| 摘要 |
PURPOSE:To realize a flexible microprogram controller using less hardware, by modifying the decoding of microinstructions by operating a part of the contents of a microinstruction register and those of a decoding mode register. CONSTITUTION:Microinstruction data is read out of a control memory 1 by being specified by an address held in a microinstruction address register 2 and then held in a microinstruction data register 3. On the basis of a part of the address of the microinstruction address register 2, data in a decoding mode memory 5 is read out and then held in a decoding mode register 6. The data held in the decoding mode register 6 and a part of the contents of the microinstruction data register 3, are processed by an operator 7, whose result is supplied to a decoder 4 to be interpreted. Therefore, different decoding outputs are obtained with the same microinstruction. |
