| 摘要 |
PURPOSE:To avoid large-sized constitution for a circuit and to improve the flexibility of operation, by providing a memory having the capacity equal to the general sum of storage capacities which are needed when plural input/output ports are used and then sharing said memory by the input/output ports. CONSTITUTION:One of the ports having input requests is selected by an input port selector 28, and a number (p) is put to the selected port. The data of the port (a) are fed to the address of a memory 21 which is indicated by an input point indication register file 22, and the address of the memory 21 is counted up. At the same time, a port having an output request is selected by an output port selector 29. Then the data is read out of the address indicated by an output point indication register file 23 of the address of the memory 21, and the address is counted. These controls are carried out with the indications of a control circuit 27. Thus the buffer storage is possible, and the storage larger than the storage capacity that is needed apparently is allotted to each port. This process ensures an operation which excels in the flexibility. |
