[Cfp-interest 2283] Re: nextup/nextdown and HUGE_VAL definition

[David Chen]

Section 5.3.1. of IEEE 754-2019 states "nextUp(x) is quiet except for
signaling NaNs".  If we follow that, no overflow in any cases.


On Mon, Nov 22, 2021 at 10:47 AM Fred J. Tydeman <tydeman at tybor.com> wrote:

> On Mon, 22 Nov 2021 10:06:22 -0800 Jim Thomas wrote:
> >
> >Reword the specification of the nextup and nextdown functions to not
> refer to the HUGE_VAL macros, along the lines Vincent suggested. For
> example,
> >
> >Replace
> >
> >       nextup(HUGE_VAL) is HUGE_VAL,
> >
> >with
> >
> >       If x is the maximum number in the type, nextup(x) is x.
> >
>
> So, on systems without infinity, since there is no next higher number
> than the maximum finite number, should that be an overflow?
> If not, than it would help to add "(without overflow)" at the end of
> what you suggest.
>
> ---
> Fred J. Tydeman        Tydeman Consulting
> tydeman at tybor.com      Testing, numerics, programming
> +1 (702) 608-6093      Vice-chair of PL22.11 (ANSI "C")
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-- 
Best Regards,
David.

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