| 摘要 |
PURPOSE:To obtain the absolute value of difference between a write area and a read area while reducing check error by obtaining the count values of both address counters by using a subtracter. CONSTITUTION:When a count value 1 of the write address counter is larger than a count value 2 of the read address counter, they are subtracted by a subtracter 3, and the spatial absolute of difference between the write area and the read area is obtained. When a count value R of a read address is larger than a count value W of a write address, the absolute value of the space of difference between the write area and the read area is calculated by subtracting a value R', for which an (m) is added to the count value R of the read address counter by an adder 4, by the subtracter 3 since the maximum address is larger only for the (m) of (2<n>-m) when the R is subtracted from the W by the subtracter 3. Thus, the spatial absolute value of difference between the write area and the read area is obtained, and the check error can be reduced. |
