ECL? was ..Re: Runtime determination of share directories?

       Ray,

[it's quite an interesting discussion for me]

   I'm not sure, but I think there will always be corner cases where you
   will get incorrect results on an x87.  It's unavoidable due to the
   80-bit registers.  Even if you set the rounding and precision modes
   correctly.  I think the cases are when a number would underflow to 0 if
   you had 64-bit doubles but doesn't when you have 80-bit long floats.

please can you give an example? I thought quaddouble was using algorithms
like TwoSum of TwoProduct which guarantee exact operations, without guard
bits.

Paul