diff options
| author | Mark Dickinson <mdickinson@enthought.com> | 2021-12-27 18:04:36 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-12-27 18:04:36 (GMT) |
| commit | 360fedc2d2ce6ccb0dab554ef45fe83f7aea1862 (patch) | |
| tree | d05c41e34152d08b963691b2eff5d678bf5956a7 /Objects | |
| parent | 2e3e0d23adca8d83722d939d6abd1e467d7578f7 (diff) | |
| download | cpython-360fedc2d2ce6ccb0dab554ef45fe83f7aea1862.zip cpython-360fedc2d2ce6ccb0dab554ef45fe83f7aea1862.tar.gz cpython-360fedc2d2ce6ccb0dab554ef45fe83f7aea1862.tar.bz2 | |
bpo-46055: Streamline inner loop for right shifts (#30243)
Diffstat (limited to 'Objects')
| -rw-r--r-- | Objects/longobject.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index 77434e6..ddb3def 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -4491,7 +4491,7 @@ long_rshift1(PyLongObject *a, Py_ssize_t wordshift, digit remshift) { PyLongObject *z = NULL; Py_ssize_t newsize, hishift, i, j; - digit lomask, himask; + twodigits accum; if (Py_SIZE(a) < 0) { /* Right shifting negative numbers is harder */ @@ -4511,16 +4511,17 @@ long_rshift1(PyLongObject *a, Py_ssize_t wordshift, digit remshift) if (newsize <= 0) return PyLong_FromLong(0); hishift = PyLong_SHIFT - remshift; - lomask = ((digit)1 << hishift) - 1; - himask = PyLong_MASK ^ lomask; z = _PyLong_New(newsize); if (z == NULL) return NULL; - for (i = 0, j = wordshift; i < newsize; i++, j++) { - z->ob_digit[i] = (a->ob_digit[j] >> remshift) & lomask; - if (i+1 < newsize) - z->ob_digit[i] |= (a->ob_digit[j+1] << hishift) & himask; + j = wordshift; + accum = a->ob_digit[j++] >> remshift; + for (i = 0; j < Py_SIZE(a); i++, j++) { + accum |= (twodigits)a->ob_digit[j] << hishift; + z->ob_digit[i] = (digit)(accum & PyLong_MASK); + accum >>= PyLong_SHIFT; } + z->ob_digit[i] = (digit)accum; z = maybe_small_long(long_normalize(z)); } return (PyObject *)z; |