Line data    Source code

       1             : #include <tommath.h>
       2             : #ifdef BN_MP_REDUCE_IS_2K_L_C
       3             : /* LibTomMath, multiple-precision integer library -- Tom St Denis
       4             :  *
       5             :  * LibTomMath is a library that provides multiple-precision
       6             :  * integer arithmetic as well as number theoretic functionality.
       7             :  *
       8             :  * The library was designed directly after the MPI library by
       9             :  * Michael Fromberger but has been written from scratch with
      10             :  * additional optimizations in place.
      11             :  *
      12             :  * The library is free for all purposes without any express
      13             :  * guarantee it works.
      14             :  *
      15             :  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
      16             :  */
      17             : 
      18             : /* determines if reduce_2k_l can be used */
      19         872 : int mp_reduce_is_2k_l(mp_int *a)
      20             : {
      21             :    int ix, iy;
      22             : 
      23         872 :    if (a->used == 0) {
      24           0 :       return MP_NO;
      25         872 :    } else if (a->used == 1) {
      26           0 :       return MP_YES;
      27         872 :    } else if (a->used > 1) {
      28             :       /* if more than half of the digits are -1 we're sold */
      29       44314 :       for (iy = ix = 0; ix < a->used; ix++) {
      30       43474 :           if (a->dp[ix] == MP_MASK) {
      31         236 :               ++iy;
      32             :           }
      33             :       }
      34         872 :       return (iy >= (a->used/2)) ? MP_YES : MP_NO;
      35             : 
      36             :    }
      37           0 :    return MP_NO;
      38             : }
      39             : 
      40             : #endif
      41             : 
      42             : /* $Source: /cvs/libtom/libtommath/bn_mp_reduce_is_2k_l.c,v $ */
      43             : /* $Revision: 1.4 $ */
      44             : /* $Date: 2006/12/28 01:25:13 $ */