RE: Questions about input-ready propagation

Hi John,

John> I'm not sure what you mean by "two messages occur at the
John> port back to back".

This is a case where the infrastructure is capable of `moving'
the second message one uclock cycle after the first. In this
case TransmitReady and ReceiveReady are both asserted for two
clock cycles. This case is not shown in Figure 10 on p. 26
and I was wondering what the rule for input-ready propagation
for the second message is in this case. If input-ready is
propagated it will inevitably propagate to the SW side *after*
the message it refers to has actually moved. This makes me
wonder if IsReady() should even be called in this case.

John> Input ready does not result from sends of messages to the
John> input port.

I understand that.

John> It results from indications from the input port that the
John> H/W side is ready to receive a message. Each such indication
John> (detected via ReceiveReady) will result in the calling of the
John> callback.

I am still not sure how to deal with batches of back-to-back
messages although reading what you just said makes me believe
you might prefer to treat a batch of back-to-back messages as
a single message for the purpose of input-ready propagation.
What do you think?

Thanks for taking time to answer these questions.

Per
Received on Tue May 4 05:47:30 2004