PREVENTING DEVICE FOR FOUL WRITING TO MAIN MEMORY

摘要

PURPOSE:To prevent completely the foul writing and to improve the reliability by applying an interruption to a CPU when the writing is impossible with a subject address. CONSTITUTION:When a CPU21 performs writing to a main memory 22 in accordance with an execution instruction of the memory 22, a means 26 is provided to extract and store the writable address on the memory 22. The address stored in the means 26 is compared 27 and 28 with the subject address to be written by the CPU21. Then an interruption is applied to the CPU21 by the comparison output when the address to be written exceeds the range of the memory address. Thus the writing action is inhibited.