sysdeps/ieee754/ldbl-128/s_truncl.c

   1 /* Truncate argument to nearest integral value not larger than the argument.
   2    Copyright (C) 1997-2020 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    <https://www.gnu.org/licenses/>.  */
  20
  21 #define NO_MATH_REDIRECT
  22 #include <math.h>
  23
  24 #include <math_private.h>
  25 #include <libm-alias-ldouble.h>
  26 #include <math-use-builtins.h>
  27
  28
  29 _Float128
  30 __truncl (_Float128 x)
  31 {
  32 #if USE_TRUNCL_BUILTIN
  33   return __builtin_truncl (x);
  34 #else
  35   /* Use generic implementation.  */
  36   int32_t j0;
  37   uint64_t i0, i1, sx;
  38
  39   GET_LDOUBLE_WORDS64 (i0, i1, x);
  40   sx = i0 & 0x8000000000000000ULL;
  41   j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  42   if (j0 < 48)
  43     {
  44       if (j0 < 0)
  45         /* The magnitude of the number is < 1 so the result is +-0.  */
  46         SET_LDOUBLE_WORDS64 (x, sx, 0);
  47       else
  48         SET_LDOUBLE_WORDS64 (x, i0 & ~(0x0000ffffffffffffLL >> j0), 0);
  49     }
  50   else if (j0 > 111)
  51     {
  52       if (j0 == 0x4000)
  53         /* x is inf or NaN.  */
  54         return x + x;
  55     }
  56   else
  57     {
  58       SET_LDOUBLE_WORDS64 (x, i0, i1 & ~(0xffffffffffffffffULL >> (j0 - 48)));
  59     }
  60
  61   return x;
  62 #endif /* ! USE_TRUNCL_BUILTIN  */
  63 }
  64 libm_alias_ldouble (__trunc, trunc)