In this paper the application of Instruction Set Emulation for rapid prototyping of SoCs will be presented. The emulation works in a way that both the software and the hardware behaviour of the emulated processor core is reproduced cycle accurately. This requires the use of hardware and software components. The hardware component consists of a board containing a VLIW processor and FPGAs. The software component is an instruction set simulator of the core running on the VLIW processor. The FPGAs are used for emulating the SoC bus of this processor core. This way the simulation of an instruction set of a processor core has been extended to a real emulation of this core that can be used for rapid prototyping.