MyNOR: Single board computer that uses a single NOR gate as its ALU

Re:MyNOR: Single board computer that uses a single NOR gate ... by dvdkhlng on Tuesday November 24, 2020 @03:28AM (#25196453)

I think the idea is that you use registers and apply the NOR gate multiple times. In this sense the NOR gate is universal, while an OR gate nor a XOR gate are neither universal.

I.e.

  XOR(x,y) = NOR(0, NOR(NOR(x,y), NOR(NOR(x,0),NOR(y,0)))))

(maybe not the most minimal version and maybe even wrong)

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Re:MyNOR: Single board computer that uses a single NOR gate ... by ant6n on Tuesday November 24, 2020 @04:36AM (#25196820)

Fun logic tongue twister: Neither an or gate nor an xor gate are universal

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Re:MyNOR: Single board computer that uses a single NOR gate ... by apetersonBFI on Tuesday November 24, 2020 @08:27AM (#25198214)

Any expression or series of gates of only ORs has the non-decreasing property, changing an input from 0 to 1 can never change the result from 1 to 0. So you can't implement any gate that needs that using ORs.

Similarly, any collection of XOR gates is simply a summation mod 2.

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