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I've noticed that the sentence “Compliant with RVA23 excluding V extension” has apparently been a bit confusing to some reporters in the tech press lately. It

I've noticed that the sentence “Compliant with RVA23 excluding V extension” has apparently been a bit confusing to some reporters in the tech press lately. It means that the UR-DP1000 chip would have been RVA23-compliant if only it had supported the V (Vector) extension. The Vector extension is mandatory in the RVA23 profile. There are other chips out there even closer to being RVA23-compliant, that have V but not a couple of scalar extensions. The latter have been emulated in software using trap handlers, but there was a significant performance penalty. V is such a big extension, with many instructions and requiring more resources, that I don't think that it would be worth the effort.

fidotron 9mo ago
> The latter have been emulated in software using trap handlers, but there was a significant performance penalty. This is a thing SoC vendors have done before without informing their customers until it's way too late. Quite a few players in that industry really do have shockingly poor ethical standards.
- PunchyHamster 9mo ago
  I'm sure it is in footnote in datasheet
  - fidotron 9mo ago
    No, they really are that grimy and will pull tricks like this until you call them out on them. They will then issue errata later, after millions of devices have been shipped.
  - reactordev 9mo ago
    In 6pt mandarin.
- fweimer 9mo ago
  I'm not sure if it's intentional. AWS doesn't have CPU features in their EC2 product documentation, either. It doesn't necessarily mean that they can disable CPU features for instances covered by existing customer contracts.
  - fidotron 9mo ago
    > I'm not sure if it's intentional This is the sort of comment that makes people lose faith in HN. There totally are cases where it's intentional, and no they are not discussed on the internet for obvious reasons. People in the industry will absolutely know what I'm on about.
    - fweimer 9mo ago
      I didn't intend to dismiss your experience. From the opposite (software) side, these things are hard to document, and unclear hardware requirement documentation result from the complexity and (perhaps) unresolved internal conflict.
      - u8080 9mo ago
        >these things are hard to document No, it's not.

fidotron 9mo ago

> The latter have been emulated in software using trap handlers, but there was a significant performance penalty. This is a thing SoC vendors have done before without informing their customers until it's way too late. Quite a few players in that industry really do have shockingly poor ethical standards.

PunchyHamster 9mo ago
I'm sure it is in footnote in datasheet
- fidotron 9mo ago
  No, they really are that grimy and will pull tricks like this until you call them out on them. They will then issue errata later, after millions of devices have been shipped.
- reactordev 9mo ago
  In 6pt mandarin.
fweimer 9mo ago
I'm not sure if it's intentional. AWS doesn't have CPU features in their EC2 product documentation, either. It doesn't necessarily mean that they can disable CPU features for instances covered by existing customer contracts.
- fidotron 9mo ago
  > I'm not sure if it's intentional This is the sort of comment that makes people lose faith in HN. There totally are cases where it's intentional, and no they are not discussed on the internet for obvious reasons. People in the industry will absolutely know what I'm on about.
  - fweimer 9mo ago
    I didn't intend to dismiss your experience. From the opposite (software) side, these things are hard to document, and unclear hardware requirement documentation result from the complexity and (perhaps) unresolved internal conflict.
    - u8080 9mo ago
      >these things are hard to document No, it's not.