github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/generic/toom_eval_dgr3_pm1.c (about)

     1  /* mpn_toom_eval_dgr3_pm1 -- Evaluate a degree 3 polynomial in +1 and -1
     2  
     3     Contributed to the GNU project by Niels Möller
     4  
     5     THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE.  IT IS ONLY
     6     SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES.  IN FACT, IT IS ALMOST
     7     GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
     8  
     9  Copyright 2009 Free Software Foundation, Inc.
    10  
    11  This file is part of the GNU MP Library.
    12  
    13  The GNU MP Library is free software; you can redistribute it and/or modify
    14  it under the terms of either:
    15  
    16    * the GNU Lesser General Public License as published by the Free
    17      Software Foundation; either version 3 of the License, or (at your
    18      option) any later version.
    19  
    20  or
    21  
    22    * the GNU General Public License as published by the Free Software
    23      Foundation; either version 2 of the License, or (at your option) any
    24      later version.
    25  
    26  or both in parallel, as here.
    27  
    28  The GNU MP Library is distributed in the hope that it will be useful, but
    29  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    30  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    31  for more details.
    32  
    33  You should have received copies of the GNU General Public License and the
    34  GNU Lesser General Public License along with the GNU MP Library.  If not,
    35  see https://www.gnu.org/licenses/.  */
    36  
    37  
    38  #include "gmp.h"
    39  #include "gmp-impl.h"
    40  
    41  int
    42  mpn_toom_eval_dgr3_pm1 (mp_ptr xp1, mp_ptr xm1,
    43  			mp_srcptr xp, mp_size_t n, mp_size_t x3n, mp_ptr tp)
    44  {
    45    int neg;
    46  
    47    ASSERT (x3n > 0);
    48    ASSERT (x3n <= n);
    49  
    50    xp1[n] = mpn_add_n (xp1, xp, xp + 2*n, n);
    51    tp[n] = mpn_add (tp, xp + n, n, xp + 3*n, x3n);
    52  
    53    neg = (mpn_cmp (xp1, tp, n + 1) < 0) ? ~0 : 0;
    54  
    55  #if HAVE_NATIVE_mpn_add_n_sub_n
    56    if (neg)
    57      mpn_add_n_sub_n (xp1, xm1, tp, xp1, n + 1);
    58    else
    59      mpn_add_n_sub_n (xp1, xm1, xp1, tp, n + 1);
    60  #else
    61    if (neg)
    62      mpn_sub_n (xm1, tp, xp1, n + 1);
    63    else
    64      mpn_sub_n (xm1, xp1, tp, n + 1);
    65  
    66    mpn_add_n (xp1, xp1, tp, n + 1);
    67  #endif
    68  
    69    ASSERT (xp1[n] <= 3);
    70    ASSERT (xm1[n] <= 1);
    71  
    72    return neg;
    73  }