| 摘要 |
PURPOSE:To prevent a main storage area form being destroyed by providing a means comparing a memory address transmitted from a CPU and a main storage start address using in sharing and commoly one physical memory by a main storage and a control storage. CONSTITUTION:The CPU6 transmits a memory address (CPU-A) to a bus 19 at memory access. In case of CPUA<MSSA (main storage start address 8), an output of a comparator 10 only in a comparator circuit 9 and when the CPU6 requests a control storage access, since a signal line 20 is set, the access is permitted. In case of CPU=MSSA or CPUA>MSSA, either a coparator 11 or a comparator 12 is set and when the CPU6 request the main storage access, a signal line 21 is set, then the access is permitted. |
