* util.c (ruby_strtod): this code uses FPU's rounding system.

But x86's FPU calculates double precision floating-point
  numbers in 80bit precision, so it fails to round the value.
  So ensure the value is assigned a variable. [ruby-dev:42551]
  see also [ruby-math:00802]
  http://www.shudo.net/java-grandprix99/strictfp/

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29729 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
naruse 2010-11-09 01:57:49 +00:00
Родитель b3c7867df7
Коммит c383fbf93f
3 изменённых файлов: 16 добавлений и 2 удалений

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@ -1,3 +1,12 @@
Tue Nov 9 10:44:19 2010 NARUSE, Yui <naruse@ruby-lang.org>
* util.c (ruby_strtod): this code uses FPU's rounding system.
But x86's FPU calculates double precision floating-point
numbers in 80bit precision, so it fails to round the value.
So ensure the value is assigned a variable. [ruby-dev:42551]
see also [ruby-math:00802]
http://www.shudo.net/java-grandprix99/strictfp/
Tue Nov 9 07:30:15 2010 Nobuyoshi Nakada <nobu@ruby-lang.org> Tue Nov 9 07:30:15 2010 Nobuyoshi Nakada <nobu@ruby-lang.org>
* error.c (rb_syserr_new): new function to make SystemCallError * error.c (rb_syserr_new): new function to make SystemCallError

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@ -190,6 +190,8 @@ class TestSprintf < Test::Unit::TestCase
sprintf("%20.0f", 36893488147419107329.0)) sprintf("%20.0f", 36893488147419107329.0))
assert_equal(" Inf", sprintf("% 0e", 1.0/0.0), "moved from btest/knownbug") assert_equal(" Inf", sprintf("% 0e", 1.0/0.0), "moved from btest/knownbug")
assert_equal(" -0.", sprintf("%#10.0f", -0.5), "[ruby-dev:42552]") assert_equal(" -0.", sprintf("%#10.0f", -0.5), "[ruby-dev:42552]")
assert_equal("0x1.p+2", sprintf('%.0a', Float('0x1.fp+1')), "[ruby-dev:42551]")
assert_equal("-0x1.0p+2", sprintf('%.0a', Float('-0x1.ffp+1')), "[ruby-dev:42551]")
end end
def test_float_hex def test_float_hex

7
util.c
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@ -4014,10 +4014,13 @@ ruby_hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign,
/* Round to the desired number of digits. */ /* Round to the desired number of digits. */
if (SIGFIGS > ndigits && ndigits > 0) { if (SIGFIGS > ndigits && ndigits > 0) {
float redux = 1.0f; float redux = 1.0f;
volatile double d;
int offset = 4 * ndigits + DBL_MAX_EXP - 4 - DBL_MANT_DIG; int offset = 4 * ndigits + DBL_MAX_EXP - 4 - DBL_MANT_DIG;
dexp_set(u, offset); dexp_set(u, offset);
u.d += redux; d = u.d;
u.d -= redux; d += redux;
d -= redux;
u.d = d;
*decpt += dexp_get(u) - offset; *decpt += dexp_get(u) - offset;
} }