What are the conditions under which the EU enter into the WAIT mode?

What are the conditions under which the EU enter into the WAIT mode?

The EU goes into the WAIT mode in the following three conditions:

- If an instruction requires an access to a memory location which is not present in the queue the EU enters into the WAIT state.

- The EU enters into the WAIT mode when a JUMP instruction is executed. In such cases the existing queue contents are removed the EU waits for more instructions
from the new address in the memory.

- Certain instructions can take quite some time to execute in such cases the EU again goes into the WAIT state. For cases such as these the BIU waits till the EU is able
to extract some bytes from the queue.