Consider dedicated structure construct

[yupferris]

I was thinking about caches today. I currently implement them with 3 separate memories - one for valid bits, one for tag words, and one for data words. But it might be advantageous to merge these into a single memory (eg. If it helps implementation later in the pipeline). In this case, we would want to store all of this information in a single memory word, and ideally we’d like this “packing” and “unpacking” to be as safe and comfortable to use as possible. Note that this may put pressure on raising MAX_SIGNAL_BIT_WIDTH, which is ofc possible, but potentially a lot of effort.

I’m not entirely sure what this might look like.