LCOV - code coverage report
Current view: top level - source4/heimdal/lib/hcrypto/libtommath - bn_mp_mul_2d.c (source / functions) Hit Total Coverage
Test: coverage report for abartlet/fix-coverage dd10fb34 Lines: 20 25 80.0 %
Date: 2021-09-23 10:06:22 Functions: 1 1 100.0 %

          Line data    Source code
       1             : #include <tommath.h>
       2             : #ifdef BN_MP_MUL_2D_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             : /* shift left by a certain bit count */
      19      744988 : int mp_mul_2d (mp_int * a, int b, mp_int * c)
      20             : {
      21             :   mp_digit d;
      22             :   int      res;
      23             : 
      24             :   /* copy */
      25      744988 :   if (a != c) {
      26           0 :      if ((res = mp_copy (a, c)) != MP_OKAY) {
      27           0 :        return res;
      28             :      }
      29             :   }
      30             : 
      31      744988 :   if (c->alloc < (int)(c->used + b/DIGIT_BIT + 1)) {
      32        1668 :      if ((res = mp_grow (c, c->used + b / DIGIT_BIT + 1)) != MP_OKAY) {
      33           0 :        return res;
      34             :      }
      35             :   }
      36             : 
      37             :   /* shift by as many digits in the bit count */
      38      744988 :   if (b >= (int)DIGIT_BIT) {
      39           0 :     if ((res = mp_lshd (c, b / DIGIT_BIT)) != MP_OKAY) {
      40           0 :       return res;
      41             :     }
      42             :   }
      43             : 
      44             :   /* shift any bit count < DIGIT_BIT */
      45      744988 :   d = (mp_digit) (b % DIGIT_BIT);
      46      744988 :   if (d != 0) {
      47             :     register mp_digit *tmpc, shift, mask, r, rr;
      48             :     register int x;
      49             : 
      50             :     /* bitmask for carries */
      51      744988 :     mask = (((mp_digit)1) << d) - 1;
      52             : 
      53             :     /* shift for msbs */
      54      744988 :     shift = DIGIT_BIT - d;
      55             : 
      56             :     /* alias */
      57      744988 :     tmpc = c->dp;
      58             : 
      59             :     /* carry */
      60      744988 :     r    = 0;
      61    29942986 :     for (x = 0; x < c->used; x++) {
      62             :       /* get the higher bits of the current word */
      63    29197998 :       rr = (*tmpc >> shift) & mask;
      64             : 
      65             :       /* shift the current word and OR in the carry */
      66    29197998 :       *tmpc = ((*tmpc << d) | r) & MP_MASK;
      67    29197998 :       ++tmpc;
      68             : 
      69             :       /* set the carry to the carry bits of the current word */
      70    29197998 :       r = rr;
      71             :     }
      72             : 
      73             :     /* set final carry */
      74      744988 :     if (r != 0) {
      75        1260 :        c->dp[(c->used)++] = r;
      76             :     }
      77             :   }
      78      744988 :   mp_clamp (c);
      79      744988 :   return MP_OKAY;
      80             : }
      81             : #endif
      82             : 
      83             : /* $Source: /cvs/libtom/libtommath/bn_mp_mul_2d.c,v $ */
      84             : /* $Revision: 1.4 $ */
      85             : /* $Date: 2006/12/28 01:25:13 $ */

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