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# GITS_CWRITER, ITS Write Register

The GITS_CWRITER characteristics are:

## Purpose

Specifies the offset from GITS_CBASER where software writes the next ITS command.

## Configuration

RW fields in this register reset to architecturally UNKNOWN values.

Bits [63:32] and bits [31:0] are accessible separately.

## Attributes

GITS_CWRITER is a 64-bit register.

## Field descriptions

The GITS_CWRITER bit assignments are:

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
RES0
RES0 | Offset | RES0 | Retry
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

#### Bits [63:20]

Reserved, RES0.

#### Offset, bits [19:5]

Bits [19:5] of the offset from GITS_CBASER. Bits [4:0] of the offset are zero.

This field resets to an architecturally UNKNOWN value.

#### Bits [4:1]

Reserved, RES0.

#### Retry, bit [0]

Writing this bit has the following effects:

Retry | Meaning
--- | ---
0b0 | No effect on the processing commands by the ITS.
0b1 | Restarts the processing of commands by the ITS if it stalled because of a command error. Note If the processing of commands is not stalled because of a command error, writing 1 to this bit has no effect.

When read, this bit is RES0.

See The ITS Command Interface for more information.

If GITS_CWRITER is written with a value outside of the valid range specified by GITS_CBASER.Physical_Address and GITS_CBASER.Size, behavior is a CONSTRAINED UNPREDICTABLE choice, as follows:

- The command queue is considered invalid, and no further commands are processed until GITS_CWRITER is written with a value that is in the valid range.
- The value is treated as a valid UNKNOWN value.

An implementation might choose to report a system error in an IMPLEMENTATION DEFINED manner.

## Accessing the GITS_CWRITER

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

Component | Offset | Instance
--- | --- | ---
GIC ITS control | 0x0088 | GITS_CWRITER

This interface is accessible as follows:

- When GICD_CTLR.DS == 0b0 access to this register is RW.
- When IsAccessSecure() access to this register is RW.
- When !IsAccessSecure() access to this register is RW.

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

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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