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MyNOR: Single board computer that uses a single NOR gate as its ALU
11–20 of 70 posts
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#12It is possible to build a CPU without a single gate: http://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents/...
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#13This reminds me of Dave Taylor's idea for "pinky processors". These were similarly minimal, relying on conditional branches to do much of the work. Taylor thought massive numbers of these clocked at high frequencies would deliver more computation than complex high-IPC processors. He was wrong, as the failures of the Pentium 4 and AMD's Bulldozer would later demonstrate, but at least he was ahead of his time.
Unlike Taylor's ideas, this MyNOR actually exists in the real world, which is all the more impressive considering how impractical it is.
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#14Earlier quoted context omitted.
Yes, but this thing advertises that it uses a single NOR gate as an ALU.
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.
False advertising, then, IMO.
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#15I wonder how this ALU works. From what I remember ALUs use lot of XOR gates because an adder is simply a network of XOR gates with carry propagation. How could a NOR gate do one bit addition? Add two bits ... XOR ... NOR 0 + 0 = 0...........0...........1 0 + 1 = 1...........1...........0 1 + 0 = 1...........1...........0 1 + 1 = 0...........0...........0
The nor gate (like nand) is a universal gate. You can implement all the other gate with a combination of nor gate. See https://en.m.wikipedia.org/wiki/NOR_logic#XOR for example.
Not with a 'single NOR gate'.
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#16This is very impressive, especially the add ons like the calculator and Lcd, show how much work can be done with 2600 instructions per second when things are highly optimized.
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#17It's obvious a lot if work went into the project and I salute the creator.
This is a computing device made out of 74 series chips. I wonder when I'll see a computing device on HN made out of discrete transistors, capacitors, etc
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#18It's obvious a lot if work went into the project and I salute the creator. This is a computing device made out of 74 series chips. I wonder when I'll see a computing device on HN made out of discrete transistors, capacitors, etc
There are several, but this one is my favorite:
This was made from a netlist that was reverse engineered from microscope images of the 6502 die, and I think uses a roughly similar die layout. It uses discrete transistors and a handful of transistor array ICs (because you need an exposed "body" pin in order to make a functional pass gate).
Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#19What sort of simulator is required to go from “running” to ordering a prototype board 26 days later?
I had assumed physical breadboards and wires and chips were always necessary to prototype...
2019-11-02 The first version of the MyNOR simulator is running. The circuit works!
2019-11-17 I have finished the work on the microcode. I added support for MyNOR to my cross-assembler myca.
2019-11-28 PCB layout completed. A friend told me about JLCPCB, so I ordered the prototype board there.Re: MyNOR: Single board computer that uses a single NOR gate as its ALU
#20Earlier quoted context omitted.
The nor gate (like nand) is a universal gate. You can implement all the other gate with a combination of nor gate. See https://en.m.wikipedia.org/wiki/NOR_logic#XOR for example.
Not with a ' single NOR gate'.
Yes .. if you feed its output to its input on the next cycle.