vas-y, viens, on recrée un ordi dans Minecraft — Transcript

Learn how to build an 8-bit computer in Minecraft using redstone circuits and logic gates, explaining binary math and computer architecture.

Key Takeaways

Binary logic and math form the core of all digital computing.
Redstone in Minecraft can simulate real-world electronic components like logic gates and adders.
Building an 8-bit computer involves chaining logic gates and handling carry bits in addition.
Complex operations like multiplication and division can be broken down into simpler arithmetic operations.
Understanding computer architecture is accessible through hands-on projects like this Minecraft build.

Summary

The video explains the basics of electricity and binary (0 and 1) as the foundation of digital computing.
It introduces redstone in Minecraft as an analog to electrical circuits, capable of representing binary states.
The concept of binary numbers and counting using powers of two is explained in detail.
Basic logic gates (OR, AND, XOR) are built using redstone torches to perform binary addition.
The video demonstrates building a full adder circuit to add two bits with carry handling.
Chaining multiple full adders allows the creation of an 8-bit adder capable of adding two 8-bit numbers.
The video touches on how multiplication and division can be implemented using addition and subtraction.
It compares redstone torches to real-life transistors and explains their role in logic gates.
Further components like registers, decoders, and an ALU (Arithmetic Logic Unit) are introduced for building a functional computer.
The video encourages learning through building and collaboration, highlighting the educational value of Minecraft for understanding computing.

Chapters

Full Transcript — Download SRT & Markdown

Speaker A

Electricity. Its presence and its absence. Zero. One. That’s all we need. Every notification, every app, every game, every message, every story, every song, every selfie, every site, every call, every single pixel on your screen, it’s all just a matter of zeros

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and ones. In Minecraft, there’s this powder, redstone. It can also be on or off.

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Zero or one. You know what that means? We need to figure out how to do math with just that.

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We need to figure out how to do math with just that. If we can do math, we can do anything.

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If we can do math, we can do anything. Because everything can be represented with numbers.

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The color of a pixel? Just three numbers. The intensity of red, green, and blue mixed together to get what you see on the screen.

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An image? Just a collection of pixels. So, a bunch of numbers. A sound? It’s a wave.

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And a wave is just a sequence of numbers over time. If we can do math, we can do everything.

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So first, we need to figure out how to create numbers. The problem is, we only have two values.

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Zero or one. So what? We humans only use ten values. And that’s enough to count to infinity.

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Well, nothing changes. We’ll do exactly the same thing. When you count, you start with all the digits we know in order.

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Then, when you run out, you start back at zero. And you put a 1 in front.

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And repeat. You count. Then you add a 2. And repeat. And so on, until you reach 99.

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You add a 1 in front, reset everything else to zero. And you go again.

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Over and over. In the end, each individual digit we count represents the number of powers of ten in our final number.

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Here, for example. This number is 3 times 10 to the power of 0 plus 2 times 10 to the power of 1 plus 1 times 10 to the power of 2.

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We’ll use the same logic with our 0 and 1. We start at zero. Then 1.

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Then reset everything to zero. And add a 1 on the side. Then we have 1 1.

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Then reset everything to zero. And add a 1 on the side. And so on.

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This time, each individual digit represents a power of 2. Not 10. Since we only have two possible values this time.

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Each individual digit is what we call a bit. So this number is 0 times 2 to the power of 0 plus 1 times 2 to the power of 1 plus 1 times 2 to the power of 2 plus 1 times 2 to the power of 3.

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That makes 14. And now we can represent numbers. The limit is simply the number of circuits we’re willing to use.

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With 4 circuits, we have 4 bits. And we can count up to 2 to the power of 4.

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Which is 16 in decimal. We’ll use 8 bits. We can count from 0 to 255.

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That’s 256 values. So we’re going to build an 8-bit computer. The one you’re watching this video on is probably a 64-bit computer.

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Which can count up to... This number. Yeah, it’s gigantic. But that’s a lot of connections to manage.

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Way too many to build in Minecraft. Just 8 is already enough. Now, doing math with just one number is not really possible.

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So we’ll add a second one. And now, we’d like to add them together. That would already be great.

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Okay, let’s calm down and start with just two 1-bit numbers. Not 8. Always start with the simplest case to understand.

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Binary addition, once again, is just like decimal addition. 0 plus 0 equals 0. 0 plus 1 equals 1.

