Audit code for duplicate functions, or functions that could use clearer names

[erichte-ibm]

This is part of the eventual greater refactor to try to share code between the backends as best as possible. Functions should have clear names describing what they do, and ideally do as little as possible to avoid massive monolith functions with excessive levels of indentation. Duplicate functions should be merged into some common code.

This also refers to an eventual rework of generic.c, perhaps a common/ source directory.