CNTVCTSS

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CNTVCTSS, Counter-timer Self-Synchronized Virtual Count register

Purpose

Holds the 64-bit virtual count value. The virtual count value is equal to the physical count value visible in CNTPCT minus the virtual offset visible in CNTVOFF.

Configuration

AArch32 System register CNTVCTSS bits [63:0] are architecturally mapped to AArch64 System register CNTVCTSS_EL0[63:0].

This register is present only when FEAT_AA32 is implemented and FEAT_ECV is implemented. Otherwise, direct accesses to CNTVCTSS are UNDEFINED.

All reads to the CNTVCTSS occur in program order relative to reads to CNTVCT or CNTVCTSS.

This register is a view of the CNTVCT register for which reads appear to occur in program order relative to other instructions, without the need for any explicit synchronization. Reads of this register return a value consistent with the counter not being read until the read instruction is known to be non-speculative.

Attributes

Field descriptions

SSVirtualCount, bits [63:0]

Accessing CNTVCTSS

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

MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>

coproc	CRm	opc1
0b1111	0b1110	0b1001

if !(IsFeatureImplemented(FEAT_AA32) && IsFeatureImplemented(FEAT_ECV)) then Undefined(); elsif PSTATE.EL == EL0 then if IsFeatureImplemented(FEAT_AA64EL1) && !ELUsingAArch32(EL1) && !ELIsInHost(EL0) && CNTKCTL_EL1().EL0VCTEN == '0' then if EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && HCR_EL2().TGE == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x04); else AArch64_AArch32SystemAccessTrap(EL1, 0x04); end; elsif IsFeatureImplemented(FEAT_AA32EL1) && ELUsingAArch32(EL1) && CNTKCTL().PL0VCTEN == '0' then if EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && HCR_EL2().TGE == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HCR().TGE == '1' then AArch32_TakeHypTrapException(0x00); else Undefined(); end; elsif ELIsInHost(EL0) && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && CNTHCTL_EL2().EL0VCTEN == '0' then AArch64_AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && !ELIsInHost(EL0) && CNTHCTL_EL2().EL1TVCT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x04); else if HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && (!EL2Enabled() || !ELIsInHost(EL0)) then R(t, t2) = PhysicalCountInt() - CNTVOFF_EL2(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) && !ELUsingAArch32(EL2) && (!EL2Enabled() || !ELIsInHost(EL0)) then R(t, t2) = PhysicalCountInt() - CNTVOFF(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF(); else R(t, t2) = PhysicalCountInt(); end; end; elsif PSTATE.EL == EL1 then if EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && CNTHCTL_EL2().EL1TVCT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x04); else if HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF_EL2(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF(); else R(t, t2) = PhysicalCountInt(); end; end; elsif PSTATE.EL == EL2 then if HaveEL(EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF(); else R(t, t2) = PhysicalCountInt(); end; elsif PSTATE.EL == EL3 then if HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF_EL2(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) then R(t, t2) = PhysicalCountInt() - CNTVOFF(); else R(t, t2) = PhysicalCountInt(); end; end;

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SSVirtualCount
SSVirtualCount