1  /* Round argument to nearest integral value according to current rounding
       2     direction.
       3     Copyright (C) 1997-2018 Free Software Foundation, Inc.
       4     This file is part of the GNU C Library.
       5     Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
       6  		  Jakub Jelinek <jj@ultra.linux.cz>, 1999.
       7  
       8     The GNU C Library is free software; you can redistribute it and/or
       9     modify it under the terms of the GNU Lesser General Public
      10     License as published by the Free Software Foundation; either
      11     version 2.1 of the License, or (at your option) any later version.
      12  
      13     The GNU C Library is distributed in the hope that it will be useful,
      14     but WITHOUT ANY WARRANTY; without even the implied warranty of
      15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      16     Lesser General Public License for more details.
      17  
      18     You should have received a copy of the GNU Lesser General Public
      19     License along with the GNU C Library; if not, see
      20     <http://www.gnu.org/licenses/>.  */
      21  
      22  #include "quadmath-imp.h"
      23  
      24  static const __float128 two112[2] =
      25  {
      26    5.19229685853482762853049632922009600E+33Q, /* 0x406F000000000000, 0 */
      27   -5.19229685853482762853049632922009600E+33Q  /* 0xC06F000000000000, 0 */
      28  };
      29  
      30  long int
      31  lrintq (__float128 x)
      32  {
      33    int32_t j0;
      34    uint64_t i0,i1;
      35    __float128 w;
      36    __float128 t;
      37    long int result;
      38    int sx;
      39  
      40    GET_FLT128_WORDS64 (i0, i1, x);
      41    j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      42    sx = i0 >> 63;
      43    i0 &= 0x0000ffffffffffffLL;
      44    i0 |= 0x0001000000000000LL;
      45  
      46    if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
      47      {
      48        if (j0 < 48)
      49  	{
      50  #if defined FE_INVALID || defined FE_INEXACT
      51  	  /* X < LONG_MAX + 1 implied by J0 < 31.  */
      52  	  if (sizeof (long int) == 4
      53  	      && x > (__float128) LONG_MAX)
      54  	    {
      55  	      /* In the event of overflow we must raise the "invalid"
      56  		 exception, but not "inexact".  */
      57  	      t = nearbyintq (x);
      58  	      feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
      59  	    }
      60  	  else
      61  #endif
      62  	    {
      63  	      w = two112[sx] + x;
      64  	      t = w - two112[sx];
      65  	    }
      66  	  GET_FLT128_WORDS64 (i0, i1, t);
      67  	  j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      68  	  i0 &= 0x0000ffffffffffffLL;
      69  	  i0 |= 0x0001000000000000LL;
      70  
      71  	  result = (j0 < 0 ? 0 : i0 >> (48 - j0));
      72  	}
      73        else if (j0 >= 112)
      74  	result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
      75        else
      76  	{
      77  #if defined FE_INVALID || defined FE_INEXACT
      78  	  /* X < LONG_MAX + 1 implied by J0 < 63.  */
      79  	  if (sizeof (long int) == 8
      80  	      && x > (__float128) LONG_MAX)
      81  	    {
      82  	      /* In the event of overflow we must raise the "invalid"
      83  		 exception, but not "inexact".  */
      84  	      t = nearbyintq (x);
      85  	      feraiseexcept (t == LONG_MAX ? FE_INEXACT : FE_INVALID);
      86  	    }
      87  	  else
      88  #endif
      89  	    {
      90  	      w = two112[sx] + x;
      91  	      t = w - two112[sx];
      92  	    }
      93  	  GET_FLT128_WORDS64 (i0, i1, t);
      94  	  j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
      95  	  i0 &= 0x0000ffffffffffffLL;
      96  	  i0 |= 0x0001000000000000LL;
      97  
      98  	  if (j0 == 48)
      99  	    result = (long int) i0;
     100  	  else
     101  	    result = ((long int) i0 << (j0 - 48)) | (i1 >> (112 - j0));
     102  	}
     103      }
     104    else
     105      {
     106        /* The number is too large.  Unless it rounds to LONG_MIN,
     107  	 FE_INVALID must be raised and the return value is
     108  	 unspecified.  */
     109  #if defined FE_INVALID || defined FE_INEXACT
     110        if (x < (__float128) LONG_MIN
     111  	  && x > (__float128) LONG_MIN - 1)
     112  	{
     113  	  /* If truncation produces LONG_MIN, the cast will not raise
     114  	     the exception, but may raise "inexact".  */
     115  	  t = nearbyintq (x);
     116  	  feraiseexcept (t == LONG_MIN ? FE_INEXACT : FE_INVALID);
     117  	  return LONG_MIN;
     118  	}
     119        else if (FIX_FLT128_LONG_CONVERT_OVERFLOW && x != (__float128) LONG_MIN)
     120  	{
     121  	  feraiseexcept (FE_INVALID);
     122  	  return sx == 0 ? LONG_MAX : LONG_MIN;
     123  	}
     124  
     125  #endif
     126        return (long int) x;
     127      }
     128  
     129    return sx ? -result : result;
     130  }