release/src/router/dropbear/libtommath/bn_mp_and.c

   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@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 $ */