SRFFE Primitive
The SRFFE primitive allows you to specify an SR-type flipflop with clock enable.
Note: When the ENA (clock enable) input is high, the flipflop passes a
            signal that is dependent on the S and R inputs to
               Q. When the ENA input is low, the state of
               Q is maintained, regardless of the S and
               R inputs.
         For devices that do not support clock enable, logic synthesis generates logic equations containing flipflops with clock enables. These logic equations correctly emulate the logic specified in the project.
Note:  For information about Intel® Quartus® Prime primitive instantiation, go to Using a Intel® Quartus® Prime
            Logic Function.