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The First RISC: John Cocke and the IBM 801
- brucehoult 2y agoThey mention the CDC 6600 from 1964 and yet for some unknown reason apparently don't consider it (or the Cray 1) to be RISC. I certainly do! > Taking an idea from the Control Data 6600 (the first ‘Supercomputer’ designed by Seymour Cray) the new machine would have a ‘load-store’ architecture where simple ‘load’ or ‘store’ instructions would be the only way of accessing or changing memory Actually, it didn't have load and store instructions at all! Moving a new value into one of the A address registers automatically started a load (A1-A5) or store (A6-A7) to/from the corresponding 60 bit X data register. Only A0 didn't have such a side-effect. This is kind of weird, but I don't think disqualifies it from being RISC. Everything else is basically the same as modern RISC. It had around 70 instructions, covering both integer and floating point.