| 摘要 |
<p>PURPOSE:To attain proper processing to a faulty state by detecting positively the occurrence of overflow and underflow state and selecting a packet address for write and read processing through the use of the result. CONSTITUTION:An overflow detection means 101 detects the occurrence of an overflow state from packet address information from a write address advancing means 81 and packet address information of a readout address storage area 72. An overflow detection means 102 detects the occurrence of an underflow state from packet address information from a write address advancing means 91 and packet address information of a readout address storage area 71. A write address selection means 820 in the detection of the overflow state selects a packet address obtained by a remotest write address designation means 82 as a packet address for write processing. A readout address selection means 90 in the detection of the underflow state selects a packet address obtained by a remotest readout address designation means 92 as a packet address for the readout processing.</p> |
