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TRCCNTCTLR<n>: Trace Counter Control Register <n>, n = 0 - 3

Purpose

Controls the operation of Counter <n>.

Configuration

External register TRCCNTCTLR<n> bits [31:0] are architecturally mapped to AArch64 System register TRCCNTCTLR<n>[31:0].

This register is present only when FEAT_ETE is implemented, FEAT_TRC_EXT is implemented and UInt(TRCIDR5.NUMCNTR) > n. Otherwise, direct accesses to TRCCNTCTLR<n> are RES0.

Attributes

TRCCNTCTLR<n> is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0CNTCHAINRLDSELFRLDEVENT_TYPERES0RLDEVENT_SELCNTEVENT_TYPERES0CNTEVENT_SEL

Bits [31:18]

Reserved, RES0.

CNTCHAIN, bit [17]

When n is odd:

For TRCCNTCTLR3 and TRCCNTCTLR1, this field controls whether the Counter decrements when a reload event occurs for Counter <n-1>.

CNTCHAINMeaning
0b0

The Counter does not decrement when a reload event for Counter <n-1> occurs.

0b1

Counter <n> decrements when a reload event for Counter <n-1> occurs. This concatenates Counter <n> and Counter <n-1>, to provide a larger count value.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

RLDSELF, bit [16]

Controls whether a reload event occurs for the Counter, when the Counter reaches zero.

RLDSELFMeaning
0b0

Normal mode.

The Counter is in Normal mode.

0b1

Self-reload mode.

The Counter is in Self-reload mode.

The reset behavior of this field is:

RLDEVENT_TYPE, bit [15]

Selects an event, that when it occurs causes a reload event for Counter <n>

Chooses the type of Resource Selector.

RLDEVENT_TYPEMeaning
0b0

A single Resource Selector.

TRCCNTCTLR<n>.RLDEVENT.SEL[4:0] selects the single Resource Selector, from 0-31, used to activate the resource event.

0b1

A Boolean-combined pair of Resource Selectors.

TRCCNTCTLR<n>.RLDEVENT.SEL[3:0] selects the Resource Selector pair, from 0-15, that has a Boolean function that is applied to it whose output is used to activate the resource event. TRCCNTCTLR<n>.RLDEVENT.SEL[4] is RES0.

The reset behavior of this field is:

Bits [14:13]

Reserved, RES0.

RLDEVENT_SEL, bits [12:8]

Selects an event, that when it occurs causes a reload event for Counter <n>

Defines the selected Resource Selector or pair of Resource Selectors. TRCCNTCTLR<n>.RLDEVENT.TYPE controls whether TRCCNTCTLR<n>.RLDEVENT.SEL is the index of a single Resource Selector, or the index of a pair of Resource Selectors.

If an unimplemented Resource Selector is selected using this field, the behavior of the resource event is UNPREDICTABLE, and the resource event might fire or might not fire when the resources are not in the Paused state.

Selecting Resource Selector pair 0 using this field is UNPREDICTABLE, and the resource event might fire or might not fire when the resources are not in the Paused state.

The reset behavior of this field is:

CNTEVENT_TYPE, bit [7]

Selects an event, that when it occurs causes Counter <n> to decrement.

Chooses the type of Resource Selector.

CNTEVENT_TYPEMeaning
0b0

A single Resource Selector.

TRCCNTCTLR<n>.CNTEVENT.SEL[4:0] selects the single Resource Selector, from 0-31, used to activate the resource event.

0b1

A Boolean-combined pair of Resource Selectors.

TRCCNTCTLR<n>.CNTEVENT.SEL[3:0] selects the Resource Selector pair, from 0-15, that has a Boolean function that is applied to it whose output is used to activate the resource event. TRCCNTCTLR<n>.CNTEVENT.SEL[4] is RES0.

The reset behavior of this field is:

Bits [6:5]

Reserved, RES0.

CNTEVENT_SEL, bits [4:0]

Selects an event, that when it occurs causes Counter <n> to decrement.

Defines the selected Resource Selector or pair of Resource Selectors. TRCCNTCTLR<n>.CNTEVENT.TYPE controls whether TRCCNTCTLR<n>.CNTEVENT.SEL is the index of a single Resource Selector, or the index of a pair of Resource Selectors.

If an unimplemented Resource Selector is selected using this field, the behavior of the resource event is UNPREDICTABLE, and the resource event might fire or might not fire when the resources are not in the Paused state.

Selecting Resource Selector pair 0 using this field is UNPREDICTABLE, and the resource event might fire or might not fire when the resources are not in the Paused state.

The reset behavior of this field is:

Accessing TRCCNTCTLR<n>

Must be programmed if TRCRSCTLR<a>.GROUP == 0b0010 and TRCRSCTLR<a>.COUNTERS[n] == 1.

Writes are CONSTRAINED UNPREDICTABLE if the trace unit is not in the Idle state.

TRCCNTCTLR<n> can be accessed through the external debug interface:

ComponentOffsetInstance
ETE0x150 + (4 * n)TRCCNTCTLR<n>

This interface is accessible as follows: