1  /* Round long double value to long long int.
       2     Copyright (C) 1997-2023 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     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <fenv.h>
      20  #include <limits.h>
      21  #include <math.h>
      22  
      23  #include <math_private.h>
      24  #include <libm-alias-ldouble.h>
      25  
      26  
      27  long long int
      28  __llroundl (long double x)
      29  {
      30    int32_t j0;
      31    uint32_t se, i1, i0;
      32    long long int result;
      33    int sign;
      34  
      35    GET_LDOUBLE_WORDS (se, i0, i1, x);
      36    j0 = (se & 0x7fff) - 0x3fff;
      37    sign = (se & 0x8000) != 0 ? -1 : 1;
      38  
      39    if (j0 < 31)
      40      {
      41        if (j0 < 0)
      42  	return j0 < -1 ? 0 : sign;
      43        else
      44  	{
      45  	  uint32_t j = i0 + (0x40000000 >> j0);
      46  	  if (j < i0)
      47  	    {
      48  	      j >>= 1;
      49  	      j |= 0x80000000;
      50  	      ++j0;
      51  	    }
      52  
      53  	  result = j >> (31 - j0);
      54  	}
      55      }
      56    else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
      57      {
      58        if (j0 >= 63)
      59  	result = (((long long int) i0 << 32) | i1) << (j0 - 63);
      60        else
      61  	{
      62  	  uint32_t j = i1 + (0x80000000 >> (j0 - 31));
      63  
      64  	  result = (long long int) i0;
      65  	  if (j < i1)
      66  	    ++result;
      67  
      68  	  if (j0 > 31)
      69  	    {
      70  	      result = (result << (j0 - 31)) | (j >> (63 - j0));
      71  #ifdef FE_INVALID
      72  	      if (sign == 1 && result == LLONG_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.  It is left implementation defined
      82  	 what happens.  */
      83        return (long long int) x;
      84      }
      85  
      86    return sign * result;
      87  }
      88  
      89  libm_alias_ldouble (__llround, llround)