| 摘要 |
PURPOSE:To extend the number of stack stages of a micro-subroutine by switching to a stack of other sequencer, when a stack of one sequencer has become full, in case of executing the micro-subroutine. CONSTITUTION:When a stack of a sequencer 21 becomes full, the sequencer 21 cannot call more micro-subroutines. Accordingly, a control logic 5 is switched to a sequencer 22 from the sequencer 21. That is to say, in a cycle of an address E (jumps to addresses A-E of a main program M), an output signal from the control logic 5 goes to enable signals E1=H, E2=L, and output control signals OC1,=H, OC2=L, and the gates G1 and G2 are opened and closed, respectively. Accordingly, a control clock pulse CP is supplied to the sequencer 22 from an output CP2 of the gate G2, and the sequencer 22 is made enable.
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