B1.77
Instruction Set Attribute Register 3
The ID_ISAR3 characteristics are:
Purpose
Provides information about the instruction sets implemented by the processor in AArch32.
Usage constraints
This register is accessible as follows:
EL0
(NS)
EL0
(S)
EL1
(NS)
EL1
(S)
EL2 EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
-
RO
RO
RO
RO
RO
Must be interpreted with ID_ISAR0, ID_ISAR1, ID_ISAR2, ID_ISAR4, and ID_ISAR5. See:
•
B1.74 Instruction Set Attribute Register 0
•
B1.75 Instruction Set Attribute Register 1
•
B1.76 Instruction Set Attribute Register 2
•
B1.78 Instruction Set Attribute Register 4
•
B1.79 Instruction Set Attribute Register 5
Configurations
ID_ISAR3 is architecturally mapped to AArch64 register ID_ISAR3_EL1. See
Instruction Set Attribute Register 3, EL1
.
There is one copy of this register that is used in both Secure and Non-secure states.
Attributes
ID_ISAR3 is a 32-bit register.
TabBranch
31
28 27
24 23
20 19
16 15
12 11
8 7
4 3
0
ThumbCopy
SVC
Saturate
ThumbEE
SynchPrim
SIMD
TrueNOP
Figure B1-32 ID_ISAR3 bit assignments
ThumbEE, [31:28]
Indicates the implemented Thumb Execution Environment (T32EE) instructions:
0x0
None implemented.
TrueNOP, [27:24]
Indicates support for True NOP instructions:
0x1
True
NOP
instructions in both the A32 and T32 instruction sets, and additional NOP-
compatible hints.
ThumbCopy, [23:20]
Indicates the support for T32 non flag-setting
MOV
instructions:
0x1
Support for T32 instruction set encoding T1 of the
MOV
(register) instruction, copying
from a low register to a low register.
TabBranch, [19:16]
Indicates the implemented Table Branch instructions in the T32 instruction set.
0x1
The
TBB
and
TBH
instructions.
B1 AArch32 system registers
B1.77 Instruction Set Attribute Register 3
100236_0100_00_en
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B1-275
Non-Confidential
Summary of Contents for Cortex-A35
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