1  /* Round long double to integer away from zero.
       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 NO_MATH_REDIRECT
      20  #include <math.h>
      21  
      22  #include <math_private.h>
      23  #include <libm-alias-ldouble.h>
      24  #include <math-use-builtins.h>
      25  
      26  
      27  _Float128
      28  __roundl (_Float128 x)
      29  {
      30  #if USE_ROUNDL_BUILTIN
      31    return __builtin_roundl (x);
      32  #else
      33    /* Use generic implementation.  */
      34    int32_t j0;
      35    uint64_t i1, i0;
      36  
      37    GET_LDOUBLE_WORDS64 (i0, i1, x);
      38    j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      39    if (j0 < 48)
      40      {
      41        if (j0 < 0)
      42  	{
      43  	  i0 &= 0x8000000000000000ULL;
      44  	  if (j0 == -1)
      45  	    i0 |= 0x3fff000000000000LL;
      46  	  i1 = 0;
      47  	}
      48        else
      49  	{
      50  	  uint64_t i = 0x0000ffffffffffffLL >> j0;
      51  	  if (((i0 & i) | i1) == 0)
      52  	    /* X is integral.  */
      53  	    return x;
      54  
      55  	  i0 += 0x0000800000000000LL >> j0;
      56  	  i0 &= ~i;
      57  	  i1 = 0;
      58  	}
      59      }
      60    else if (j0 > 111)
      61      {
      62        if (j0 == 0x4000)
      63  	/* Inf or NaN.  */
      64  	return x + x;
      65        else
      66  	return x;
      67      }
      68    else
      69      {
      70        uint64_t i = -1ULL >> (j0 - 48);
      71        if ((i1 & i) == 0)
      72  	/* X is integral.  */
      73  	return x;
      74  
      75        uint64_t j = i1 + (1LL << (111 - j0));
      76        if (j < i1)
      77  	i0 += 1;
      78        i1 = j;
      79        i1 &= ~i;
      80      }
      81  
      82    SET_LDOUBLE_WORDS64 (x, i0, i1);
      83    return x;
      84  #endif /* ! USE_ROUNDL_BUILTIN  */
      85  }
      86  libm_alias_ldouble (__round, round)