I have watched your complete playlist on construction and working of the 8 bit computer. It provided me deep understanding and conceptual clarity of digital electronics and microprocessors. Thank you.
Ben eater needs to be awarded by a global platform. People say he is the Bob Ross of programming but I think its even more than that. I bet over the course of a generation he helped generate trillions in economic value. Millions of people have gotten jobs because of what they have been taught in his videos.
Hello Ben, i have been through all 30 videos " building an 8 bit breadboard computer" serie and have made all components but cannot follow you here since i can't find control logic and instruction register videos . I think we should see these two videos at the end of the 30 serie just before these two "programming" videos. This serie is SO well done and so exciting . I'm waiting for these videos to complete my computer and be able to program it like you do here. Thanks!
M. Sierra so? Ben gets the notifications about any comment, period. Posting this comment on the video that came out a couple months ago in 2018 is no more effective than this...
So in your machine, you basically have wasted clock cycles for T5 on LDA and various instructions which need less steps. But is there a way to skip the steps that aren't required and start at T0 for the next instruction?
Very nice.. Like the layout of the breadboards. You really did good showing how it works by stepping through it and giving detailed information. Do you have schematics for it?
just a question, are RAM and PROGRAM memory the same in that computer, so the program could change in the fly his own code? leading to unpredictable results in most of the cases, but could it be used to show something cool?
It's like that on x86. Programs are run from ram. The difference is that on x86, the computer loads the program into memory for you and then executes it, and has memory protection, so the code in memory can't be modified by the program. (In modern os')
Suddenly I understand how a punch card could be a program, without looking it up specifically. And how a hard drive can act in the same way, so we can load programs without manually physically doing it. Purely editing by software is so, so much nicer, my mind feels all bendy right now. Abstraction is amazing. I think I'll stick to higher level programming though!
how do you sync up the enable out and set in wires. like if the enable out control wire goes off the set wire may save nothing into the appropriate register. hope my question makes sense.
It would have been helpful to have had another note onscreen listing all the instructions, which would have made it more intuitively understandable why e.g. LDA is 1 and HLT is 15, etc. I know that was already (DIP-switch-)programmed into memory at this point, but it would have explained the bits that do show up on the memory contents and instruction register LEDs. The memory addresses 4 and 5 are obvious here, but the instruction bits are not. Similarly, it would have helped to also have included a legend for the control word bits.
The control word is telling which registers to Set and which to Enable. All the registers read off the same data bus, so for any given instruction, only one register should be Enabled to output it's contents to the bus, and typically only one will be Set to store the bus value. For example, the LoaD A instruction at 4:47 in the video, for the t4 micro-instruction, Enables the memory address to output to the bus, and Sets the A register to the value on the bus. So the control word isn't incrementing, so much as it's dictating what each register should do.
The answer lies in the basic understanding of Flipflops (not sure how he did it, but that's how it's usually done) and its difference to a latch. A LATCH takes over the input data as long as 'high' is on the enable pin, a FLIPFLOP only takes over the input data at the low-to-high edge of the enable pin. It happens so fast that the output of the flipflop changes AFTER the write has happened, and then when the propagated feedback looped data arrives at the FLIPFLOP, it won't read it any more. At least that's the simplified version explanation. Hope that made it clear. Greetz
has Ben published a component list? I've got everything up to the RAM IC's but don't know what he uses for the large packages at the bottom, for the Output/Address/Control Word Registers
When you add the data in A and B and then store that in A, what's stopping the new value in A from automatically being added to B and then stored again in A (overwriting the previous data, then adding to B and continuing in a loop forever)?
I've been watching you series for a while, and are going to make my own version, but I'll be using 8 bit instruction set, 16 bit addressing, using bank switching. Here's a translation of you program in this video LDZ 0x8 LDA LDZ 0x9 ADD OTB HLT
hello i would like to say i am 12 years old and the only one in my class that loves arduino microcontrolers and robotic c , python, c+, c++ , and command line on windows i am imprest with this computer were did you come up with this intestine design?
