Wikipedia
MikroSim
MikroSim is an educational software computer program for hardware-non-specific explanation of the general functioning and behaviour of a virtual processor, running on the Microsoft Windows operating system. Devices like miniaturized calculators, microcontroller, microprocessors, and computer can be explained on custom-developed instruction code on a register transfer level controlled by sequences of micro instructions ( microcode). Based on this it is possible to develop an instruction set to control a virtual application board at higher level of abstraction.