Timings.

	 * exponentiation using the reciprocal-based quick remaindering

	 * algorithm is used.

	 *

	 * (For computations  a^p mod m  where  a, p, m  are of the same

	 * length, BN_mod_exp_recp takes roughly 50 .. 70 % the time

	 * required by the standard algorithm, and BN_mod_exp takes

	 * about 33 .. 40 % of it.

	 * [Timings obtained with expspeed.c on a AMD K6-2 platform under Linux,

	 * with various OpenSSL debugging macros defined.  YMMV.])

	 * (Timing obtained with expspeed.c [computations  a^p mod m

	 * where  a, p, m  are of the same length: 256, 512, 1024, 2048,

	 * 4096, 8192 bits], compared to the running time of the

	 * standard algorithm:

	 *

	 *   BN_mod_exp_mont   33 .. 40 %  [AMD K6-2, Linux, debug configuration]

         *                     55 .. 77 %  [UltraSparc processor, but

	 *                                  debug-solaris-sparcv8-gcc conf.]

	 * 

	 *   BN_mod_exp_recp   50 .. 70 %  [AMD K6-2, Linux, debug configuration]

	 *                     62 .. 118 % [UltraSparc, debug-solaris-sparcv8-gcc]

	 *

	 * On the Sparc, BN_mod_exp_recp was faster than BN_mod_exp_mont

	 * at 2048 and more bits, but at 512 and 1024 bits, it was

	 * slower even than the standard algorithm!

	 *

	 * "Real" timings [linux-elf, solaris-sparcv9-gcc configurations]

	 * should be obtained when the new Montgomery reduction code

	 * has been integrated into OpenSSL.)

	 */

#define MONT_MUL_MOD