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CNTVCTSS_EL0: 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_EL0 minus the virtual offset visible in CNTVOFF_EL2.

Configuration

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

This register is present only when FEAT_ECV is implemented. Otherwise, direct accesses to CNTVCTSS_EL0 are UNDEFINED.

All reads to the CNTVCTSS_EL0 occur in program order relative to reads to CNTVCT_EL0 or CNTVCTSS_EL0.

This register is a self-synchronised view of the CNTVCT_EL0 counter, and cannot be read speculatively.

Attributes

CNTVCTSS_EL0 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
Self-synchronized virtual count value
Self-synchronized virtual count value

Bits [63:0]

Self-synchronized virtual count value.

The reset behavior of this field is:

Accessing CNTVCTSS_EL0

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

MRS <Xt>, CNTVCTSS_EL0

op0op1CRnCRmop2
0b110b0110b11100b00000b110

if PSTATE.EL == EL0 then if !ELIsInHost(EL0) && CNTKCTL_EL1.EL0VCTEN == '0' then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif ELIsInHost(EL0) && CNTHCTL_EL2.EL0VCTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELIsInHost(EL0) && CNTHCTL_EL2.EL1TVCT == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else if HaveEL(EL2) && (!EL2Enabled() || !ELIsInHost(EL0)) then X[t, 64] = PhysicalCountInt() - CNTVOFF_EL2; else X[t, 64] = PhysicalCountInt(); elsif PSTATE.EL == EL1 then if EL2Enabled() && CNTHCTL_EL2.EL1TVCT == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else if HaveEL(EL2) then X[t, 64] = PhysicalCountInt() - CNTVOFF_EL2; else X[t, 64] = PhysicalCountInt(); elsif PSTATE.EL == EL2 then if !ELIsInHost(EL2) then X[t, 64] = PhysicalCountInt() - CNTVOFF_EL2; else X[t, 64] = PhysicalCountInt(); elsif PSTATE.EL == EL3 then if HaveEL(EL2) && !ELUsingAArch32(EL2) then X[t, 64] = PhysicalCountInt() - CNTVOFF_EL2; elsif HaveEL(EL2) && ELUsingAArch32(EL2) then X[t, 64] = PhysicalCountInt() - CNTVOFF; else X[t, 64] = PhysicalCountInt();