1  /* Round float 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-float.h>
      25  #include <fix-fp-int-convert-overflow.h>
      26  
      27  
      28  long long int
      29  __llroundf (float x)
      30  {
      31    int32_t j0;
      32    uint32_t i;
      33    long long int result;
      34    int sign;
      35  
      36    GET_FLOAT_WORD (i, x);
      37    j0 = ((i >> 23) & 0xff) - 0x7f;
      38    sign = (i & 0x80000000) != 0 ? -1 : 1;
      39    i &= 0x7fffff;
      40    i |= 0x800000;
      41  
      42    if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
      43      {
      44        if (j0 < 0)
      45  	return j0 < -1 ? 0 : sign;
      46        else if (j0 >= 23)
      47  	result = (long long int) i << (j0 - 23);
      48        else
      49  	{
      50  	  i += 0x400000 >> j0;
      51  
      52  	  result = i >> (23 - j0);
      53  	}
      54      }
      55    else
      56      {
      57  #ifdef FE_INVALID
      58        /* The number is too large.  Unless it rounds to LLONG_MIN,
      59  	 FE_INVALID must be raised and the return value is
      60  	 unspecified.  */
      61        if (FIX_FLT_LLONG_CONVERT_OVERFLOW && x != (float) LLONG_MIN)
      62  	{
      63  	  feraiseexcept (FE_INVALID);
      64  	  return sign == 1 ? LLONG_MAX : LLONG_MIN;
      65  	}
      66  #endif
      67        return (long long int) x;
      68      }
      69  
      70    return sign * result;
      71  }
      72  
      73  libm_alias_float (__llround, llround)