/**
  * write the field, note the code could easily be extracted and templated but then would get
  * autoboxing and unable to optimise inlining
  *
  * @param encoder
  * @param mapWriter
  * @param value
  */
 public void write(
     final FastFixBuilder encoder, final PresenceMapWriter mapWriter, final double value) {
   _prevDecimal.set(value);
   _exp.write(encoder, _prevDecimal.getExponent());
   _mant.write(encoder, _prevDecimal.getMantissa());
 }
 @Override
 public boolean requiresPMap() {
   return _exp.requiresPMap() || _mant.requiresPMap();
 }
 public void reset() {
   _prevDecimal.set(_initExp, _initMant);
   _exp.reset();
   _mant.reset();
 }