| 摘要 |
PROBLEM TO BE SOLVED: To efficiently execute transfer in the case of one-to-one transfer and also to execute one-to-multiple transfer when a data is transferred between a main memory and a plurality of input/output devices. SOLUTION: One-byte data to be transferred from each input/output device is stored in a data field 400 and also stored in an I/O identifying field 410 together with identifying data of each input/output device. The data stored in the data field 400 is stored in a position where a succeeding byte position register (421 or 423) designated by identifying data of the input/output device in a buffer 450 is '1'. In this case, the succeeding byte position register is rotated in right to prepare for succeeding data storage whenever the data is stored. When an identifying data exists, the data is stored in the buffer 340 in order. When the data for the portion of four bytes exists or the data to be written next is another kind of identifying data, the data of the buffer 450 is written in a main storage device (main memory) on a system bus. Only the byte of a position being '1' in an effective byte register 460 is a writing object.
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