Unused addresses in embedded memory block ? are they lost ?

Hello,

I am very sorry to insist : I have just found a post on a similar subject, where dsl said that

I wanted to ask him with private message, but I am too new to the forum to send PM.

He said :

"

Any memory block has to be made up of entire M9K blocks - even though the system build will show the actual memory cells used (not overly useful).

the one exception is that is will use the second port to let two users share the same m9k block - provided the access modes allow it."

So, if i understand well, when a M9k or M144k is partially used as a single port memory, quartus can fit another instance to the memory left, which is accessible with the second port ?

Where can this be configured ?

Thank you for your answer.

Cecile