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Diffstat (limited to 'Doc/whatsnew/2.7.rst')
| -rw-r--r-- | Doc/whatsnew/2.7.rst | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Doc/whatsnew/2.7.rst b/Doc/whatsnew/2.7.rst index 8037b13..e44a42b 100644 --- a/Doc/whatsnew/2.7.rst +++ b/Doc/whatsnew/2.7.rst @@ -86,6 +86,30 @@ Some smaller changes made to the core Python language are: (Contributed by Fredrik Johansson and Victor Stinner; :issue:`3439`.) +* Integers are now stored internally either in base 2**15 or in base + 2**30, the base being determined at build time. Previously, they + were always stored in base 2**15. Using base 2**30 gives + significant performance improvements on 64-bit machines, but + benchmark results on 32-bit machines have been mixed. Therefore, + the default is to use base 2**30 on 64-bit machines and base 2**15 + on 32-bit machines; on Unix, there's a new configure option + --enable-big-digits that can be used to override this default. + + Apart from the performance improvements this change should be + invisible to end users, with one exception: for testing and + debugging purposes there's a new structseq ``sys.long_info`` that + provides information about the internal format, giving the number of + bits per digit and the size in bytes of the C type used to store + each digit:: + + >>> import sys + >>> sys.long_info + sys.long_info(bits_per_digit=30, sizeof_digit=4) + + + (Contributed by Mark Dickinson; :issue:`4258`.) + + .. ====================================================================== |