Warnings; Nonthreshold Events - IBM PowerPC 604 User Manual

9.1.2.2.3 Warnings
The following warnings should be noted:
• Not all load and store operations are monitored. Only those in queue position 0 of
their respective load/store queues are monitored.
• The 604 cannot accurately track threshold events with respect to the following types
of loads and stores:
- Unaligned load and store operations that cross a word boundary
- Load and store multiple operations
- Load and store string operations
• The lateral L2 cache intervention signal is controlled by the L2 cache controller
being used. If the L2 cache controller does not provide this functionality, the events
that use this signal (PMCl events 9 and 10) become obsolete.
9.1.2.3 Nonthreshold Events
Nonthreshold events are all events except for PMCl events 9, 10, 23, or 24. Any PMI
signaled from nonthreshold events operate the same way. There is no distinction (in the SIA
and SDA registers) between an interrupt generated by a time-base register bit transition or
from PMC2 or PMCl becoming negative. In these cases the SIA contains the address of
the last instruction.completed during the cycle the PMI was signaled The SDA contains an
effective address of some instruction currently being processed.
Under these events the SIA and SDA does not contain information belonging to the same
instruction.
Chapter 9. Performance Monitor
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