Challenge: Make a data type for holding one of 8 directions allowing increment and overflow

[Liam McGillivray]

On Thursday, 14 March 2024 at 01:58:46 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> The cost of an add + increment then a bitwise and is only 2-4 
> cycles on a Haswell cpu. Depending upon if its working solely 
> in registers (via inlining) or its operating on ram.
>
> Whereas if you need to do branching (if statement, loops), this 
> is an unpredictable cost and loops where a simple bitwise 
> operation can be done is out right non-optimized.
>
> As for exceptions, totally not required. You can solve this by 
> simply making your state private so nobody else can mutate it. 
> Bounds checking will ensure if the state is corrupted it'll 
> error out if you use the lookup method I suggested above.

I tried to rework the functions to use bitwise operations, but it 
was difficult to figure out the correct logic. I decided that 
it's not worth the hassle, so I just changed the value storage 
from `bool[3]` to `ubyte`. Now it works much more like your 
version.
https://github.com/LiamM32/Open_Emblem/blob/c2014ab3f77e89c0cedcd6dbf7f8362ebfac33a9/source/common.d

I did a little reading, so now I understand what it means when 
you have `&= 7`. But I want to ask, is this faster than `%= 8`? 
If not, I would like to change it to the latter for readability.