This thing gave me an idea. I love it. I'm thinking of making my own computer, whose only purpose is to be the foundation of a simulation world that is inhabited by neural networks, and their goal is to attempt to communicate with me. But they would have to pass a bunch of tests(in their world) before they can meet with me. and maybe i'll add the ability to connect a monitor and controller so that I can walk around and take a look at things and interact and stuff.
+Rasmus0909 Oh yeah, I woke up about a week later. I have this idea of making a computer that has one purpose and that's to have hardwired neural nets control a simulation. I have one vague idea just floating around in my head, but I can't quite figure out how to make it happen. For now I'm thinking that I have to use a mixture or AC and DC currents but other than that I'm just gonna have to what Anthony Khodanian suggests and code a simulation.
+Anthony Khodanian Yeah, I know how to do all that. I've just had this idea of making a hardwired specialized system. But for now I think that I'm just gonna make a small Operating System dedicated to the task. This way I could try and utilize the full power of the computer without having to worry about how many microsoft services I have running in the background.
The memory addresses are four bits because each instruction is within one byte, which is 8 bits, so there is four bits for the instruction, and four bits for the address. He could have 8-bit addresses, but he would have to rebuild the entire computer.
yeah. the "explaining" of how this computer works is wrong, and the only answer this computer is able to give is 42 because it's the answer to life, the universe and everything.
The most costly part with such a project would normally be the RAM, but in this case it is just 16 bytes, so this isn't a problem. I am currently making a 16 bit computer with 10 bit addresses, so that means 2048 bytes and in my case that would be the most expensive part, if I decide to actually install all 2048 bytes, which I probably won't do.
So every singular instruction takes 6 cycles? Thats... longer than i thought o_O Is this still the same for modern 64bit CPUs? For the question what would happen if you could advance beyond the HLT: It would read the 14 (00001110) as an instruction (in this case 0000 NOP with parameter 1110) so nothing would happen. Next is the 28 (00011100), which means 0001= LDA with 1100=12, so it would read memory address 12 into register A (which is probably 0b0). After that, everything is 0b0, so just NOP commands.
Two things happen in modern CPUs: ⅰ) Processing is pipelined. For example, assuming each instruction takes six phases, a CPU would be executing six instructions at once but each would be in a different phase. While one instruction is finishing, instruction four steps behind is being fetched and an address if instruction five steps behind is being loaded. With this, even though each instruction takes six clock cycles, an instruction is executed every cycle. ⅱ) There are multiple ALUs which means that CPU can perform multiple operations at once. If one instruction sums two registers and another sums some other registers, those two operations can be carried out in parallel. This is of course simplified, and there are multiple things that complicate the issue such as: ⅰ) Data dependencies: ‘a = a + b’ instruction followed by ‘a = a + c’ cannot be executed in parallel since result of the latter depends on the result of the former. To mitigate, CPU will try and rearrange instructions and execute them out of order. For example, sequence ‘a = a + b; a = a + c; d = e + f’ can be rewritten as: ‘a = a + b; d = e + f; a = a + c’. ⅱ) Control dependencies: conditional jumps mess with the pipeline since what next instruction needs to be executed depends on the result of the current one. This means that it’s not possible to know which next instruction to fetch before the current one finishes. To mitigate, CPU will try to predict which branch is taken and execute instructions from that branch. If later the prediction turns out to be false, all the calculations will be discarded. x86 architecture also includes conditional move instructions, for example ‘set EAX to 10 if carry flag is set’. This changes control dependency into data dependency which has lower penalty on misprediction. ⅲ) Different number of different execution units: A CPU might be able to perform two additions at once but may be unable to perform two multiplications at once just because it has some components duplicated but others not. Similarly to ⅰ), CPU may try to mitigate by rearranging operations. And I didn’t even mention memory yet. A memory read can take dozens or even hundreds of clock cycles. ‘How much clock cycles an instruction takes’ is nowadays a very complicated question to answer and you probably can count number of people who know the answer to that on your fingers.
