A data processor capable of automatically storing in an external memory all essential information relating to the internal state thereof upon the detection of an access fault during instruction execution. Upon correction of the cause of the fault, the data processor automatically retrieves the stored state information and restores the state thereof in accordance with the retrieved state information. The data processor then resumes execution of the instruction. The faulted access may be selectively rerun upon the resumption of instruction execution. Means are provided to verify that the retrieved state information is valid.
Method and apparatus for instruction restart processing in a microprogram-controlled data processing apparatus, wherein, in restarting an instruction execution after instruction suspension, the internal information of the data processing apparatus at the time of instruction execution suspension is saved in a memory, and after a suspension cause removal process performed the saved internal information is recovered. A check point address associated with the address of a currently executing microprogram is stored in accordance with a designation by the microprogram. After a suspension causes removal process is performed, the execution of the instruction restarts using the check point address. If a check point address has not been stored after the suspension cause removal process is performed, the execution of the instruction restarts from a read operation of the suspended instruction from the main storage.
A method of exchanging information in a processing system including the steps of issuing a clock synchronizing instruction from an operating system, holding the clock synchronizing instruction in a communication information holding unit, suppressing the updating of internal state information in a first arithmetic unit in response to the holding signal, outputting a communication demand signal from the communication information holding unit to a system control unit, freezing the updating of the calendar clock values in respective first and second arithmetic processing units, receiving in the system control unit the first clock value from the first arithmetic processing unit, storing the first calendar clock value in the second arithmetic processing unit, issuing a restarting signal to the arithmetic processing units, and issuing a microprogram actuating instruction to the arithmetic processing units from the system control unit.
A method of exchanging information in a processing system including the steps of storing the internal state information of a first arithmetic processing unit upon occurrence of a fault into a system control unit, sending a processor relief instruction from the system control unit to a second arithmetic processing unit, suppressing the updating of the internal state information of the second arithmetic processing unit, storing the internal state information of the second processing unit into the system control unit, transferring the internal state information of the first arithmetic processing unit from the system control unit to the second arithmetic processing unit, and sending a reset and actuating signal from the system control unit to the second arithmetic processing unit.
An information processing system comprises at least one arithmetic processing unit operating under the control of a microprogram and a system control unit which exchanges information with the arithmetic processing unit. The system control unit is not required to perform distinction processing between one source of interruption, for example a fault notice, and another source of interruption, for example a clock synchronization demand.
Method and apparatus for instruction restart processing in a microprogram - controlled data processing apparatus, wherein, in restarting an instruction execution after instruction suspension, the internal information of the data processing apparatus at the time of instruction execution suspension is saved in a memory, and after a suspension cause removal process performed the saved internal information is recovered. A check point address associated with the address of a currently executing microprogram is stored in accordance with a designation by the microprogram. After a suspension causes removal process is performed, the execution of the instruction restarts using the check point address. If a check point address has not been stored after the suspension cause removal process is performed, the execution of the instruction restarts from a read operation of the suspended instruction from the main storage.
