- * There's quite a lot of prime searching to be done. The constant
- * @BITSLOP@ is a (low) approximation to the base-2 log of the expected
- * number of steps to find a prime number. Experimentation shows that
- * numbers around 10 seem to be good.
+ * Let's suppose we're trying to make an %$N$%-bit prime. The expected
+ * number of steps tends to increase linearly with size, i.e., we need to
+ * take about %2^k N$% steps for some %$k$%. If we're jumping by a
+ * %$J$%-bit quantity each time, from an %$N$%-bit starting point, then we
+ * will only be able to find a match if %$2^k N 2^{J-1} \le 2^{N-1}$%,
+ * i.e., if %$J \le N - (k + \log_2 N)$%.
+ *
+ * Experimentation shows that taking %$k + \log_2 N = 12$% works well for
+ * %$N = 1024$%, so %$k = 2$%. Add a few extra bits for luck.