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| author | Victor Stinner <vstinner@python.org> | 2020-06-08 14:30:33 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-06-08 14:30:33 (GMT) |
| commit | c6b292cdeee689f0bfac6c1e2c2d4e4e01fa8d9e (patch) | |
| tree | 4a7686465f3ed4a171382d4717ad558d82413951 /Objects | |
| parent | 301f0d4ff9b6bd60599eea0612904f65a92e6dd9 (diff) | |
| download | cpython-c6b292cdeee689f0bfac6c1e2c2d4e4e01fa8d9e.zip cpython-c6b292cdeee689f0bfac6c1e2c2d4e4e01fa8d9e.tar.gz cpython-c6b292cdeee689f0bfac6c1e2c2d4e4e01fa8d9e.tar.bz2 | |
bpo-29882: Add _Py_popcount32() function (GH-20518)
* Rename pycore_byteswap.h to pycore_bitutils.h.
* Move popcount_digit() to pycore_bitutils.h as _Py_popcount32().
* _Py_popcount32() uses GCC and clang builtin function if available.
* Add unit tests to _Py_popcount32().
Diffstat (limited to 'Objects')
| -rw-r--r-- | Objects/longobject.c | 15 | ||||
| -rw-r--r-- | Objects/stringlib/codecs.h | 2 |
2 files changed, 8 insertions, 9 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index 0b209a4..ce10c4f 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -3,8 +3,9 @@ /* XXX The functional organization of this file is terrible */ #include "Python.h" -#include "pycore_interp.h" // _PY_NSMALLPOSINTS -#include "pycore_pystate.h" // _Py_IsMainInterpreter() +#include "pycore_bitutils.h" // _Py_popcount32() +#include "pycore_interp.h" // _PY_NSMALLPOSINTS +#include "pycore_pystate.h" // _Py_IsMainInterpreter() #include "longintrepr.h" #include <float.h> @@ -5307,12 +5308,10 @@ int_bit_length_impl(PyObject *self) static int popcount_digit(digit d) { - /* 32bit SWAR popcount. */ - uint32_t u = d; - u -= (u >> 1) & 0x55555555U; - u = (u & 0x33333333U) + ((u >> 2) & 0x33333333U); - u = (u + (u >> 4)) & 0x0f0f0f0fU; - return (uint32_t)(u * 0x01010101U) >> 24; + // digit can be larger than uint32_t, but only PyLong_SHIFT bits + // of it will be ever used. + Py_BUILD_ASSERT(PyLong_SHIFT <= 32); + return _Py_popcount32((uint32_t)d); } /*[clinic input] diff --git a/Objects/stringlib/codecs.h b/Objects/stringlib/codecs.h index 9b2a29b..197605b 100644 --- a/Objects/stringlib/codecs.h +++ b/Objects/stringlib/codecs.h @@ -4,7 +4,7 @@ # error "codecs.h is specific to Unicode" #endif -#include "pycore_byteswap.h" // _Py_bswap32() +#include "pycore_bitutils.h" // _Py_bswap32() /* Mask to quickly check whether a C 'long' contains a non-ASCII, UTF8-encoded char. */ |