The treatment mannered null CPU core of the operating system program which operates the processor system and

摘要

PROBLEM TO BE SOLVED: To prevent unauthorized access from an application program to a system register wherein control information of a function unit is stored.;SOLUTION: A processor system 1 includes a CPU core 10, function units 11A and 11B connected to the CPU core 10, and a system register bank 12 wherein control information and operation states of the CPU core and function units 11A and 11B are stored. The system register bank 12 is divided into a plurality of banks BK1 to BK4 each of which includes one or more system registers. The bank BK4 is a user bank allowed to be accessed by an application program executed by the CPU core 10, and access from the application program to banks BK1 to BK3 other than the bank BK4 is inhibited.;COPYRIGHT: (C)2008,JPO&INPIT