Multi-Function Logic Gate

My first Minecraft-related video on Youtube showcases a "Multi-Function Logic Gate", which is a compenent made out of Redstone (a semiconductor-like material in minecraft) with which simple computing devices can be built.

This particular component was designed in response to considering all of the operations that an ALU (the calculator portion of a computer) would have to perform, and realizing that due to DeMorgan's Law, many of the "Bitwise Logical Operations" (comparing A1 with B1, A2 with B2, etc...) were very similar to each other.

DeMorgan's Law states that the logical functions AND, NAND, OR and NOR can all be converted into each other by selectively inverting the Inputs or Outputs of the function.
not( A AND B ) = A NAND B
(notA) AND (notB) = A NOR B
not( (notA) AND (notB) ) = A OR B

Another logic-gate, "XOR" or "Exclusive OR" (which is very similar to the sense of the word "or" in the English language) can be used as a "Selective Inverter" to either let a signal through normally or to invert it at the flick of a switch. I placed an XOR at the Inputs and Output of each unit (3 per unit) so that I could use this "Selective Inversion" property to convert the NAND gate at the core of my device into 3 other Logical Functions.

I added the "Disable B input" control-point to my gate when I read somewhere that ALUs ought to have an "Invert" function as well, and thought: "Heck, what could possibly go wrong with that?"

Category:

Gaming

Tags:

• Minecraft
• redstone
• logic
• gate
• function
• computer
• CPU
• ALU
• electronics
• video game

[ExoVampire]

Hey Hans. Would you mind if I showed you my Multi rapid pulse?

[HansLemurson]

@ExoVampire

"Multi rapid pulse"? What's that. Does it have anything to do with a Logic Unit?

[iammrhellohowareyou]

Nice! woulnt this be like an 4 bit logic- based ALU? becouse most of the functions of an ALU would be to and or xor nand, all of that jazz.

[HansLemurson]

@iammrhellohowareyou

This would be a "Logic Unit", but can't by itself to arithmetic. It's true that if I combined it with a bit-shifter I could do addition by doing multiple passes of AND and XOR, but this particular device can't do XOR. I've made a Universal logic gate in November which can do all 16 though. I'm currently working on a CPU which uses an ALU that can do addition, subtraction, shifting and all 16 logical operations, but only 4 of them are useful.

[Cool12309FromRoblox]

The false was made by forcing all wires on and then inverting the output, right?

[HansLemurson]

@Cool12309FromRoblox

Yes, before the addition of Pistons, that was the only way to force a line off; force it to 1 then invert. With pistons, you have the option of a more straightforward disconnection if you want by removing blocks from next to repeaters, or by cutting wire running up a step. The latter is quite useful since it lets you cut a signal without adding any additional delay to the wire it's running through.

[ExoVampire]

@HansLemurson It's a rapid pulse, but it have multiple outputs from torches (-:

It is based on trapping a switching circuit.

[DaKaz1990]

now some xor, toggle, and pulsar capability and that thing would be the shiz

[LizTaylorsGhost]

This is really remarkable stuff, honestly remarkable. I've watched this one and the others since discovering your channel and its astonishing that you had the patience and wherewithal to set up devices like this.

[batmanbugscanfly]

next time can u please upload a schematic :P