This allows you to experiment with basic PPC Assembly code directly on your computer.
It saves you the trouble of running assembly on a PowerPC-based system since computers generally use x86 assembly so PowerPC is not natively supported. Also, by using the interpreter you will not crash if you access a bad memory address for instance and you can try again immediately.
Here.
You only need to have Java installed.
Because it takes a lot of time to implement them. Progress on this might be made later on. Have a look through the source code to find out what is supported. It should be easy to tell.