code: function encode (value) {
  	var x = new Buffer(8);
  	var h, l;
  	
  	x.writeDoubleBE(value, 0);
  	
  	if(value < 0) {
  		x.writeUInt32BE((~x.readUInt32BE(0)) >>> 0, 0);
  		x.writeUInt32BE((~x.readUInt32BE(4)) >>> 0, 4);
  	} else {
  		/* non-negative; set the leading bit. */
  		x.writeUInt8(x.readUInt8(0) | 0x80, 0);
  	}
  	
  	return '\ue2f2' + enc85(x); 
  	/* 
  		The prefix is from the unicode private use area,
  		and is expected to not appear as the first character
  		of string key components. 2f2 is decimal 754, for
  		IEEE 754 (the floating point spec)
  	*/
  }
docs: /*
  This function encodes 64-bit floats such that
  bitwise comparison of the binary corresponds
  to the numeric comparison of the original
  values.
  
  It does the equivalent of two's complement
  encoding of negative numbers, and sets the
  highest bit for non-negative values.
  
  Returns an 8-byte big-endian binary buffer.