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 int
      35  __lrintl (long double x)
      36  {
      37    int32_t se,j0;
      38    uint32_t i0, i1;
      39    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 < 31)
      50      {
      51  #if defined FE_INVALID || defined FE_INEXACT
      52        /* X < LONG_MAX + 1 implied by J0 < 31.  */
      53        if (sizeof (long int) == 4
      54  	  && x > (long double) LONG_MAX)
      55  	{
      56  	  /* In the event of overflow we must raise the "invalid"
      57  	     exception, but not "inexact".  */
      58  	  t = __nearbyintl (x);
      59  	  feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
      60  	}
      61        else
      62  #endif
      63  	{
      64  	  w = two63[sx] + x;
      65  	  t = w - two63[sx];
      66  	}
      67        GET_LDOUBLE_WORDS (se, i0, i1, t);
      68        j0 = (se & 0x7fff) - 0x3fff;
      69  
      70        result = (j0 < 0 ? 0 : i0 >> (31 - j0));
      71      }
      72    else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
      73      {
      74        if (j0 >= 63)
      75  	result = ((long int) i0 << (j0 - 31)) | (i1 << (j0 - 63));
      76        else
      77  	{
      78  #if defined FE_INVALID || defined FE_INEXACT
      79  	  /* X < LONG_MAX + 1 implied by J0 < 63.  */
      80  	  if (sizeof (long int) == 8
      81  	      && x > (long double) LONG_MAX)
      82  	    {
      83  	      /* In the event of overflow we must raise the "invalid"
      84  		 exception, but not "inexact".  */
      85  	      t = __nearbyintl (x);
      86  	      feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
      87  	    }
      88  	  else
      89  #endif
      90  	    {
      91  	      w = two63[sx] + x;
      92  	      t = w - two63[sx];
      93  	    }
      94  	  GET_LDOUBLE_WORDS (se, i0, i1, t);
      95  	  j0 = (se & 0x7fff) - 0x3fff;
      96  
      97  	  if (j0 == 31)
      98  	    result = (long int) i0;
      99  	  else
     100  	    result = ((long int) i0 << (j0 - 31)) | (i1 >> (63 - j0));
     101  	}
     102      }
     103    else
     104      {
     105        /* The number is too large.  Unless it rounds to LONG_MIN,
     106  	 FE_INVALID must be raised and the return value is
     107  	 unspecified.  */
     108  #if defined FE_INVALID || defined FE_INEXACT
     109        if (sizeof (long int) == 4
     110  	  && x < (long double) LONG_MIN
     111  	  && x > (long double) LONG_MIN - 1.0L)
     112  	{
     113  	  /* If truncation produces LONG_MIN, the cast will not raise
     114  	     the exception, but may raise "inexact".  */
     115  	  t = __nearbyintl (x);
     116  	  feraiseexcept (t == LONG_MIN ? FE_INEXACT : FE_INVALID);
     117  	  return LONG_MIN;
     118  	}
     119  #endif
     120        return (long int) x;
     121      }
     122  
     123    return sx ? -result : result;
     124  }
     125  
     126  libm_alias_ldouble (__lrint, lrint)