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1 plus 0, same thing. But 1 plus 1 goes beyond our possible values. So we do what we do in decimal.

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We put a 0 and carry a 1. That makes 10. And that’s correct. 1 plus 1 does indeed make 2.

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With our two bits, there are three possible outcomes. 1 0, 0 1, or 0 0.

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Let’s represent them in redstone in Minecraft. A starting circuit for each of the two numbers we’re adding.

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And an output circuit that will give the result after the addition. Let’s add lamps to better visualize the circuits that are on or off.

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The lamp on the right should light up only if one of the two input circuits is active.

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If both are active at the same time, it stays off. Same if neither is active.

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For the lamp on the left, it only lights up when both input circuits are active.

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What we want is to achieve a precise result based on a certain logic that depends on the input data.

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In other words, we want to create what we call logic gates. A logic gate takes two input circuits and based on their value, produces a precise result.

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So let’s pause our addition project and build these logic gates. Let’s start with the OR gate—it’s the simplest.

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We want the result to be 1 if at least one of the two inputs is 1.

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To do this, simply connect the two inputs together and lead them to the output.

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This way, no matter which input is activated, the result is 1. Unless both inputs are 0.

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Now the AND gate. To build it, we need a new item: the redstone torch.

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This torch activates a circuit when left on its own. But if the block it’s attached to is connected to another active circuit, the torch turns off.

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Basically, it allows us to invert an input value. To make an AND gate, we place a torch here and connect it to two other torches.

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These two other torches power the block it’s attached to. So the main torch stays off.

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The only way to turn it on is to turn off both top torches. And that only happens when both input values are active, meaning they’re both 1.

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And there you go, our AND gate. In real life, a redstone torch doesn’t exist.

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We use something called a transistor. Three pins. The collector, the base, the emitter. If you place it in a circuit and don’t power the base, the transistor won’t let current through.

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But if you power the base, it allows current to flow. It’s not exactly the same as our torch, but it’s quite similar.

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That’s how we create logic gates in real life. And that’s why there are so many transistors in your computer.

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Okay, back to Minecraft. Another super-useful logic gate: XOR. The result is 1 only if one of the two inputs is active.

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And we build it like this. If no input is active, the two torches here turn on, cutting the current to the final two torches.

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Which means the result is 0. If one input is on, part of the circuit turns off, allowing one of the final torches to stay lit.

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And if both inputs are on, this torch can now light up and cut off the current to the final two torches.

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Alright. Next gates. We’ve got 3 left. NAND, NOR, XNOR. And as the "N" in their names suggests, they’re just the AND, OR, and XOR gates, but inverted.

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And as mentioned earlier, to invert a circuit, just add a redstone torch at the end.

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So we take our old gates and simply add a torch at the end. And now we’ve got all possible logic gates.

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Back to our addition. We said we wanted the lamp on the right to light up only when one of the two inputs is active.

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We need the XOR gate for that! And for the lamp on the left, it’s the AND gate!

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Now we have a circuit that can add 2 bits. Alright, when there are more bits, things get a bit more complicated.

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But not by much. We just need to account for the carry from the previous calculation.

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So now we have 3 inputs: the top bit, the bottom bit, and the carry from before.

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And the trick is to do the calculation in two steps. First, we add the two main bits using our XOR and AND gates.

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Then we take the result of that sum and add it to the previous carry bit.

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So, another XOR and another AND gate. And to get the global carry, we combine the carry from the first calculation with the second one using an OR gate.

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You can test it—it works. We’ve just created what’s called a full adder. Now, if we go back to our two 8-bit numbers, we just need to chain 8 full adders together, one after the other, to perform the calculation.

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Each time, the carry from the previous calculation is fed into the full adder for the next two bits.

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Personally, I designed it like this. Yeah, it’s a bit weird, I know. But here, I combined everything using verticality to save space.

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And check this out. I can now do 4 plus 3. And it gives me 7.

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We’ve got a calculator. Well, not quite. What about multiplication, subtraction, division!? Okay, multiplication is just a bunch of additions.

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So technically, we already have it. Division can be done using subtraction. By counting how many times we subtract one number fr

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So, the only thing we’re missing is subtraction. And then we can do all the math in the world.

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And it might sound crazy, but we can perform subtraction using addition. This is thanks to the fact that we’re limited to 8 bits.

