yosys/tests/techmap/dfflibmap_dffn_dffe.lib

library(test) {
  cell (dffn) {
    area : 6;
    ff("IQ", "IQN") {
      next_state : "D";
      clocked_on : "!CLK";
    } 
    pin(D) {
      direction : input;
    }
    pin(CLK) {
      direction : input;
    }
    pin(Q) {
      direction: output;
      function : "IQ";
    }
    pin(QN) {
      direction: output;
      function : "IQN";
    } 
  }
  cell (dffe) {
    area : 6;
    ff("IQ", "IQN") {
      next_state : "(D&EN) | (IQ&!EN)";
      clocked_on : "!CLK";
    }
    pin(D) {
      direction : input;
    }
    pin(EN) {
      direction : input;
    }
    pin(CLK) {
      direction : input;
    }
    pin(Q) {
      direction: output;
      function : "IQ";
    }
    pin(QN) {
      direction: output;
      function : "IQN";
    }
  }
}