| 摘要 |
PURPOSE:To realize the common use of a microprogram and reduce the quantity of microprogram, by properly holding the working contents of an arithmetic circuit that is indicated by a microinstruction. CONSTITUTION:The working designation codes of the selecting circuits 4 and 5 plus an arithmetic circuit 6 are set to a register 7. On the other hand, the bits p, q and r of a register 8 hold the corresponding A0, A1 and A2 when the value of the said bits are logic ''0'' and set the indication codes given from a microinstruction to the corresponding A0, A1 and A2 when the values of the bits are ''1'', respectively. In other words, only an instruction inherent to arithmetic working is set to the register 7 and then held or combined with a common instruction to decide the working of the circuits 4, 5 and 6. |