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Interesting vid.
Imagine how much of hardware logic is going through your computer/phone, at super fast speed right now.
Your videos are plain addictive!
I have watched your complete playlist on construction and working of the 8 bit computer. It provided me deep understanding and conceptual clarity of digital electronics and microprocessors. Thank you.
Ben eater needs to be awarded by a global platform. People say he is the Bob Ross of programming but I think its even more than that. I bet over the course of a generation he helped generate trillions in economic value. Millions of people have gotten jobs because of what they have been taught in his videos.
Hello Ben, i have been through all 30 videos " building an 8 bit breadboard computer" serie and have made all components but cannot follow you here since i can't find control logic and instruction register videos . I think we should see these two videos at the end of the 30 serie just before these two "programming" videos.
This serie is SO well done and so exciting .
I'm waiting for these videos to complete my computer and be able to program it like you do here. Thanks!
You do realize this video was posted 2015?
M. Sierra so? Ben gets the notifications about any comment, period. Posting this comment on the video that came out a couple months ago in 2018 is no more effective than this...
Vary nice machine language program example executing in single step mode and explaining control logic of the CPU operation
This is seriously the most interesting series I've watched in many moons. I've been intently watching and just amazed. Thanks for doing this.
Has Microsoft tried to install Windows 10 on this Computer yet?
And are you using the 74181 as the ALU?
I Love Minimal Computing
Joy of Lego ko
Can I please get the schematic and parts list for this? I would like to build one as a school project.
I don't think I've ever "rewound" a video so many times just to see some lights blink. Neat stuff!
Truly wonderful, putting theory to actual in practice and making a working solution.
These are incredibly helpful!! Thank you for taking the time to make these videos. Your demonstrations are very well paced and informative.
How on Earth can this only have 40k views???!
niche! But rad
That is so cooool! I've always wanted to know how a computer works exactly.
Thank you for your amazing explanations and detail of the process. What you are doing is really valuable.
What RAM and ROM chips did you use? Because I'm looking for some that are also easy to program like these
So in your machine, you basically have wasted clock cycles for T5 on LDA and various instructions which need less steps. But is there a way to skip the steps that aren't required and start at T0 for the next instruction?
Great to understand how the clock speed works!! Thanks for the good work!!
This has taught me alot about control logic thank you for all of your videos about this computer :)
Brilliant. ..I am addicted to this channel!
42, the answer to everything!
Even to the question "What's 14 plus 29?"
it's called experimental error.
lol, i gave this comment its 42nd like
Lol 42 likes
Excellent explanation and great series of videos
Very nice.. Like the layout of the breadboards. You really did good showing how it works by stepping through it and giving detailed information. Do you have schematics for it?
just a question, are RAM and PROGRAM memory the same in that computer, so the program could change in the fly his own code? leading to unpredictable results in most of the cases, but could it be used to show something cool?
It's like that on x86. Programs are run from ram. The difference is that on x86, the computer loads the program into memory for you and then executes it, and has memory protection, so the code in memory can't be modified by the program. (In modern os')
brings back old memories.
Suddenly I understand how a punch card could be a program, without looking it up specifically. And how a hard drive can act in the same way, so we can load programs without manually physically doing it. Purely editing by software is so, so much nicer, my mind feels all bendy right now. Abstraction is amazing. I think I'll stick to higher level programming though!
Great computer you have there, better than a PS4
probably even runs at 1080p 60fps
It have 10 GHz processor 😂
Even my old atari was way better than PS4 or any other consoles!
yeah. show me a ps4 you can write assembly on without hacking.
That is the coolest light-show I've ever seen!
Hello Ben, i'm just wondering what power source are you using to power this computer?
enjoyed your videos and in depth explanations. Liked and subscribed. Thank you for making them
Your channel rocks! Thanks for all the work youre sharing!!!
how do you sync up the enable out and set in wires. like if the enable out control wire goes off the set wire may save nothing into the appropriate register. hope my question makes sense.
