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# AMCNTENCLR1_EL0, Activity Monitors Count Enable Clear Register 1

The AMCNTENCLR1_EL0 characteristics are:

## Purpose

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

## Configuration

AArch64 System register AMCNTENCLR1_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMCNTENCLR1[31:0] .

AArch64 System register AMCNTENCLR1_EL0 bits [31:0] are architecturally mapped to External register AMCNTENCLR1[31:0] .

This register is present only when AMUv1 is implemented. Otherwise, direct accesses to AMCNTENCLR1_EL0 are UNDEFINED.

Some or all RW fields of this register have defined reset values. These apply only if the PE resets into an Exception level that is using AArch64. Otherwise, RW fields in this register reset to architecturally UNKNOWN values.

## Attributes

AMCNTENCLR1_EL0 is a 64-bit register.

## Field descriptions

The AMCNTENCLR1_EL0 bit assignments are:

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
RES0
P<n>, bit [n]
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0

#### Bits [63:32]

Reserved, RES0.

#### P<n>, bit [n], for n = 0 to 31

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

Bits [31:N] are RAZ/WI. N is the value in AMCGCR_EL0.CG1NC.

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, disables AMEVCNTR1<n>_EL0.

On a Cold reset, this field resets to 0.

## Accessing the AMCNTENCLR1_EL0

If the number of auxiliary activity monitor event counters implemented is zero, reads and writes of AMCNTENCLR1_EL0 are CONSTRAINED UNPREDICTABLE, and the following behaviors are permitted:

- Accesses to the register are UNDEFINED.
- Accesses to the register behave as RAZ/WI.
- Accesses to the register execute as a NOP.

Note

The number of auxiliary activity monitor event counters implemented is zero exactly when AMCFGR_EL0.NCG == 0b0000.

Accesses to this register use the following encodings:

#### MRS <Xt>, AMCNTENCLR1_EL0

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b011 | 0b1101 | 0b0011 | 0b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && AMUSERENR_EL0.EN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMCNTENCLR1_EL0; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMCNTENCLR1_EL0; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMCNTENCLR1_EL0; elsif PSTATE.EL == EL3 then return AMCNTENCLR1_EL0;

#### MSR AMCNTENCLR1_EL0, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b011 | 0b1101 | 0b0011 | 0b000

if IsHighestEL(PSTATE.EL) then AMCNTENCLR1_EL0 = X[t]; else UNDEFINED;

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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