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A comment on MyNOR: Single board computer that uses a single NOR gate as its ALU. Parent comment

Re:MyNOR: Single board computer that uses a single NOR gate ... by theresistor on Tuesday November 24, 2020 @03:25AM (#25196424)
NOR (like NAND) is a universal logic gate. You can build any other logic gate out of just NORs.

For this ALU, you’d presumably write a subroutine that computed XORs in terms of NORs, and then use that as a primitive for building an adder.

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Re:MyNOR: Single board computer that uses a single NOR gate ... by pmiller2 on Tuesday November 24, 2020 @03:26AM (#25196436)
Yes, but this thing advertises that it uses a single NOR gate as an ALU.
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Re:MyNOR: Single board computer that uses a single NOR gate ... by theresistor on Tuesday November 24, 2020 @03:28AM (#25196452)
That’s just moving the composition between hardware and software - the equivalence still applies. I can build any logic (software) function out of a function that evaluates NOR.
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Re:MyNOR: Single board computer that uses a single NOR gate ... by pmiller2 on Tuesday November 24, 2020 @03:59AM (#25196615)
False advertising, then, IMO.
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Re:MyNOR: Single board computer that uses a single NOR gate ... by srott on Tuesday November 24, 2020 @04:35AM (#25196816)
No, AFAIU the computation is serialized, driven by the microcode and this gate is reused for every step
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Re:MyNOR: Single board computer that uses a single NOR gate ... by garmaine on Tuesday November 24, 2020 @04:22AM (#25196740)
...but that's exactly the claim, restated.
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Re:MyNOR: Single board computer that uses a single NOR gate ... by pmiller2 on Tuesday November 24, 2020 @05:02AM (#25197011)
Not really. It's completely trivial, if extremely slow (which the article acknowledges) to emulate an ALU in software, with access to a single, universal hardware gate. Why don't they just say "we put a NOR gate on a chip, then added all this other stuff (RAM, boot EEPROM, etc.) to make it function as a computer." That would, at least, be a non-misleading statement of the claim.
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Re:MyNOR: Single board computer that uses a single NOR gate ... by magicalhippo on Tuesday November 24, 2020 @03:58PM (#25202940)
Yes, it's a "Single board computer with 20 ICs, and a single-gate ALU".

To me it's not really an ALU either, since the NOR gate doesn't really do the job I expect from an ALU.

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Re:MyNOR: Single board computer that uses a single NOR gate ... by garmaine on Tuesday November 24, 2020 @04:16PM (#25203081)
That’s how I interpreted the OP though... I really don’t know what you were reading into it.
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