1  /* Round argument to nearest integral value according to current rounding
       2     direction.
       3     Copyright (C) 1997-2023 Free Software Foundation, Inc.
       4     This file is part of the GNU C Library.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #include <fenv.h>
      21  #include <limits.h>
      22  #include <math.h>
      23  
      24  #include <math_private.h>
      25  #include <libm-alias-ldouble.h>
      26  
      27  static const long double two63[2] =
      28  {
      29    9.223372036854775808000000e+18, /* 0x403E, 0x00000000, 0x00000000 */
      30   -9.223372036854775808000000e+18  /* 0xC03E, 0x00000000, 0x00000000 */
      31  };
      32  
      33  
      34  long long int
      35  __llrintl (long double x)
      36  {
      37    int32_t se,j0;
      38    uint32_t i0, i1;
      39    long long int result;
      40    long double w;
      41    long double t;
      42    int sx;
      43  
      44    GET_LDOUBLE_WORDS (se, i0, i1, x);
      45  
      46    sx = (se >> 15) & 1;
      47    j0 = (se & 0x7fff) - 0x3fff;
      48  
      49    if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
      50      {
      51        if (j0 >= 63)
      52  	result = (((long long int) i0 << 32) | i1) << (j0 - 63);
      53        else
      54  	{
      55  #if defined FE_INVALID || defined FE_INEXACT
      56  	  /* X < LLONG_MAX + 1 implied by J0 < 63.  */
      57  	  if (x > (long double) LLONG_MAX)
      58  	    {
      59  	      /* In the event of overflow we must raise the "invalid"
      60  		 exception, but not "inexact".  */
      61  	      t = __nearbyintl (x);
      62  	      feraiseexcept (t == LLONG_MAX ? FE_INEXACT : FE_INVALID);
      63  	    }
      64  	  else
      65  #endif
      66  	    {
      67  	      w = two63[sx] + x;
      68  	      t = w - two63[sx];
      69  	    }
      70  	  GET_LDOUBLE_WORDS (se, i0, i1, t);
      71  	  j0 = (se & 0x7fff) - 0x3fff;
      72  
      73  	  if (j0 < 0)
      74  	    result = 0;
      75  	  else if (j0 <= 31)
      76  	    result = i0 >> (31 - j0);
      77  	  else
      78  	    result = ((long long int) i0 << (j0 - 31)) | (i1 >> (63 - j0));
      79  	}
      80      }
      81    else
      82      {
      83        /* The number is too large.  It is left implementation defined
      84  	 what happens.  */
      85        return (long long int) x;
      86      }
      87  
      88    return sx ? -result : result;
      89  }
      90  
      91  libm_alias_ldouble (__llrint, llrint)