**Minecraft name:**

Shinrod

**What do you like the most about redstone?:**

Be able to build whatever you want

**What’s a thing you have made which demonstrates redstone knowledge?:**

An hexadecimal adder without binary conversion.

**What does the thing do?:**

It adds up to 16 signals in hex and outputs two lines X and Y such as SUM(inputs) = 16*X + Y.

For two inputs A and B, it works as follows :

```
if A + B < 16:
X = 0
Y = A + B
# implemented as Y = 15 - (15 - A - B)
else:
# A + B > 15
X = 1
Y = A + B - 16
# implemented as Y = B - (15 - A) - 1
```

**Image(s) and/or video(s) of the device:**

1 slice of the adder :

The inputs are the barrels with green numbers (the two barrel on the middle left).

The top part (orange) computes Y when A + B < 16.

The bottom part (blue) computes Y when A + B > 15.

The yellow line powers on if A + B > 15. It turns off the Top Y and put X to 1.

The green line inject Y back in the system for the next layers. (I didn’t include the comparator line here for clarity. It is represented by the green glass).

Here, A = 13 and B = 8. 13+8 = 21 = 16*1 + 5. So X = 1 and Y = 5.

- Here is an example with A = 3 and B = 8 (which gives X = 0 and Y = 11):

- And here is an edge case with A = 13 and B = 3, so that A+B = 16 (giving X = 1 and Y = 0).

- And here is the full adder, with slices combined:

The inputs are the barrels of the middle column.

- And the results for the sum of the range [1, 15] (sum= 120 = 16*7 + 8, giving X = 7 and Y = 8) :

I reproduced the first slice on my plot, you can visit if you want to see it:

`/p visit Shinrod`

**What do you plan on making for your build trial?:**

I have heard there is a lot of ALU, so let’s settle for that. I have a design with SUM, AND, OR, XOR, left/right shift and negations of the output (NAND, NOR, NXOR…).

**Do you agree with the rules?:**

Yes