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Diffstat (limited to 'Build/source/libs/mpfr/mpfr-3.1.2/src/set_q.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-3.1.2/src/set_q.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-3.1.2/src/set_q.c b/Build/source/libs/mpfr/mpfr-3.1.2/src/set_q.c new file mode 100644 index 00000000000..1a4e5117fbf --- /dev/null +++ b/Build/source/libs/mpfr/mpfr-3.1.2/src/set_q.c @@ -0,0 +1,133 @@ +/* mpfr_set_q -- set a floating-point number from a multiple-precision rational + +Copyright 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. +Contributed by the AriC and Caramel projects, INRIA. + +This file is part of the GNU MPFR Library. + +The GNU MPFR Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 3 of the License, or (at your +option) any later version. + +The GNU MPFR Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see +http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., +51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#define MPFR_NEED_LONGLONG_H +#include "mpfr-impl.h" + +/* + * Set f to z, choosing the smallest precision for f + * so that z = f*(2^BPML)*zs*2^(RetVal) + */ +static int +set_z (mpfr_ptr f, mpz_srcptr z, mp_size_t *zs) +{ + mp_limb_t *p; + mp_size_t s; + int c; + mpfr_prec_t pf; + + MPFR_ASSERTD (mpz_sgn (z) != 0); + + /* Remove useless ending 0 */ + for (p = PTR (z), s = *zs = ABS (SIZ (z)) ; *p == 0; p++, s--) + MPFR_ASSERTD (s >= 0); + + /* Get working precision */ + count_leading_zeros (c, p[s-1]); + pf = s * GMP_NUMB_BITS - c; + if (pf < MPFR_PREC_MIN) + pf = MPFR_PREC_MIN; + mpfr_init2 (f, pf); + + /* Copy Mantissa */ + if (MPFR_LIKELY (c)) + mpn_lshift (MPFR_MANT (f), p, s, c); + else + MPN_COPY (MPFR_MANT (f), p, s); + + MPFR_SET_SIGN (f, mpz_sgn (z)); + MPFR_SET_EXP (f, 0); + + return -c; +} + +/* set f to the rational q */ +int +mpfr_set_q (mpfr_ptr f, mpq_srcptr q, mpfr_rnd_t rnd) +{ + mpz_srcptr num, den; + mpfr_t n, d; + int inexact; + int cn, cd; + long shift; + mp_size_t sn, sd; + MPFR_SAVE_EXPO_DECL (expo); + + num = mpq_numref (q); + den = mpq_denref (q); + /* NAN and INF for mpq are not really documented, but could be found */ + if (MPFR_UNLIKELY (mpz_sgn (num) == 0)) + { + if (MPFR_UNLIKELY (mpz_sgn (den) == 0)) + { + MPFR_SET_NAN (f); + MPFR_RET_NAN; + } + else + { + MPFR_SET_ZERO (f); + MPFR_SET_POS (f); + MPFR_RET (0); + } + } + if (MPFR_UNLIKELY (mpz_sgn (den) == 0)) + { + MPFR_SET_INF (f); + MPFR_SET_SIGN (f, mpz_sgn (num)); + MPFR_RET (0); + } + + MPFR_SAVE_EXPO_MARK (expo); + + cn = set_z (n, num, &sn); + cd = set_z (d, den, &sd); + + sn -= sd; + if (MPFR_UNLIKELY (sn > MPFR_EMAX_MAX / GMP_NUMB_BITS)) + { + inexact = mpfr_overflow (f, rnd, MPFR_SIGN (f)); + goto end; + } + if (MPFR_UNLIKELY (sn < MPFR_EMIN_MIN / GMP_NUMB_BITS -1)) + { + if (rnd == MPFR_RNDN) + rnd = MPFR_RNDZ; + inexact = mpfr_underflow (f, rnd, MPFR_SIGN (f)); + goto end; + } + + inexact = mpfr_div (f, n, d, rnd); + shift = GMP_NUMB_BITS*sn+cn-cd; + MPFR_ASSERTD (shift == GMP_NUMB_BITS*sn+cn-cd); + cd = mpfr_mul_2si (f, f, shift, rnd); + MPFR_SAVE_EXPO_FREE (expo); + if (MPFR_UNLIKELY (cd != 0)) + inexact = cd; + else + inexact = mpfr_check_range (f, inexact, rnd); + end: + mpfr_clear (d); + mpfr_clear (n); + return inexact; +} + + |