github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpz/mod.c (about)

     1  /* mpz_mod -- The mathematical mod function.
     2  
     3  Copyright 1991, 1993-1996, 2001, 2002, 2005, 2010, 2012 Free Software
     4  Foundation, Inc.
     5  
     6  This file is part of the GNU MP Library.
     7  
     8  The GNU MP Library is free software; you can redistribute it and/or modify
     9  it under the terms of either:
    10  
    11    * the GNU Lesser General Public License as published by the Free
    12      Software Foundation; either version 3 of the License, or (at your
    13      option) any later version.
    14  
    15  or
    16  
    17    * the GNU General Public License as published by the Free Software
    18      Foundation; either version 2 of the License, or (at your option) any
    19      later version.
    20  
    21  or both in parallel, as here.
    22  
    23  The GNU MP Library is distributed in the hope that it will be useful, but
    24  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    25  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    26  for more details.
    27  
    28  You should have received copies of the GNU General Public License and the
    29  GNU Lesser General Public License along with the GNU MP Library.  If not,
    30  see https://www.gnu.org/licenses/.  */
    31  
    32  #include "gmp.h"
    33  #include "gmp-impl.h"
    34  
    35  void
    36  mpz_mod (mpz_ptr rem, mpz_srcptr dividend, mpz_srcptr divisor)
    37  {
    38    mp_size_t rn, bn;
    39    mpz_t temp_divisor;
    40    TMP_DECL;
    41  
    42    TMP_MARK;
    43  
    44    bn = ABSIZ(divisor);
    45  
    46    /* We need the original value of the divisor after the remainder has been
    47       preliminary calculated.  We have to copy it to temporary space if it's
    48       the same variable as REM.  */
    49    if (rem == divisor)
    50      {
    51        PTR(temp_divisor) = TMP_ALLOC_LIMBS (bn);
    52        MPN_COPY (PTR(temp_divisor), PTR(divisor), bn);
    53      }
    54    else
    55      {
    56        PTR(temp_divisor) = PTR(divisor);
    57      }
    58    SIZ(temp_divisor) = bn;
    59    divisor = temp_divisor;
    60  
    61    mpz_tdiv_r (rem, dividend, divisor);
    62  
    63    rn = SIZ (rem);
    64    if (rn < 0)
    65      mpz_add (rem, rem, divisor);
    66  
    67    TMP_FREE;
    68  }