+ * Revision 1.9 2004/04/01 12:50:09 mdw
+ * Add cyclic group abstraction, with test code. Separate off exponentation
+ * functions for better static linking. Fix a buttload of bugs on the way.
+ * Generally ensure that negative exponents do inversion correctly. Add
+ * table of standard prime-field subgroups. (Binary field subgroups are
+ * currently unimplemented but easy to add if anyone ever finds a good one.)
+ *
+ * Revision 1.8 2001/06/16 13:00:20 mdw
+ * Use the generic exponentiation functions.
+ *
+ * Revision 1.7 2001/04/19 18:25:26 mdw
+ * Use sliding-window exponentiation.
+ *
+ * Revision 1.6 2000/10/08 12:03:44 mdw
+ * (mpbarrett_reduce): Cope with negative numbers.
+ *
+ * Revision 1.5 2000/07/29 17:04:33 mdw
+ * Change to use left-to-right bitwise exponentiation. This will improve
+ * performance when the base is small.
+ *
+ * Revision 1.4 2000/06/17 11:45:09 mdw
+ * Major memory management overhaul. Added arena support. Use the secure
+ * arena for secret integers. Replace and improve the MP management macros
+ * (e.g., replace MP_MODIFY by MP_DEST).
+ *
+ * Revision 1.3 1999/12/12 15:08:52 mdw
+ * Don't bother shifting %$q$% in @mpbarrett_reduce@, just skip the least
+ * significant digits.
+ *
+ * Revision 1.2 1999/12/11 01:50:56 mdw
+ * Improve initialization slightly.
+ *