System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-16
ID021414
Non-Confidential
Table 4-15
shows the MPIDR_EL1 bit assignments.
To access the MPIDR_EL1:
MRS <Xt>, MPIDR_EL1 ; Read MPIDR_EL1 into Xt
Register access is encoded as follows:
The EDDEVAFF0 and EDDEVAFF1 can be accessed through the internal memory-mapped
interface and the external debug interface, offsets
0xFA8
and
0xFAC
respectively.
4.3.3
Revision ID Register
The REVIDR_EL1 characteristics are:
Purpose
Provides implementation-specific minor revision information that can be
interpreted only in conjunction with the Main ID Register.
Table 4-15 MPIDR_EL1 bit assignments
Bits
Name
Function
[63:40]
-
Reserved,
RES
0.
[39:32]
Aff3
Affinity level 3. Highest level affinity field.
Reserved,
RES
0.
[31]
-
Reserved,
RES
1.
[30]
U
Indicates a single core system, as distinct from core 0 in a cluster. This value is:
0
Core is part of a cluster.
[29:25]
-
Reserved,
RES
0.
[24]
MT
Indicates whether the lowest level of affinity consists of logical cores that are implemented using a
multi-threading type approach. This value is:
0
Performance of cores at the lowest affinity level is largely independent.
[23:16]
Aff2
Affinity level 2. Second highest level affinity field.
Indicates the value read in the
CLUSTERIDAFF2
configuration signal.
[15:8]
Aff1
Affinity level 1. Third highest level affinity field.
Indicates the value read in the
CLUSTERIDAFF1
configuration signal.
[7:0]
Aff0
Affinity level 0. Lowest level affinity field.
Indicates the core number in the Cortex-A53 processor. The possible values are:
0x0
A cluster with one core only.
0x0
,
0x1
A cluster with two cores.
0x0
,
0x1
,
0x2
A cluster with three cores.
0x0
,
0x1
,
0x2
,
0x3
A cluster with four cores.
Table 4-16 MPIDR access encoding
op0
op1
CRn
CRm
op2
11
000
0000
0000
101