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The AMEVCNTR0<n>_EL0 characteristics are:
Provides access to the architected activity monitor event counters.
AArch64 System register AMEVCNTR0<n>_EL0 bits [63:0] are architecturally mapped to AArch32 System register AMEVCNTR0<n>[63:0] .
AArch64 System register AMEVCNTR0<n>_EL0 bits [63:0] are architecturally mapped to External register AMEVCNTR0<n>[63:0] .
This register is present only when AMUv1 is implemented. Otherwise, direct accesses to AMEVCNTR0<n>_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.
AMEVCNTR0<n>_EL0 is a 64-bit register.
The AMEVCNTR0<n>_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 |
ACNT | |||||||||||||||||||||||||||||||
ACNT | |||||||||||||||||||||||||||||||
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 |
Architected activity monitor event counter n.
Value of architected activity monitor event counter n, where n is the number of this register and is a number from 0 to 15.
If ARMv8.6-AMU is implemented, HCR_EL2.AMVOFFEN is 1, SCR_EL3.AMVOFFEN is 10, HCR_EL2.{E2H, TGE} is not {1,1}, and EL2 is implemented in the current Security state, access to these registers at EL0 or EL1 return (PCount<63:0> - AMEVCNTVOFF0<n>_EL2<63:0>).
PCount is the physical count returned when AMEVCNTR0<n>_EL0 is read from EL2 or EL3.
If the counter is enabled, writes to this register have UNPREDICTABLE results.
On a Cold reset, this field resets to 0.
If <n> is greater than or equal to the number of architected activity monitor event counters, reads and writes of AMEVCNTR0<n>_EL0 are UNDEFINEDCONSTRAINED UNPREDICTABLE., and the following behaviors are permitted:
AMCGCR_EL0.CG0NC identifies the number of architected activity monitor event counters.
Accesses to this register use the following encodings:
op0 | op1 | CRn | CRm | op2 |
---|---|---|---|---|
0b11 | 0b011 | 0b1101 | 0b010:n[3] | n[2:0] |
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 EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HAFGRTR_EL2.AMEVCNTR0<n>_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMEVCNTR0_EL0[UInt(CRm<0>:op2<2:0>)]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HAFGRTR_EL2.AMEVCNTR0<n>_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMEVCNTR0_EL0[UInt(CRm<0>:op2<2:0>)]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return AMEVCNTR0_EL0[UInt(CRm<0>:op2<2:0>)]; elsif PSTATE.EL == EL3 then return AMEVCNTR0_EL0[UInt(CRm<0>:op2<2:0>)];
op0 | op1 | CRn | CRm | op2 |
---|---|---|---|---|
0b11 | 0b011 | 0b1101 | 0b010:n[3] | n[2:0] |
if IsHighestEL(PSTATE.EL) then AMEVCNTR0_EL0[UInt(CRm<0>:op2<2:0>)] = X[t]; else UNDEFINED;
1327/1209/2019 1518:1348; 391b5248b29fb2f001ef74792eaacbd6fc72f2116134483bd14dc8c12a99c984cbfe3431cc1c9707
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