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-rw-r--r--Build/source/libs/mpfr/mpfr-src/src/expm1.c43
1 files changed, 20 insertions, 23 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/expm1.c b/Build/source/libs/mpfr/mpfr-src/src/expm1.c
index b43a7d75253..cf67f24ca55 100644
--- a/Build/source/libs/mpfr/mpfr-src/src/expm1.c
+++ b/Build/source/libs/mpfr/mpfr-src/src/expm1.c
@@ -1,6 +1,6 @@
/* mpfr_expm1 -- Compute exp(x)-1
-Copyright 2001-2019 Free Software Foundation, Inc.
+Copyright 2001-2020 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.
This file is part of the GNU MPFR Library.
@@ -84,19 +84,22 @@ mpfr_expm1 (mpfr_ptr y, mpfr_srcptr x , mpfr_rnd_t rnd_mode)
{
mp_limb_t t_limb[(64 - 1) / GMP_NUMB_BITS + 1];
mpfr_t t;
- mpfr_exp_t err;
+ mpfr_eexp_t err;
MPFR_TMP_INIT1(t_limb, t, 64);
+ /* since x < 0, to get an upper bound on x/log(2), we need to divide
+ by an upper bound on log(2) */
mpfr_div (t, x, __gmpfr_const_log2_RNDU, MPFR_RNDU); /* > x / ln(2) */
- err = mpfr_cmp_si (t, MPFR_EMIN_MIN >= -LONG_MAX ?
- MPFR_EMIN_MIN : -LONG_MAX) <= 0 ?
- - (MPFR_EMIN_MIN >= -LONG_MAX ? MPFR_EMIN_MIN : -LONG_MAX) :
- - mpfr_get_si (t, MPFR_RNDU);
+ err = mpfr_get_exp_t (t, MPFR_RNDU);
+ MPFR_ASSERTD (err < 0);
+ err = err < - MPFR_EXP_MAX ? MPFR_EXP_MAX : - err;
+ /* err = -max(ceil(t),-MPFR_EXP_MAX). */
+ MPFR_LOG_MSG (("err=%" MPFR_EXP_FSPEC "d\n", err));
/* exp(x) = 2^(x/ln(2))
- <= 2^max(MPFR_EMIN_MIN,-LONG_MAX,ceil(x/ln(2)+epsilon))
+ <= 2^max(-MPFR_EXP_MAX,ceil(x/ln(2)+epsilon))
with epsilon > 0 */
- MPFR_SMALL_INPUT_AFTER_SAVE_EXPO (y, __gmpfr_mone, err, 0, 0,
- rnd_mode, expo, {});
+ MPFR_SMALL_INPUT_AFTER_SAVE_EXPO (y, __gmpfr_mone, (mpfr_exp_t) err,
+ 0, 0, rnd_mode, expo, {});
}
/* General case */
@@ -129,26 +132,20 @@ mpfr_expm1 (mpfr_ptr y, mpfr_srcptr x , mpfr_rnd_t rnd_mode)
/* exp(x) may overflow and underflow */
MPFR_BLOCK (flags, mpfr_exp (t, x, MPFR_RNDN));
- if (MPFR_OVERFLOW (flags))
+
+ if (MPFR_OVERFLOW (flags)) /* overflow case */
{
inexact = mpfr_overflow (y, rnd_mode, MPFR_SIGN_POS);
MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, MPFR_FLAGS_OVERFLOW);
break;
}
- else if (MPFR_UNDERFLOW (flags))
- {
- inexact = mpfr_set_si (y, -1, rnd_mode);
- MPFR_ASSERTD (inexact == 0);
- inexact = -1;
- if (MPFR_IS_LIKE_RNDZ (rnd_mode, 1))
- {
- inexact = 1;
- mpfr_nexttozero (y);
- }
- break;
- }
- exp_te = MPFR_GET_EXP (t); /* FIXME: exp(x) may overflow! */
+ /* To get an underflow in exp(x), we need exp(x) < 0.5*2^MPFR_EMIN_MIN
+ thus x/log(2) < MPFR_EMIN_MIN-1. But in that case the above
+ MPFR_SMALL_INPUT_AFTER_SAVE_EXPO() will return the result. */
+ MPFR_ASSERTD(!MPFR_UNDERFLOW (flags));
+
+ exp_te = MPFR_GET_EXP (t);
mpfr_sub_ui (t, t, 1, MPFR_RNDN); /* exp(x)-1 */
/* error estimate */