Re: [Gems-users] question on time in eventqueue


Date: Thu, 25 Jan 2007 21:54:37 -0600 (CST)
From: Mike Marty <mikem@xxxxxxxxxxx>
Subject: Re: [Gems-users] question on time in eventqueue
> SLICC defines a state machine -- no state can change more than once per cycle, so all future transitions,
> output changes, etc, must have at least delay 1.
>

Thats not really true.  A state can change more than once in a cycle.
For example, a Directory controller could receive two GETS messages in the
same cycle that are both handled (and both potentially state changing..for
example the first GETS could transition to S where the second might
transition to SS indicating multiple outstanding GETS requests).

The EventQueue is a priority heap.  Adding a new entry that is the minimum
could be dicey...for example if could change the current root of the tree.
We've always enforced that adding something to the EventQueue must have a
wakeup at least 1 cycle in the future.  If you try modifying this
behavior, I'd be interested to hear your experiences.
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