This computes gives the answer to the Ultimate Question of Life, the Universe, and Everything.
I also would love some schematics for this so I can build one.
Would be a very enjoyable project for me to do.
He actually sells kits on his website which instruct you how you would build one (i think). www.beneater.com
This is so impressive, thank you for sharing! Definitely showing this to motivate my Digital Logic students :)
It would have been helpful to have had another note onscreen listing all the instructions, which would have made it more intuitively understandable why e.g. LDA is 1 and HLT is 15, etc. I know that was already (DIP-switch-)programmed into memory at this point, but it would have explained the bits that do show up on the memory contents and instruction register LEDs. The memory addresses 4 and 5 are obvious here, but the instruction bits are not.
Similarly, it would have helped to also have included a legend for the control word bits.
is there any reason why the control word changes in that specific sequence? Could it have just incremented like the program counter did?
The control word is telling which registers to Set and which to Enable. All the registers read off the same data bus, so for any given instruction, only one register should be Enabled to output it's contents to the bus, and typically only one will be Set to store the bus value. For example, the LoaD A instruction at 4:47 in the video, for the t4 micro-instruction, Enables the memory address to output to the bus, and Sets the A register to the value on the bus. So the control word isn't incrementing, so much as it's dictating what each register should do.
With the add instruction, how do you make sure that there is no feedback loop when you store the Sum to the A registry?
The answer lies in the basic understanding of Flipflops (not sure how he did it, but that's how it's usually done) and its difference to a latch.
A LATCH takes over the input data as long as 'high' is on the enable pin, a FLIPFLOP only takes over the input data at the low-to-high edge of the enable pin. It happens so fast that the output of the flipflop changes AFTER the write has happened, and then when the propagated feedback looped data arrives at the FLIPFLOP, it won't read it any more.
At least that's the simplified version explanation.
Hope that made it clear.
Greetz
M. Sierra isn't it heavily dependent on the length of the rising (or falling) edge of the clock?
Brilliant! Very interesting and well-presented.
Hey Ben, not sure how to PM you. FYI there is someone posting this exact vid on YT with the same name. Love the content; keep it coming!
which books you referred to build this stuff and how you build this circuit thats more important can you help me to make this circuit
has Ben published a component list?
I've got everything up to the RAM IC's but don't know what he uses for the large packages at the bottom, for the Output/Address/Control Word Registers
where are micro instructions stored? what're they written in? who writes them?
Tom Riddle writes them in his diary, of course.
Sam H they are stored in the ROM memory, which is programmed manually with dip switches. See the other videos. There is one where he shows that.
you did a great series of 23 videos explaining computer work....but i can't quite find the next videos....so did you complete that series??
could you possibly make a dual core cpu and tell us how a bus and cache works?
+sasdlasokdalkfdalksfa You'd have better luck fooling around with a FPGA.
Austin Bentley i've heard about fpga chips like the spartan, could i create an emulator on one and possily hook it up to a graphics driver?
Have you found a way to emulate an FPGA that worked for your purposes?
When you add the data in A and B and then store that in A, what's stopping the new value in A from automatically being added to B and then stored again in A (overwriting the previous data, then adding to B and continuing in a loop forever)?
Cause he did alu to A register move only once
Seems to be the SAP-1 architecture if anyone is looking for it.
whats the name of the ram ic or is it a self build flip flop circuit ?
I've been watching you series for a while, and are going to make my own version, but I'll be using 8 bit instruction set, 16 bit addressing, using bank switching.
Here's a translation of you program in this video
LDZ 0x8
LDA
LDZ 0x9
ADD
OTB
HLT
Ben, this is super.
Please build a 2 or 4 bit version of this as a tutorial. That would make it make even more sense! Nice computer by the way.
The is the most beautiful thing I've ever seen in my entire life
Instead of using RAM, can I use an EEPROM to replace the RAM?
