Don't focus too much on signedness. It's rather about the method how signed integers are represented in a given implementation. The r?? are 64-bit, and the e?? are 32-bit registers. There is no such attribute like "signed" or "unsigned" for registers. As we are talking about two's complement to represent signed integers, the -1 just means all bits are set 1. Similarly, 4294967295 means 32 bits are set that represent -1 as a 32-bit signed integer.
Originally Posted by aGerman
