TRBDEVAFF Device Affinity Register TRBDEVAFF is in the Core power domain when FEAT_TRBE_EXT is implemented TRBE 0xFA8 TRBDEVAFF When DoubleLockStatus() or !IsCorePowered() ERROR RO For additional information, see the CoreSight Architecture Specification. Reads the same value as the MPIDR_EL1 register for the PE that this trace buffer has affinity with. Depending on the IMPLEMENTATION DEFINED nature of the system, it might be possible that TRBDEVAFF is read before system firmware has configured the trace buffer and/or the PE or group of PEs that the trace buffer has affinity with. When this is the case, TRBDEVAFF reads as zero. TRBE TRBDEVAFF is a 64-bit register. 63 40 63:40 Reserved, RES0. Aff3 39 32 39:32 Affinity level 3. See the description of Aff0 for more information. This field has an IMPLEMENTATION DEFINED value. RO 31 31 31 Reserved, RAO/WI. U 30 30 30 Indicates a Uniprocessor system, as distinct from PE 0 in a multiprocessor system. 0b0 Processor is part of a multiprocessor system. 0b1 Processor is part of a uniprocessor system. RO 29 25 29:25 Reserved, RES0. MT 24 24 24 Indicates whether the lowest level of affinity consists of logical PEs that are implemented using an interdependent approach, such as multithreading. See the description of Aff0 for more information about affinity levels. This field does not indicate that multithreading is implemented and does not indicate that PEs with different affinity level 0 values, and the same values for affinity level 1 and higher are implemented. 0b0 Performance of PEs with different affinity level 0 values, and the same values for affinity level 1 and higher, is largely independent. 0b1 Performance of PEs with different affinity level 0 values, and the same values for affinity level 1 and higher, is very interdependent. RO Aff2 23 16 23:16 Affinity level 2. See the description of Aff0 for more information. This field has an IMPLEMENTATION DEFINED value. RO Aff1 15 8 15:8 Affinity level 1. See the description of Aff0 for more information. This field has an IMPLEMENTATION DEFINED value. RO Aff0 7 0 7:0 Affinity level 0. The value of the MPIDR.{Aff2, Aff1, Aff0} or MPIDR_EL1.{Aff3, Aff2, Aff1, Aff0} set of fields of each PE must be unique within the system as a whole. This field has an IMPLEMENTATION DEFINED value. RO 2026-03-26 20:27:25 2026-03_rel