AMCG1IDR_EL0 Activity Monitors Counter Group 1 Identification Register when FEAT_AMUv1p1 is implemented Defines which auxiliary counters are implemented, and which of them have a corresponding virtual offset register, AMEVCNTVOFF1<n>_EL2 implemented. AMU AMCG1IDR_EL0 is a 64-bit register. 63 32 63:32 Reserved, RES0. AMEVCNTOFF1<n>_EL2 31 16 31:16 Indicates which implemented auxiliary counters have a corresponding virtual offset register, AMEVCNTVOFF1<n>_EL2 implemented. 15 0 0b0 AMEVCNTR1<n>_EL0 does not have an offset, or is not implemented. 0b1 The offset AMEVCNTVOFF1<n>_EL2 is implemented for AMEVCNTR1<n>_EL0. AMEVCNTR1<n>_EL0 15 0 15:0 Indicates which auxiliary counters AMEVCNTR1<n>_EL0 are implemented. 15 0 0b0 AMEVCNTR1<n>_EL0 is not implemented. 0b1 AMEVCNTR1<n>_EL0 is implemented. MRS <Xt>, AMCG1IDR_EL0 if !IsFeatureImplemented(FEAT_AMUv1p1) then Undefined(); elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TAM == '1' then Undefined(); elsif AMUSERENR_EL0().EN == '0' then if EL2Enabled() && HCR_EL2().TGE == '1' then AArch64_SystemAccessTrap(EL2, 0x18); else AArch64_SystemAccessTrap(EL1, 0x18); end; elsif EL2Enabled() && CPTR_EL2().TAM == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = AMCG1IDR_EL0(); end; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TAM == '1' then Undefined(); elsif EL2Enabled() && CPTR_EL2().TAM == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = AMCG1IDR_EL0(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3().TAM == '1' then Undefined(); elsif HaveEL(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = AMCG1IDR_EL0(); end; elsif PSTATE.EL == EL3 then X{64}(t) = AMCG1IDR_EL0(); end; 2026-03-26 20:27:25 2026-03_rel