CNTV_TVAL, Counter-timer Virtual Timer TimerValue register

The CNTV_TVAL characteristics are:

Purpose

Holds the timer value for the virtual timer.

Configuration

AArch32 System register CNTV_TVAL bits [31:0] are architecturally mapped to AArch64 System register CNTV_TVAL_EL0[31:0].

This register is present only when AArch32 is supported. Otherwise, direct accesses to CNTV_TVAL are UNDEFINED.

Attributes

CNTV_TVAL is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
TimerValue

TimerValue, bits [31:0]

The TimerValue view of the virtual timer.

On a read of this register:

On a write of this register, CNTV_CVAL is set to (CNTVCT + TimerValue), where TimerValue is treated as a signed 32-bit integer.

When CNTP_CTL.ENABLE is 1, the timer condition is met when (CNTVCT - CNTP_CVAL) is greater than or equal to zero. This means that TimerValue acts like a 32-bit downcounter timer. When the timer condition is met:

When CNTV_CTL.ENABLE is 0, the timer condition is not met, but CNTVCT continues to count, so the TimerValue view appears to continue to count down.

The reset behavior of this field is:

Accessing CNTV_TVAL

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

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b11100b00110b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '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' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented(FEAT_SEL2) then return CNTHVS_TVAL_EL2; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then return CNTHV_TVAL_EL2; else return CNTV_TVAL; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else return CNTV_TVAL; elsif PSTATE.EL == EL2 then return CNTV_TVAL; elsif PSTATE.EL == EL3 then return CNTV_TVAL;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b11100b00110b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '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' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented(FEAT_SEL2) then CNTHVS_TVAL_EL2 = R[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then CNTHV_TVAL_EL2 = R[t]; else CNTV_TVAL = R[t]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else CNTV_TVAL = R[t]; elsif PSTATE.EL == EL2 then CNTV_TVAL = R[t]; elsif PSTATE.EL == EL3 then CNTV_TVAL = R[t];


20/09/2021 12:37; d4a233ffbdfb36e47856c443a7ce9a85f5e501ca

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