Home | History | Annotate | Download | only in libtommath
      1 #include <tommath.h>
      2 #ifdef BN_MP_AND_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 /* AND two ints together */
     19 int
     20 mp_and (mp_int * a, mp_int * b, mp_int * c)
     21 {
     22   int     res, ix, px;
     23   mp_int  t, *x;
     24 
     25   if (a->used > b->used) {
     26     if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
     27       return res;
     28     }
     29     px = b->used;
     30     x = b;
     31   } else {
     32     if ((res = mp_init_copy (&t, b)) != MP_OKAY) {
     33       return res;
     34     }
     35     px = a->used;
     36     x = a;
     37   }
     38 
     39   for (ix = 0; ix < px; ix++) {
     40     t.dp[ix] &= x->dp[ix];
     41   }
     42 
     43   /* zero digits above the last from the smallest mp_int */
     44   for (; ix < t.used; ix++) {
     45     t.dp[ix] = 0;
     46   }
     47 
     48   mp_clamp (&t);
     49   mp_exch (c, &t);
     50   mp_clear (&t);
     51   return MP_OKAY;
     52 }
     53 #endif
     54 
     55 /* $Source: /cvs/libtom/libtommath/bn_mp_and.c,v $ */
     56 /* $Revision: 1.3 $ */
     57 /* $Date: 2006/03/31 14:18:44 $ */
     58