Intel 460GX 1:0 Reload Mode, Bits Description, 14Count Data Cycles, 13:10 Initiating Agent Selection, 9:8 Transaction Destination Selection

Register Descriptions

Once configured to count, all counters in the SAC and each PXB can be (nearly) simultaneously started and stopped using a separate enable.

1:0 Reload Mode

Reload has priority over increment. That is, if a Reload event and a count event happen simultaneously, the count event has no effect.

0Never Reload

1Reload when this counter overflows.

2Reload when the other counter overflows.

3Reload unless the other counter increments.

2.5.3.3PME[1:0]: Performance Monitoring Event Selection

Address Offset:	E8 - EBh	Size:	16 bits each
Default Value:	0000h each	Attribute:	Read/Write

The PME registers specify the particular event to track in the performance monitoring counters. The PXB supports tracking of PCI bus transactions (both specific and generic), and PCI bus signal assertion. Bus transactions may be qualified by the originating agent and transaction destination.

Accumulated event counts are held in the PMD registers, while the PMR registers specify the action to performed on event detection.

Bits Description

15reserved (0)

14Count Data Cycles

1:Count data cycles associated with selected event

0:Count the selected event

13:10 Initiating Agent Selection

This field qualifies the tracking of bus transactions by limiting event detection to those transactions issued by specific agents. That is, unless otherwise noted for the specific event selected (below), the agent initiating the bus transaction must match the selection specified here for the transaction to be tracked.

0000	Agent 0	1000	reserved
0001	Agent 1	1001	reserved
0010	Agent 2	1010	reserved
0011	Agent 3	1011	reserved
0100	Agent 4	1100	reserved
0101	Agent 5	1101	South bridge
0110	reserved	1110	460GX chipset agent (i.e.
			outbound)
0111	reserved	1111	Any agent

Note: This field is applicable only if the PCI bus is operated in internal-arbiter mode. If the bus is operated using an external arbiter, this field must be set to Any Agent to trigger any events.

9:8 Transaction Destination Selection

This field qualifies the tracking of bus transactions by limiting event detection to those transactions directed to a specific resource. That is, unless otherwise noted for the specific event selected (below), the source or destination of the data must match the selection specified here for the transaction to be tracked.

	00	any	10	PCI Target
	01	Main Memory	11	Parallel Segment Peer
7:6	reserved

Intel® 460GX Chipset Software Developer’s Manual 2-37