| 摘要 |
PURPOSE:To process errors, etc. with high efficiency by comparing an access code with a memory protection code in case an error is detected with a conversion buffer, etc. and at the same time using a buffer invalid flag and an address conversion exception flag. CONSTITUTION:When no coincidence is obtained between a memory protection code and an access code given from an MPU1, an error signal is delivered if an access is impossible after having comparison 9 between both said codes. Then a buffer invalid flag 11 is set when the buffer invalid bit V of the data read out of an address conversion buffer 3 is equal to '1'. Then the access of an access destination device is suppressed and a sub-MPU2 is started. This MPU2 produces a physical address corresponding to a logical address delivered from the MPU1 and performs a writing action to a buffer 3 to reset the flag 11. Then the retrieval is given to a segment table, etc. for production of a physical address. Under such conditions, and address conversion exception flag 12 and a control flag 13 are set with the flag 11 reset respectively as long as an invalid page, etc. are detected. |
