sysdeps/m68k/m680x0/fpu/s_llrint.c

   1 /* Round argument to nearest integral value according to current rounding
   2    direction.
   3    Copyright (C) 1997-2019 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library.  If not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <math.h>
  22 #include <math_private.h>
  23 #include <libm-alias-double.h>
  24 #include "mathimpl.h"
  25
  26 long long int
  27 __llrint (double x)
  28 {
  29   int32_t e;
  30   uint32_t h, l, s;
  31   long long int result;
  32
  33   x = __m81_u(__rint) (x);
  34
  35   /* We could use __fixxfdi from libgcc, but here we can take advantage of
  36      the known floating point format.  */
  37   EXTRACT_WORDS (h, l, x);
  38
  39   e = ((h >> 20) & 0x7ff) - 0x3ff;
  40   if (e < 0)
  41     return 0;
  42   s = h;
  43   h &= 0xfffff;
  44   h |= 0x100000;
  45
  46   if (e < 63)
  47     {
  48       if (e > 52)
  49         {
  50           h <<= e - 52;
  51           h |= l >> (84 - e);
  52           l <<= e - 52;
  53           result = ((long long int) h << 32) | l;
  54         }
  55       else if (e > 20)
  56         {
  57           l >>= 52 - e;
  58           l |= h << (e - 20);
  59           h >>= 52 - e;
  60           result = ((long long int) h << 32) | l;
  61         }
  62       else
  63         result = h >> (20 - e);
  64       if (s & 0x80000000)
  65         result = -result;
  66     }
  67   else
  68     /* The number is too large or not finite.  The standard leaves it
  69        undefined what to return when the number is too large to fit in a
  70        `long long int'.  */
  71     result = -1LL;
  72
  73   return result;
  74 }
  75
  76 libm_alias_double (__llrint, llrint)