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Re: /internet
- To: Per Bothner <bothner at cygnus dot com>
- Subject: Re: /internet
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Thu, 17 Dec 1998 21:20:27 -0700
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <199812170055.QAA14233@cygnus.com>you write:
> > The rules for FP are different becuase it's not 100% certain that the
> > results after reassociation will be the same as before reassociation. Th
> ough
> > I believe in the case reassociating a series of multiplies we are safe.
>
> How about:
> x = "semi-Infinity"; /* something that when squared will overflow */
> (x * x) * (1/x) /* +Infinity */
> x * (x * (1/x)) == x * 1.0 (approximately) == x;
Ah. Shit. That's what I was missing.
Bummer. This may severely restrict what we can do in this space for floating
point since we can't use the as-if rule. Oh well...
jeff