The Web really needs a good resource on answering this question. I didn't see one in quick search. These links each have pieces of the answer:

https://www.inf.ed.ac.uk/teaching/courses/pa/Notes/lecture11...

https://stackoverflow.com/questions/49098533/vpu-vs-fpu-vs-g...

https://www.quora.com/What-is-the-main-difference-between-SI...