| 摘要 |
PURPOSE:To execute the calculation of the data of 32 bits and the calculation of the data of 16 bits easily and at a high speed in the same manner by providing two sets of ALU parts for the data of 16 bits. CONSTITUTION:Two sets (4a and 4b) of ALU parts of the data of 16 bits are provided, a selector 8 is placed so that the carrying signal from the highest order bit of the second ALU part 4b or the carrying signal from the external part can be connected to a carrying bit input terminal 9a of the first ALU part 4a, and by the selector 8, the carrying signal from the ALU part 4b is connected so that it can be inputted to a carrying bit input terminal 9a of the ALU part 4a, the unit is operated as the arithmetic unit of the data of 32 bits, and when a carrying signal CR from the external part is connected so that it can be inputted to a carrying bit input terminal 9a of the ALU part 4a, the unit is operated as two sets of the arithmetic units of the data of 16 bits. When the unit is used as 16 bits, swapping circuits 7a, 7b and 7c are provided so that the data can be calculated by any ALU part. |
