| 摘要 |
PURPOSE:To prevent the reduction of the overall executing speed of a microprogram by deciding the propriety for acceptance of the processing request which is given from outside by a control flag. CONSTITUTION:The address of a memory circuit 11 is designated by an address (a) given from a processor circuit 14 and the circuit 11 reads out a control flag (b) that controls the decision whether an instruction code (c) and an external processing request should be accepted or not. A deciding circuit 12 decides whether the external processing request (d) should be accepted or not by the flag (b) and outputs a signal showing the acceptance of the request (d) and a signal showing the non-acceptance of the request (d) in the form of the signal (f). A selection circuit 13 selects an instruction code (g) given from another external means in case the signal (f) shows the acceptance of the external processing request (d). While the circuit 13 selects an instruction code (c) delivered from a memory circuit in case the signal (f) shows the non-acceptance of the request (d) and outputs the code (c) to the circuit 14 in the form of an instruction code (h).
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