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From: mitchalsup@aol.com (MitchAlsup1)
Newsgroups: comp.arch
Subject: Re: Making Lemonade (Floating-point format changes)
Date: Tue, 21 May 2024 17:11:22 +0000
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Michael S wrote:

> On Mon, 20 May 2024 21:17:15 +0200
> Terje Mathisen <terje.mathisen@tmsw.no> wrote:
>> 
>> As you note, it is only when using RoundToPlus (or Minus) Infinity
>> that an arbitrary small product can still produce a non-zero result.
>> 
>> Terje
>> 
>> 

> I think, we were discussing multiplication stage of FMA rather than
> multiplication proper.
> In case of FMA, zeroness (zeroity ?) and sign of tiny product matter in
> all standard IEEE rounding mode except default (RNE).


Imagine, instead, if IEEE 754 had defined positive underflow with the
result of positive tiny, negative underflow with negative tiny,
positive overflow with positive infinity-epsilon and negative
overflow with negative infinity+epsilon.

Here, the fact overflow or underflow happened is recorded in the
result, and these results remain identifiable from real infinities
or real zeros.

But that ship sailed 50 years ago.