Thread

1. jstanley · 1790072957 · focus · HN ↗

   This is not the first RNG bug on Zen 2, I recall after I first got mine that some application or other would quit immediately at startup because rdrand always returned -1, i.e. all 1s. It was fixed with a microcode update.

   Do we now learn that they fixed "always generate all 1s" with "never generate all 0s"??

   EDIT: I've been unable to reproduce the problem on my CPU, FWIW. It's a Ryzen 5 3600.

   EDIT2: OK, update, I can reproduce it with rdrand16, rdrand32 is fine but rdrand16 can never generate all 0s. So my CPU does have this problem!

   1. yk · 1790073386 · focus · HN ↗

          return 4 # Determined by fair dice roll.

      1. Gander5739 · 1790073835 · focus · HN ↗

         <a href="https:&#x2F;&#x2F;xkcd.com&#x2F;221&#x2F;" rel="nofollow">https:&#x2F;&#x2F;xkcd.com&#x2F;221&#x2F; for those not in the know

         1. Betelbuddy · 1790074224 · focus · HN ↗

            <a href="https:&#x2F;&#x2F;i.imgur.com&#x2F;bwFWMqQ.png" rel="nofollow">https:&#x2F;&#x2F;i.imgur.com&#x2F;bwFWMqQ.png

            1. [deleted] · 1790076017 · focus · HN ↗

               [deleted]

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