CSE 230 - LogiSim ALU Tutorial

[@twh-wria]

"First I'm gonna show you some basic gates"... proceeds to show the AND gate... "Now, we're going to make an ALU" aaaand that went 0-100 real quick

[@GregPotts96]

Hi Will

[@laura_22]

It was not so bad, if you follow every step carefull it all makes sense, kind of, a little bit

[@prmos09]

Excellent tutorial! I have seen a lot of videos explaining how to make a 1-bit adder. This is the first video that explains step by step how to make an entire 8-bit ALU, besides it is also a great tutorial on how to start using Logisim. Congratulations, great work!

[@willft520]

Great tutorial!! So well explained! I should be doing homework right now, but this is definitely more fun!

[@yawsokpor3061]

Thanks very much for this tutorial a Student at LYIT at Donegal in Ireland in the Field of Applied Computing so this lesson is very helpful to me.

[@rock3tcatU233]

You're the best logic design teacher I've come across!

[@skilz8098]

Check out Ben Eater's videos here on youtube; he does more than just that he builds an 8bit cpu on a bread board and explains it step by step!

[@aleiaknight]

Thanks so much! I am a robotics student at UAT and we don't go over it enough in class so this really helps!! :D

[@brandonmessenger5989]

Amazing video. This really helped me out with a project I had for class. You did a great job walking me through the process. Thanks!

[@RyanMeuth]

They're for using the ALU to do comparisons - we setup the alu to do a subtraction, then if a and b inputs are equal, the zero flag goes high, and we can use it to trigger a branch. The negative flag is for a "less than" style comparison, in the same way.

[@shadabshaikh4995]

Just can't thank u more sir.... U just made my life easy

[@PeskyTheWabbit]

literally saved me the night before my 3bit ALU project was due

[@PeskyTheWabbit]

@Astropathix XIII passed the class and have graduated now.

[@agfd5659]

@@PeskyTheWabbit congrats!

[@kwakukwabia3805]

Pls what is the significance of the less and set in the ALU?

[@MohammadMahadiHassain]

Amazing Video, Very Easy Explanation Thank You From Bangladesh

[@drbsr1948]

I got it built and working just fine. Thanks

[@danyang9130]

It's really useful and so necessary for me !Thanks!

[@user-sq5yo8nl7m]

I’m working on a project where I’m creating a 12 bit alu based on 2 6 bit alus would you have any time to help me ?

[@candilikoglu3999]

How does changing the sub and Cin to 1 make the operation subtraction?

[@manologrhacker]

Nice tutorial. Well explained and easy to follow, I enjoyed.

[@raulbarriga7416]

How would I add a comparator to this ALU? The comparator only has 3 outputs for greater than, equal to, & less than. How would I add the comparator adjacent to the bitwise gates & adder/subtractor?

[@leifcnp]

Cool, thanks for the intro to logisim!

[@phddgrd]

awesome, I haven't tried this software ! it seems so practical... thanks... I'm really into digital design right now !

[@kwakukwabia3805]

Please what's the significance of the Set and less buttons??

[@ldiazmdiaz]

This brought me back memories from Devry in the 1980's.

[@sravanishatdarsanam9847]

I have a question. We only connected the Set operation of the most significant bit with less than operation in the least significant bit. Y are we not wiring the rest of the SET operations in the 8-Bit ALU?

[@DeneuveBrutus]

...It was that easy.... *bangs head on computer*

[@cory99998]

Learn binary / binary adding and learn about logic gates before following along here. Best / only way to understand this is from the ground up which this video doesn't do a great job of

[@agfd5659]

@@cory99998 Understanding how it works is one thing. But actually designing and laying out the logic gates in a sensible manner is something else.

[@qqqqq9422]

which books for logic design u learn from?

[@muneeraalmarri4514]

I have project in Simple CPU in LogiSim, so can you please help me

[@myyandar]

Hi Ryan. This video helped me to complete a class exercise. The pace, steps and language makes it very easy to follow.. Please, do you have other videos that teach how to add multiplication, division and overflow detection? I want to extend what I learnt from this video as I understand it very well. All the videos out there are either too fast, the language not clear (mostly Indian English, even though very good English but with heavy accent). Can you help, please?

[@carolina1315]

Is there project files that I can download?? I want to test your circuit with files. Please, make more tutorials about computer circuits.

[@nikolaiholingster5460]

I can't wait for the next part!

[@joeyorofino101]

L

[@SergDaLife]

hey Ryan, could you attach "circ" file of that ALU to me please?

[@jbcentral1545]

I have just followed this video step by step and the bloody thing doesn't work! I must have done something wrong :(

[@sabrimevis]

Hello. Whats the version of your Logisim? I cant resize my objects. I tried almost every version but still doesnt work for me :(

[@kiillme16]

why the AND operation doesn't work when you are creating the first alu?

