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AMCGCR

AMCGCR, Activity Monitors Counter Group Configuration Register

The AMCGCR characteristics are:

Purpose

Provides information on the number of activity monitor event counters implemented within each counter group.

Configuration

External register AMCGCR bits [31:0] are architecturally mapped to AArch64 System register AMCGCR_EL0[31:0] when FEAT_AMU_EXT32 is implemented.

External register AMCGCR bits [63:0] are architecturally mapped to AArch64 System register AMCGCR_EL0[63:0] when FEAT_AMU_EXT64 is implemented.

External register AMCGCR bits [31:0] are architecturally mapped to AArch32 System register AMCGCR[31:0].

It is IMPLEMENTATION DEFINED whether AMCGCR is implemented in the Core power domain or in the Debug power domain.

This register is present only when FEAT_AMUv1 is implemented and FEAT_AMU_EXT is implemented. Otherwise, direct accesses to AMCGCR are RES0.

Attributes

AMCGCR is a:

This register is part of the AMU block.

Field descriptions

When FEAT_AMU_EXT64 is implemented:

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
RES0CG1NCCG0NC

Bits [63:16]

Reserved, RES0.

CG1NC, bits [15:8]

Counter Group 1 Number of Counters. The number of counters in the auxiliary counter group.

In an implementation that includes FEAT_AMUv1, the permitted range of values is 0 to 16.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

CG0NC, bits [7:0]

Counter Group 0 Number of Counters. The number of counters in the architected counter group.

Reads as 0x04.

Access to this field is RO.

Otherwise:

313029282726252423222120191817161514131211109876543210
RES0CG1NCCG0NC

Bits [31:16]

Reserved, RES0.

CG1NC, bits [15:8]

Counter Group 1 Number of Counters. The number of counters in the auxiliary counter group.

In an implementation that includes FEAT_AMUv1, the permitted range of values is 0 to 16.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

CG0NC, bits [7:0]

Counter Group 0 Number of Counters. The number of counters in the architected counter group.

Reads as 0x04.

Access to this field is RO.

Accessing AMCGCR

Accesses to this register use the following encodings:

When FEAT_AMU_EXT64 is implemented

Accessible at offset 0xCE0 from AMU

When FEAT_AMU_EXT32 is implemented

Accessible at offset 0xCE0 from AMU


2026-03-12 12:23:09, 2025-09_rel_asl1

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