Export enable. This bit permits events to be exported to another debug device, such as a trace
macrocell, over an event bus. The possible values are:
0b0
Export of events is disabled. This is the reset value.
0b1
Export of events is enabled.
No events are exported when counting is prohibited.
This field does not affect the generation of Performance Monitors overflow interrupt requests or
signaling to a cross-trigger interface (CTI) that can be implemented as signals exported from the
PE.
When this register has an architecturally defined reset value, if this field is implemented as an
RW field, it resets to 0.
D, [3]
Clock divider. The possible values are:
0b0
When enabled, counter CCNT counts every clock cycle. This is the reset value.
0b1
When enabled, counter CCNT counts once every 64 clock cycles.
Arm deprecates use of PMCR.D =
0b1
.
C, [2]
Cycle counter reset. This bit is WO. The effects of writing to this bit are:
0b0
No action. This is the reset value.
0b1
Reset PMCCNTR to zero.
This bit is always RAZ.
Resetting PMCCNTR does not clear the PMCCNTR overflow bit to 0. See the
Arm
®
Architecture Reference Manual Armv8, for Armv8-A architecture profile
for more information.
P, [1]
Event counter reset. This bit is WO. The effects of writing to this bit are:
0b0
No action. This is the reset value.
0b1
Reset all event counters accessible in the current EL, not including PMCCNTR, to
zero.
This bit is always RAZ.
In Non-secure EL0 and EL1, a write of 1 to this bit does not reset event counters that
HDCR.HPMN or MDCR_EL2.HPMN reserves for EL2 use.
In EL2 and EL3, a write of 1 to this bit resets all the event counters.
Resetting the event counters does not clear any overflow bits to 0.
E, [0]
Enable. The possible values are:
0b0
All counters that are accessible at Non-secure EL1, including PMCCNTR, are
disabled. This is the reset value.
0b1
When this register has an architecturally defined reset value, this field resets to 0.
This bit is RW.
This bit does not affect the operation of event counters that HDCR.HPMN or
MDCR_EL2.HPMN reserves for EL2 use.
When this register has an architecturally defined reset value, this field resets to 0.
D4 AArch32 PMU registers
D4.4 PMCR, Performance Monitors Control Register
100798_0300_00_en
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Summary of Contents for Cortex-A76 Core
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