1/* Round double value to long long int.
2   Copyright (C) 1997 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6   The GNU C Library is free software; you can redistribute it and/or
7   modify it under the terms of the GNU Lesser General Public
8   License as published by the Free Software Foundation; either
9   version 2.1 of the License, or (at your option) any later version.
10
11   The GNU C Library is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public
17   License along with the GNU C Library; if not, write to the Free
18   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19   02111-1307 USA.  */
20
21#include <math.h>
22
23#include "math_private.h"
24
25
26long long int
27__llround (double x)
28{
29  int32_t j0;
30  u_int32_t i1, i0;
31  long long int result;
32  int sign;
33
34  EXTRACT_WORDS (i0, i1, x);
35  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
36  sign = (i0 & 0x80000000) != 0 ? -1 : 1;
37  i0 &= 0xfffff;
38  i0 |= 0x100000;
39
40  if (j0 < 20)
41    {
42      if (j0 < 0)
43	return j0 < -1 ? 0 : sign;
44      else
45	{
46	  i0 += 0x80000 >> j0;
47
48	  result = i0 >> (20 - j0);
49	}
50    }
51  else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
52    {
53      if (j0 >= 52)
54	result = (((long long int) i0 << 32) | i1) << (j0 - 52);
55      else
56	{
57	  u_int32_t j = i1 + (0x80000000 >> (j0 - 20));
58	  if (j < i1)
59	    ++i0;
60
61	  if (j0 == 20)
62	    result = (long long int) i0;
63	  else
64	    result = ((long long int) i0 << (j0 - 20)) | (j >> (52 - j0));
65	}
66    }
67  else
68    {
69      /* The number is too large.  It is left implementation defined
70	 what happens.  */
71      return (long long int) x;
72    }
73
74  return sign * result;
75}
76
77weak_alias (__llround, llround)
78#ifdef NO_LONG_DOUBLE
79strong_alias (__llround, __llroundl)
80weak_alias (__llround, llroundl)
81#endif
82