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IBM2520L8767
IBM Processor for ATM Resources
Buffer Pool Management (POOLS)
Page 218 of 553
atmrm.chapt04.01
08/27/99
9
Packet High Priority with Request
Timer
When set, this bit will cause POOLs to time the wait for packet memory service and
when the timer expires move to high priority.
8
Control High Priority with Request
Timer
When set, this bit will cause POOLs to time the wait for control memory service and
when the timer expires move to high priority.
7
Fast Free Mode
When this bit is set, Fast Free Mode is enabled. When POOLs is in Fast Free Mode it
does not write out the buffer map with the modified control information that indicates
that the map is unused. When in this mode unused buffer free error checking is dis-
abled.
6
Initialization Mode
When the value of the bit is ‘0’, initialization mode is set. When the value is 1, opera-
tional mode is set. During initialization mode indexes are in the upper 16 bits of the
data word. It is assumed that when initialization mode is on other normal operations
are not active such as transmit or receive. During operational mode packet addresses
assumed to be on the data bus.
5
Virtual Memory Mode
When set to ‘0’, virtual memory mode is enabled. When set to ‘1’, real memory mode
is enabled.
4
Limit Event Generation
When set, this bit will cause POOLs to limit the issuance of events to RXQUE when a
GTD threshold, Total Threshold or POOL Threshold is reached. It will issue the first
event and disable the related event enable bit. Software must then reset the bit if it
wishes to see another such event. However, it is possible that events may be lost
when this bit is set on.
3
Enable Event Interface
When set, this bit will cause POOLs to issue resource events to RXQUE when a GTD
threshold, Total Threshold or POOL Threshold is reached.
2
Enable Out of Range Index
Checking
When set, this bit will cause POOLs to check the indexes that are streaming by to be
checked against a maximum value for that size index. If the normal initialization
sequence is used, these maximum values will auto set.
1
Force All Queue Transactions to
Memory
When set, this will disable the internal tail to head transfer path within the queue. All
indexes will proceed into memory before being brought to the head of the queue. This
effectively preserves the operational history in memory. However, some caution is
warranted since four full entries are required for a write to memory. This could cause
indexes to get "stuck" at the back of the queue. When this residue occurs, a zero
pointer will be returned even though the operation might have otherwise returned a
valid pointer.
0
Diagnostic Mode
When set, POOLs is in diagnostic mode. When cleared, POOLs is in normal mode.
When in diagnostic mode, state machines are held in idle. If they are already active,
when they next go to idle they will hold there.
Bit(s)
Function
Description