Withdraw: Review: 4396272 - Parsing doubles fails to follow IEEE for largest decimal that should yield 0

Brian Burkhalter brian.burkhalter at oracle.com
Thu Feb 21 22:32:20 UTC 2013

I am withdrawing this patch for the time being as properly the changes should also go into the fork sun.misc.FormattedFloatingDecimal. I'll post an updated patch once it is available.



On Feb 14, 2013, at 5:23 PM, Brian Burkhalter wrote:

> The patch below is as submitted to OpenJDK bugzilla but with enhanced comments. It pertains to the correction loop in the doubleValue() method of FloatingDecimal. The situation appears to arise when the candidate value is less than 2*Double.MIN_NORMAL as for such values the ULP is less than 2*Double.MIN_VALUE so that the intermediate result 0.5*ULP is less than Double.MIN_VALUE which rounds to zero per FP-strict and the correction is therefore zero. Thus the candidate value is unchanged. The fix is to add the ULP to twice the candidate value, obtain the intermediate result, and then halve it to obtain the adjusted candidate.
> I am relatively new to IEEE-754 and this area of the code so any comments would be appreciated.
> Thanks,
> Brian
> diff -r 1405ad6afb1e -r 36482ed9bb7e src/share/classes/sun/misc/FloatingDecimal.java
> --- a/src/share/classes/sun/misc/FloatingDecimal.java	Thu Feb 14 11:09:07 2013 -0800
> +++ b/src/share/classes/sun/misc/FloatingDecimal.java	Thu Feb 14 16:47:53 2013 -0800

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