In order to improve the functionality of a computer-assisted design, test and/or development environment for a data processing circuit arrangement, the instructions of the circuit arrangement are stored in a machine-readable manner in a data base with the binary representations thereof. The allocation of a predefined binary representation (instruction code) to an instruction occurs in a modifiable manner. In this way, processors can be developed which are specialized and optimized in terms of processing specific software applications. The invention also relates to a computer-assisted design, test and/or circuit environment corresponding the above-mentioned method.