| 摘要 |
PURPOSE:To read out microinstructions in a high speed, by selecting first the first micro instruction from the first storage device and selecting thereafter following micro instructions from the second storage device. CONSTITUTION:The microinstruction address (start address+1) read out from a storage device EAS by an instruction code is set to a counter MIC; and when a storage device CS is accessed by this address, the next microinstruction is set to a register OP after a time 5r (r is a clock period). Meanwhile, since the start microinstruction is read out in parallel with setting of the address from the device EAS to the counter MIC, this microinstruction is set to the register OP by the time of 3r. Thus, since the start microinstruction is outputted in the time of 3r, the read time is shortened by 2r in comparison with the conventional method. Following microinstructions from the device CS are outputted by a selecting circuit SEL provided between a register CSDR and an error correcting circuit ECC. |
