sysdeps/ieee754/ldbl-128/s_llrintl.c

   1 /* Round argument to nearest integral value according to current rounding
   2    direction.
   3    Copyright (C) 1997-2016 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 <fenv.h>
  23 #include <limits.h>
  24 #include <math.h>
  25
  26 #include <math_private.h>
  27 #include <fix-fp-int-convert-overflow.h>
  28
  29 static const _Float128 two112[2] =
  30 {
  31   L(5.19229685853482762853049632922009600E+33), /* 0x406F000000000000, 0 */
  32  L(-5.19229685853482762853049632922009600E+33)  /* 0xC06F000000000000, 0 */
  33 };
  34
  35 long long int
  36 __llrintl (_Float128 x)
  37 {
  38   int32_t j0;
  39   u_int64_t i0,i1;
  40   _Float128 w;
  41   _Float128 t;
  42   long long int result;
  43   int sx;
  44
  45   GET_LDOUBLE_WORDS64 (i0, i1, x);
  46   j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  47   sx = i0 >> 63;
  48   i0 &= 0x0000ffffffffffffLL;
  49   i0 |= 0x0001000000000000LL;
  50
  51   if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
  52     {
  53 #if defined FE_INVALID || defined FE_INEXACT
  54       /* X < LLONG_MAX + 1 implied by J0 < 63.  */
  55       if (x > (_Float128) LLONG_MAX)
  56         {
  57           /* In the event of overflow we must raise the "invalid"
  58              exception, but not "inexact".  */
  59           t = __nearbyintl (x);
  60           feraiseexcept (t == LLONG_MAX ? FE_INEXACT : FE_INVALID);
  61         }
  62       else
  63 #endif
  64         {
  65           w = two112[sx] + x;
  66           t = w - two112[sx];
  67         }
  68       GET_LDOUBLE_WORDS64 (i0, i1, t);
  69       j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  70       i0 &= 0x0000ffffffffffffLL;
  71       i0 |= 0x0001000000000000LL;
  72
  73       if (j0 < 0)
  74         result = 0;
  75       else if (j0 <= 48)
  76         result = i0 >> (48 - j0);
  77       else
  78         result = ((long long int) i0 << (j0 - 48)) | (i1 >> (112 - j0));
  79     }
  80   else
  81     {
  82       /* The number is too large.  Unless it rounds to LLONG_MIN,
  83          FE_INVALID must be raised and the return value is
  84          unspecified.  */
  85 #if defined FE_INVALID || defined FE_INEXACT
  86       if (x < (_Float128) LLONG_MIN
  87           && x > (_Float128) LLONG_MIN - 1)
  88         {
  89           /* If truncation produces LLONG_MIN, the cast will not raise
  90              the exception, but may raise "inexact".  */
  91           t = __nearbyintl (x);
  92           feraiseexcept (t == LLONG_MIN ? FE_INEXACT : FE_INVALID);
  93           return LLONG_MIN;
  94         }
  95       else if (FIX_LDBL_LLONG_CONVERT_OVERFLOW && x != (_Float128) LLONG_MIN)
  96         {
  97           feraiseexcept (FE_INVALID);
  98           return sx == 0 ? LLONG_MAX : LLONG_MIN;
  99         }
 100
 101 #endif
 102       return (long long int) x;
 103     }
 104
 105   return sx ? -result : result;
 106 }
 107
 108 weak_alias (__llrintl, llrintl)