AMCNTENCLR0

Disable control bits for the architected activity monitors event counters, AMEVCNTR0<n>_EL0.

Configuration

AArch64 System register AMCNTENCLR0_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMCNTENCLR0[31:0].

AArch64 System register AMCNTENCLR0_EL0 bits [31:0] are architecturally mapped to External register AMU.AMCNTENCLR0[31:0].

AArch64 System register AMCNTENCLR0_EL0 bits [31:0] are architecturally mapped to External register AMU.AMCNTENCLR[31:0].

AArch64 System register AMCNTENCLR0_EL0 bits [31:0] are architecturally mapped to External register AMU.AMCNTENSET0[31:0].

This register is present only when FEAT_AMUv1 is implemented. Otherwise, direct accesses to AMCNTENCLR0_EL0 are UNDEFINED.

Attributes

Field descriptions

Bits [63:16]

Bits [15:4]

P<n>, bit [n], for n = 3 to 0

Activity monitor event counter disable bit for AMEVCNTR0<n>_EL0.

Note

AMCGCR_EL0.CG0NC identifies the number of architected activity monitor event counters. In an implementation that includes FEAT_AMUv1, the number of architected activity monitor event counters is 4.

Possible values of each bit are:

P<n>	Meaning
0b0	When read, means that AMEVCNTR0<n>_EL0 is disabled. When written, has no effect.
0b1	When read, means that AMEVCNTR0<n>_EL0 is enabled. When written, disables AMEVCNTR0<n>_EL0.

The reset behavior of this field is:

On an AMU reset, this field resets to 0.

Accessing AMCNTENCLR0_EL0

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

MRS <Xt>, AMCNTENCLR0_EL0

op0	op1	CRn	CRm	op2
0b11	0b011	0b1101	0b0010	0b100

if 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.AMCNTEN0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = AMCNTENCLR0_EL0; 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.AMCNTEN0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = AMCNTENCLR0_EL0; 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); else X[t, 64] = AMCNTENCLR0_EL0; elsif PSTATE.EL == EL3 then X[t, 64] = AMCNTENCLR0_EL0;

MSR AMCNTENCLR0_EL0, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b011	0b1101	0b0010	0b100

if IsHighestEL(PSTATE.EL) then AMCNTENCLR0_EL0 = X[t, 64]; else UNDEFINED;

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
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
RES0
RES0																RAZ/WI												P3	P2	P1	P0

AMCNTENCLR0_EL0, Activity Monitors Count Enable Clear Register 0

Purpose