[@numero7mojeangering]

you can also use pull resistor insted of constant

[@luminity4408]

this video was released on my birthday

[@Maltebyte2]

Great Tutorial! My Logisim stoped working keeps freezing? Do you know any alternative logic gate software?

[@tcc1234]

Logicly, Logic Gate Simulator by Steve Kollmansberger are good alternatives.

[@phononify]

Great -- very nicely explained. Thanks a lot for sharing. Great would be the check on overflow in status with XOR of bit 7 and 6 carrier bit -- Can that software be attached to other programs helping in a hardware layout, as well ?

[@freddygonzalez6711]

Can you give the files of circuit?? I want to test it on my machine. Thanks for try to teach a very interesting field of computational sciences.

[@guangxzhu4019]

very clear for beginners. thanks.

[@ShrekPNG]

why to create 8 of 1b alu if you can create one 8b alu? logisim implements 8b adders, substracters and logic gates

[@eloleelole]

Great teaching !

[@lilcata]

A very good one thanks!

[@dasharos1736]

Do you know how to write HDL code for it? Please answer.. I'm really stuck

[@shaysframe1472]

What about the last Carry out in the last 1bit-ALU

[@BannanaOfDoom]

Okay so I got trouble, when I try to wire the first bit of the giant NOR it connects to all the wires it crosses. Also how am I going to make it compare numbers? I really need help on that one.

[@marshalcraft]

can make a 1 bit comparison by first branching two inputs so now there is copy of inputs, one goes into and and, the second pair gets negated and inputed into an and, result of two ands then go into an or the result will be 1 if both 1 or both 0.

[@khalilullahakbari2067]

Thank you Ryan How a nice explanation :)

[@nortronics]

Great bit of software - thanks for the video. As the software is no longer being updated, does anyone know of a new alternative?

[@PrateekJaiswal5]

Where is the truth table of this ALU circuit???

[@ar.teukie3847]

But how can I add shr and shl in this circuit????

[@zhongzhengwang7141]

Thank you for this video. Could you give me some tip on how to design a 8-bit Program Counter, just as one shown in the video CSE230: Muddiest Points - Datapath and Control Unit Design ? Thank you very much!

[@themanyone]

Nice job. It works!

[@herousall9353]

That's really cool, Merci!

[@ShadyBajary]

Is that shortcut you are used to connect all splitter outputs to All "A" input bits by one click "At time 17:27" ?

[@HamguyBacon]

he skipped the video.

[@alejandrohernandez-jj4sk]

amazing video, thank you so much

[@Jkauppa]

try to make a just-in-time minimal logic element (component) operation switching alu, mini-fpga instead of giant asic, to prevent footprint blow-out

[@Jkauppa]

chip-munks, pun intended, is the best

[@mateoslab]

What does the less and set do?

[@debarjo]

Can you please explain why we need the zero or negative flags in the alu for cpu design??

[@omarhmedat2064]

For comparison

[@harshanarayan7363]

Lol, nobody had replied to him for five years

[@skilz8098]

ALU = Arithmetic and Logical Unit. Arithmetic Operations: Unary(single operand) { (-) Negation, (+) unary addition or integer promotion pending on types}; Binary(two operands) { +, -, *, /, % and compound +=, -=, *=, /=, %=}, Increment{++} and Decrement{--} same as {x += 1 or x -= 1}, Logical Bit manipulation: Unary {!, ~} Negation and Complement, Binary{&, |, ^, !|, !&, !^} , compound binary { &=, |=, ^=, etc.} Bit shifting {} shift left and shift right same as divide by 2 and multiply by two in Binary Arithmetic. Logical Comparison. { , !=, &&, || } Not All ALU's support all of these arithmetic and logical operations as some of these can be done in software if the CPU architecture has a small or simplified instruction set, and not all ALU's support Multiplication and Division. However some very sophisticated machines will support All possible operations on binary digits. It's a trade off for capabilities and performance vs size and cost.

[@kevinparsley6806]

@@harshanarayan7363 the publisher of the video replied to him 5 yrs ago outside of the thread, but right above it..

[@davidprock904]

@@harshanarayan7363 wow, good call

[@danimewblitz7160]

What about the Control Unit?

[@manuelavendano2199]

Hey man, how can I detect overflow in your example?

[@agfd5659]

The most significant 1-bit ALU's carry out bit can be used to determine overflow.

[@DaveDugganITPro]

What video or screencast editing software allows for the speed up please? that is a cool effect. great job - thank you

[@RyanMeuth]

Dave Duggan I use windows movie maker. Thanks!

