MULTIPROCESSOR DEVICE

PURPOSE:To reduce the overhead required for master and slave processors to perform communication processing by mapping a memory of a slave processor selected by a master processor in a fixed area of a system memory space as a shared memory. CONSTITUTION:A local memory 12 and a shared memory 13 are memory mapped from a CPU 11 and can be seen. While another processor unit 17 acquires a master processor right and accesses the memory 13 via an external system bus 18. In such a case, the series number of the unit 17 containing the memory 13 for accessing is written in a register of a processor selector 14. Thus the memory 13 is mapped in a system memory map and the unit 17 is made accessible. Then the communication of data can be performed with transfer of memories.