I learned assembly with an 8086 emulator, and I've had the pleasure of writing assembly for bare-metal ARM microcontrollers. But you're right, modern x86 assembly is a whole different beast. I've tried looking through their manuals, but as I recall their manuals are largely unapproachable +3000 page tomes.

My comment was written with the 8086 emulator in mind. It was great because you could view what was in each register, as well as the inspect any section of memory.