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AMUSERENR

AMUSERENR, Activity Monitors User Enable Register

The AMUSERENR characteristics are:

Purpose

Global user enable register for the activity monitors. Enables or disables EL0 access to the activity monitors. AMUSERENR is applicable to both the architected and the auxiliary counter groups.

Configuration

AArch32 System register AMUSERENR bits [31:0] are architecturally mapped to AArch64 System register AMUSERENR_EL0[31:0].

This register is present only when FEAT_AMUv1 is implemented and FEAT_AA32 is implemented. Otherwise, direct accesses to AMUSERENR are UNDEFINED.

Attributes

AMUSERENR is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0EN

Bits [31:1]

Reserved, RES0.

EN, bit [0]

Traps EL0 accesses to the activity monitors registers to EL1.

ENMeaning
0b0

EL0 accesses to the activity monitors registers are trapped to EL1.

0b1

This control does not cause any instructions to be trapped. Software can access all activity monitor registers at EL0.

Note

The reset behavior of this field is:

Accessing AMUSERENR

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

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b11010b00100b011

if !(IsFeatureImplemented(FEAT_AMUv1) && IsFeatureImplemented(FEAT_AA32)) then Undefined(); elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then Undefined(); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && !ELIsInHost(EL0) && HSTR_EL2().T13 == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HSTR().T13 == '1' then AArch32_TakeHypTrapException(0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && CPTR_EL2().TAM == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HCPTR().TAM == '1' then AArch32_TakeHypTrapException(0x03); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; else R(t) = AMUSERENR(); end; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && HSTR_EL2().T13 == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HSTR().T13 == '1' then AArch32_TakeHypTrapException(0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && CPTR_EL2().TAM == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HCPTR().TAM == '1' then AArch32_TakeHypTrapException(0x03); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; else R(t) = AMUSERENR(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then Undefined(); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; else R(t) = AMUSERENR(); end; elsif PSTATE.EL == EL3 then R(t) = AMUSERENR(); end;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b11010b00100b011

if !(IsFeatureImplemented(FEAT_AMUv1) && IsFeatureImplemented(FEAT_AA32)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && HSTR_EL2().T13 == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HSTR().T13 == '1' then AArch32_TakeHypTrapException(0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && CPTR_EL2().TAM == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HCPTR().TAM == '1' then AArch32_TakeHypTrapException(0x03); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; else AMUSERENR() = R(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then Undefined(); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && CPTR_EL3().TAM == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; else AMUSERENR() = R(t); end; elsif PSTATE.EL == EL3 then AMUSERENR() = R(t); end;


2026-03-12 12:23:09, 2025-09_rel_asl1

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