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# ICV_RPR_EL1, Interrupt Controller Virtual Running Priority Register

The ICV_RPR_EL1 characteristics are:

## Purpose

Indicates the Running priority of the virtual CPU interface.

## Configuration

AArch64 System register ICV_RPR_EL1 performs the same function as AArch32 System register ICV_RPR.

This register is present only when GICv3 is implemented and EL2 is implemented. Otherwise, direct accesses to ICV_RPR_EL1 are UNDEFINED.

## Attributes

ICV_RPR_EL1 is a 64-bit register.

## Field descriptions

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
NMI | RES0
RES0 | Priority

#### NMI, bit [63]
When FEAT_GICv3_NMI is implemented:

Indicates whether the running priority is from a NMI.

NMI | Meaning
--- | ---
0b0 | There is no active Group 1 NMI, or all active Group 1 NMIs have undergone priority drop.
0b1 | There is an active Group 1 NMI.

####
Otherwise:

Reserved, RES0.

#### Bits [62:8]

Reserved, RES0.

#### Priority, bits [7:0]

The current running priority on the virtual CPU interface. This is the group priority of the current active virtual interrupt.

If there are no active interrupts on the virtual CPU interface, or all active interrupts have undergone a priority drop, the value returned is the Idle priority.

The priority returned is the group priority as if the BPR for the current Exception level and Security state was set to the minimum value of BPR for the number of implemented priority bits.

Note

If 8 bits of priority are implemented the group priority is bits[7:1] of the priority.

## Accessing ICV_RPR_EL1

If there are no active interrupts on the virtual CPU interface, or all active interrupts have undergone a priority drop, the value returned is the Idle priority.

Software cannot determine the number of implemented priority bits from a read of this register.

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

#### MRS <Xt>, ICC_RPR_EL1

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b000 | 0b1100 | 0b1011 | 0b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif ICC_SRE_EL1.SRE == '0' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && ICH_HCR_EL2.TC == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && HCR_EL2.FMO == '1' then X[t, 64] = ICV_RPR_EL1; elsif EL2Enabled() && HCR_EL2.IMO == '1' then X[t, 64] = ICV_RPR_EL1; elsif HaveEL(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_RPR_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif ICC_SRE_EL2.SRE == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_RPR_EL1; elsif PSTATE.EL == EL3 then if ICC_SRE_EL3.SRE == '0' then AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_RPR_EL1;

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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