LCOV - code coverage report
Current view: top level - source4/heimdal/lib/hcrypto/libtommath - bn_mp_reduce_2k_l.c (source / functions) Hit Total Coverage
Test: coverage report for abartlet/fix-coverage dd10fb34 Lines: 0 17 0.0 %
Date: 2021-09-23 10:06:22 Functions: 0 1 0.0 %

          Line data    Source code
       1             : #include <tommath.h>
       2             : #ifdef BN_MP_REDUCE_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             : /* reduces a modulo n where n is of the form 2**p - d
      19             :    This differs from reduce_2k since "d" can be larger
      20             :    than a single digit.
      21             : */
      22           0 : int mp_reduce_2k_l(mp_int *a, mp_int *n, mp_int *d)
      23             : {
      24             :    mp_int q;
      25             :    int    p, res;
      26             : 
      27           0 :    if ((res = mp_init(&q)) != MP_OKAY) {
      28           0 :       return res;
      29             :    }
      30             : 
      31           0 :    p = mp_count_bits(n);
      32           0 : top:
      33             :    /* q = a/2**p, a = a mod 2**p */
      34           0 :    if ((res = mp_div_2d(a, p, &q, a)) != MP_OKAY) {
      35           0 :       goto ERR;
      36             :    }
      37             : 
      38             :    /* q = q * d */
      39           0 :    if ((res = mp_mul(&q, d, &q)) != MP_OKAY) {
      40           0 :       goto ERR;
      41             :    }
      42             : 
      43             :    /* a = a + q */
      44           0 :    if ((res = s_mp_add(a, &q, a)) != MP_OKAY) {
      45           0 :       goto ERR;
      46             :    }
      47             : 
      48           0 :    if (mp_cmp_mag(a, n) != MP_LT) {
      49           0 :       s_mp_sub(a, n, a);
      50           0 :       goto top;
      51             :    }
      52             : 
      53           0 : ERR:
      54           0 :    mp_clear(&q);
      55           0 :    return res;
      56             : }
      57             : 
      58             : #endif
      59             : 
      60             : /* $Source: /cvs/libtom/libtommath/bn_mp_reduce_2k_l.c,v $ */
      61             : /* $Revision: 1.4 $ */
      62             : /* $Date: 2006/12/28 01:25:13 $ */

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