1 /* mpfr_get_si -- convert a floating-point number to a signed long.
3 Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
4 Contributed by the AriC and Caramel projects, INRIA.
6 This file is part of the GNU MPFR Library.
8 The GNU MPFR Library is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or (at your
11 option) any later version.
13 The GNU MPFR Library is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16 License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
20 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
23 #include "mpfr-impl.h"
26 mpfr_get_si (mpfr_srcptr f, mpfr_rnd_t rnd)
32 if (MPFR_UNLIKELY (!mpfr_fits_slong_p (f, rnd)))
35 return MPFR_IS_NAN (f) ? 0 :
36 MPFR_IS_NEG (f) ? LONG_MIN : LONG_MAX;
42 /* determine prec of long */
43 for (s = LONG_MIN, prec = 0; s != 0; s /= 2, prec++)
46 /* first round to prec bits */
48 mpfr_rint (x, f, rnd);
50 /* warning: if x=0, taking its exponent is illegal */
51 if (MPFR_UNLIKELY (MPFR_IS_ZERO(x)))
59 /* now the result is in the most significant limb of x */
60 exp = MPFR_GET_EXP (x); /* since |x| >= 1, exp >= 1 */
61 n = MPFR_LIMB_SIZE(x);
62 a = MPFR_MANT(x)[n - 1] >> (GMP_NUMB_BITS - exp);
63 s = MPFR_SIGN(f) > 0 ? a : a <= LONG_MAX ? - (long) a : LONG_MIN;