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Because what happens when we go beyond 8 bits? It loops back to 0. We’re essentially in the same situation as a 60-second timer.

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If it’s at 30 seconds and I want to subtract 20 seconds, I can do it normally via subtraction.

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Or, I can add in such a way that it makes a full loop and ends up in the same place.

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That’s called modulo. With our adder, we can do the same thing in 8 bits.

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7 minus 6 is the same as 7 plus 250. Look, if I do it, I still get 1 as the result.

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Just like if I had done the subtraction. The question is, how do we go from -6 to +250?

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Well, you just take the binary number you want to subtract, invert it, and add 1.

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In other words, when you want to perform a subtraction, you do an addition while inverting the bits of the number to subtract and setting the initial carry value to 1 to add 1.

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And now we can do subtractions. Alright, let’s go back to our original two 8-bit numbers.

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We’re going to connect them to all the logic gates so we can execute operations as needed.

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But we’ll also connect them to our adder, which can now also perform subtractions. We add controls on the side to select which operation we want to perform and a spot where the result is clearly displayed.

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And here’s what it looks like. I can do 5 plus 3 or 5 minus 3 if I want, or even 5 AND 3 and I get the result.

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With 8 bits, I can do arithmetic and logic. We’ve just created an Arithmetic Logic Unit.

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An 8-bit ALU. Yes, mine is messy. You’ll find much more efficient designs online. I recommend MattBatWings if you want to improve your redstone skills or build a Minecraft computer.

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Without him, I probably wouldn’t have been able to make this video. But what we’ve accomplished here is, I think, the perfect answer for people who tell me, “I want to code, but I don’t know where to start.” Well, I didn’t know where to start with this computer either.

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You see what it’s supposed to look like online. There’s redstone everywhere, it’s gigantic, it looks impossible, it’s intimidating.

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But if you go step by step, starting with the basics, you realize you’ve gone from a single redstone wire to logic gates to a complete ALU.

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And it wasn’t that hard. It’s the same with coding. For example, if I told you to hack a website, you’d have no idea where to start. That’s normal.

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You have to start at level 0, with basic vulnerabilities to understand the fundamentals. Then move to the next level until you have solid knowledge.

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“But how do I learn the basics? I don’t know where to look!” Well, I’ve got something for you.

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The Cyber Ninja CTF. An online competition made for high school students where you solve challenges in programming, ethical hacking, and OSINT to capture points.

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It lets you learn in a fun way with a space-themed storyline, and there’s also a community aspect.

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You’re not alone. If you’re stuck, you can ask for help from others. Make some friends.

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Make some friends. Events like these are perfect because they give you a goal. You’re learning with a purpose—it’s motivating.

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And if you do well, there are over €1,500 in prizes to be won. It’s organized by students at Oteria.

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A five-year school dedicated to cybersecurity that will guide you through the challenges to make sure everything goes smoothly.

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Registration is free and open until January 31. So don’t wait—there are already 150 students signed up.

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The first round is on February 1, and the top 60 will meet at Oteria’s campus on March 29 for the grand finale.

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I’ll leave the link in the description, and they also have a Discord so you can be part of the community.

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Trust me, hackathons like this are the best way to stay motivated and see if programming is for you.

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So go for it! Okay, back to our ALU. The problem we have is that the result… well, we’re not doing anything with it.

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Once we move to the next operation, it disappears. We don’t want it to disappear.

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We want to be able to save it. We need to create memory. The first problem we need to solve is: How do we save the state of a circuit?

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Because right now, it disappears as soon as I turn it off. The answer? Two repeaters placed like this.

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When this one is on, the current here can’t flow. But when I turn it off, the current flows.

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Then if I activate it again and turn off the other one, bingo! We’ve saved whether our circuit was on or off just before.

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What we need is a continuous current that lets us remember what the state was before.

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And if we want to change the saved state, we just turn off this current for a brief moment.

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We can do that with a torch and a button. Here, we’ve saved that this bit was 0.

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I want to change it. I press the button, and boom! It’s saved. We’ll stick to this principle, but now we’ll do it for 8 bits that I can save.

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Here, I select a number. Then if I press the button, it’s saved. And what we’ve built is the equivalent of a CPU register that we use when coding in assembly, for instance.

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But one register isn’t enough. So we’ll copy this several times to have multiple registers.

