AMCNTENSET0

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AMCNTENSET0_EL0, Activity Monitors Count Enable Set Register 0

Purpose

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

Configuration

AArch64 System register AMCNTENSET0_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMCNTENSET0[31:0].

AArch64 System register AMCNTENSET0_EL0 bits [31:0] are architecturally mapped to External register AMCNTENSET0[31:0].

AArch64 System register AMCNTENSET0_EL0 bits [31:0] are architecturally mapped to External register AMCNTENSET[31:0].

AArch64 System register AMCNTENSET0_EL0 bits [31:0] are architecturally mapped to External register AMCNTENCLR0[31:0].

This register is present only when FEAT_AMUv1 is implemented. Otherwise, direct accesses to AMCNTENSET0_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 enable 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, enables AMEVCNTR0<n>_EL0.

The reset behavior of this field is:

On an AMU reset, this field resets to '0'.

Accessing this field has the following behavior:

When n >= 4, access to this field is RAZ/WI.
Otherwise, access to this field is W1S.

Accessing AMCNTENSET0_EL0

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

MRS <Xt>, AMCNTENSET0_EL0

op0	op1	CRn	CRm	op2
0b11	0b011	0b1101	0b0010	0b101

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().AMCNTEN0 == '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) = AMCNTENSET0_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().AMCNTEN0 == '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) = AMCNTENSET0_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) = AMCNTENSET0_EL0(); end; elsif PSTATE.EL == EL3 then X{64}(t) = AMCNTENSET0_EL0(); end;

MSR AMCNTENSET0_EL0, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b011	0b1101	0b0010	0b101

if !IsFeatureImplemented(FEAT_AMUv1) then Undefined(); elsif IsHighestEL(PSTATE.EL) then AMCNTENSET0_EL0() = X{64}(t); else Undefined(); end;

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