code: function pointFpMultiplyTwo(j,x,k) {
    var i;
    if(j.bitLength() > k.bitLength())
      i = j.bitLength() - 1;
    else
      i = k.bitLength() - 1;
  
    var R = this.curve.getInfinity();
    var both = this.add(x);
    while(i >= 0) {
      R = R.twice();
      if(j.testBit(i)) {
        if(k.testBit(i)) {
          R = R.add(both);
        }
        else {
          R = R.add(this);
        }
      }
      else {
        if(k.testBit(i)) {
          R = R.add(x);
        }
      }
      --i;
    }
  
    return R;
  }
docs: Compute this*j + x*k (simultaneous multiplication)