diff options
Diffstat (limited to 'Lib/decimal.py')
| -rw-r--r-- | Lib/decimal.py | 47 |
1 files changed, 31 insertions, 16 deletions
diff --git a/Lib/decimal.py b/Lib/decimal.py index 39ce582..7f95768 100644 --- a/Lib/decimal.py +++ b/Lib/decimal.py @@ -1646,24 +1646,39 @@ class Decimal(object): """ other = _convert_other(other, raiseit=True) - third = _convert_other(third, raiseit=True) - - if context is None: - context = getcontext() - - # do self*other in fresh context with no traps and no rounding - mul_context = Context(traps=[], flags=[], - _rounding_decision=NEVER_ROUND) - product = self.__mul__(other, mul_context) - if mul_context.flags[InvalidOperation]: - # reraise in current context - return context._raise_error(InvalidOperation, - 'invalid multiplication in fma', - 1, product) + # compute product; raise InvalidOperation if either operand is + # a signaling NaN or if the product is zero times infinity. + if self._is_special or other._is_special: + if context is None: + context = getcontext() + if self._exp == 'N': + return context._raise_error(InvalidOperation, 'sNaN', + 1, self) + if other._exp == 'N': + return context._raise_error(InvalidOperation, 'sNaN', + 1, other) + if self._exp == 'n': + product = self + elif other._exp == 'n': + product = other + elif self._exp == 'F': + if not other: + return context._raise_error(InvalidOperation, + 'INF * 0 in fma') + product = Infsign[self._sign ^ other._sign] + elif other._exp == 'F': + if not self: + return context._raise_error(InvalidOperation, + '0 * INF in fma') + product = Infsign[self._sign ^ other._sign] + else: + product = _dec_from_triple(self._sign ^ other._sign, + str(int(self._int) * int(other._int)), + self._exp + other._exp) - ans = product.__add__(third, context) - return ans + third = _convert_other(third, raiseit=True) + return product.__add__(third, context) def _power_modulo(self, other, modulo, context=None): """Three argument version of __pow__""" |