At school we have been programming in MIPS assembly language for some time. I'm interested into delving into x86 assembly and I have heard that is somewhat harder (even my MIPS textbook says this).
What core information should I know as a MIPS programmer before making the dive into the x86 world?
x86 has a very limited set of available registers compared to most other architectures. This doesn't really make the assembly language any harder to learn, but sometimes makes it harder to implement code in practice.
Also, because of the x86 history of strong backward compatibility, the instruction set is not terribly symmetric (definitely pre-RISC) and there can be lots of exceptions to the rule and corner cases to pay attention to.