Re: floats ??????

[Eric Blake]

In the .class file, any version of NaN is legal (both fff8000000000000 
and 7ff8000000000000 are NaNs, and which one is prefered by the 
architecture is machine dependent). This may be a bug in 
doubleToLongBits for not flattening to the Java canonical NaN properly. 
 Also, since jikes 1.13, jikes emulates all floating point ops when 
calculating compiled constants, rather than using hardware floating 
point, so the particular problem you mention may be solved in a newer 
version of jikes.

I'm still trying to convince the jikes release manager that it is time 
for 1.17; as 1.16 incorrectly compiles a few of the Classpath files, 
while exiting with a success status.  The current CVS of jikes does not 
have these problems with Classpath, as far as I can tell.

Chris Gray wrote:
> On 16 Sep 2002, John Leuner wrote:
>
>
> > It's almost certainly a kissme bug.
>
>
> Mind you some versions at least of Jikes generate a bad bit pattern for NaN:
>
>   FAIL $$java.lang.Double$$doubleToLongBits(double)long$$Value Double.NaN$$: 
>   gnu.testlet.wonka.lang.Double.DoubleTest: doubleToLongBits(double)long (number 9)
>   got -2251799813685248 but expected 9221120237041090560 
>   NaN = fff8000000000000, but should be 0x7ff8000000000000 
>
> That's jikes 1.12, which was the last version to be able to compile Wonka
> without generating bad code or dumping core ...


--
This signature intentionally left boring.

Eric Blake             address@hidden
  BYU student, free software programmer