potential error in fdlibm asin

[Andrew Haley]

On 05/12/16 10:30, Volker Simonis wrote:
> On Mon, Dec 5, 2016 at 11:10 AM, Andrew Haley <aph at redhat.com> wrote:
>> On 02/12/16 14:24, Lindenmaier, Goetz wrote:
>>>
>>> I found one copy of this code in the internet where the "else" is removed,
>>> but it's not completely the same:
>>> https://github.com/jerryscript-project/jerryscript/blob/master/jerry-libm/asin.c
>>>
>>> Does anybody have the knowledge to tell me what's wrong?
>>> Does anybody know how to contribute a fix to netlib fdlibm?
>>
>> I think the only way to proceed with this is to find an input argument
>> which is affected by this very odd code.  If there is one. does it
>> give a correct or an incorrect result?  If not, we don't care and it
>> can be tidied up later.
> 
> What would be the ultimate reference to to compare a potentially
> incorrect result against if "the Java math library is defined with
> respect to fdlibm version 5.3" [1] ?
> 
> [1] https://docs.oracle.com/javase/8/docs/api/java/lang/StrictMath.html

The ultimate reference is hard to determine, but we need to know a value
of asin which is more than a couple of ulp or so away from the correct
value.

Andrew.