+
−#include <tommath.h>
+
−#ifdef BN_MP_REDUCE_IS_2K_L_C
+
−/* LibTomMath, multiple-precision integer library -- Tom St Denis
+
− *
+
− * LibTomMath is a library that provides multiple-precision
+
− * integer arithmetic as well as number theoretic functionality.
+
− *
+
− * The library was designed directly after the MPI library by
+
− * Michael Fromberger but has been written from scratch with
+
− * additional optimizations in place.
+
− *
+
− * The library is free for all purposes without any express
+
− * guarantee it works.
+
− *
+
− * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+
− */
+
−
+
−/* determines if reduce_2k_l can be used */
+
−int mp_reduce_is_2k_l(mp_int *a)
+
−{
+
−   int ix, iy;
+
−   
+
−   if (a->used == 0) {
+
−      return MP_NO;
+
−   } else if (a->used == 1) {
+
−      return MP_YES;
+
−   } else if (a->used > 1) {
+
−      /* if more than half of the digits are -1 we're sold */
+
−      for (iy = ix = 0; ix < a->used; ix++) {
+
−          if (a->dp[ix] == MP_MASK) {
+
−              ++iy;
+
−          }
+
−      }
+
−      return (iy >= (a->used/2)) ? MP_YES : MP_NO;
+
−      
+
−   }
+
−   return MP_NO;
+
−}
+
−
+
−#endif