| 摘要 |
PURPOSE:To manage the field of a microinstruction code without expanding it for the selection of a micro operation code by selecting the micro operation code using a macroinstruction code and the microinstruction code. CONSTITUTION:A part corresponding to a step which inspects a branch condition is encoded, and is set as the micro operation code, and it is inputted to a selector 13. At such a time, when n-number of micro branch codes are present, branch operation codes are inputted to lines 21, 22,...2n respectively. A macroinstruction code register 11 holds the macroinstruction code inputted from an outside, and a decoder 12 inputs the code held at the register 11, and outputs a selection signal to a selector 13. The selector 13 selects one branch operation code by the selection signal, and outputs it to a selector 14. Also, to the selector 14, a signal from the field for the selection of the branch operation code out of the fields of the microinstruction code in execution at present is inputted through a line 18, and the branch operation code to be outputted is selected.
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