Intel 460GX - Manual (Page 58)

Register Descriptions
2-38 Intel® 460GX Chipset Software Developer’s Manual
5:0 Event Selection
This field specifies the basic PCI bus transaction or PCI bus signal to be monitored.
All other encodings are reserved.
NOTE:1. Counting data cycles is undefined for this selection.
2.5.4 GXB
2.5.4.1 AGP_PMD_0,1: AGP Performance Monitor Data Registers
Function Number: BFN+1
Address Offset: 50h, 58h Size: 64 bits
Default Value: 0 Attribute: Read/Write
Sticky: No Locked: No
This counter may be configured to track AGP bus events as well as events internal to the GXB.
Event detection may be configured to increment a counter, affect performance monitoring pins, and
issue an interrupt request on counter overflow.
The value written to this address, loads the counter and is also saved in a reload register. Each
counter can be configured to reload the data.
The AGP_G_PMD register holds the performance monitoring count value. 39-bits of the counter
are used for event counting, the 40th-bit is used as a overflow detection bit. The 39-bit count value
allows up to 70 minutes of event collection at 133 MHz. Event selection is controlled by the PMC
registers.
Each counter may be stopped/started independently, using the controls available in the associated
PMD register.
Bits Description
63:40 reserved(0)
39 Overflow
This bit is asserted when the Event Count bit 38 carries into bit 39.
Individual Bus Transactions
00 0000
reserved 00 1000 reserved
00 0001 reserved 00 1001 reserved
00 0010 I/O Read 00 1010 reserved
00 0011 I/O Write 00 1011 reserved
00 0100 reserved 00 1100 Memory Read Multiple
00 0101 reserved 00 1101 Dual Address Cycle
00 0110 Memory Read 00 1110 Memory Read Line
00 0111 Memory Write 00 1111 Memory Write & Invalidate
Generic (Grouped) Bus Transactions
010 000
Any bus transaction 010 100 Any I/O transaction
010 001 Any memory transaction 010 101 Any I/O or memory
transactions
010 010 Any memory read 010 110 Any I/O or memory read
010 011 Any memory write 010 111 Any I/O or memory write
Bus Signal Assertions
011 000
reserved 011 100 reserved
011 001 reserved 011 101 reserved
011 010 RETRY
1
011 110 LOCK
011 011 reserved 011 111 ACK64