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 (at) gmail.com, http://math.libtomcrypt.com 16 */ 17 18 /* determines if reduce_2k_l can be used */ 19 int mp_reduce_is_2k_l(mp_int *a) 20 { 21 int ix, iy; 22 23 if (a->used == 0) { 24 return MP_NO; 25 } else if (a->used == 1) { 26 return MP_YES; 27 } else if (a->used > 1) { 28 /* if more than half of the digits are -1 we're sold */ 29 for (iy = ix = 0; ix < a->used; ix++) { 30 if (a->dp[ix] == MP_MASK) { 31 ++iy; 32 } 33 } 34 return (iy >= (a->used/2)) ? MP_YES : MP_NO; 35 36 } 37 return MP_NO; 38 } 39 40 #endif 41 42 /* $Source: /cvs/libtom/libtommath/bn_mp_reduce_is_2k_l.c,v $ */ 43 /* $Revision: 1.3 $ */ 44 /* $Date: 2006/03/31 14:18:44 $ */ 45
