1/* mpfr_sqrt_ui -- square root of a machine integer
2
3Copyright 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
4Contributed by the AriC and Caramel projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#define MPFR_NEED_LONGLONG_H
24#include "mpfr-impl.h"
25
26int
27mpfr_sqrt_ui (mpfr_ptr r, unsigned long u, mpfr_rnd_t rnd_mode)
28{
29  if (u)
30    {
31      mpfr_t uu;
32      mp_limb_t up[1];
33      unsigned long cnt;
34      int inex;
35      MPFR_SAVE_EXPO_DECL (expo);
36
37      MPFR_TMP_INIT1 (up, uu, GMP_NUMB_BITS);
38      MPFR_ASSERTN (u == (mp_limb_t) u);
39      count_leading_zeros (cnt, (mp_limb_t) u);
40      *up = (mp_limb_t) u << cnt;
41
42      MPFR_SAVE_EXPO_MARK (expo);
43      MPFR_SET_EXP (uu, GMP_NUMB_BITS - cnt);
44      inex = mpfr_sqrt(r, uu, rnd_mode);
45      MPFR_SAVE_EXPO_FREE (expo);
46      return mpfr_check_range(r, inex, rnd_mode);
47    }
48  else /* sqrt(0) = 0 */
49    {
50      MPFR_SET_ZERO(r);
51      MPFR_SET_POS(r);
52      MPFR_RET(0);
53    }
54}
55