EDCIDSR External Debug Context ID Sample Register EDCIDSR is in the Core power domain when FEAT_PCSRv8 is implemented and FEAT_PCSRv8p2 is not implemented Debug 0x0A4 EDCIDSR When DoubleLockStatus(), or !IsCorePowered(), or OSLockStatus() ERROR RO Contains the sampled value of the Context ID, captured on reading EDPCSR[31:0]. Debug Implemented only if the OPTIONAL PC Sample-based Profiling Extension is implemented in the external debug registers space. FEAT_PCSRv8p2 implements the PC Sample-based Profiling Extension in the Performance Monitors registers space. EDCIDSR is a 32-bit register. CONTEXTIDR 31 0 31:0 Context ID. The value of CONTEXTIDR that is associated with the most recent EDPCSR sample. When the most recent EDPCSR sample is generated: If EL1 is using AArch64, then the Context ID is sampled from CONTEXTIDR_EL1. If EL1 is using AArch32, then the Context ID is sampled from CONTEXTIDR. If EL3 is implemented and is using AArch32, then CONTEXTIDR is a banked register, and EDCIDSR samples the current banked copy of CONTEXTIDR for the Security state that is associated with the most recent EDPCSR sample. Because the value written to EDCIDSR is an indirect read of CONTEXTIDR, it is CONSTRAINED UNPREDICTABLE whether EDCIDSR is set to the original or new value if EDPCSR samples: An instruction that writes to CONTEXTIDR. The next Context synchronization event. Any instruction executed between these two instructions. AU IMPLEMENTATION DEFINED extensions to external debug might make the value of this register UNKNOWN, see 'Permitted behavior that might make the PC Sample-based profiling registers UNKNOWN'. 2026-03-26 20:27:25 2026-03_rel