| 摘要 |
PURPOSE:To use effectively a microinstruction without taking its sole possession at each program instruction, and to decrease the number of bits of the microinstruction, by branching a microprogram routine of a control memory. CONSTITUTION:A microinstruction from a control memory 2 is held in a register 3. A control memory address register 4 holds selectively an address of a microinstruction to be executed in the next time, and supplied it to the control memory 2. A control memory 11 supplies the first specified field to the register 4 through a register 12, and supplies the second specified field to a decoder 13. A selecting circuit 20 selects plural specified output signals of an instruction register 1 by a signal of the decoder 13, and its signals are held by a flip-flop 15. A branch detecting circuit 14 detects and branches some event having microinstruction. |
