Merged revisions 59323-59332 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r59324 | georg.brandl | 2007-12-04 17:10:02 +0100 (Tue, 04 Dec 2007) | 3 lines

  Add "Python on Unix" document, mostly written for GHOP
  by Shriphani Palakodety.
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  r59325 | facundo.batista | 2007-12-04 17:31:53 +0100 (Tue, 04 Dec 2007) | 3 lines


  fma speedup by avoiding to create a Context. Thanks Mark Dickinson.
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  r59326 | christian.heimes | 2007-12-04 17:36:20 +0100 (Tue, 04 Dec 2007) | 2 lines

  Added warning that make install may overwrite or masquerade the default python binary. Use make altinstall instead.
  A native English speaker may want to rephrase the paragraph. ;)
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  r59327 | georg.brandl | 2007-12-04 17:50:28 +0100 (Tue, 04 Dec 2007) | 2 lines

  Fix duplicate label and a typo.
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  r59329 | georg.brandl | 2007-12-04 18:46:27 +0100 (Tue, 04 Dec 2007) | 2 lines

  Add tutorial and examples to logging docs, from GHOP student "oscar8thegrouch".
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  r59332 | christian.heimes | 2007-12-04 19:43:19 +0100 (Tue, 04 Dec 2007) | 1 line

  These optimizations create smaller and a bit faster code on my machine. I've also disabled an optimization that may be dangerous. Intrinsic functions conflict with errno.
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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__"""