Yes, I guess so
brilliant, nice work
Do you have schematic of the computer of yours ? It's sort of fun to make...
What sort of educational background do you have? I enjoy electronic tinkering but I'd have no idea how to start on a project like this without TH-cam.
just a random question,how much voltage does this take
5v he says it another vid
BuildingBloxs yeah 5v is standard in small electronics
Can I connect it to a display? And write a simple C++ game or whatever? Could you show how to? :)
I would hope for such intelligence you are rewarded a well paying job you enjoy.
I understand! This does compute!
What are you using as a clock signal?
+Matthew Ferrie The button he's pressing repeatedly.
+Constantino Fine Art Is he using a 555?
+Matthew Ferrie I'm not sure about him, but he has done videos on 555 timer clocks. Those videos are pretty recent.
Dude this is amazing, this needs more likes.
hello i would like to say i am 12 years old and the only one in my class that loves arduino microcontrolers and robotic c , python, c+, c++ , and command line on windows i am imprest with this computer were did you come up with this intestine design?
Maybe you need to give it a few years, considering that you can't even spell correctly.
Don't be a dick.
Best explanatiom ever!
Amazing! Thank you!
Hi, great job! Could you explain how you convert the binary result 00101010 into the two 7 segment displaying "4" and "2" ?
+Sébastien PETRE I don't think he actually implemented a binary decoder to show the output, the 7-segment display already takes the input in binary...
Just do some k map...you will arrive at the answer
And that is an overview of how you compute life, the universe and everything...
Can I please get the schematics and the parts list?
Loop through all the videos. He has put the parts list in the respective descriptions.
How many clock cycles did it take to calculate 42?
It would be great to have a written discription of each clock cycle.
Three instructions, six cycles each. If you want to include HLT instruction add another three cycles.
EXCELLENT ;.........GREAT JOB . THANK YOU
This thing gave me an idea. I love it.
I'm thinking of making my own computer, whose only purpose is to be the foundation of a simulation world that is inhabited by neural networks, and their goal is to attempt to communicate with me. But they would have to pass a bunch of tests(in their world) before they can meet with me.
and maybe i'll add the ability to connect a monitor and controller so that I can walk around and take a look at things and interact and stuff.
Either you're the next Nikola Tesla or you're in for a wake-up call. Good luck :)
How about you try coding the simulation first? Or maybe learn how to code a neural network? Or, you know, code at all.
+Rasmus0909
Oh yeah, I woke up about a week later. I have this idea of making a computer that has one purpose and that's to have hardwired neural nets control a simulation.
I have one vague idea just floating around in my head, but I can't quite figure out how to make it happen.
For now I'm thinking that I have to use a mixture or AC and DC currents but other than that I'm just gonna have to what Anthony Khodanian suggests and code a simulation.
+Anthony Khodanian
Yeah, I know how to do all that. I've just had this idea of making a hardwired specialized system.
But for now I think that I'm just gonna make a small Operating System dedicated to the task. This way I could try and utilize the full power of the computer without having to worry about how many microsoft services I have running in the background.
And this is what happens millions of times every second in a computer
Could someone explain to me why the memory adress is in 4-bit and not 8-bit? There has to be a reason right?
The memory addresses are four bits because each instruction is within one byte, which is 8 bits, so there is four bits for the instruction, and four bits for the address. He could have 8-bit addresses, but he would have to rebuild the entire computer.
which book did you read to learn micro architecture? you did a great job there!
+Ricardo Mazeto
hitch hikers guide
This is a bit like the trainer I used in school. It ran on the 8086.
absolutely cool. amazing.
Excellent !!
Where did you get all of your wires?
Thanks, this is great!
What are you using as RAM?
try and get it so that you can somehow connect a ATA hard drive and then get it to import some integers before it calculates stuff if its in run mode
Alfie Whitson that is waaaaay to complex for his simple little computer.
Cool Video.
This is the best computer for people that don't like spam and malware... ;)
Very Good
Hi. Howw i buy this important things ?
