B2.33
Architectural Feature Trap Register, EL3
The CPTR_EL3 characteristics are:
Purpose
Controls trapping to EL3 for accesses to CPACR, Trace functionality and registers associated
with Advanced SIMD and floating-point execution. Controls EL3 access to this functionality.
CPTR_EL3 is part of the Security registers functional group.
Usage constraints
This register is accessible as follows:
EL0 EL1
(NS)
EL1
(S)
EL2 EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
-
-
-
RW
RW
Configurations
There are no configuration notes.
Attributes
CPTR_EL3 is a 32-bit register.
31
0
RES
0
RES
0
TFP
10 9
11
30
TCPAC
19
20
21
RES
0
TTA
12
13
14
Figure B2-8 CPTR_EL3 bit assignments
TCPAC, [31]
This causes a direct access to the CPACR_EL1 from EL1 or the CPTR_EL2 from EL2 to trap to
EL3 unless it is trapped at EL2. The possible values are:
0
Does not cause access to the CPACR_EL1 or CPTR_EL2 to be trapped.
1
Causes access to the CPACR_EL1 or CPTR_EL2 to be trapped.
[30:21]
Reserved,
RES0
.
TTA, [20]
Trap Trace Access.
Not implemented.
RES0
.
[19:11]
Reserved,
RES0
.
TFP, [10]
This causes instructions that access the registers associated with Advanced SIMD or floating-
point execution to trap to EL3 when executed from any exception level, unless trapped to EL1
or EL2. The possible values are:
B2 AArch64 system registers
B2.33 Architectural Feature Trap Register, EL3
100236_0100_00_en
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B2-406
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Summary of Contents for Cortex-A35
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