Power Architecture Rip Van Winkle

For some reason (I guess it is the job…) I was browsing through the Power ISA version 2.06 specification last week and hit the following gem of an instruction: “rvwinkle“. It is named after a short story I had never heard about, but which apparently is sufficiently well-known in the US literary canon to warrant a sleep mode being named after it.

Anyway, here is a screenshot of the manual:

ripvanwinkle ppc mode

It is one of four thread-sleep-state control instructions in the 64-bit server variant of the Power ISA. Essentially, it is an IBM extension for their POWER series machines, as well as the Cell and Xenon CPUs I guess. See the Power ISA tutorial from the Power Architecture Developer’s Conference 2007 for some more on this.

I like this kind of whimsicalness in technical systems. It makes them human and more approachable. Sometimes, big companies (and small companies) once they are mature end up trying a bit too hard to sound business-wise and “professional”… ending up being plain boring and stone-faced and cold. There is no contraction between a chuckle and a professional system for most people.

Some people would put the Power Architecture “eieio” instruction in the same category of slightly funny. However, the limit for all assembly languages I have ever encountered seems to be the natural name for an instruction to Sign EXtend something. It is never called what it “should” be.

Note that this instruction is not new, it has been around since 2005 at least, probably longer. There are no history notes in the manual, and I have no intention of reading through lots of old manuals to find the first when this one did not appear.

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