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AMCNTENSET1_EL0

AMCNTENSET1_EL0, Activity Monitors Count Enable Set Register 1

The AMCNTENSET1_EL0 characteristics are:

Purpose

Enable control bits for the auxiliary activity monitors event counters, AMEVCNTR1<n>_EL0.

Configuration

AArch64 System register AMCNTENSET1_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMCNTENSET1[31:0].

AArch64 System register AMCNTENSET1_EL0 bits [31:0] are architecturally mapped to External register AMCNTENSET1[31:0].

AArch64 System register AMCNTENSET1_EL0 bits [31:0] are architecturally mapped to External register AMCNTENCLR1[31:0].

AArch64 System register AMCNTENSET1_EL0 bits [31:0] are architecturally mapped to External register AMCNTENSET[63:32].

This register is present only when FEAT_AMUv1 is implemented. Otherwise, direct accesses to AMCNTENSET1_EL0 are UNDEFINED.

Attributes

AMCNTENSET1_EL0 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
RES0P15P14P13P12P11P10P9P8P7P6P5P4P3P2P1P0

Bits [63:16]

Reserved, RES0.

P<n>, bit [n], for n = 15 to 0

Activity monitor event counter enable bit for AMEVCNTR1<n>_EL0.

Possible values of each bit are:

P<n>Meaning
0b0

When read, means that AMEVCNTR1<n>_EL0 is disabled. When written, has no effect.

0b1

When read, means that AMEVCNTR1<n>_EL0 is enabled. When written, enables AMEVCNTR1<n>_EL0.

The reset behavior of this field is:

Accessing this field has the following behavior:

Accessing AMCNTENSET1_EL0

If there are no auxiliary monitor event counters implemented, reads and writes of AMCNTENSET1_EL0 are UNDEFINED.

Note

There are no implemented auxiliary activity monitor event counters when AMCFGR_EL0.NCG == 0b0000.

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, AMCNTENSET1_EL0

op0op1CRnCRmop2
0b110b0110b11010b00110b001

if !IsFeatureImplemented(FEAT_AMUv1) 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 EL2Enabled() && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HAFGRTR_EL2().AMCNTEN1 == '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) = AMCNTENSET1_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 EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HAFGRTR_EL2().AMCNTEN1 == '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) = AMCNTENSET1_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) = AMCNTENSET1_EL0(); end; elsif PSTATE.EL == EL3 then X{64}(t) = AMCNTENSET1_EL0(); end;

MSR AMCNTENSET1_EL0, <Xt>

op0op1CRnCRmop2
0b110b0110b11010b00110b001

if !IsFeatureImplemented(FEAT_AMUv1) then Undefined(); elsif IsHighestEL(PSTATE.EL) then AMCNTENSET1_EL0() = X{64}(t); else Undefined(); end;


2026-03-26 20:27:25, 2026-03_rel

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