CNTVCT, Counter-timer Virtual Count register

The CNTVCT characteristics are:

Purpose

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

Configuration

AArch32 System register CNTVCT bits [63:0] are architecturally mapped to AArch64 System register CNTVCT_EL0[63:0].

This register is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to CNTVCT are UNDEFINED.

The value of this register is the same as the value of CNTPCT in the following conditions:

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

Attributes

CNTVCT is a 64-bit register.

Field descriptions

The CNTVCT bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
Virtual count value
Virtual count value

Bits [63:0]

Virtual count value.

On a Warm reset, this field resets to an architecturally UNKNOWN value.

Accessing the CNTVCT

Accesses to this register use the following encodings:

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

coprocCRmopc1
0b11110b11100b0001

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.AArch32SystemAccessTrap(EL2, 0x04); else AArch64.AArch32SystemAccessTrap(EL1, 0x04); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VCTEN == '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' && CNTHCTL_EL2.EL0VCTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVCT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else if HaveEL(EL2) && !ELUsingAArch32(EL2) && (!EL2Enabled() || HCR_EL2.<E2H,TGE> != '11') then return PhysicalCountInt() - CNTVOFF_EL2; elsif HaveEL(EL2) && ELUsingAArch32(EL2) then return PhysicalCountInt() - CNTVOFF; else return PhysicalCountInt(); elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CNTHCTL_EL2.EL1TVCT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else if HaveEL(EL2) && !ELUsingAArch32(EL2) then return PhysicalCountInt() - CNTVOFF_EL2; elsif HaveEL(EL2) && ELUsingAArch32(EL2) then return PhysicalCountInt() - CNTVOFF; else return PhysicalCountInt(); elsif PSTATE.EL == EL2 then return PhysicalCountInt() - CNTVOFF; elsif PSTATE.EL == EL3 then if HaveEL(EL2) then return PhysicalCountInt() - CNTVOFF; else return PhysicalCountInt();


30/03/2021 20:51; e3551d56dc294a4d55296a6c10544191ada08a8e

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