diff options
Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/sub_ui.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-src/src/sub_ui.c | 78 |
1 files changed, 49 insertions, 29 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/sub_ui.c b/Build/source/libs/mpfr/mpfr-src/src/sub_ui.c index 63689dd5d8b..9bca863a3aa 100644 --- a/Build/source/libs/mpfr/mpfr-src/src/sub_ui.c +++ b/Build/source/libs/mpfr/mpfr-src/src/sub_ui.c @@ -27,35 +27,55 @@ http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., int mpfr_sub_ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int u, mpfr_rnd_t rnd_mode) { - if (MPFR_LIKELY (u != 0)) /* if u=0, do nothing */ + MPFR_LOG_FUNC + (("x[%Pu]=%.*Rg u=%lu rnd=%d", + mpfr_get_prec(x), mpfr_log_prec, x, u, rnd_mode), + ("y[%Pu]=%.*Rg", mpfr_get_prec (y), mpfr_log_prec, y)); + + /* (unsigned long) 0 is assumed to be a real 0 (unsigned) */ + if (MPFR_UNLIKELY (u == 0)) + return mpfr_set (y, x, rnd_mode); + + /* This block is actually useless, but this is a minor optimization. */ + if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x))) { - mpfr_t uu; - mp_limb_t up[1]; - unsigned long cnt; - int inex; - - MPFR_SAVE_EXPO_DECL (expo); - - MPFR_LOG_FUNC - (("x[%Pu]=%.*Rg u=%lu rnd=%d", - mpfr_get_prec(x), mpfr_log_prec, x, u, rnd_mode), - ("y[%Pu]=%.*Rg inexact=%d", - mpfr_get_prec(y), mpfr_log_prec, y, inex)); - - MPFR_TMP_INIT1 (up, uu, GMP_NUMB_BITS); - MPFR_ASSERTN (u == (mp_limb_t) u); - count_leading_zeros (cnt, (mp_limb_t) u); - *up = (mp_limb_t) u << cnt; - - /* Optimization note: Exponent save/restore operations may be - removed if mpfr_sub works even when uu is out-of-range. */ - MPFR_SAVE_EXPO_MARK (expo); - MPFR_SET_EXP (uu, GMP_NUMB_BITS - cnt); - inex = mpfr_sub (y, x, uu, rnd_mode); - MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags); - MPFR_SAVE_EXPO_FREE (expo); - return mpfr_check_range (y, inex, rnd_mode); + if (MPFR_IS_NAN (x)) + { + MPFR_SET_NAN (y); + MPFR_RET_NAN; + } + if (MPFR_IS_INF (x)) + { + MPFR_SET_INF (y); + MPFR_SET_SAME_SIGN (y, x); + MPFR_RET (0); /* +/-infinity is exact */ + } + /* The case x being zero is handled below: we can't use mpfr_set_si + as the opposite of u does not necessarily fit in a long. */ } - else - return mpfr_set (y, x, rnd_mode); + + /* Main code */ + { + mpfr_t uu; + mp_limb_t up[1]; + int cnt; + int inex; + MPFR_SAVE_EXPO_DECL (expo); + + MPFR_TMP_INIT1 (up, uu, GMP_NUMB_BITS); + MPFR_STAT_STATIC_ASSERT (MPFR_LIMB_MAX >= ULONG_MAX); + /* So, u fits in a mp_limb_t, which justifies the casts below. */ + MPFR_ASSERTD (u != 0); + count_leading_zeros (cnt, (mp_limb_t) u); + *up = (mp_limb_t) u << cnt; + + /* Optimization note: Exponent save/restore operations may be + removed if mpfr_sub works even when uu is out-of-range. */ + MPFR_SAVE_EXPO_MARK (expo); + MPFR_SET_EXP (uu, GMP_NUMB_BITS - cnt); + inex = mpfr_sub (y, x, uu, rnd_mode); + MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags); + MPFR_SAVE_EXPO_FREE (expo); + return mpfr_check_range (y, inex, rnd_mode); + } } |