code: func asciiHex16(n int) []byte {
  	var ret [4]byte
  	ret[0] = byteToASCIIHex(byte(n & 0xf000 >> 12))
  	ret[1] = byteToASCIIHex(byte(n & 0x0f00 >> 8))
  	ret[2] = byteToASCIIHex(byte(n & 0x00f0 >> 4))
  	ret[3] = byteToASCIIHex(byte(n & 0x000f))
  
  	return ret[:]
  }
docs: // Returns the hexadecimal ascii representation of the 16 less
  // significant bits of n.  The length of the returned slice will always
  // be 4.  Example: if n is 1234 (0x4d2), the return value will be
  // []byte{'0', '4', 'd', '2'}.