1  /* Round long double value to long int.
       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 "quadmath-imp.h"
      22  
      23  long int
      24  lroundq (__float128 x)
      25  {
      26    int64_t j0;
      27    uint64_t i1, i0;
      28    long int result;
      29    int sign;
      30  
      31    GET_FLT128_WORDS64 (i0, i1, x);
      32    j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      33    sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
      34    i0 &= 0x0000ffffffffffffLL;
      35    i0 |= 0x0001000000000000LL;
      36  
      37    if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
      38      {
      39        if (j0 < 48)
      40  	{
      41  	  if (j0 < 0)
      42  	    return j0 < -1 ? 0 : sign;
      43  	  else
      44  	    {
      45  	      i0 += 0x0000800000000000LL >> j0;
      46  	      result = i0 >> (48 - j0);
      47  #ifdef FE_INVALID
      48  	      if (sizeof (long int) == 4
      49  		  && sign == 1
      50  		  && result == LONG_MIN)
      51  		/* Rounding brought the value out of range.  */
      52  		feraiseexcept (FE_INVALID);
      53  #endif
      54  	    }
      55  	}
      56        else if (j0 >= 112)
      57  	result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
      58        else
      59  	{
      60  	  uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
      61  	  if (j < i1)
      62  	    ++i0;
      63  
      64  	  if (j0 == 48)
      65  	    result = (long int) i0;
      66  	  else
      67  	    {
      68  	      result = ((long int) i0 << (j0 - 48)) | (j >> (112 - j0));
      69  #ifdef FE_INVALID
      70  	      if (sizeof (long int) == 8
      71  		  && sign == 1
      72  		  && result == LONG_MIN)
      73  		/* Rounding brought the value out of range.  */
      74  		feraiseexcept (FE_INVALID);
      75  #endif
      76  	    }
      77  	}
      78      }
      79    else
      80      {
      81        /* The number is too large.  Unless it rounds to LONG_MIN,
      82  	 FE_INVALID must be raised and the return value is
      83  	 unspecified.  */
      84  #ifdef FE_INVALID
      85        if (FIX_FLT128_LONG_CONVERT_OVERFLOW
      86  	  && !(sign == -1 && x > (__float128) LONG_MIN - 0.5Q))
      87  	{
      88  	  feraiseexcept (FE_INVALID);
      89  	  return sign == 1 ? LONG_MAX : LONG_MIN;
      90  	}
      91        else if (!FIX_FLT128_LONG_CONVERT_OVERFLOW
      92  	       && x <= (__float128) LONG_MIN - 0.5Q)
      93  	{
      94  	  /* If truncation produces LONG_MIN, the cast will not raise
      95  	     the exception, but may raise "inexact".  */
      96  	  feraiseexcept (FE_INVALID);
      97  	  return LONG_MIN;
      98  	}
      99  #endif
     100        /* The number is too large.  It is left implementation defined
     101  	 what happens.  */
     102        return (long int) x;
     103      }
     104  
     105    return sign * result;
     106  }