From NAND To Tetris, Part 4a: Arithmetic Logic Lab

In the lab for our Arithmetic Logic we make a number of simple arithmetic circuits, and then spend the majority of our time on the ALU. Mistakes, as always, are made.

00:00 Introduction
00:24 Overview
00:53 Half-Adder
04:12 Full-Adder
08:57 16-Bit Adder
14:09 16-Bit Incrementer
16:04 ALU: Introductory comments
19:04 ALU: Diagramming
39:21 ALU: Writing the HDL
45:44 Sermon: Mistakes are part of the process
53:00 Conclusion

[wyatt]

The ALU diagramming was very eye-opening. Thank you.

[hffl]

I rarely log in to leave comments, but i must say, you've been a lifesaver and your initiative of going through these fundamentals echoes a light for any aspirational computing students out there. (You've actually managed to explain binaries in a so clear way, along with these representational diagrams). Keep up the great work.

Like it's 1979, Best Regards!

[eZaFJDUBB]

you are a blessing man thank you for taking the time to explain some things and not just speed run through, taking the course now and without your help would be stuck

[arthur_p_dent]

Eternally grateful to have you here to help guide me along on this journey.

[briannalaird]

I just have to say thank you!!
I've learned more in the first 10 minutes than I have in the 3 hours I spent watching uni

[vincentadams]

Loved the video! Definitely much easier to picture everything recreating it on logisim rather than just doing the hdl.
Greetings from Spain

[ameeruljunaidi]

I find drawing the diagram helps so much! Thanks for this!

[Anubis]

I actually came across your video while I was banging my head on the walls.
I was able to build ALL functoion and custom chips to achive all functions but I couldn't get start HOW to Wire everything together. Then I found your video...which is a life saver for me...I understood how to tackle bigger problem with your simple approche
Thank you so much for your time and effort.

[Gupatik]

I'm here again for the second week, and I think this is where I'll stick till I finish this great course with you. Thank you so much

[jss]

Huge thanks for these videos. You really are a great teacher!

[clamr]

Thank you so much. You explained this so well, it should be included with the N2T course itself.

[tvox]

Thank you for explaining! You explained better than my tutors and professors at University 👍

[iyadzain]

Nice explanation, please keep up the good work

[richardgarrison]

Thank you, this really helps boost my understanding.

[gabrielkirklin]

It's always interesting to learn about the history and design of classic computer chips like the Z80. The fact that the 8-bit ALU inside the chip is actually two 4-bit ALUs put together in a clever design shows how engineers were able to work within the constraints of early technology to create powerful computing machines. It's fascinating to see how far we've come in terms of CPU complexity since then. As for the request for feedback, it's great to see creators open to hearing from their audience and I hope that viewers will take the opportunity to share their thoughts and insights in the comments. Overall, it's been a fun and informative journey through the world of 1979 programming.

[IvanToshkov]

You can simplify the diagrams with tunnels further. You can have as many tunnels with the same name as you want and they all will be connected. So instead of the readyX, readyY and readyOut tunnel to "exit" in 1 place, you can make them exit in 2 and directly connect them to where they are needed.

[Josh_J]

hi, i wanted to ask if you could perhaps do the complete nand2tetris course all the way to the end (using all tools other than the hardware simulator)

[matasmilukas]

Thank you for the video! It is a lifesaver!

[DavidLindes]

Very cool. I managed to get a working ALU before going through this, but watched it anyway, and I'm glad I did, because I found a number of ways to refactor some stuff and make it cleaner, and it was cool to see the diagram, too (I did it the hard way, without Digital, and did OK, but... it would have been helpful). Thanks! (2+ years later. :D)

[yuvrajkumar]

thank you sir this video is really helpful