| 摘要 |
PURPOSE:To recognize the operation of respective ports and to simplify the control procedure of respective ports by comparing the contents of data in a memory access buffer which are the contents of respective ports. CONSTITUTION:In order to check whether a precedently started memory access is completed or not, a start address of the memory access buffer 2 starting the memory access previously specified by a microprogram is sent from a microprocessor 1 to a bus 12. The start addresses of the buffer 2 previously specified by the microprogram are sent from respective ports 31-34 to a comparator 6. The compared result output of the comparator 6 and information V indicting whether the port concerned out of the ports 31-34 is started or stopped are supplied to an AND gate 7. When the AND operation of both the contents is executed, whether the port holding the address concerned ends the memory access or not is checked. |
