| 摘要 |
PURPOSE:To increase the efficiency of an operation by installing both a microprogram storage ROM and a nanoprogram storage ROM. CONSTITUTION:The microinstruction read out of the main memory is stored in the instruction buffer register 310 and then decomposed into the instruction code plus the 1st and 2nd operands to be stored in the register 320, 330 and 340 each. An access is given to the micro ROM370 by the instruction code stored in the register 320 to read out a microinstruction. When this microinstruction is an arithmetic instruction, it is sent to the operation part 100 along with the 1st and 2nd operand data to give an access to the nano ROM410. Thus a nanoinstruction is read out to control the operation carried out at the part 100. Thus a branch instruction or the like is executed with a microinstruction, and the operation instruction is executed by a nanoinstruction read out by the microinstruction. As a result, the efficiency is increased for the operation. |
