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PMCCNTR, Performance Monitors Cycle Count Register
The PMCCNTR characteristics are:
Purpose
Holds the value of the processor Cycle Counter, CCNT, that counts processor clock cycles. See 'Time as measured by the Performance Monitors cycle counter' for more information.
PMCCFILTR determines the modes and states in which the PMCCNTR can increment.
Configuration
AArch32 System register PMCCNTR bits [63:0] are architecturally mapped to AArch64 System register PMCCNTR_EL0[63:0] .
AArch32 System register PMCCNTR bits [63:0] are architecturally mapped to External register PMCCNTR_EL0[63:0] .
This register is present only when AArch32 is supported at any Exception level and PMUv3 is implemented. Otherwise, direct accesses to PMCCNTR are UNDEFINED.
All counters are subject to any changes in clock frequency, including clock stopping caused by the WFI and WFE instructions. This means that it is CONSTRAINED UNPREDICTABLE whether or not PMCCNTR continues to increment when clocks are stopped by WFI and WFE instructions.
Attributes
PMCCNTR is a 64-bit register that can also be accessed as a 32-bit value. If it is accessed as a 32-bit register, accesses read and write bits [31:0] and do not modify bits [63:32].
Field descriptions
The PMCCNTR 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 |
| CCNT | |||||||||||||||||||||||||||||||
| CCNT | |||||||||||||||||||||||||||||||
| 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 |
CCNT, bits [63:0]
Cycle count. Depending on the values of PMCR.{LC,D}, this field increments in one of the following ways:
- Every processor clock cycle.
- Every 64th processor clock cycle.
Writing 1 to PMCR.C sets this field to 0.
On a Warm reset, this field resets to an architecturally UNKNOWN value.
Accessing the PMCCNTR
Accesses to this register use the following encodings:
MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
| coproc | opc1 | CRn | CRm | opc2 |
|---|---|---|---|---|
| 0b1111 | 0b000 | 0b1001 | 0b1101 | 0b000 |
if PSTATE.EL == EL0 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.<CR,EN> == '00' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
else
AArch64.AArch32SystemAccessTrap(EL1, 0x03);
elsif ELUsingAArch32(EL1) && PMUSERENR.<CR,EN> == '00' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
AArch32.TakeHypTrapException(0x00);
else
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.PMCCNTR_EL0 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x03);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
return PMCCNTR<31:0>;
elsif PSTATE.EL == EL1 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x03);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
return PMCCNTR<31:0>;
elsif PSTATE.EL == EL2 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
return PMCCNTR<31:0>;
elsif PSTATE.EL == EL3 then
return PMCCNTR<31:0>;
MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
| coproc | opc1 | CRn | CRm | opc2 |
|---|---|---|---|---|
| 0b1111 | 0b000 | 0b1001 | 0b1101 | 0b000 |
if PSTATE.EL == EL0 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.EN == '0' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
else
AArch64.AArch32SystemAccessTrap(EL1, 0x03);
elsif ELUsingAArch32(EL1) && PMUSERENR.EN == '0' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
AArch32.TakeHypTrapException(0x00);
else
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.PMCCNTR_EL0 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x03);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
PMCCNTR = ZeroExtend(R[t]);
elsif PSTATE.EL == EL1 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x03);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x03);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
PMCCNTR = ZeroExtend(R[t]);
elsif PSTATE.EL == EL2 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x03);
else
PMCCNTR = ZeroExtend(R[t]);
elsif PSTATE.EL == EL3 then
PMCCNTR = ZeroExtend(R[t]);
MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>
| coproc | CRm | opc1 |
|---|---|---|
| 0b1111 | 0b1001 | 0b0000 |
if PSTATE.EL == EL0 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.<CR,EN> == '00' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
else
AArch64.AArch32SystemAccessTrap(EL1, 0x04);
elsif ELUsingAArch32(EL1) && PMUSERENR.<CR,EN> == '00' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
AArch32.TakeHypTrapException(0x00);
else
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.PMCCNTR_EL0 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x04);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
return PMCCNTR;
elsif PSTATE.EL == EL1 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x04);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
return PMCCNTR;
elsif PSTATE.EL == EL2 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
return PMCCNTR;
elsif PSTATE.EL == EL3 then
return PMCCNTR;
MCRR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>
| coproc | CRm | opc1 |
|---|---|---|
| 0b1111 | 0b1001 | 0b0000 |
if PSTATE.EL == EL0 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.EN == '0' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
else
AArch64.AArch32SystemAccessTrap(EL1, 0x04);
elsif ELUsingAArch32(EL1) && PMUSERENR.EN == '0' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
AArch32.TakeHypTrapException(0x00);
else
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.PMCCNTR_EL0 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x04);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
PMCCNTR = R[t2]:R[t];
elsif PSTATE.EL == EL1 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T9 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then
AArch32.TakeHypTrapException(0x04);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x04);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then
AArch32.TakeHypTrapException(0x04);
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
PMCCNTR = R[t2]:R[t];
elsif PSTATE.EL == EL2 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
UNDEFINED;
elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.AArch32SystemAccessTrap(EL3, 0x04);
else
PMCCNTR = R[t2]:R[t];
elsif PSTATE.EL == EL3 then
PMCCNTR = R[t2]:R[t];