diff options
| -rw-r--r-- | Doc/using/configure.rst | 3 | ||||
| -rw-r--r-- | Doc/whatsnew/3.11.rst | 10 | ||||
| -rw-r--r-- | Include/pyport.h | 16 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Build/2022-01-09-11-24-54.bpo-45569.zCIENy.rst | 5 | ||||
| -rwxr-xr-x | configure | 2 | ||||
| -rw-r--r-- | configure.ac | 2 |
6 files changed, 22 insertions, 16 deletions
diff --git a/Doc/using/configure.rst b/Doc/using/configure.rst index 771ad3c..f1c156c 100644 --- a/Doc/using/configure.rst +++ b/Doc/using/configure.rst @@ -35,8 +35,7 @@ General Options Define the size in bits of Python :class:`int` digits: 15 or 30 bits. - By default, the number of bits is selected depending on ``sizeof(void*)``: - 30 bits if ``void*`` size is 64-bit or larger, 15 bits otherwise. + By default, the digit size is 30. Define the ``PYLONG_BITS_IN_DIGIT`` to ``15`` or ``30``. diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst index 6a6c22c..96d6e26 100644 --- a/Doc/whatsnew/3.11.rst +++ b/Doc/whatsnew/3.11.rst @@ -622,6 +622,16 @@ Build Changes like Pyodide. (Contributed by Christian Heimes and Ethan Smith in :issue:`40280`.) +* CPython will now use 30-bit digits by default for the Python :class:`int` + implementation. Previously, the default was to use 30-bit digits on platforms + with ``SIZEOF_VOID_P >= 8``, and 15-bit digits otherwise. It's still possible + to explicitly request use of 15-bit digits via either the + ``--enable-big-digits`` option to the configure script or (for Windows) the + ``PYLONG_BITS_IN_DIGIT`` variable in ``PC/pyconfig.h``, but this option may + be removed at some point in the future. (Contributed by Mark Dickinson in + :issue:`45569`.) + + C API Changes ============= diff --git a/Include/pyport.h b/Include/pyport.h index 81b1bde..d27b3dd 100644 --- a/Include/pyport.h +++ b/Include/pyport.h @@ -85,20 +85,12 @@ Used in: Py_SAFE_DOWNCAST #define PY_INT32_T int32_t #define PY_INT64_T int64_t -/* If PYLONG_BITS_IN_DIGIT is not defined then we'll use 30-bit digits if all - the necessary integer types are available, and we're on a 64-bit platform - (as determined by SIZEOF_VOID_P); otherwise we use 15-bit digits. - - From pyodide: WASM has 32 bit pointers but has native 64 bit arithmetic - so it is more efficient to use 30 bit digits. +/* PYLONG_BITS_IN_DIGIT describes the number of bits per "digit" (limb) in the + * PyLongObject implementation (longintrepr.h). It's currently either 30 or 15, + * defaulting to 30. The 15-bit digit option may be removed in the future. */ - #ifndef PYLONG_BITS_IN_DIGIT -#if SIZEOF_VOID_P >= 8 || defined(__wasm__) -# define PYLONG_BITS_IN_DIGIT 30 -#else -# define PYLONG_BITS_IN_DIGIT 15 -#endif +#define PYLONG_BITS_IN_DIGIT 30 #endif /* uintptr_t is the C9X name for an unsigned integral type such that a diff --git a/Misc/NEWS.d/next/Build/2022-01-09-11-24-54.bpo-45569.zCIENy.rst b/Misc/NEWS.d/next/Build/2022-01-09-11-24-54.bpo-45569.zCIENy.rst new file mode 100644 index 0000000..69716cd --- /dev/null +++ b/Misc/NEWS.d/next/Build/2022-01-09-11-24-54.bpo-45569.zCIENy.rst @@ -0,0 +1,5 @@ +The build now defaults to using 30-bit digits for Python integers. Previously +either 15-bit or 30-bit digits would be selected, depending on the platform. +15-bit digits may still be selected using the ``--enable-big-digits=15`` option +to the ``configure`` script, or by defining ``PYLONG_BITS_IN_DIGIT`` in +``pyconfig.h``. @@ -1730,7 +1730,7 @@ Optional Features: Doc/library/socket.rst (default is yes if supported) --enable-big-digits[=15|30] use big digits (30 or 15 bits) for Python longs - (default is system-dependent)] + (default is 30)] --disable-test-modules don't build nor install test modules Optional Packages: diff --git a/configure.ac b/configure.ac index 300d793..7b084a2 100644 --- a/configure.ac +++ b/configure.ac @@ -5084,7 +5084,7 @@ AC_CHECK_DECLS([RTLD_LAZY, RTLD_NOW, RTLD_GLOBAL, RTLD_LOCAL, RTLD_NODELETE, RTL # determine what size digit to use for Python's longs AC_MSG_CHECKING([digit size for Python's longs]) AC_ARG_ENABLE(big-digits, -AS_HELP_STRING([--enable-big-digits@<:@=15|30@:>@],[use big digits (30 or 15 bits) for Python longs (default is system-dependent)]]), +AS_HELP_STRING([--enable-big-digits@<:@=15|30@:>@],[use big digits (30 or 15 bits) for Python longs (default is 30)]]), [case $enable_big_digits in yes) enable_big_digits=30 ;; |