DLA adder fun!

[Konstacon]

As you may know, me and block were talking about "DLA". You were probably like "Wtf is DLA!" but here you will not ask that again! DLA stands for Decoder Lookup Adder. It uses decoders to decode all possible inputs, and encodes it into the output. At first it was called ILA for Ineffeciant Lookup Adder. Block made the first design, it was a speed of 9.5 ticks! I knew I could improve, so I jumped in and made a 4 tick ILA. I thought it wasn't ineffeciant, so I named it DLA. It was quite big, but did the job. Want to see a DLA? Ask me! Thanks, snug.

Also, props to block for making ILA.

[BlockandCube]

ILA was meant as a joke, you know, but DLA is turning out to be awesome.

[newomaster]

Make a DLA ripple carry adder that uses decoders to calculate sum and cout per bit as a normal ripple carry adder would, and then ripple them to make an (probably not efficient) interesting adder.

[Iceglade]

Hmm... that would actually be kind of cool, and not nearly as huge as the original idea of say, a 16-bit DLA (which is obviously pretty much impossible). I'm going to personally try it right now

[Konstacon]

Make a DLA ripple carry adder that uses decoders to calculate sum and cout per bit as a normal ripple carry adder would, and then ripple them to make an (probably not efficient) interesting adder.

I have done that, I can build one if you want, but it is REALLY big for 8 bit. But it still works.

[WrytXander]

So supposing you have pretty good decoders, I am not sure if what I am going to say is possible but, make a full adder completely out of decoders. Which would have inputs: A, B, Cout and outputs Sum Cin. (Ofcourse ) and than just hook up to carry outs / carry ins. Is that ready what you are doing? Since you could have a cell based DLA, and like a giant all-possible-combinations adder.

[newomaster]

Here's a decoder adder I made. Basically it just decodes every possible combination of adder inputs and outputs the correct values for sum and carry out. It's very slow and inefficient (3 tick ripple blah), but whatever it was fun to make :3

[Iceglade]

Hate to be the guy to bump threads... but thought I'd might as well considering I saw Newo's, and went ahead and made a 2 tick carry design. This is technically better than normal RCA due to the fact that each operation is 2 ticks, including direct throughput to the adder. Whereas in a normal RCA, each XOR is 2 ticks, combining into 4, the decoder logic remains at 2 in my design.

How about we call it LTC (lookup table carry)?



TL;DR: Better direct throughput by combining the half adders.

[Chibill]

I will start work on my 8 bit 10 tick decoder again for this.

[Iceglade]

You will never need more than a 3 bit decoder for LTC.

[Ntwede]

My new ALU uses a DLA to count how many 1's are in a number. for example, the number 7 in binary has 3 1's (111) and 12 woul dhave 2 (1100). They're awesome.

[Chibill]

I can do this with 2 bit decoders and it may be 1 tick. Then the encoding.