| 摘要 |
PURPOSE:To restart properly processing which being executed before the occurrence of an interruption by identifying the transfer of right to occupy a common system bus depends on whether a program or an interruption. CONSTITUTION:When a CPUB is given the right to occupy the bus, an FF circuit 22 is reset. At this time, if an interruption is caused, the interruption control line 30 of the system bus 14 is energized and an FF circuit 20 is reset. Consequently, the CPUB is placed in a hold state and a CPUA is run to transfer the right to occupy the bus to the CPUA. When the interruption processing of the CPUA is completed, the CPUA reads the state of the FF circuit 22 to decide on whether the transfer of the right to occupy is caused by an interruption or program. When the transfer is caused by an interruption, the FF circuit 20 is reset on the completion of the interruption processing and the right to occupy is returned to the CPUB to restart the original processing. |
