| 摘要 |
PURPOSE:To simplify the constitution of an arithmetic controlling section, by doubling part of a control storage and selecting one of the doubled part in accordance with calculated results. CONSTITUTION:When a control address MA is ''A'', both the 1st and 2nd storage devices 1 and 2 are accessed and each microinstruction is read out, and then, ''a'' is ouputted from the 1st storage device 1. Since the SELC field of a microinstruction related to the control of a multiplexer 4 is usually ''0'', the multiplexer 4 selectes the 1st control storage 1 and makes outputs and the ''a'' is fetched and executed by a microinstruction register 5 by means of a clock. In the example shown in the figure, the 2nd control storage 2 is selected since the least signification bit of the calculated results of the microinstruction (a) is ''0'' and the microinstruction (a) is fetched by the microinstruction register 5 and executed. As a result of the execution, a control address C is generated.
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