| 摘要 |
PURPOSE:To execute a series of interrupt processings without setting a central processing unit to the holding state undesiredly, by referring to contents of an input/output system area to enter into execution of interrupt processings and resetting the pending state of interrupt request and input/output interrupt. CONSTITUTION:When receiving an interrupt request signal, a central processing unit 1-0 takes in required information from an input/output system area 6 in accordance with an interrupt unit and performs interrupt processings. If the mode of interrupt in a channel unit is applied, contents of an interrupt pending latch 7 are reset when the central processing unit 1 receives the interrupt request signal from an interrupt request signal transmitting part 15; but if the mode of interrupt in an interrupt level unit is applied, said contents are reset when an interrupt queue is empty. A channel device dequeues interrupts in the interrupt queue in the former mode, and the central processing unit handles unitedly dequeued interrupts in the latter mode. After the latch 7 is reset, an interrupt request indicating latch 16 is reset. |
