TRCEXTINSELR<n> Trace External Input Select Register <n> when FEAT_ETE is implemented, System register access to the trace unit registers is implemented, and UInt(TRCIDR5.NUMEXTINSEL) > n 0 3 TRCEXTINSELR<n> Architectural External 31 0 31 0 31 0 31 0 Use this to set, or read, which External Inputs are resources to the trace unit. The name TRCEXTINSELR is an alias of TRCEXTINSELR0. Trace TRCEXTINSELR<n> is a 64-bit register. 63 16 63:16 Reserved, RES0. evtCount 15 0 15:0 PMU event to select. The event number as defined by the Arm ARM. Software must program this field with a PMU event that is supported by the PE being programmed. If evtCount is programmed to a PMU event that is reserved or not supported by the PE, the behavior depends on the PMU event type: For the range 0x0000 to 0x003F, then the PMU event is not active, and the value returned by a direct or external read of the evtCount field is the value written to the field. For IMPLEMENTATION DEFINED PMU events, it is UNPREDICTABLE what PMU event, if any, is counted, and the value returned by a direct or external read of the evtCount field is UNKNOWN. UNPREDICTABLE means the PMU event must not expose privileged information. Arm recommends that the behavior across a family of implementations is defined such that if a given implementation does not include a PMU event from a set of common IMPLEMENTATION DEFINED PMU events, then no PMU event is counted and the value read back on evtCount is the value written. AU Must be programmed if any of the following is true: TRCRSCTLR<a>.GROUP == 0b0000 and TRCRSCTLR<a>.EXTIN[n] == 1. Writes are CONSTRAINED UNPREDICTABLE if the trace unit is not in the Idle state. 0-3 MRS <Xt>, TRCEXTINSELR<m> let m:integer = UInt(CRm[1:0]); if m >= NUM_TRACE_EXTERNAL_INPUT_SELECTOR_RESOURCES then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TTA == '1' then Undefined(); elsif CPACR_EL1().TTA == '1' then AArch64_SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && CPTR_EL2().TTA == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGRTR_EL2().TRC == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TTA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X{64}(t) = TRCEXTINSELR(m); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TTA == '1' then Undefined(); elsif CPTR_EL2().TTA == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TTA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X{64}(t) = TRCEXTINSELR(m); end; elsif PSTATE.EL == EL3 then if CPTR_EL3().TTA == '1' then AArch64_SystemAccessTrap(EL3, 0x18); elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X{64}(t) = TRCEXTINSELR(m); end; end; 0-3 MSR TRCEXTINSELR<m>, <Xt> let m:integer = UInt(CRm[1:0]); if m >= NUM_TRACE_EXTERNAL_INPUT_SELECTOR_RESOURCES then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TTA == '1' then Undefined(); elsif CPACR_EL1().TTA == '1' then AArch64_SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && CPTR_EL2().TTA == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGWTR_EL2().TRC == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TTA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else TRCEXTINSELR(m) = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TTA == '1' then Undefined(); elsif CPTR_EL2().TTA == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TTA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else TRCEXTINSELR(m) = X{64}(t); end; elsif PSTATE.EL == EL3 then if CPTR_EL3().TTA == '1' then AArch64_SystemAccessTrap(EL3, 0x18); elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1().OSLK == '0' && HaltingAllowed() && EDSCR2().TTA == '1' then Halt(DebugHalt_SoftwareAccess); else TRCEXTINSELR(m) = X{64}(t); end; end; 2026-03-26 20:27:25 2026-03_rel