Processing system having device for testing the correct execution of instructions

摘要

Processing system for interpreting and carrying out a set of logically related instructions stored into a software program, the execution of a given instruction by the processing system involving the decoding and the execution of a corresponding set of microcommands. The processing system stores a signature portion corresponding to the macrocommand portion of a given instruction which is to be interpreted and executed, and signature data in response to the actual decoding and execution process of the microcommands involved in the execution of the instruction. The processing system further compares the computed signature data with the signature portion in order to detect the occurrence of an error in the decoding and execution process of the given instruction. In one embodiment of the invention, the processing system is such that one instruction is interpreted and executed in one elementary machine cycle. In a second embodiment of the invention, the execution of a given instruction involves the succession of multiple elementary machine cycles.