code: public double readDouble()
          throws IOException
      {
          int tag = read();
  
          switch (tag) {
              case 'T':
                  return 1;
              case 'F':
                  return 0;
              case 'I':
                  return parseInt();
              case 'L':
                  return (double) parseLong();
              case 'D':
                  return parseDouble();
  
              default:
                  throw expect("long", tag);
          }
      }
docs: Reads a double
  
  <pre>
  D b64 b56 b48 b40 b32 b24 b16 b8
  </pre>