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  #include <fix-fp-int-convert-overflow.h>
      26  
      27  long long int
      28  __llroundl (_Float128 x)
      29  {
      30    int64_t j0;
      31    uint64_t i1, i0;
      32    long long int result;
      33    int sign;
      34  
      35    GET_LDOUBLE_WORDS64 (i0, i1, x);
      36    j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      37    sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
      38    i0 &= 0x0000ffffffffffffLL;
      39    i0 |= 0x0001000000000000LL;
      40  
      41    if (j0 < 48)
      42      {
      43        if (j0 < 0)
      44  	return j0 < -1 ? 0 : sign;
      45        else
      46  	{
      47  	  i0 += 0x0000800000000000LL >> j0;
      48  	  result = i0 >> (48 - j0);
      49  	}
      50      }
      51    else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
      52      {
      53        if (j0 >= 112)
      54  	result = ((long long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
      55        else
      56  	{
      57  	  uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
      58  	  if (j < i1)
      59  	    ++i0;
      60  
      61  	  if (j0 == 48)
      62  	    result = (long long int) i0;
      63  	  else
      64  	    {
      65  	      result = ((long long int) i0 << (j0 - 48)) | (j >> (112 - j0));
      66  #ifdef FE_INVALID
      67  	      if (sign == 1 && result == LLONG_MIN)
      68  		/* Rounding brought the value out of range.  */
      69  		feraiseexcept (FE_INVALID);
      70  #endif
      71  	    }
      72  	}
      73      }
      74    else
      75      {
      76        /* The number is too large.  Unless it rounds to LLONG_MIN,
      77  	 FE_INVALID must be raised and the return value is
      78  	 unspecified.  */
      79  #ifdef FE_INVALID
      80        if (FIX_LDBL_LLONG_CONVERT_OVERFLOW
      81  	  && !(sign == -1 && x > (_Float128) LLONG_MIN - L(0.5)))
      82  	{
      83  	  feraiseexcept (FE_INVALID);
      84  	  return sign == 1 ? LLONG_MAX : LLONG_MIN;
      85  	}
      86        else if (!FIX_LDBL_LLONG_CONVERT_OVERFLOW
      87  	       && x <= (_Float128) LLONG_MIN - L(0.5))
      88  	{
      89  	  /* If truncation produces LLONG_MIN, the cast will not raise
      90  	     the exception, but may raise "inexact".  */
      91  	  feraiseexcept (FE_INVALID);
      92  	  return LLONG_MIN;
      93  	}
      94  #endif
      95        return (long long int) x;
      96      }
      97  
      98    return sign * result;
      99  }
     100  
     101  libm_alias_ldouble (__llround, llround)