SPACE SWITCHING CONTROL SYSTEM FOR CPU MEMORY

摘要

PURPOSE:To allow a main-body side CPU to access the entire space of, for example, a CPU-card side memory by selecting mapping registers and allowing the main-body side CPU to access the entire space of the memory of another CPU. CONSTITUTION:The memory 4 on a CPU card which has a CPU 3 of architecture different from the main-body side CPU 1 (or CPU operating an OS) is divided into banks B-0 to B-4 in constant units. The main-body side CPU 1 when accessing a shared memory 2-0 becomes able to access one of the banks B-0 to B-4 corresponding to one of mapping registers 5-0 to 5-4. Consequently, the entire memory space on the side the CPU card can be viewed from the main body side 1 and further the CPU card side 2 has no shared memory space, so its memory is not oppressed and data need not be copied to a shared memory part so as to show the data to the main body side 1.