1  /* Round 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  #define lround __hidden_lround
      20  #define __lround __hidden___lround
      21  
      22  #include <fenv.h>
      23  #include <limits.h>
      24  #include <math.h>
      25  #include <sysdep.h>
      26  
      27  #include <math_private.h>
      28  #include <libm-alias-double.h>
      29  #include <fix-fp-int-convert-overflow.h>
      30  
      31  long long int
      32  __llround (double x)
      33  {
      34    int32_t j0;
      35    int64_t i0;
      36    long long int result;
      37    int sign;
      38  
      39    EXTRACT_WORDS64 (i0, x);
      40    j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
      41    sign = i0 < 0 ? -1 : 1;
      42    i0 &= UINT64_C(0xfffffffffffff);
      43    i0 |= UINT64_C(0x10000000000000);
      44  
      45    if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
      46      {
      47        if (j0 < 0)
      48  	return j0 < -1 ? 0 : sign;
      49        else if (j0 >= 52)
      50  	result = i0 << (j0 - 52);
      51        else
      52  	{
      53  	  i0 += UINT64_C(0x8000000000000) >> j0;
      54  
      55  	  result = i0 >> (52 - j0);
      56  	}
      57      }
      58    else
      59      {
      60  #ifdef FE_INVALID
      61        /* The number is too large.  Unless it rounds to LLONG_MIN,
      62  	 FE_INVALID must be raised and the return value is
      63  	 unspecified.  */
      64        if (FIX_DBL_LLONG_CONVERT_OVERFLOW && x != (double) LLONG_MIN)
      65  	{
      66  	  feraiseexcept (FE_INVALID);
      67  	  return sign == 1 ? LLONG_MAX : LLONG_MIN;
      68  	}
      69  #endif
      70        return (long long int) x;
      71      }
      72  
      73    return sign * result;
      74  }
      75  
      76  libm_alias_double (__llround, llround)
      77  
      78  /* long has the same width as long long on LP64 machines, so use an alias.  */
      79  #undef lround
      80  #undef __lround
      81  #ifdef _LP64
      82  strong_alias (__llround, __lround)
      83  libm_alias_double (__lround, lround)
      84  #endif