I began learning assembly from MIPS (a RISC microprocessor). An emulator called SPIM could be downloaded and installed freely from the author's website. http://pages.cs.wisc.edu/~larus/spim.html
SPIM provides an easy to use interface with a console to return the results. Users could also inspect registers from the emulator.
The author of SPIM recommends many useful resources, available on the website (scroll down to 'Resources').
