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

The TRCCNTVR<n> characteristics are:

## Purpose

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

## Configuration

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

This register is present only when TRCIDR5.NUMCNTR > n and ETE is implemented. Otherwise, direct accesses to TRCCNTVR<n> are UNDEFINED.

## Attributes

TRCCNTVR<n> is a 64-bit register.

## Field descriptions

The TRCCNTVR<n> bit assignments are:

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
RES0
RES0 | VALUE
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

#### Bits [63:16]

Reserved, RES0.

#### VALUE, bits [15:0]

Contains the count value of counter.

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

## Accessing the TRCCNTVR<n>

Must be programmed if TRCRSCTLR<a>.GROUP == 0b0010 and TRCRSCTLR<a>.COUNTERS[n] == 0b1.

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.

Accesses to this register use the following encodings:

#### MRS <Xt>, TRCCNTVR<n>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b001 | 0b0000 | 0b10[n:1:0] | 0b101

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if CPACR_EL1.TTA == '1' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return TRCCNTVR[UInt(CRm<1:0>)]; elsif PSTATE.EL == EL2 then if CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return TRCCNTVR[UInt(CRm<1:0>)]; elsif PSTATE.EL == EL3 then if CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return TRCCNTVR[UInt(CRm<1:0>)];

#### MSR TRCCNTVR<n>, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b001 | 0b0000 | 0b10[n:1:0] | 0b101

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if CPACR_EL1.TTA == '1' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else TRCCNTVR[UInt(CRm<1:0>)] = X[t]; elsif PSTATE.EL == EL2 then if CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else TRCCNTVR[UInt(CRm<1:0>)] = X[t]; elsif PSTATE.EL == EL3 then if CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else TRCCNTVR[UInt(CRm<1:0>)] = X[t];

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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