Java 8 RFR 6378503: In java.math.BigDecimal, division by one returns zero

[Brian Burkhalter]

Hi Joe,

On Jul 25, 2013, at 2:28 PM, Brian Burkhalter wrote:

>> I took a look through the code and I don't see how sdiff == Integer.MIN_VALUE is handled.
> 
> This case, if compareMagnitude() does not return at lines 2668 or 2670, intentionally falls through to line 2690. Otherwise, if hypothetically sdiff were equal to Integer.MIN_VALUE, then evaluating line 2677 would overflow. It is not actually apparent to me however whether line 2671 would ever be reached were sdiff == Integer.MIN_VALUE.

I have updated the comments at lines 2673 and 2682 of BigDecimal:

http://cr.openjdk.java.net/~bpb/6378503/

>> In any case, as long as the runtimes and memory usage are tractable, the set of test cases should be augmented to include sdiff == Integer.MIN_VALUE and (long)Integer.MIN_VALUE + 1, etc.
> 
> From what I can tell by inspection, sdiff mirrors the MathContext precision (mcp) and all paths will attempt to calculate 10^e where "e" is approximately or exactly mcp. This computation would run for days. I don't yet see a way to test these cases.

Thanks,

Brian