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Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/get_float128.c')
-rw-r--r--Build/source/libs/mpfr/mpfr-src/src/get_float128.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/get_float128.c b/Build/source/libs/mpfr/mpfr-src/src/get_float128.c
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+++ b/Build/source/libs/mpfr/mpfr-src/src/get_float128.c
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+/* mpfr_get_float128 -- convert a multiple precision floating-point
+ number to a __float128 number
+
+Copyright 2012-2017 Free Software Foundation, Inc.
+Contributed by the AriC and Caramba 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"
+
+#ifdef MPFR_WANT_FLOAT128
+
+/* generic code */
+__float128
+mpfr_get_float128 (mpfr_srcptr x, mpfr_rnd_t rnd_mode)
+{
+
+ if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
+ return (__float128) mpfr_get_d (x, rnd_mode);
+ else /* now x is a normal non-zero number */
+ {
+ __float128 r; /* result */
+ __float128 m;
+ mpfr_exp_t e; /* exponent of x (before rounding) */
+ mpfr_exp_t sh; /* exponent shift, so that x/2^sh is in the double range */
+ const int emin = -16381;
+ const int esub = emin - IEEE_FLOAT128_MANT_DIG;
+ int sign;
+
+ sign = MPFR_SIGN (x);
+ e = MPFR_GET_EXP (x);
+
+ if (MPFR_UNLIKELY (e <= esub))
+ {
+ if (MPFR_IS_LIKE_RNDZ (rnd_mode, sign < 0) ||
+ (rnd_mode == MPFR_RNDN && (e < esub || mpfr_powerof2_raw (x))))
+ return sign < 0 ? -0.0 : 0.0;
+ r = 1.0;
+ sh = esub;
+ }
+ else
+ {
+ mpfr_t y;
+ mp_limb_t *yp;
+ int prec, i; /* small enough to fit in an int */
+ MPFR_SAVE_EXPO_DECL (expo);
+
+ MPFR_SAVE_EXPO_MARK (expo);
+
+ /* First round x to the target __float128 precision, taking the
+ reduced precision of the subnormals into account, so that all
+ subsequent operations are exact (this avoids double rounding
+ problems). */
+ prec = e < emin ? e - esub : IEEE_FLOAT128_MANT_DIG;
+ MPFR_ASSERTD (prec >= MPFR_PREC_MIN);
+ mpfr_init2 (y, prec);
+
+ mpfr_set (y, x, rnd_mode);
+ sh = MPFR_GET_EXP (y);
+ MPFR_SET_EXP (y, 0);
+ MPFR_SET_POS (y);
+ yp = MPFR_MANT (y);
+
+ r = 0.0;
+ for (i = 0; i < MPFR_LIMB_SIZE (y); i++)
+ {
+ /* Note: MPFR_LIMB_MAX is avoided below as it might not
+ always work if GMP_NUMB_BITS > IEEE_FLOAT128_MANT_DIG.
+ MPFR_LIMB_HIGHBIT has the advantage to fit on 1 bit. */
+ r += yp[i];
+ r *= 1 / (2 * (__float128) MPFR_LIMB_HIGHBIT);
+ }
+
+ mpfr_clear (y);
+
+ MPFR_SAVE_EXPO_FREE (expo);
+ }
+
+ /* we now have to multiply r by 2^sh */
+ MPFR_ASSERTD (r > 0);
+ if (sh != 0)
+ {
+ /* An overflow may occur (example: 0.5*2^1024) */
+ while (r < 1.0)
+ {
+ r += r;
+ sh--;
+ }
+
+ if (sh > 0)
+ m = 2.0;
+ else
+ {
+ m = 0.5;
+ sh = -sh;
+ }
+
+ for (;;)
+ {
+ if (sh % 2)
+ r = r * m;
+ sh >>= 1;
+ if (sh == 0)
+ break;
+ m = m * m;
+ }
+ }
+ if (sign < 0)
+ r = -r;
+ return r;
+ }
+}
+
+#endif /* MPFR_WANT_FLOAT128 */