[Cuis-dev] denormals

[Luciano Notarfrancesco]

Right, I see, depends on the application… I’m not doing that for every
float, for pcm audio i just flush to zero anything under -90 dB, and I saw
some people add a little dither noise instead, but in other cases it’s not
so straight forward… I’m not sure I’m doing it right for filter
coefficients, etc, I’ll look more carefully at how other similar projects
do it. Thanks!

On Fri, Nov 21, 2025 at 02:06 Martin McClure <martin at hand2mouse.com> wrote:

> Avoiding subnormal floats is desirable, since subnormals have fewer
> significant bits than normal floats. This should ideally be done by
> designing the application to do its computations so that subnormals are
> never created. Forcing subnormals to go to zero is the wrong direction
> entirely -- that is saying "I've lost some bits of accuracy, so now let's
> throw away *all* the bits and have *no* accuracy."
>
> A faster path to a wrong answer is seldom, if ever, a good trade.
>
> Regards,
>
> -Martin
> On 11/20/25 10:00 AM, Luciano Notarfrancesco via Cuis-dev wrote:
>
> It seems to me that when working with floats in Cuis we should try to
> avoid denormals (or subnormals, i.e. floats that are very close to 0 but
> not 0). They used to be slower than other floats in old CPUs, and they are
> not so much of a problem anymore in modern CPUs, but I think they would
> still be problematic in Cuis because they turn into BoxedFloat64 (instead
> of SmallFloat64). What’s the best way to handle them? For the time being I
> implemented BoxedFloat64>>undenormalized as:
>     self isDenormalized ifTrue: [^ 0.0]
> and in Float just returns self. The method isDenormalized comes in the
> base image, but it’s not super fast. Is there a better way to do it?
>
>
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