kc3-lang/gnulib/lib/fmodl.c

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• Hash : 9e83e486
  Author :
  Date : 2012-02-27T11:35:41
  

  fmodl-ieee: Fix test failures.
  
  * lib/fmodl.c (fmodl): Treat Inf specially.
  * modules/fmodl (Depends-on): Add isinf.
  

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• lib/fmodl.c

• /* Remainder.
     Copyright (C) 2011-2012 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <math.h>
  
  #if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
  
  long double
  fmodl (long double x, long double y)
  {
    return fmod (x, y);
  }
  
  #else
  
  long double
  fmodl (long double x, long double y)
  {
    if (isinf (y))
      return x;
    else
      {
        long double q = - truncl (x / y);
        long double r = fmal (q, y, x); /* = x + q * y, computed in one step */
        /* Correct possible rounding errors in the quotient x / y.  */
        if (y >= 0)
          {
            if (x >= 0)
              {
                /* Expect 0 <= r < y.  */
                if (r < 0)
                  q += 1, r = fmal (q, y, x);
                else if (r >= y)
                  q -= 1, r = fmal (q, y, x);
              }
            else
              {
                /* Expect - y < r <= 0.  */
                if (r > 0)
                  q -= 1, r = fmal (q, y, x);
                else if (r <= - y)
                  q += 1, r = fmal (q, y, x);
              }
          }
        else
          {
            if (x >= 0)
              {
                /* Expect 0 <= r < - y.  */
                if (r < 0)
                  q -= 1, r = fmal (q, y, x);
                else if (r >= - y)
                  q += 1, r = fmal (q, y, x);
              }
            else
              {
                /* Expect y < r <= 0.  */
                if (r > 0)
                  q += 1, r = fmal (q, y, x);
                else if (r <= y)
                  q -= 1, r = fmal (q, y, x);
              }
          }
        return r;
      }
  }
  
  #endif
  

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