I guess the unused entries spell "bad FC" (for floating constant). Also I think constants 6 through 10 are relevant for the decimal-to-binary conversion or vice versa, as evident from the following observation:<p><pre><code> 0x5c3bd5191b525a249 ~= 2^123 / 10^17
0x470de4df820000000 = 2^13 * 10^16</code></pre>