ibm3206k0424 ETC-unknow, ibm3206k0424 Datasheet - Page 379

• Manufacturer Part Number: ibm3206k0424
• Description: Ibm Processor For Network Resources
• Manufacturer: ETC-unknow

Preliminary
RXQUE Normal Operation
This section describes how to use the receive queues (rxq) and the rxq operations.
The receive queue contains events for the end user to process. These events are obtained by the user by
executing the rxq deq operation. The user can be notified of new events by setting up the threshold and inter-
rupt enable registers appropriately. Otherwise, the rxq length register can be polled to check for events.
The deq operation is executed by reading the deq register address for the appropriate rxq. The event at the
head of the queue is returned and the event is removed from the queue. Some events have a packet/cell
buffer associated with it. This buffer is owned by the user, and it is the users responsibility to free this buffer.
The following pseudo code illustrates how an rxq could be processed:
RXQUE Dequeue Event Loop
RXQUE Queue Full Operation
When a receive queue is full (length is equal to maximum length), the appropriate status bit is set. When a
queue is full, all subsequent events are flushed until room is available in the receive queue. If a buffer was
associated with the event and the RXQUE-Properties-Register bit Disable Auto-Free is not set, then that
buffer is freed back to POOLS.
When an event is dropped, the event dropped status bit is set and the event data that was dropped can be
found in RXQUE Last Event Dropped Register. The RXQUE Last Event Dropped Register will not be
changed until the event dropped status bit is cleared.
It is not good to let a receive queue become full.
pnr25.chapt05.01
August 14, 2000
// rxq was polled or int ocurred to get here
Event = RXQUE->Deq;
if (Event neq 0) {
}
EventType = Event & 0x7f;
Event = Event & ~(0x7f); // calc lc or buffer ptr
switch (EventType) {
}
case(Event1):
case(Event2):
case(EventX):
ProcessSimpleEvent1(Event);
break;
ProcessSimpleEvent2(Event);
break;
ProcessSimpleEventX(Event);
break;
// need to check for null event
// read an event from rxq
// calc event type
IBM Processor for Network Resources
Receive Queues (RXQUE)
Page 379 of 676
IBM3206K0424