Minecraft Forums

Hai I'm making a calculator with my buddy and I'm trying to find out how to make it as compact as possible. Also the way we layed out the wiring it has to be 2 wide :/ Any help would be awesome :biggrin.gif:

Inverting on of the inputs is correct. If you want an adder/subtracter - plop XOR circuits on the B inputs. One side of the XORs become the B inputs and the other all tie to each other so that when you want to subtract, you simply activate that line and it flips all the B inputs.

Quote from Grizdale

1) take a 2 wide adder *cough*
2) invert 1 set of the inputs (so half of the total inputs)
3) invert the outputs
4) enjoy your subtractor

inverted inputs are + and non-inverted inputs are -

Note: I have never actually done this. this is just how I figure it would work. So any one feel free to correct me if I'm wrong.

Tried it and when I subtract 10-9 it comes out as 2 not 1

Thanks guys :biggrin.gif: it works

Wow my old post returns xD
I tested this on a standard adder from the wiki and one of Grizdale's adder from before.
The outcome was different o.O But I have heard that Grizdale's adder had broke from the 1.0.0 update... Not too sure about that.

Anyway great to have the person who started my redstone interest post on my thread :biggrin.gif:

Quote from TheXboxNut

Shame, i hope it gets fixed :/

And really? I seriously love it when people say things like that :biggrin.gif: , i'm honoured to have been of service :smile.gif:

xD Yes really.

Ima try and test his adder right now to see if it works...

Edit: It works =P

Quote from TheXboxNut

Ok i'm getting some seriously weird maths coming out of the adder now.. since when was 5 + 3 equal to 4?..

Can you post the link to whatever schematic you're using? Or how you came about to build his design? Hopefully the one i found is simply outdated..

Nope it works for me. I'm using the world download version. No schematics.