| 摘要 |
PURPOSE:To attain the operation of bits just by writing the necessary data into a pair of registers by giving a write inhibiting or granting function to one of both registers capable of the simultaneous accesses for the bit corresponding to the other register. CONSTITUTION:When a certain bit of an A register 1 is 1, for example, the write is inhibited to the corresponding bit of a B register 2. Then this write is granted when the bit of the register 1 is 0. Here it is supposed that both registers 1 and 2 have the initial value 0H. Under such conditions, 5FH is written at one time to both registers 1 and 2. Thus the register 2 is inhibited to perform the write to the bit whose corresponding bit of register 1 is 1 owing to 5H of register 1; the bit is kept at initial value 0. While the register 2 is granted to perform the write to the bit whose corresponding bit is 0. Therefore the initial value is rewritten to 1 from 0 and the value of the register 2 is finally set at AH. As a result, the operation of bits is attained just with the write of a single time to both registers 1 and 2. |
