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Diffstat (limited to 'Build/source/libs/mpfr/mpfr-3.1.2/src/get_f.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-3.1.2/src/get_f.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-3.1.2/src/get_f.c b/Build/source/libs/mpfr/mpfr-3.1.2/src/get_f.c new file mode 100644 index 00000000000..67b2962d79b --- /dev/null +++ b/Build/source/libs/mpfr/mpfr-3.1.2/src/get_f.c @@ -0,0 +1,148 @@ +/* mpfr_get_f -- convert a MPFR number to a GNU MPF number + +Copyright 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. */ + +#include "mpfr-impl.h" + +/* Since MPFR-3.0, return the usual inexact value. + The erange flag is set if an error occurred in the conversion + (y is NaN, +Inf, or -Inf that have no equivalent in mpf) +*/ +int +mpfr_get_f (mpf_ptr x, mpfr_srcptr y, mpfr_rnd_t rnd_mode) +{ + int inex; + mp_size_t sx, sy; + mpfr_prec_t precx, precy; + mp_limb_t *xp; + int sh; + + if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(y))) + { + if (MPFR_IS_ZERO(y)) + { + mpf_set_ui (x, 0); + return 0; + } + else if (MPFR_IS_NAN (y)) + { + MPFR_SET_ERANGE (); + return 0; + } + else /* y is plus infinity (resp. minus infinity), set x to the maximum + value (resp. the minimum value) in precision PREC(x) */ + { + int i; + mp_limb_t *xp; + + MPFR_SET_ERANGE (); + + /* To this day, [mp_exp_t] and mp_size_t are #defined as the same + type */ + EXP (x) = MP_SIZE_T_MAX; + + sx = PREC (x); + SIZ (x) = sx; + xp = PTR (x); + for (i = 0; i < sx; i++) + xp[i] = MP_LIMB_T_MAX; + + if (MPFR_IS_POS (y)) + return -1; + else + { + mpf_neg (x, x); + return +1; + } + } + } + + sx = PREC(x); /* number of limbs of the mantissa of x */ + + precy = MPFR_PREC(y); + precx = (mpfr_prec_t) sx * GMP_NUMB_BITS; + sy = MPFR_LIMB_SIZE (y); + + xp = PTR (x); + + /* since mpf numbers are represented in base 2^GMP_NUMB_BITS, + we loose -EXP(y) % GMP_NUMB_BITS bits in the most significant limb */ + sh = MPFR_GET_EXP(y) % GMP_NUMB_BITS; + sh = sh <= 0 ? - sh : GMP_NUMB_BITS - sh; + MPFR_ASSERTD (sh >= 0); + if (precy + sh <= precx) /* we can copy directly */ + { + mp_size_t ds; + + MPFR_ASSERTN (sx >= sy); + ds = sx - sy; + + if (sh != 0) + { + mp_limb_t out; + out = mpn_rshift (xp + ds, MPFR_MANT(y), sy, sh); + MPFR_ASSERTN (ds > 0 || out == 0); + if (ds > 0) + xp[--ds] = out; + } + else + MPN_COPY (xp + ds, MPFR_MANT (y), sy); + if (ds > 0) + MPN_ZERO (xp, ds); + EXP(x) = (MPFR_GET_EXP(y) + sh) / GMP_NUMB_BITS; + inex = 0; + } + else /* we have to round to precx - sh bits */ + { + mpfr_t z; + mp_size_t sz; + + /* Recall that precx = (mpfr_prec_t) sx * GMP_NUMB_BITS, thus removing + sh bits (sh < GMP_NUMB_BITSS) won't reduce the number of limbs. */ + mpfr_init2 (z, precx - sh); + sz = MPFR_LIMB_SIZE (z); + MPFR_ASSERTN (sx == sz); + + inex = mpfr_set (z, y, rnd_mode); + /* warning, sh may change due to rounding, but then z is a power of two, + thus we can safely ignore its last bit which is 0 */ + sh = MPFR_GET_EXP(z) % GMP_NUMB_BITS; + sh = sh <= 0 ? - sh : GMP_NUMB_BITS - sh; + MPFR_ASSERTD (sh >= 0); + if (sh != 0) + { + mp_limb_t out; + out = mpn_rshift (xp, MPFR_MANT(z), sz, sh); + /* If sh hasn't changed, it is the number of the non-significant + bits in the lowest limb of z. Therefore out == 0. */ + MPFR_ASSERTD (out == 0); (void) out; /* avoid a warning */ + } + else + MPN_COPY (xp, MPFR_MANT(z), sz); + EXP(x) = (MPFR_GET_EXP(z) + sh) / GMP_NUMB_BITS; + mpfr_clear (z); + } + + /* set size and sign */ + SIZ(x) = (MPFR_FROM_SIGN_TO_INT(MPFR_SIGN(y)) < 0) ? -sx : sx; + + return inex; +} |