Thread

Subnormal floating-point numbers are expensive on Intel processors

69 points · 54 comments · zdw

rf15 · 1789732795 · focus · HN ↗
...Is this running extra micro code to fix some hardware bug/unreliability? How can this happen? Doesn't look like a normal design decision.
1. aardvark179 · 1789733550 · focus · HN ↗
  I don’t know if any bugs contribute to this but this in the intel case but it has been very common historically for subnormal performance to be lower on many processors, and things like the Alpha required you to handle them in software if the COU fired a trap.
  Have a look at <a href="https://en.wikipedia.org/wiki/Subnormal_number" rel="nofollow">https://en.wikipedia.org/wiki/Subnormal_number for some context.

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