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To store more results, more data—we’ll make 7 registers, specifically. Why 7? Because I decided so.

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We just need a way to select which register we want to save our result into.

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For that, we need 3 bits to count from 1 to 7. And what we want is that, based on the number I select, the current stops for only one register to allow writing.

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So we’ll link all our registers to these 3 bits. And then, for each register, depending on its number, we’ll add torches in the right places.

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Register 1, for example, just has a torch at the first bit. This way, if I select the number 1, only this bit is activated.

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And the torch for register 1 turns off, just as we wanted. If I keep bit 1 active and add bit 2, register 1 turns back on because we connected it accordingly.

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But register 3 turns off because I added 2 torches: one for bit 0 and one for bit 1.

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Ultimately, the placement of the torches that power each register corresponds to its binary number.

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This circuit that selects one output based on an input number is called a decoder.

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This one is a 3-bit decoder. Now, if I connect the result from the ALU to all this, I can select a register and save it there.

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But saving variables we can’t use isn’t very practical. We’d like to use our registers to feed our ALU.

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For example, deciding to add the value in register 2 to the value in register 1 and save that in register 3.

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So, we need to be able to read each register. And to select the register we want to read, we’ll do the same as we did to select the register we want to write into—with a 3-bit decoder.

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But what we want is that when there’s no current, the register is read, sending the saved bit values.

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To achieve that, we need a comparator. This item in Minecraft compares two circuits, and if the bottom circuit is stronger than the side one, the current flows.

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Otherwise, it doesn’t. That’s exactly what we need. We connect each bit of the register to a comparator.

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And we connect this comparator to another circuit constantly powered by a redstone torch. When we turn off the torch, the comparator lets the current from the register pass through.

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And now, we can read our registers. We’ll just make it so we can read two at the same time by duplicating each register.

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Why did we do that? Because our ALU has two inputs. So we need two registers to feed it.

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Thus, we need to read two. We connect everything to the ALU, and look at what we have.

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Our ALU, our registers, and data buses that let them communicate. And now, the earlier diagram has become reality.

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But for now, I have to do everything manually. I select the ALU operation manually.

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I select the register to write to manually. I select the input registers for the ALU manually.

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We want to program all this! And honestly, we’re not missing much to get there.

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We can select a write register via a binary number. We can select two read registers via two more binary numbers.

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But we can’t select an ALU operation using a binary number. Right now, I have to choose using the correct lever.

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We need to change that. Everything should be selectable via a binary number. And why would that help automate things?

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Why would that help automate things? Shut up and let me cook. Alright, it’s not very complicated.

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We’ll simply assign a number to each operation we can perform. In total, this would require 3 bits.

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But we’ll use 4 bits. Because in the future, I’ll add 4 more operations. We can now build a component that, based on a given number input, activates the correct operation.

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This is done using a 4-bit decoder, this time. We call it the control ROM.

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This is where all the instructions a CPU can execute are stored, along with their associated numbers.

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If I input 1, the ROM activates addition on the ALU. And now, if I want to add register 1 and register 2 and store the result in register 3, I can represent this entirely using binary numbers.

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0001 0011 0001 0010 These binary numbers are circuits. We take the first 4 circuits.

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Connect them to the ROM to select the correct operation. Take the next 4. Connect them to the write register address.

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Take the next 4. Connect them to the first input register address. And take the last 4.

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Connect them to the second input register address. And we’ve performed the addition. If I want to subtract, no problem.

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I just change the start to 0010. And it’s sent directly to the ROM, which selects the subtraction mode on the ALU.

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And bam! My new instruction is executed. Do you see the potential here? Before continuing, I added one more instruction.

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Load. To load a number into a register without going through the ALU. When we use this operation, a little switch changes our circuits to allow it.

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Okay, let’s recap. I can write a program, then translate it into binary. Or what we call machine code.

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Each binary number, I can execute. As we saw earlier. Now we just need to do it for every line of code.

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We’d need to save each line of the program, then read them one by one.

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Save. Read. We’ve already done that! They’re registers! So I’ll create 64 registers, this time 16 bits, where I’ll store my binary code.

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Line 1, line 2, line 3. And it can go up to 64 lines of code.

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Then, if I select register 1, it reads it. And it executes the first line of my program.

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I select register 2, it executes the second line. And so on. We’re so close!

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We just need to automate two things. First, the writing of each line of code into each of our special registers.

