diff options
Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/ui_sub.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-src/src/ui_sub.c | 64 |
1 files changed, 34 insertions, 30 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/ui_sub.c b/Build/source/libs/mpfr/mpfr-src/src/ui_sub.c index 0ef7917c389..d5fae6e1c13 100644 --- a/Build/source/libs/mpfr/mpfr-src/src/ui_sub.c +++ b/Build/source/libs/mpfr/mpfr-src/src/ui_sub.c @@ -31,48 +31,52 @@ mpfr_ui_sub (mpfr_ptr y, unsigned long int u, mpfr_srcptr x, mpfr_rnd_t rnd_mode u, mpfr_get_prec(x), mpfr_log_prec, x, 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_neg (y, x, rnd_mode); - if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(x))) + if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x))) { - if (MPFR_IS_NAN(x)) + if (MPFR_IS_NAN (x)) { - MPFR_SET_NAN(y); + MPFR_SET_NAN (y); MPFR_RET_NAN; } - else if (MPFR_IS_INF(x)) + if (MPFR_IS_INF (x)) { /* u - Inf = -Inf and u - -Inf = +Inf */ - MPFR_SET_INF(y); - MPFR_SET_OPPOSITE_SIGN(y,x); - MPFR_RET(0); /* +/-infinity is exact */ + MPFR_SET_INF (y); + MPFR_SET_OPPOSITE_SIGN (y, x); + MPFR_RET (0); /* +/-infinity is exact */ } - else /* x is zero */ - /* u - 0 = u */ - return mpfr_set_ui(y, u, rnd_mode); + MPFR_ASSERTD (MPFR_IS_ZERO (x) && u != 0); + /* Note: the fact that u != 0 is important due to signed zeros. */ + /* u - 0 = u */ + return mpfr_set_ui (y, u, rnd_mode); } - else - { - mpfr_t uu; - mp_limb_t up[1]; - int cnt; - int inex; - MPFR_SAVE_EXPO_DECL (expo); + /* 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_ASSERTN(u == (mp_limb_t) u); - count_leading_zeros (cnt, (mp_limb_t) u); - up[0] = (mp_limb_t) u << cnt; + 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[0] = (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, uu, x, rnd_mode); - MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags); - MPFR_SAVE_EXPO_FREE (expo); - return mpfr_check_range(y, inex, rnd_mode); - } + /* 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, uu, x, rnd_mode); + MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags); + MPFR_SAVE_EXPO_FREE (expo); + return mpfr_check_range (y, inex, rnd_mode); + } } |