Blame view

Giac_maj/libtommath-0.39/bn_mp_mod.c 1.06 KB
6663b6c9   adorian   projet complet av...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
  #include <tommath.h>
  #ifdef BN_MP_MOD_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@gmail.com, http://math.libtomcrypt.com
   */
  
  /* c = a mod b, 0 <= c < b */
  int
  mp_mod (mp_int * a, mp_int * b, mp_int * c)
  {
    mp_int  t;
    int     res;
  
    if ((res = mp_init (&t)) != MP_OKAY) {
      return res;
    }
  
    if ((res = mp_div (a, b, NULL, &t)) != MP_OKAY) {
      mp_clear (&t);
      return res;
    }
  
    if (t.sign != b->sign) {
      res = mp_add (b, &t, c);
    } else {
      res = MP_OKAY;
      mp_exch (&t, c);
    }
  
    mp_clear (&t);
    return res;
  }
  #endif
  
  /* $Source: /cvs/libtom/libtommath/bn_mp_mod.c,v $ */
  /* $Revision: 1.3 $ */
  /* $Date: 2006/03/31 14:18:44 $ */