| 摘要 |
PURPOSE:To improve the utilizing efficiency of a memory, by providing a circuit which makes only a specific bit effective among bit selecting signals, a bit position selecting circuit which selects the bit position of the output from the circuit mentioned above on a data bus, and a code bit extending circuit. CONSTITUTION:In ordinary memory accessing, a bit select signal 21 makes all bits effective, but bit selecting signals which make only lower rank bits (b), intermediate rank bits (c), or higher rank bits (d) effective also exist. In accordance with the bit selecting signal 21, effective bits are fetched from a bit selecting circuit 22 and a bit position selecting circuit 24, and outputted onto a data bus 14. In this way, accessing in which one word of the data memory is divided into parts >=2 is performed and, therefore, the memory is effectively used. |
