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Further down the thread: > Not to mention, Intel have been in bed with the NSA for the longest time. > Secret areas on the chip, pop instructions, microcode a

• nitrogen 13y ago
  AIUI the story goes like this: for a long time NSA required all CPU vendors to provide a "popcount" instruction (to count the number of one bits in a register) for any hardware contract. NSA was buying a lot of Intel processors, but Intel CPUs lacked a documented popcount instruction until very recently. So, there was speculation that an undocumented opcode would function as a popcount instruction in older Intel CPUs (perhaps after modifying the CPU microcode), and from there people speculate that there may be other undocumented instructions and CPU features. Or so the story goes.