Christiaan, this seems a house number.
What is the equipment and what is the surrounding of the device? I.e., is there a crystal soldered to a pair of pins? Are there any analog paths (opamps, for example) that are connected to the device? Similar thing to digital paths (serial ports or memory for example)?
The intent is to try and match the device with a similarly-looking device in the same package, such as a C2x or C5x DSP.
Even if you find the package, there is a high probability this is a ROM masked device, which makes the replacement quite difficult.