Blurb about the increased precision of float literals in .pyc/.pyo files.
diff --git a/Misc/NEWS b/Misc/NEWS
index f2150d5..7906613 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -3,6 +3,26 @@
Core
+- Float (and complex) literals in source code were evaluated to full
+ precision only when running from a .py file; the same code loaded from a
+ .pyc (or .pyo) file could suffer numeric differences starting at about the
+ 12th significant decimal digit. For example, on a machine with IEEE-754
+ floating arithmetic,
+
+ x = 9007199254740992.0
+ print long(x)
+
+ printed 9007199254740992 if run directly from .py, but 9007199254740000
+ if from a compiled (.pyc or .pyo) file. This was due to marshal using
+ str(float) instead of repr(float) when building code objects. marshal
+ now uses repr(float) instead, which should reproduce floats to full
+ machine precision (assuming the platform C float<->string I/O conversion
+ functions are of good quality).
+
+ This may cause floating-point results to change in some cases, and
+ usually for the better, but may also cause numerically unstable
+ algorithms to break.
+
- Dictionary objects now support the "in" operator: "x in dict" means
the same as dict.has_key(x).