| 摘要 |
PURPOSE:To efficiently execute MAD operation, etc., at a high speed with a less number of steps, by adding a control circuit to be used for making specific operation with a less number of instruction steps to a control section. CONSTITUTION:Connections among an arithmetic and logic operator 31, status register 33, and register R3 are made in such a way that the output of one status register SRB is given to the ALU controller 41 of the operator 31 as shown in the figure. This ALU controller 41 is prepared by adding a control circuit shown in figure 3 to conventional one. The control circuit is to be used for controlling the 'addition (ADD)', 'subtraction (SUB)', and 'no operation (NOP)' in MAD operation and formed to a logic circuit, through which the ALU controller 41 can or cannot lead out a prescribed output depending upon the outputting state of the status register SRB and register R3. Therefore, specific operation of MAD operation, etc., can be executed in a less number of steps by the action of the control circuit. |
