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# TRCTRACEIDR, Trace ID Register

The TRCTRACEIDR characteristics are:

## Purpose

Sets the trace ID for instruction trace.

## Configuration

AArch64 System register TRCTRACEIDR bits [31:0] are architecturally mapped to External register TRCTRACEIDR[31:0] .

This register is present only when TRCIDR5.TRACEIDSIZE != 0x00 and ETE is implemented. Otherwise, direct accesses to TRCTRACEIDR are UNDEFINED.

## Attributes

TRCTRACEIDR is a 64-bit register.

## Field descriptions

The TRCTRACEIDR 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 | TRACEID
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 [63:7]

Reserved, RES0.

#### TRACEID, bits [6:0]

Trace ID field. Sets the trace ID value for instruction trace. The width of the field is indicated by the value of TRCIDR5.TRACEIDSIZE. Unimplemented bits are RES0.

If an implementation supports AMBA ATB, then:

- The width of the field is 7 bits.
- Writing a reserved trace ID value does not affect behavior of the trace unit but it might cause UNPREDICTABLE behavior of the trace capture infrastructure.

See the AMBA ATB Protocol Specification for information about which ATID values are reserved.

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

## Accessing the TRCTRACEIDR

Must be programmed if implemented.

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

Accesses to this register use the following encodings:

#### MRS <Xt>, TRCTRACEIDR

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b001 | 0b0000 | 0b0000 | 0b001

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 TRCTRACEIDR; 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 TRCTRACEIDR; elsif PSTATE.EL == EL3 then if CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return TRCTRACEIDR;

#### MSR TRCTRACEIDR, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b001 | 0b0000 | 0b0000 | 0b001

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 TRCTRACEIDR = 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 TRCTRACEIDR = X[t]; elsif PSTATE.EL == EL3 then if CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else TRCTRACEIDR = 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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