[PPL-devel] More floating point problems on the Alpha

Joseph S. Myers joseph@codesourcery.com
Wed Sep 24 05:24:00 GMT 2008


On Mon, 22 Sep 2008, Joe Buck wrote:

> On Mon, Sep 22, 2008 at 09:56:30PM +0200, Abramo Bagnara wrote:
> > The problem come from the fact that for astonishing reasons 1.4e-45f is
> > not seen as 1.4e-45.
> 
> Why is this astonishing?  The smallest positive single-precision IEEE
> floating point number is roughly 1.175494e-38.  Since user-specified
> numbers are rounded to the closest representable value, 1.4e-45f is
> a fancy way of typing zero.

The smallest subnormal value is approximately 1.40129846e-45F 
(__FLT_DENORM_MIN__).  The obvious conclusion is that subnormal support is 
broken or disabled on Alpha by default.

-- 
Joseph S. Myers
joseph@codesourcery.com



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