DSPemu emule a digital signal processor TMS320F243, with console interface showing the registers and memory. With DSPemu is possible test algorithms such as Filter, FFT/IFFT. This can be integrate and used with a circuit simulator.
It is a lejos emulator for the lego RCX. It can be used to test your code without having to go through the painful process of continuously uploading the code to the RCX. It does this by providing a emulation of the major parts of the lejos library.