So... is 42 is inspired by The hitchhiker galaxy guide?
That's exactly what I was thinking!
yeah. the "explaining" of how this computer works is wrong, and the only answer this computer is able to give is 42 because it's the answer to life, the universe and everything.
and at that point, a wast majority of the audience forgot the question ; )
hey it's a real life TIS -100
I wish you pointed to the schematic from the previous video instead of the breadboard. I'm getting lost with the bus connections.
amazing
Have you made an Instruction Register video, I can't find . I think this is a requirement to understand this video
How much did this cost you to make?
+Preston Stith I would guess less than $40. The breadboards are probably the most expensive part next the the ICs
It's really cool.
The most costly part with such a project would normally be the RAM, but in this case it is just 16 bytes, so this isn't a problem. I am currently making a 16 bit computer with 10 bit addresses, so that means 2048 bytes and in my case that would be the most expensive part, if I decide to actually install all 2048 bytes, which I probably won't do.
16 bit computer...10 bit addresses.. that means 6 bits for the instructions?
Amazing.... make more videos!
I also am interested in the origin and reproduction of your design.
How can i send you a message i need your help in a especific topic.
It would be easy to make a self modifying program in this computer. It would be almost impossible to debug or understand, anyway.
AWESOME PROJECT, OMG!!!!!!!!!!!
(NEW SUBSCRIBER )
Why not increment PC in T1? T2 seems unnecessary.
god send
So every singular instruction takes 6 cycles? Thats... longer than i thought o_O Is this still the same for modern 64bit CPUs?
For the question what would happen if you could advance beyond the HLT:
It would read the 14 (00001110) as an instruction (in this case 0000 NOP with parameter 1110) so nothing would happen.
Next is the 28 (00011100), which means 0001= LDA with 1100=12, so it would read memory address 12 into register A (which is probably 0b0). After that, everything is 0b0, so just NOP commands.
Modern CPUs can do multiple instructions per clock (IPC).
Two things happen in modern CPUs:
ⅰ) Processing is pipelined. For example, assuming each instruction takes six phases, a CPU would be executing six instructions at once but each would be in a different phase. While one instruction is finishing, instruction four steps behind is being fetched and an address if instruction five steps behind is being loaded. With this, even though each instruction takes six clock cycles, an instruction is executed every cycle.
ⅱ) There are multiple ALUs which means that CPU can perform multiple operations at once. If one instruction sums two registers and another sums some other registers, those two operations can be carried out in parallel.
This is of course simplified, and there are multiple things that complicate the issue such as:
ⅰ) Data dependencies: ‘a = a + b’ instruction followed by ‘a = a + c’ cannot be executed in parallel since result of the latter depends on the result of the former. To mitigate, CPU will try and rearrange instructions and execute them out of order. For example, sequence ‘a = a + b; a = a + c; d = e + f’ can be rewritten as: ‘a = a + b; d = e + f; a = a + c’.
ⅱ) Control dependencies: conditional jumps mess with the pipeline since what next instruction needs to be executed depends on the result of the current one. This means that it’s not possible to know which next instruction to fetch before the current one finishes. To mitigate, CPU will try to predict which branch is taken and execute instructions from that branch. If later the prediction turns out to be false, all the calculations will be discarded. x86 architecture also includes conditional move instructions, for example ‘set EAX to 10 if carry flag is set’. This changes control dependency into data dependency which has lower penalty on misprediction.
ⅲ) Different number of different execution units: A CPU might be able to perform two additions at once but may be unable to perform two multiplications at once just because it has some components duplicated but others not. Similarly to ⅰ), CPU may try to mitigate by rearranging operations.
And I didn’t even mention memory yet. A memory read can take dozens or even hundreds of clock cycles. ‘How much clock cycles an instruction takes’ is nowadays a very complicated question to answer and you probably can count number of people who know the answer to that on your fingers.
may I ask what is your career?
Do pipelining