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* numeric.c (int_pow): fix previous nubu's commit.

* test/ruby/test_fixnum.rb: new test.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12698 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
usa 2007-07-05 07:38:41 +00:00
parent b553a34c63
commit a0d50fa3c4
3 changed files with 39 additions and 4 deletions

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@ -1,3 +1,9 @@
Thu Jul 5 16:37:34 2007 NAKAMURA Usaku <usa@ruby-lang.org>
* numeric.c (int_pow): fix previous nubu's commit.
* test/ruby/test_fixnum.rb: new test.
Thu Jul 5 15:56:06 2007 Nobuyoshi Nakada <nobu@ruby-lang.org>
* numeric.c (int_pow): even number multiplication never be negative.

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@ -2281,7 +2281,10 @@ int_pow(long x, unsigned long y)
long z = 1;
if (neg) x = -x;
if (y & 1) z = x;
if (y & 1)
z = x;
else
neg = 0;
y &= ~1;
do {
while (y % 2 == 0) {
@ -2289,8 +2292,8 @@ int_pow(long x, unsigned long y)
if (x2 < x || !POSFIXABLE(x2)) {
VALUE v;
bignum:
v = rb_big_pow(rb_int2big(neg ? -x : x), LONG2NUM(y));
if (z != 1) v = rb_big_mul(rb_int2big(z), v);
v = rb_big_pow(rb_int2big(x), LONG2NUM(y));
if (z != 1) v = rb_big_mul(rb_int2big(neg ? -z : z), v);
return v;
}
x = x2;
@ -2304,7 +2307,7 @@ int_pow(long x, unsigned long y)
z = xz;
}
} while (--y);
if (neg && (y & 1)) z = -z;
if (neg) z = -z;
return LONG2NUM(z);
}

26
test/ruby/test_fixnum.rb Normal file
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@ -0,0 +1,26 @@
require 'test/unit'
class TestFixnum < Test::Unit::TestCase
def setup
@verbose = $VERBOSE
$VERBOSE = nil
end
def teardown
$VERBOSE = @verbose
end
def test_pow
[1, 2, 2**64, 2**63*3, 2**64*3].each do |y|
[1, 3].each do |x|
z1 = x**y
z2 = (-x)**y
if y % 2 == 1
assert_equal(z2, -z1)
else
assert_equal(z2, z1)
end
end
end
end
end