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CNTVCTSS_EL0, Counter-timer Self-Synchronized Virtual Count register

The CNTVCTSS_EL0 characteristics are:

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 ARMv8.6-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

The CNTVCTSS_EL0 bit assignments are:

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

Bits [63:0]

Self-synchronized virtual count value.

Accessing the CNTVCTSS_EL0

Accesses to this register use the following encodings:

MRS <Xt>, CNTVCTSS_EL0

op0op1CRnCRmop2
0b110b0110b11100b00000b110
if PSTATE.EL == EL0 then
    if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VCTEN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.SystemAccessTrap(EL2, 0x18);
        else
            AArch64.SystemAccessTrap(EL1, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VCTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTHCTL_EL2.EL1TVCT == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        return CNTVCTSS_EL0;
elsif PSTATE.EL == EL1 then
    if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTHCTL_EL2.EL1TVCT == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        return CNTVCTSS_EL0;
elsif PSTATE.EL == EL2 then
    return CNTVCTSS_EL0;
elsif PSTATE.EL == EL3 then
    return CNTVCTSS_EL0;
              


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