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# GICC_AIAR, CPU Interface Aliased Interrupt Acknowledge Register

The GICC_AIAR characteristics are:

## Purpose

Provides the INTID of the signaled Group 1 interrupt. A read of this register by the PE acts as an acknowledge for the interrupt.

## Configuration

This register is present only when FEAT_GICv3_LEGACY is implemented. Otherwise, direct accesses to GICC_AIAR are RES0.

When GICD_CTLR.DS==0, this register is an alias of the Non-secure view of GICC_IAR. A Secure access to this register is identical to a Non-secure access to GICC_IAR.

## Attributes

GICC_AIAR is a 32-bit register.

## Field descriptions

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
RES0 | INTID

#### Bits [31:24]

Reserved, RES0.

#### INTID, bits [23:0]

The INTID of the signaled interrupt.

Note

INTIDs 1020-1023 are reserved and convey additional information such as spurious interrupts.

When affinity routing is not enabled:

- Bits [23:13] are RES0.
- For SGIs, bits [12:10] identify the CPU interface corresponding to the source PE. For all other interrupts these bits are RES0.

## Accessing GICC_AIAR

When affinity routing is enabled for a Security state, it is a programming error to use memory-mapped registers to access the GIC.

#### GICC_AIAR can be accessed through the memory-mapped interfaces:

Component | Offset | Instance
--- | --- | ---
GIC CPU interface | 0x0020 | GICC_AIAR

This interface is accessible as follows:

- When GICD_CTLR.DS == 0, accesses to this register are RO.
- When an access is Secure, accesses to this register are RO.
- When an access is Non-secure, accesses to this register are RO.

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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