Re: Making Lemonade (Floating-point format changes)

Stefan Monnier wrote:

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.

Wouldn't that just kick the problem down the street?
For example, what should `x < y` return when both `x` and `y` are
"infinity+epsilon"?

You mean -infinity+epsilon or +infinity-epsilon. +infinity+epsilon
is +infinity ...
IEEE 754 has +infinity == +infinity && -infinity == -infinity

        Stefan