All three flush-generating conditions can be enabled together:

If more flush events are generated while a flush is in progress, the current flush is serviced before the next flush is started. Only one request for each source of flush can be pended. If a subsequent flush request signal is deasserted while the flush is still being serviced or pended, a second flush is not generated.

Figure 10.2 shows generation of flush on flushin.

Figure 10.3 shows generation of flush from a trigger event.

Figure 10.4 shows generation of a flush on manual.