| 摘要 |
PURPOSE:To shorten waiting time in the case of writing data from the outside to a register provided at a processor connected to an external bus. CONSTITUTION:When an instruction executing part 201 at a pre-processor 103 starts processing, a register/access control flag 209 is set, a busy signal 423 is turned to '1' and write from the outside to a parameter register group 207 is inhibited. Afterwards, the instruction executing part 201 performs processing while accessing both of the parameter register group 207 and a register group 208 for work. When the instruction executing part 201 clears the register access control flag 209, the busy signal 423 is turned to '0' and write from the outside to the parameter register group 207 is permitted. Afterwards, the instruction executing part 201 performs remaining processing while accessing only the register group 208 for work. Therefore, data can be written from the outside to the parameter register group 207 even without waiting that the instruction executing part 201 is turned to a standstill state. |
