SHARED MEMORY

摘要

PURPOSE:To improve a throughput by providing an occupying right decision circuit for deciding the occupying right when access requests from two ports to a storing part compete, and a data transfer control circuit for attaining the transfer of the direct data between the two ports. CONSTITUTION:A DMA control circuit DMAC for carrying out a DNA transfer control between the local memory of a system connected to one port side and the local memory of a system connected to the other port side is incorporated in a dual port RAM provided with a shared memory DPRAM and an arbiter ABT having the decision function of the occupying right to the shared memory. Thereby, the throughput in a multiprocessor system using the dual port RAM is improved according to an operation for transferring efficiently the data from the local memory of one microcomputer to the local memory of other microcomputer.