pack_float, pack_double, save_float: All the routines for creating
IEEE-format packed representations of floats and doubles simply ignored
that rounding can (in rare cases) propagate out of a long string of
1 bits. At worst, the end-off carry can (by mistake) interfere with
the exponent value, and then unpacking yields a result wrong by a factor
of 2. In less severe cases, it can end up losing more low-order bits
than intended, or fail to catch overflow *caused* by rounding.
Bugfix candidate, but I already backported this to 2.2.
In 2.3, this code remains in severe need of refactoring.
variables to store internal data. As a result, any atempts to use the
unicode system with multiple active interpreters, or successive
interpreter executions, would fail.
Now that information is stored into members of the PyInterpreterState
structure.
for specific platforms. Use this to add plat-mac and
plat-mac/lib-scriptpackages on MacOSX. Also tested for not having adverse
effects on Linux, and I think this code isn't used on Windows anyway.
Fixes#661521.
invalid, rather than returning a string of random garbage of the
estimated result length. Closes SF patch #703471 by Hye-Shik Chang.
Will backport to 2.2-maint (consider it done.)
Added two predictions:
GET_ITER --> FOR_ITER
FOR_ITER --> STORE_FAST or UNPACK_SEQUENCE
Improves timings on pybench and timeit.py. Pystone results are neutral.
Applied to common cases:
COMPARE_OP is often followed by a JUMP_IF.
JUMP_IF is usually followed by POP_TOP.
Shows improved timings on PyStone, PyBench, and specific tests
using timeit.py:
python timeit.py -s "x=1" "if x==1: pass"
python timeit.py -s "x=1" "if x==2: pass"
python timeit.py -s "x=1" "if x: pass"
python timeit.py -s "x=100" "while x!=1: x-=1"
Potential future candidates:
GET_ITER predicts FOR_ITER
FOR_ITER predicts STORE_FAST or UNPACK_SEQUENCE
Also, applied missing goto fast_next_opcode to DUP_TOPX.
(from 10) and in main() (from 1).
Add a -v option that shows the raw times. Repeating it cranks up the
display precision.
Always use the "best of N" form of output.
- Make all local variables in the template start with an underscore,
to prevent name conflicts with the timed code.
- Added a method to print a traceback that shows source lines from the
expanded template.
- Use that method in main().
My previous patches should have used fast_next_opcode
in a few places instead of continue.
Also, applied one PyInt_AS_LONG macro in a place where
the type had already been checked.
Neal Norwitz
Skip Montanaro
Fred Drake
Just van Rossum
Tim Peters
Jack Jansen
Gustavo Niemeyer
Barry Warsaw
Raymond Hettinger
Martin v. Löwis
Thomas Wouters
Guido van Rossum
Michael W. Hudson
Kurt B. Kaiser