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Because right now, I manually place the bits by setting blocks. So I created a Minecraft assembler.

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A Python program that takes a human-readable program, transforms it into machine code, and generates Minecraft commands to automatically place the redstone blocks that configure my 64 dedicated registers.

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It’s kind of like the punch cards of the old days. First problem solved. The second is that I have to manually select register 1, then 2, then 3, to execute my code.

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We’d need a counter from 1 to 64, connected to a clock. When the clock cycles, the counter increases by 1.

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When the clock cycles, the counter increases by 1. When the clock cycles, the counter increases by 1.

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And selects the next line of code. That line is read and executed with the other components of our computer, as we’ve already seen.

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Then the next clock cycle repeats the process. Alright, let’s first build the clock. It’s simple.

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Repeaters with a comparator looped on themselves. We send a pulse, and watch. It sends current at regular intervals. Now the counter.

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It’s not complicated; it’s just an adder. We’ve already built one. You start with the number 1 and the number 0.

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Then the result replaces the 0, when the clock pulse arrives. Then it repeats with 2, then 3, and so on.

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Alright, we have everything now! But before testing, I just added 3 more instructions. HALT, to stop the clock and thus the program.

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JUMP, to replace the value in our counter. And finally, JUMP IF, which selects a line of code if the last result from our ALU equals 0.

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Basically, this will allow us to create WHILE loops. To make this work, we just need to add a flag to our ALU.

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A small bit that activates if the last result is 0. Then our operation checks if this bit is active, and if it is, it changes the value of our counter to select the desired line of code.

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Alright, everything’s ready! Let’s test it with a program. Remember the multiplication we can do with additions?

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Well, we’re going to write that algorithm. And calculate 6x4. Once our code registers are set up, we can start the computer by activating the clock.

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We’ll analyze each component, and it’ll allow us to summarize everything while watching our computer in action.

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First, the counter, which handles selecting the line of code to execute. There’s a for loop executed 4 times in our program, and you can see it if you watch the counter values.

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This counter is connected to our code registers, which contain each line of our program.

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And if we stand by the output of this component, we can see the machine code for each line being output one by one.

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The bits of this machine code are then sent to the other components via the data buses, and I find it so satisfying to watch from above.

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You can clearly see the loop repeating constantly. Counter to code register, to data bus, to other components.

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Next stop, the ROM. Next stop, the ROM. That’s where the operations are selected. And you can see that’s exactly what happens as we go along.

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This guy here? That’s the ALU. It does the calculations. This guy here? That’s the ALU. It does the calculations.

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And here we’re next to its output. And finally, the registers, where we store our variables.

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Above, you have the value we want to save in a register, and below, the selection of which register to save it to.

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All in all, doing 6x4 took about 2 minutes. Yeah, this PC is pretty slow.

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All in all, doing 6x4 took about 2 minutes. Yeah, this PC is pretty slow.

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But it works. Here, we see the HALT operation has occurred, and nothing else is happening.

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Our program has finished running. It’s time for the moment of truth. Our program has finished running. It’s time for the moment of truth.

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If we select register 3, we should see the result of the 6x4 calculation displayed.

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And we get 24. We wrote an algorithm, and we executed it in Minecraft. We built a freaking computer in redstone.

Speaker A

Thanks for watching the video. It took a lot of time to make, and I’m the only one behind its creation.

Speaker A

So don’t hesitate to subscribe, like, and comment—it means a lot. Oh, and if you want more content, I now have a second channel too.

Speaker A

Oh, and if you want more content, I now have a second channel too. I’ll leave a link in the description if you’re interested.

Speaker A

I’ll leave a link in the description if you’re interested.

Topics:Minecraftredstonebinarylogic gatesfull addercomputer architecturedigital electronicstransistor8-bit computerprogramming basics

Frequently Asked Questions

What is the purpose of using redstone in Minecraft for this project?

Redstone in Minecraft acts like electrical wiring that can be on or off, allowing the creation of binary logic circuits to simulate real computer components.

How does the video explain binary addition using logic gates?

The video breaks down binary addition into simple cases using XOR and AND gates to handle sum and carry bits, then combines these into a full adder circuit.

Can this Minecraft computer perform operations beyond addition?

Yes, the video explains that multiplication can be done through repeated addition and division through repeated subtraction, extending the computer's capabilities.

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