| 摘要 |
PURPOSE:To prevent malfunction in case of important information, by constituting so that a microinstruction to be executed next can be executed to only a specific address group in the control memory, in case when a specific microinstruction has been executed. CONSTITUTION:In a control memory 1, a microprogram is dispersed and stored in a storge area A and B. In a control register 4, ''0'' is stored as an area designating information b2 when degignating the storage area A, and ''1'' is stored as b2 in the same way when designating the area B. A microinstruction read out from the area A of the control memory 1 is stored in a microinstruction register 2, its contents are decorded by decoder 3, and when it is an area designating instruction, an area designating information b1 is set to the control register 4. When the area designating information b1 is set to the control register 4, an address damping circuit 5 controls so that access to the control memory 1, which is executed next can be executed only to a specific area B. |
