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Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/subnormal.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-src/src/subnormal.c | 183 |
1 files changed, 0 insertions, 183 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/subnormal.c b/Build/source/libs/mpfr/mpfr-src/src/subnormal.c deleted file mode 100644 index 76fccf0576f..00000000000 --- a/Build/source/libs/mpfr/mpfr-src/src/subnormal.c +++ /dev/null @@ -1,183 +0,0 @@ -/* mpfr_subnormalize -- Subnormalize a floating point number - emulating sub-normal numbers. - -Copyright 2005-2020 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 -https://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" - -/* For MPFR_RNDN, we can have a problem of double rounding. - In such a case, this table helps to conclude what to do (y positive): - Rounding Bit | Sticky Bit | inexact | Action | new inexact - 0 | ? | ? | Trunc | sticky - 1 | 0 | 1 | Trunc | - 1 | 0 | 0 | Trunc if even | - 1 | 0 | -1 | AddOneUlp | - 1 | 1 | ? | AddOneUlp | - - For other rounding mode, there isn't such a problem. - Just round it again and merge the ternary values. - - Set the inexact flag if the returned ternary value is non-zero. - Set the underflow flag if a second rounding occurred (whether this - rounding is exact or not). See - https://sympa.inria.fr/sympa/arc/mpfr/2009-06/msg00000.html - https://sympa.inria.fr/sympa/arc/mpfr/2009-06/msg00008.html - https://sympa.inria.fr/sympa/arc/mpfr/2009-06/msg00010.html -*/ - -int -mpfr_subnormalize (mpfr_ptr y, int old_inexact, mpfr_rnd_t rnd) -{ - int sign; - - /* The subnormal exponent range is [ emin, emin + MPFR_PREC(y) - 2 ] */ - if (MPFR_LIKELY (MPFR_IS_SINGULAR (y) - || (MPFR_GET_EXP (y) >= - __gmpfr_emin + (mpfr_exp_t) MPFR_PREC (y) - 1))) - MPFR_RET (old_inexact); - - MPFR_SET_UNDERFLOW (); - sign = MPFR_SIGN (y); - - /* We have to emulate one bit rounding if EXP(y) = emin */ - if (MPFR_GET_EXP (y) == __gmpfr_emin) - { - /* If this is a power of 2, we don't need rounding. - It handles cases when |y| = 0.1 * 2^emin */ - if (mpfr_powerof2_raw (y)) - MPFR_RET (old_inexact); - - /* We keep the same sign for y. - Assuming Y is the real value and y the approximation - and since y is not a power of 2: 0.5*2^emin < Y < 1*2^emin - We also know the direction of the error thanks to ternary value. */ - - if (rnd == MPFR_RNDN || rnd == MPFR_RNDNA) - { - mp_limb_t *mant, rb ,sb; - mp_size_t s; - /* We need the rounding bit and the sticky bit. Read them - and use the previous table to conclude. */ - s = MPFR_LIMB_SIZE (y) - 1; - mant = MPFR_MANT (y) + s; - rb = *mant & (MPFR_LIMB_HIGHBIT >> 1); - if (rb == 0) - goto set_min; - sb = *mant & ((MPFR_LIMB_HIGHBIT >> 1) - 1); - while (sb == 0 && s-- != 0) - sb = *--mant; - if (sb != 0) - goto set_min_p1; - /* Rounding bit is 1 and sticky bit is 0. - We need to examine old inexact flag to conclude. */ - if ((old_inexact > 0 && sign > 0) || - (old_inexact < 0 && sign < 0)) - goto set_min; - /* If inexact != 0, return 0.1*2^(emin+1). - Otherwise, rounding bit = 1, sticky bit = 0 and inexact = 0 - So we have 0.1100000000000000000000000*2^emin exactly. - We return 0.1*2^(emin+1) according to the even-rounding - rule on subnormals. Note the same holds for RNDNA. */ - goto set_min_p1; - } - else if (MPFR_IS_LIKE_RNDZ (rnd, MPFR_IS_NEG (y))) - { - set_min: - mpfr_setmin (y, __gmpfr_emin); - MPFR_RET (-sign); - } - else - { - set_min_p1: - /* Note: mpfr_setmin will abort if __gmpfr_emax == __gmpfr_emin. */ - mpfr_setmin (y, __gmpfr_emin + 1); - MPFR_RET (sign); - } - } - else /* Hard case: It is more or less the same problem as mpfr_cache */ - { - mpfr_t dest; - mpfr_prec_t q; - mpfr_rnd_t rnd2; - int inexact, inex2; - - MPFR_ASSERTD (MPFR_GET_EXP (y) > __gmpfr_emin); - - /* Compute the intermediary precision */ - q = (mpfr_uexp_t) MPFR_GET_EXP (y) - __gmpfr_emin + 1; - MPFR_ASSERTD (q >= MPFR_PREC_MIN && q < MPFR_PREC (y)); - - /* TODO: perform the rounding in place. */ - mpfr_init2 (dest, q); - /* Round y in dest */ - MPFR_SET_EXP (dest, MPFR_GET_EXP (y)); - MPFR_SET_SIGN (dest, sign); - rnd2 = rnd == MPFR_RNDNA ? MPFR_RNDN : rnd; - MPFR_RNDRAW_EVEN (inexact, dest, - MPFR_MANT (y), MPFR_PREC (y), rnd2, sign, - MPFR_SET_EXP (dest, MPFR_GET_EXP (dest) + 1)); - if (MPFR_LIKELY (old_inexact != 0)) - { - if (MPFR_UNLIKELY (rnd2 == MPFR_RNDN && - (inexact == MPFR_EVEN_INEX || - inexact == -MPFR_EVEN_INEX))) - { - /* If both roundings are in the same direction, - we have to go back in the other direction. - For MPFR_RNDNA it is the same, since we are not - exactly in the middle case (old_inexact != 0). */ - if (SAME_SIGN (inexact, old_inexact)) - { - if (SAME_SIGN (inexact, MPFR_INT_SIGN (y))) - mpfr_nexttozero (dest); - else /* subnormal range, thus no overflow */ - { - mpfr_nexttoinf (dest); - MPFR_ASSERTD(!MPFR_IS_INF (dest)); - } - inexact = -inexact; - } - } - else if (MPFR_UNLIKELY (inexact == 0)) - inexact = old_inexact; - } - else if (rnd == MPFR_RNDNA && - (inexact == MPFR_EVEN_INEX || inexact == -MPFR_EVEN_INEX)) - { - /* We are in the middle case: since we used RNDN to round, we should - round in the opposite direction when inexact has the opposite - sign of y. */ - if (!SAME_SIGN (inexact, MPFR_INT_SIGN (y))) - { - mpfr_nexttoinf (dest); - MPFR_ASSERTD(!MPFR_IS_INF (dest)); - inexact = -inexact; - } - } - - inex2 = mpfr_set (y, dest, rnd); - MPFR_ASSERTN (inex2 == 0); - MPFR_ASSERTN (MPFR_IS_PURE_FP (y)); - mpfr_clear (dest); - - MPFR_RET (inexact); - } -} |