TRCCNTVR<n>: Trace Counter Value Register <n>, n = 0 - 3

Purpose

This sets or returns the value of Counter <n>.

Configuration

External register TRCCNTVR<n> bits [31:0] are architecturally mapped to AArch64 System register TRCCNTVR<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 TRCCNTVR<n> are RES0.

Attributes

TRCCNTVR<n> is a 32-bit register.

Field descriptions

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
RES0																VALUE

Bits [31:16]

Reserved, RES0.

VALUE, bits [15:0]

Contains the count value of Counter.

The reset behavior of this field is:

On a Trace unit reset, this field resets to an architecturally UNKNOWN value.

Accessing TRCCNTVR<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.

Reads from this register might return an UNKNOWN value if the trace unit is not in either of the Idle or Stable states.

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

Component	Offset	Instance
ETE	0x160 + (4 * n)	TRCCNTVR<n>

This interface is accessible as follows:

When OSLockStatus(), or !AllowExternalTraceAccess() or !IsTraceCorePowered(), accesses to this register generate an error response.
Otherwise, accesses to this register are RW.