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AMEVCNTR1<n>_EL0: Activity Monitors Event Counter Registers 1, n = 0 - 15

Purpose

Provides access to the auxiliary activity monitor event counters.

Configuration

AArch64 System register AMEVCNTR1<n>_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMEVCNTR1<n>[31:0].

AArch64 System register AMEVCNTR1<n>_EL0 bits [63:0] are architecturally mapped to External register AMU.AMEVCNTR1<n>[63:0].

This register is present only when FEAT_AMUv1 is implemented. Otherwise, direct accesses to AMEVCNTR1<n>_EL0 are UNDEFINED.

Attributes

AMEVCNTR1<n>_EL0 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
ACNT
ACNT

ACNT, bits [63:0]

Auxiliary activity monitor event counter n.

Value of auxiliary activity monitor event counter n, where n is the number of this register and is a number from 0 to 15.

If all of the following are true, reads of the AMEVCNTR1<n>_EL0 registers from EL0 or EL1 return (PCount<63:0> - AMEVCNTVOFF1<n>_EL2<63:0>), where PCount is the physical count returned when AMEVCNTR1<n>_EL0 is read from EL2 or EL3:

If the counter is enabled, writes to this register have UNPREDICTABLE results.

The reset behavior of this field is:

Accessing AMEVCNTR1<n>_EL0

If <n> is greater than or equal to the number of auxiliary activity monitor event counters, reads and writes of AMEVCNTR1<n>_EL0 are UNDEFINED.

Note

AMCGCR_EL0.CG1NC identifies the number of auxiliary activity monitor event counters.

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

MRS <Xt>, AMEVCNTR1<m>_EL0 ; Where m = 0-15

op0op1CRnCRmop2
0b110b0110b11010b110:m[3]m[2:0]

integer m = UInt(CRm<0>:op2<2:0>); if m >= NUM_AMU_CG1_MONITORS then UNDEFINED; elsif !IsG1ActivityMonitorImplemented(m) 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); 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.AMEVCNTR1<m>_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif AMCR_EL0.CG1RZ == '1' then X[t, 64] = Zeros(64); else X[t, 64] = AMEVCNTR1_EL0[m]; 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.AMEVCNTR1<m>_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif !IsHighestEL(PSTATE.EL) && AMCR_EL0.CG1RZ == '1' then X[t, 64] = Zeros(64); else X[t, 64] = AMEVCNTR1_EL0[m]; 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); elsif !IsHighestEL(PSTATE.EL) && AMCR_EL0.CG1RZ == '1' then X[t, 64] = Zeros(64); else X[t, 64] = AMEVCNTR1_EL0[m]; elsif PSTATE.EL == EL3 then X[t, 64] = AMEVCNTR1_EL0[m];

MSR AMEVCNTR1<m>_EL0, <Xt> ; Where m = 0-15

op0op1CRnCRmop2
0b110b0110b11010b110:m[3]m[2:0]

integer m = UInt(CRm<0>:op2<2:0>); if m >= NUM_AMU_CG1_MONITORS then UNDEFINED; elsif !IsG1ActivityMonitorImplemented(m) then UNDEFINED; elsif IsHighestEL(PSTATE.EL) then AMEVCNTR1_EL0[m] = X[t, 64]; else UNDEFINED;