| 摘要 |
PURPOSE:To reduce the load on a CPU by setting and resetting flags by dedicated instructions in the exclusive controller of a composite electronic computer and preventing the destruction of a flag group, and finding abnormality of a CPU which occupies flags. CONSTITUTION:Central processing units CPU 10 and CPU 11 are controlled by the exclusive controller 13 when occupying a shared memory 12 and use a test and set instruction when occupying the flag group of the flag holding part 14 of the controller 13. In this case, the expected time of flag-group occupation is stored in an expected-time storage part 15 and a timer part 16 clocks the time once a CPU starts occupying the flags; when the CPU 11 sends the test and set instruction to the controller 13, a decision part 17 compares the contents of the expected-time storage part 15 with those of the timer 16 to inform the CPU 11 that the flag group can be occupied only after the expected time of occupation, and outputs an abnormality signal to an interruption information part 18 if the flags are not released after the expected time. The information part 18 demands that the CPUs 10 and 11 diagnose each other. |
