Subnormal floating-point numbers are expensive on Intel processors

Are the results compared across architectures?

If you don't _need_ subnormals MXCSR.DAZ/FTZ (which you can get gcc to set via -mdaz-ftz) will let you ignore all of this.

This has been the case since a zillion years, since the Core 2 Duo days at minimum.

Apparently it only happens on P-cores, recent E-cores have a fast path for subnormals.

I'm still trying to understand what a subnormal number is; IE, I'm looking for the TLDR so I know just enough to know if I'm using them and need to learn more.

Unfortunately, the Wikipedia article, while probably being accurate, doesn't give a clear and concise answer.

IE, is 0.0001 a subnormal? Or is it 0.000000000000000000001?

...Is this running extra micro code to fix some hardware bug/unreliability? How can this happen? Doesn't look like a normal design decision.