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

# GMID_EL1, Multiple tag transfer ID Register

The GMID_EL1 characteristics are:

## Purpose

Indicates the block size that is accessed by the LDGM and STGM System instructions.

## Configuration

This register is present only when FEAT_MTE2 is implemented. Otherwise, direct accesses to GMID_EL1 are UNDEFINED.

## Attributes

GMID_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
RES0
RES0 | BS

#### Bits [63:4]

Reserved, RES0.

#### BS, bits [3:0]

Log2 of the block size in words. The minimum supported size is 16B (value == 2) and the maximum is 256B (value == 6).

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

## Accessing GMID_EL1

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

#### MRS <Xt>, GMID_EL1

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b001 | 0b0000 | 0b0000 | 0b100

if PSTATE.EL == EL0 then if IsFeatureImplemented(FEAT_IDST) then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); else UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.TID5 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else X[t, 64] = GMID_EL1; elsif PSTATE.EL == EL2 then X[t, 64] = GMID_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = GMID_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

Copyright © 2010-2024 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.