AMCGCR

Provides information on the number of activity monitor event counters implemented within each counter group.

Configuration

AArch64 System register AMCGCR_EL0 bits [31:0] are architecturally mapped to AArch32 System register AMCGCR[31:0].

AArch64 System register AMCGCR_EL0 bits [31:0] are architecturally mapped to External register AMU.AMCGCR[31:0] when FEAT_AMU_EXT32 is implemented.

AArch64 System register AMCGCR_EL0 bits [63:0] are architecturally mapped to External register AMU.AMCGCR[63:0] when FEAT_AMU_EXT64 is implemented.

This register is present only when FEAT_AMUv1 is implemented. Otherwise, direct accesses to AMCGCR_EL0 are UNDEFINED.

Attributes

Field descriptions

Bits [63:16]

CG1NC, bits [15:8]

Counter Group 1 Number of Counters. The number of counters in the auxiliary counter group.

The value of this field is an IMPLEMENTATION DEFINED choice of:

CG1NC	Meaning
0x00..0x10	The number of counters.

All other values are reserved.

Access to this field is RO.

CG0NC, bits [7:0]

Counter Group 0 Number of Counters. The number of counters in the architected counter group.

Reads as 0x04.

Access to this field is RO.

Accessing AMCGCR_EL0

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

MRS <Xt>, AMCGCR_EL0

op0	op1	CRn	CRm	op2
0b11	0b011	0b1101	0b0010	0b010

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 HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = AMCGCR_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 HaveEL(EL3) && CPTR_EL3.TAM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = AMCGCR_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] = AMCGCR_EL0; elsif PSTATE.EL == EL3 then X[t, 64] = AMCGCR_EL0;

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																CG1NC								CG0NC

AMCGCR_EL0, Activity Monitors Counter Group Configuration Register

Purpose