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The CCA - Carry-Cancel Adder - Printable Version

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+---- Thread: The CCA - Carry-Cancel Adder (/thread-5493.html)

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RE: About my vertical adder, the CCA - Nuuppanaani - 01-10-2015

(01-08-2015, 01:20 PM)snugglycreeper9 Wrote: The purpose of PLA is it to be horizontal and fast...

I agree with it being supposed to be fast, but WTF, how does the logic in the adder have anything to do with its physical shape? PLA can be built diagonal or vertical too? Seriously I want to hear your thoughts on this, why does PLA have to be horizontal when so many people prefer diagonal (or vertical in this case)?

RE: About my vertical adder, the CCA - Konstacon - 01-11-2015

(01-10-2015, 10:43 PM)Nuuppanaani Wrote:
(01-08-2015, 01:20 PM)snugglycreeper9 Wrote: The purpose of PLA is it to be horizontal and fast...

I agree with it being supposed to be fast, but WTF, how does the logic in the adder have anything to do with its physical shape? PLA can be built diagonal or vertical too? Seriously I want to hear your thoughts on this, why does PLA have to be horizontal when so many people prefer diagonal (or vertical in this case)?
Firstly, you'd have to come up with a diagonal LFA, and also for C1 step (handling 4 bits) you'd need a diagonal carry AND propagation.

Also, if you need diagonal adders, go to CLE, it's the same speed, and won't take nearly as much space. However, we never had really any 4 tick horizontal SS adders, which is what cut and embi went for when designing it...

If you meant VERTICAL, good luck designing a vertical LFA, then removing the first two bit calculations and making them 4 bit propagation and carry systems...

RE: About my vertical adder, the CCA - Nuuppanaani - 01-17-2015

uh oh...

So all you're saying is it's harder to implement? That's indeed true, but hasn't stopped redstoners before.

But PLA is more compact than CLE, it's optimized CLE. PLA is also synced by default. It has less signal strength problems for input & output. Great explained the shape very well in a different thread, so there's that. I prefer PLA's shape over CLE, but that's subjective.

I feel like making somesorta ranty video about PLA vs CLE because a lot of people don't seem to understand it.

RE: About my vertical adder, the CCA - Magic :^) - 01-20-2015

g-guys...
I made it 4-wide Big Grin

[Image: zBG0Apc.png]

I found out I could use XNOR instead of AND for this, as even signal strength still cancels what's coming out of the comparators.

So the signals in the generate stack are not as 'clean', but meh. I may be able to design a smaller alu too with this technique ^^

RE: About my vertical adder, the CCA - Apocryphan - 01-20-2015

congrats! i know the feel, its good.

RE: The CCA - Carry-Cancel Adder - Magic :^) - 01-26-2015

For the lulz I made a diagonal CCA ALU. Now might be a good time to point out that all the ALU designs I have for this are OR based.

It's 7 ticks (5+2 because inverters)... but hey, it's got good throughput Big Grin

[Image: 2tlbewN.png]
[Image: 3vTGE66.png]
[Image: XmiGiA9.png]
[Image: dTxHiq0.png]

RE: The CCA - Carry-Cancel Adder - Magic :^) - 01-27-2015

I've made a logisim circuit of the adder's design. It shows how much stuff is compressed by the comparators quite (horribly) well Wink

Adder cell:
[Image: lMkEB0n.png]

Carry logic:
[Image: YvjQsAD.png]

notice how it is ORing together the relevant weighted cancel wires before cancelling weighted generates

there's a .circ file in the .zip attached here
(admins plz allow .circ attachments)

RE: The CCA - Carry-Cancel Adder - tokumei - 01-27-2015

I just found out that there is a logisim build for linux Big Grin O happy day!

RE: The CCA - Carry-Cancel Adder - Magic :^) - 01-27-2015

Big Grin

decap was able to run it on his phone before iirc, I think he had to compile everything himself tho

RE: The CCA - Carry-Cancel Adder - AFtExploision - 01-27-2015

PLA is sklanky's not LFA... and it isn't cle at all