[@DaveDugganITPro]

Ryan Meuth thank you - I was not aware that movie maker had the capability to speed up audio and video like that - cool . What did you use to capture the screen please? I assume you first did a screen capture then edited the resulting video. Then you did the speed ups in movie maker ? excellent tutorial thank you

[@RyanMeuth]

Dave Duggan I used CamStudio for the initial screencap. Thanks!

[@DaveDugganITPro]

awesome tutorial

[@luciano8158]

Why do you need 3 select bits to capture 6 operations?

[@luciano8158]

how many select bits would I need if I wanted to capture 5 operations?

[@jettarinpattanajirarutchag9929]

@@luciano8158 same 3 select bit too. Becoz 3 select bit can do 1-8 operations. And 2 select bit can do 1-4 operations only.

[@luciano8158]

@@jettarinpattanajirarutchag9929 cheers, friend

[@gratzup]

Why is your last sum (25:25) wrong?

[@stewartzayat7526]

Dan it's correct

[@jettarinpattanajirarutchag9929]

101 + 101 = 01010 Right?

[@edreyquerimit8873]

Can you please send me the schematic diagram? Thank you!

[@Nathouuuutheone]

"I can AND three bits at a time" doesn't explain the data bit thing at all. It describes an AND gate with three inputs, which is what you had to begin with. I understand that the data bit variable makes every input represent more than one bit, but like... are they ORed? Or is it a specific decoded three-bit state? Or does it AND all three three-bit inputs as if it were nine independant inputs?

[@MAhmad-hd6vu]

nice lecture

[@dark4205]

The last lalf part of video called 8-bit ALU?

[@RyanMeuth]

Yes

[@dark4205]

Ryan Meuth Can you tell me why after saving the 1st part 1-bit alu, i want continue but when i make connection with 1-bit alu the wire do not get green remain blue? i tried the same with input output to one gate (NOT) and still the wires blue

[@RyanMeuth]

dark4205 1. Make sure the wire is being driven by an input object. 2. If so, it could be a simulation problem. Click Simulate->Simulation Enabled (uncheck it), then Simulate-> Reset Simulation, then Simulate->Simulation Enabled. If that doesn't work, just save your work, close the program, then re-open it.

[@dark4205]

Ryan Meuth Thank you, it is working now, it was simulation problem.

[@slimysnail6071]

Thank you so muchhh Sir

[@siesres_1032]

I have a question. How do I do A+1 or B+1 ?

[@numero7mojeangering]

Do a addition, set B to 1, you can change A and you got A+1. or set A to 1, you can change B and you got B+1.

[@Toulkun]

What is Data Bits?

[@PrashantArya-prary2]

Good job :)

[@MahmudRahmanMendax47]

Hey Bro How To Do Shift Left Logical Op In ALU..?

[@skilz8098]

You would need a shift register built into the ALU and that shift Register would need a clock signal and a few other things such as control lines... same for shift right.

[@davidprock904]

@@skilz8098 i have the design in my head for a clock-less computer, but on that note all my assembly instructions are duplicated, one set uses clock, the other set does not, arch is also wildly different. now i just got to learn how to do all this with logic gates. my design gets rid of the north and south bridge. and my SSD isnt really an SSD but acts as one as a whole, and my SSD becomes the control unit. the "software" tells the (not exactly) cores how to work together to do tasks, like virtually rearranging hardware segments to act like either network output, audio output, video card, cpu, external data storage, all on the same pair of wires/buss if you really wanted to... one at a time with just the same pair of wires.

[@beaugarner5906]

can you provide a download link

[@alamjim6117]

Amazingggggggggg

[@krishamagar188]

Can you make a video of 8 bit cpu

[@weebsharpie6975]

sos grosso sabelo, +10 y a favoritos.

[@WillplaysFort]

it says incompatible widths what do i do

[@CasWald]

i needed to change my data bits for the AND gate to 1

[@WillplaysFort]

@@CasWald oh ok

[@osmankultur1943]

good design ;)

[@ziadh.mohammed6408]

i made this alu before , with only AND,OR,XOR,NOT A,NOT B,,but i made it with only AND & OR & NOT gates even the multiplexer i done it with AND & OR gates

[@davidprock904]

i need to figure out a few ways to do multiplexing, and addressing

[@prudhvipothuraju4062]

sir, i need 32 bit alu

[@slap_my_hand]

Prudhvi Naidu Just connect 32 1 bit ALUs together.

[@stellitsa123]

thank you!

[@jamessinyangwe9078]

I need a screen shot sir

[@crummmycheese]

Thank you

[@lucasteixeira5782]

nice bro thx

[@moises32123]

Sound Like Andy Biersack XD

[@flapicat3355]

dont work

[@maestroroshi1627]

ty