Advanced Redstone Computer Tutorial ?: ALU - Finishing

In this video we add subtraction and right shifting and finish the ALU by making it 16 bit

[bennyscube]

Let me see if I'm understanding this correctly. The bit you're referring to has the glowstone over a repeater. When this bit generates a carry signal (With the piston AND), the power will go onto the glowstone, which will be able to go into that bit's XNOR, but won't be able to go down to carry to the next bit.

If this is what you mean, then yes I actually forgot that part. Fortunately, the fix is really easy, I'll just cover it in the next building video because I found another issue as well.

[thewitchking]

My friends and I are building a computer, and at first, we wanted to be original in our ALU. This changes things... Great job!!

[rcollins]

Holy Crap, Benny. You are ridiculous. I can't believe you can just fix things on the fly like that, but I guess you've been doing this for a while. I can't wait to see your final video(s) describing the final hack to make the WHOLE 16-bit ALU with ALL functions only 3 ticks. now THAT is awesome.

[GsDDesign]

The adder is built up of the logical functions. O is on, if A or B is on, but not both. Thus, you have an XOR gate. An XOR gate outputs only if A and B are not on. Which means it's got an AND gate with in it (as well as an OR gate). By disabling the AND portion of an XOR gate, you get an OR gate, and by disabling Cout from your adder, you get an XOR gate.

Every logical function you need (except right shifting) is already built in when you build an adder alone.

[Jacker]

Thanks for the explanation, man. By the way, for the program memory, are these gates for ALL bits or individually?

[OCoptimusconvoy]

Yeah those three extra functions he added allows to turn the adder into any logic gate :)

[xXepcMagicsXX]

This was supposed to be an advanced, a really quick and efficient computer. Glowstone and BUDs make this easier and possibly better.

[codycero]

When you said "There's a lever for that." I couldn't help but lol.

[Tehdarkringmaster]

Let Benny have his Christmas break, he deserves it :D

[bennyscube]

I've watched again, and I agree! Thanks for pointing this out, I'll try to do better next time. :)

[Jacker]

Mainly about carry logic, negation, Exclusive N-OR gates, control lines, etc. I might not have understood too well, though.

[OCoptimusconvoy]

It was on a video from Properinglish19 he showed 1.4.6 I think vs one of the snapshots I think it was 13w01a/b or 02a/b not sure and he showed that the only thing that works is having a piston head in place of the fence gate.

[CatoSierraWasTaken]

I use button inputs now, buttons are cool.

[OCoptimusconvoy]

Merry Christmas & a Happy New Year :D

[GsDDesign]

Mind explaining a bit more? Are you talking about for control lines to enable or disable logical functions?

If so, I would recommend wiring up a single control line for a particular function of your ALU as opposed to individual bits, so that you don't accidentally do a logical OR function on half of your data, while doing Addition on another.

[bennyscube]

That would eventually stop the loop, yes. Until that happens though, the adder will remain in an invalid state, so it's best just to put it there so you never have to worry about. Besides, how will it hurt anything by having it there anyways?

[OmegaCraftable]

I think we should continue on, I've been working in 1.2.5 simply because I haven't been able to install SPC on a later version and it hasn't been difficult to redesign things.

[CharlesPIV]

Awesome video Benny, but do you really need that piece of glow stone for the carry line? Wouldn't the piston behind it just push out the block and stop it from looping.

[bobjamie]

I agree, restart with a new 1.5 friendly series ( I can't wait for 1.5)

[Palerider]

that ridiculous fix... that melted my brain