Re: [9fans] Floating point and dividing by 0

[erik quanstrom <quanstro@quanstro.net>]

On Fri Apr 18 15:54:00 EDT 2014, riddler876@gmail.com wrote:

> Hello again,
>
> Continuing on with my floating point adventures, I have a question that I
> hope someone can provide some input on.
>
> I'm general idea of what I'm doing the following:
>     double zero = 0.0;
>     notify(fpnotecatch); //Ignore divide by zero note for a moment
>     double pInf = 1.0/zero;
>     notify(0); //Back to default note handler
>
>     if(isInf(pInf, 1) <= 0 && isInf(pInf, 0) <= 0) exits("Divide by zero
> did not result in infinity");
>
> The error "did not result in infinity" is always tripped. My understanding
> is that according to the spec it should have resulted in either + or -
> infinity.
>
> I suspect it's not required as there was a note thrown instead, and I can't
> think of any reason why you would deliberately ignore the note like I do of
> the top of my head. Thought I would mention it anyway see what input you
> guys had.

which kernel is this with?  also, be sure to note the fcr (see getfcr(2)).


- erik