The sse1 instruction provide the option of register-register, but also support register-memory. I didn't realize it supported register-register mode, so now I see why it would be less obvious to you.
Why is copying a value from register to memory (or memory to register) "RISC" while performing some logical operation to the value to the value as moves "not risc"?
I'd agree that memory to memory is "not risc", but given the amount of work necessary to do a register access, it's unclear why doing work on a value is "not risc".
Datapaths are NOT the complex part of a microprocessor.
