Just an "SPU" emulator ??
Well for better understanding... all the isolated modules of the ps3 ARE just SPU ELF's
What does this mean ? You can emulate the PS3's module's like metldr, isoldr, aim_spu_module, fdm_spu_module, aacsmodule.spu, cprmodule.spu, and so on.
Additional it can decrypt the header of the elf and show the commands and system calls used without the need to first reverse them.
Hope that make some things clear.