System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-128
ID021414
Non-Confidential
4.3.79
CPU Extended Control Register, EL1
The CPUECTLR_EL1 characteristics are:
Purpose
Provides additional
IMPLEMENTATION
DEFINED
configuration and control
options for the processor.
Usage constraints
This register is accessible as follows:
The CPUECTLR_EL1 can be written dynamically.
The CPUECTLR_EL1 is write accessible in EL1 if
ACTLR_EL3.CPUECTLR is 1 and ACTLR_EL2.CPUECTLR is 1, or
ACTLR_EL3.CPUECTLR is 1 and SCR.NS is 0.
The CPUECTLR_EL1 is write accessible in EL2 if
ACTLR_EL3.CPUECTLR is 1.
Configurations
The CPUECTLR_EL1 is:
•
Architecturally mapped to the AArch32 CPUECTLR register. See
CPU Extended Control Register
on page 4-271
.
Attributes
CPUECTLR_EL1 is a 64-bit register.
Figure 4-72
shows the CPUECTLR_EL1 bit assignments.
Figure 4-72 CPUECTLR_EL1 bit assignments
EL0
EL1
(NS)
EL1
(S)
EL2
EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
RW
RW
RW
RW
RW
7 6 5
3 2
RES
0
0
63
SMPEN
Advanced-SIMD/FP retention control
CPU retention control