Comment by monocasa

There's levels of microcode.

It's not too uncommon for each pipeline stage or so to have their own uop formats as each stage computes what it was designed to and culls what later stages don't need.

Because of this it's not that weird to see both a single rmw uops at, says the initial decode and microcode layer, that then gets cracked into the different uops for the different functional units later on.