[userbinator]

It's not that difficult, but I think the main obstacle is gathering and representing the collection of knowledge in a useful form.

There was a disassembler called Sourcer that would annotate code with a set of predetermined comments based on its knowledge of the PC hardware. For example a sequence of instructions that enabled the interrupt controller by setting a specific bit in its register would be identified and get the comment "enable interrupt controller". I seem to remember IDA can do the same thing, although it's been a while since I last used it.