sysdeps/powerpc/powerpc32/fpu/s_llrint.c

   1 /* Round a double value to a long long in the current rounding mode.
   2    Copyright (C) 1997-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <limits.h>
  20 #include <math.h>
  21 #include <math_ldbl_opt.h>
  22 #include <math_private.h>
  23 #include <stdint.h>
  24 #include <libm-alias-double.h>
  25
  26 long long int
  27 __llrint (double x)
  28 {
  29   double rx = rint (x);
  30   if (HAVE_PPC_FCTIDZ || rx != x)
  31     return (long long int) rx;
  32   else
  33     {
  34       /* Avoid incorrect exceptions from libgcc conversions (as of GCC
  35          5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>.  */
  36       if (fabs (rx) < 0x1p31)
  37         return (long long int) (long int) rx;
  38       uint64_t i0;
  39       EXTRACT_WORDS64 (i0, rx);
  40       int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff;
  41       if (exponent < 63)
  42         {
  43           unsigned long long int mant
  44             = (i0 & ((1ULL << 52) - 1)) | (1ULL << 52);
  45           if (exponent < 52)
  46             mant >>= 52 - exponent;
  47           else
  48             mant <<= exponent - 52;
  49           return (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant);
  50         }
  51       else if (rx == (double) LLONG_MIN)
  52         return LLONG_MIN;
  53       else
  54         return (long long int) (long int) rx << 32;
  55     }
  56 }
  57 libm_alias_double (__llrint, llrint)