| 摘要 |
PURPOSE:To realize an repetitive operation system having a short operation time in an economical way for the central control unit that is controlled by the microprogram, by giving a control to the frequency of operation performing a repetition with an external counter circuit. CONSTITUTION:A control operation is given by the microprogram muPG to the product of the figure stored in the register BR and the 8-digit figure stored in the register Q, and such product is stored in the register R1. In this case, the figure 8 is supplied in the binary display to the 16-notation counter circuit CTR that controls a repetitive operation circuit from the terminals P0-P3. The figure stored in the register BR is stored in the register R1, and the instruction to shift the R1 to the right by a bit, if stored in the microinstruction CMIR, is decided by the decoder DEC and then advances the CTR by 1 along with the clock CL to store figure 9. A decision is given whether the CTR is overflow or not, and an operation is repeated until the CTR has an overflow. With an overflow, the signal OVF is delivered to proceed to the next step. Thus the instruction to subtract the figure by one with every repetitive operation can be excluded to reduce the operation time. |
