| 摘要 |
PURPOSE:To shorten the processing time of a memory control device by obtaining the OR and AND of internal and external data of a memory and rewriting a specified bit only. CONSTITUTION:External data q0-q3 of a memory outputted from a CPU25 are supplied to data input terminals of memories 12-15. If the logical operation is limited to the AND operation and OR operation and when the AND of the external data of a memory and internal data of an address of the memories 12-15 is obtained, data P0-P3 of the bit of the internal data of the memories 12-15 corresponding to the bit which is ''0'' of the external data q0-q3 are rewritten to ''0''. When the OR is obtained, data P0-P1 of the bit of the internal data of the memories 12-15 corresponding to the bit which is ''1'' of the external data q0-q3 are rewritten to ''1''. |
