code: public MACAddress toEUI64(boolean asMAC) {
  		if(!isExtended()) {//getSegmentCount() == EXTENDED_UNIQUE_IDENTIFIER_48_SEGMENT_COUNT
  			MACAddressCreator creator = getAddressCreator();
  			MACAddressSegment segs[] = creator.createSegmentArray(EXTENDED_UNIQUE_IDENTIFIER_64_SEGMENT_COUNT);
  			MACAddressSection section = getSection();
  			section.getSegments(0,  3, segs, 0);
  			MACAddressSegment ffSegment = creator.createSegment(0xff);
  			segs[3] = ffSegment;
  			segs[4] = asMAC ? ffSegment : creator.createSegment(0xfe);
  			section.getSegments(3,  6, segs, 5);
  			Integer prefLength = getPrefixLength();
  			if(prefLength != null) {
  				MACAddressSection resultSection = creator.createSectionInternal(segs, true);
  				if(prefLength >= 24) {
  					prefLength += MACAddress.BITS_PER_SEGMENT << 1; //two segments
  				}
  				resultSection.assignPrefixLength(prefLength);
  			}
  			return creator.createAddressInternal(segs);
  		} else {
  			MACAddressSection section = getSection();
  			MACAddressSegment seg3 = section.getSegment(3);
  			MACAddressSegment seg4 = section.getSegment(4);
  			if(seg3.matches(0xff) && seg4.matches(asMAC ? 0xff : 0xfe)) {
  				return this;
  			}
  		}
  		throw new IncompatibleAddressException(this, "ipaddress.mac.error.not.eui.convertible");
  	}
docs: Convert to IPv6 EUI-64 section
  
  http://standards.ieee.org/develop/regauth/tut/eui64.pdf
  
  @param asMAC if true, this address is considered MAC and the EUI-64 is extended using ff-ff, otherwise this address is considered EUI-48 and extended using ff-fe
  Note that IPv6 treats MAC as EUI-48 and extends MAC to IPv6 addresses using ff-fe
  @return