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Backout broken backport. (Sorry.)

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This commit is contained in:
Mark Dickinson 2010-12-04 12:42:18 +00:00
parent 11e77ffcbc
commit 33154388f9
3 changed files with 14 additions and 38 deletions
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30
Lib/test/test_float.py
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@ -12,6 +12,16 @@ import re
INF = float("inf")
NAN = float("nan")
have_getformat = hasattr(float, "__getformat__")
requires_getformat = unittest.skipUnless(have_getformat,
"requires __getformat__")
requires_setformat = unittest.skipUnless(hasattr(float, "__setformat__"),
"requires __setformat__")
# decorator for skipping tests on non-IEEE 754 platforms
requires_IEEE_754 = unittest.skipUnless(have_getformat and
float.__getformat__("double").startswith("IEEE"),
"test requires IEEE 754 doubles")
#locate file with float format test values
test_dir = os.path.dirname(__file__) or os.curdir
format_testfile = os.path.join(test_dir, 'formatfloat_testcases.txt')
@ -231,26 +241,6 @@ class GeneralFloatCases(unittest.TestCase):
self.assertTrue(d == d, "{%r : None} not equal to itself" % f)
@requires_IEEE_754
def test_float_mod(self):
# Check behaviour of % operator for IEEE 754 special cases.
# In particular, check signs of zeros.
mod = operator.mod
self.assertEqualAndEqualSign(mod(-1.0, 1.0), 0.0)
self.assertEqualAndEqualSign(mod(-1e-100, 1.0), 1.0)
self.assertEqualAndEqualSign(mod(-0.0, 1.0), 0.0)
self.assertEqualAndEqualSign(mod(0.0, 1.0), 0.0)
self.assertEqualAndEqualSign(mod(1e-100, 1.0), 1e-100)
self.assertEqualAndEqualSign(mod(1.0, 1.0), 0.0)
self.assertEqualAndEqualSign(mod(-1.0, -1.0), -0.0)
self.assertEqualAndEqualSign(mod(-1e-100, -1.0), -1e-100)
self.assertEqualAndEqualSign(mod(-0.0, -1.0), -0.0)
self.assertEqualAndEqualSign(mod(0.0, -1.0), -0.0)
self.assertEqualAndEqualSign(mod(1e-100, -1.0), -1.0)
self.assertEqualAndEqualSign(mod(1.0, -1.0), -0.0)
class FormatFunctionsTestCase(unittest.TestCase):

4
Misc/NEWS
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@ -10,10 +10,6 @@ What's New in Python 3.1.4?
Core and Builtins
-----------------
- Issue #10596: Fix float.__mod__ to have the same behaviour as
float.__divmod__ with respect to signed zeros. -4.0 % 4.0 should be
0.0, not -0.0.
Library
-------

18
Objects/floatobject.c
View File

@ -600,20 +600,10 @@ float_rem(PyObject *v, PyObject *w)
#endif
PyFPE_START_PROTECT("modulo", return 0)
mod = fmod(vx, wx);
if (mod) {
/* ensure the remainder has the same sign as the denominator */
if ((wx < 0) != (mod < 0)) {
mod += wx;
}
}
else {
/* the remainder is zero, and in the presence of signed zeroes
fmod returns different results across platforms; ensure
it has the same sign as the denominator; we'd like to do
"mod = wx * 0.0", but that may get optimized away */
mod *= mod; /* hide "mod = +0" from optimizer */
if (wx < 0.0)
mod = -mod;
/* note: checking mod*wx < 0 is incorrect -- underflows to
0 if wx < sqrt(smallest nonzero double) */
if (mod && ((wx < 0) != (mod < 0))) {
mod += wx;
}
PyFPE_END_PROTECT(mod)
return PyFloat_FromDouble(mod);