Registers have small storage for temporary results. They are memory locations directly connected to CPU.
How do they work?
Consider the following ARM Assembly code:
ADD r2, r1, r3This adds r1 and r3 and stores results in r2.
Who figures this out?
If we are writing assembly by hand we have to know which registers exist and what they are used for, and how to use them correctly. In higher-level languages like C it is the compiler’s job.