Program execution protection

摘要

The method involves filling an area of a volatile memory i.e. RAM (14) of a circuit with bad opcode (BOP) instructions leading to an exception processing, before executing a program to be controlled. The program is contained with instructions for replacing all or part of the instructions by valid normal opcode (NOP) instructions. A jump area is provided for executing all or part of the instructions contained at a program execution end of instructions.