sysdeps/ieee754/ldbl-128/s_truncl.c

   1 /* Truncate argument to nearest integral value not larger than the argument.
   2    Copyright (C) 1997-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
   5                   Jakub Jelinek <jj@ultra.linux.cz>, 1999.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <math.h>
  22
  23 #include <math_private.h>
  24 #include <libm-alias-ldouble.h>
  25
  26
  27 _Float128
  28 __truncl (_Float128 x)
  29 {
  30   int32_t j0;
  31   uint64_t i0, i1, sx;
  32
  33   GET_LDOUBLE_WORDS64 (i0, i1, x);
  34   sx = i0 & 0x8000000000000000ULL;
  35   j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  36   if (j0 < 48)
  37     {
  38       if (j0 < 0)
  39         /* The magnitude of the number is < 1 so the result is +-0.  */
  40         SET_LDOUBLE_WORDS64 (x, sx, 0);
  41       else
  42         SET_LDOUBLE_WORDS64 (x, i0 & ~(0x0000ffffffffffffLL >> j0), 0);
  43     }
  44   else if (j0 > 111)
  45     {
  46       if (j0 == 0x4000)
  47         /* x is inf or NaN.  */
  48         return x + x;
  49     }
  50   else
  51     {
  52       SET_LDOUBLE_WORDS64 (x, i0, i1 & ~(0xffffffffffffffffULL >> (j0 - 48)));
  53     }
  54
  55   return x;
  56 }
  57 libm_alias_ldouble (__trunc, trunc)