What are the origins of the phrase “operate on register[s]”?

Question

I am curious as to whether this phrase gained wide spread usage after the incorporation of registers in computer microprocessors.

Simple example:

Morality operates on a number of registers: age, religion, personal experiences.

Answer 1

I would venture to say that the phrase has not yet gained widespread usage at all in the sense you describe. For instance, a search for the specific phrase you cited turns up only a handful of instances.

Setting that aside, I think we can still look at the changes in usage over time.

A simple Google search for "on a number of registers" turns up many examples, but a lot of them are specifically in the sense of operating on computer registers. Skimming the list turned up only a few instances of the sort of usage you're asking about.

An NGram search shows that the phrase "number of registers" has, in general, followed the prevalence of computer registers - increasing in the '50s and then decreasing in the '90s (as low-level assembly language programming fell out of favor).

Skimming NGram results pre-1950 shows only a few instances. Most of them are around voting registers of some sort. Again, none of the sort of examples you describe.

So based on all that, I would conclude that: Yes, the use of "registers" in the sense of your example, while not exactly common, is something that evolved concurrent to the advent of computer registers.

Edit to add: When I say that they evolved concurrently, that is not to imply that this usage has anything to do with computer registers. As MetaEd points out in the comment above, the OP's usage comes from music. The OP's question was whether it "gained widespread use" after the advent of computers or not, and it seems that it did gain in use after the advent of computers.