63:56

0h

RO

Reserved

55:32

0h

RW/V

(hbo_​filter_​uarch_​use)

hbo_​filter

31:24

0h

RW/V

(thresh)

Threshold on Counter Increment
Threshold is used, along with the invert bit, to compare against the incoming increment value that will be added to the counter.
For events that increment by more than 1 per cycle, if the threshold is set to a value greater than 1, the data register will accumulate instances in which the event increment is >= threshold.
e.g. say you have an event to accumulate the occupancy of a 64-entry queue every cycle. By setting the threshold value to 60, the data register would count the number of cycles the queues occupancy was >= 60.

23

0h

RW/V

(invert)

Invert comparison against Threshold.
0 comparison will be is event increment >= threshold?
1 comparison is inverted - is event increment < threshold?

e.g. for a 64-entry queue, if SW wanted to know how many cycles the queue had fewer than 4 entries, SW should set the threshold to 4 and set the invert bit to 1.

22:21

0h

RO

Reserved

20

0h

RW/V

(frz_​on_​ov)

Freeze on Overflow
When an overflow is detected from this register, a PMON overflow message is sent to the global control.
This bit will tell the global control whether it should assert the global freeze for all counters in the same domain.

19

0h

RO

Reserved

18

0h

RW/V

(edge_​det)

Edge Detect
When set to 1, rather than measuring the event in each cycle it is active, the corresponding counter will increment when a 0 to 1 transition (i.e. rising edge) is detected.
When 0, the counter will increment in each cycle that the event is asserted.

17

0h

RW/1S/V

(rst)

Reset
When set to 1, the corresponding counter will be cleared to 0.

16

0h

RO

Reserved

15:8

0h

RW/V

(umask)

For additional IP specific encoding space often used as a subevent mask

7:0

0h

RW/V

(ev_​sel)

Event Select
Minimum field to select which of the available events should be recorded in the paired data register. Additional bits in the control register may also be required to select from the available events.

0x0 == Count Nothing
0x1 == Count Local Clockticks