[rrd-developers] a portable rrd format

[Alex van den Bogaerdt]

On Thu, Jun 21, 2007 at 09:06:27AM +0200, Alex van den Bogaerdt wrote:
> On Thu, Jun 21, 2007 at 08:14:41AM +0200, Tobias Oetiker wrote:
> 
> > > Is there really a need to convert NaNs to the local architecture or
> > > will processors deal with different but correct types?
> > > I'm not talking endianness here; I'm talking about 0x7ff400...
> > > vs. 0x7ff800... vs 0x7ff00...1 and so on.
> > 
> > I don't know, but I would rather not bet on this ...
> 
> Ack.  Just wondering...

According to wikipedia:

"precisely specified encoding of the bits, so that all compliant
 computers would interpret bit patterns the same way. This made
 it possible to transfer floating-point numbers from one computer
 to another."

This does mean every processor should treat a number with an
exponent of all 1, and a fraction not equal to zero, as NaN,
no matter what this fraction actually is (high bit set, low
bit set, all set, and so on).


By the way: I also found http://en.wikipedia.org/wiki/IEEE_754r

HTH
Alex