fighter aircraft at low speed. Of course, it makes much more sense to deflect the horizontal tail such that it helps in the roll.

At high roll rates, adverse yaw is created by the difference in local angle of attack at left and right aileron. Plus an aeroplane with low wing span will start to nutate: it wants to spin about its rotation axis with the highest moment of inertia, so tends to want to convert roll into pitch from inertial coupling. So high roll rates are a different kettle of fish in aeroplanes with short wing span, with lots of work to do for the fly-by-wire computers. 


  In the F-16, is rudder used to arrest the adverse yaw effects...


Most probably not. Adverse yaw from aileron deflection is not a large issue on fighter aircraft.