B2.60
AArch32 Instruction Set Attribute Register 3, EL1
The ID_ISAR3_EL1 characteristics are:
Purpose
Provides information about the instruction sets implemented by the processor in AArch32.
Usage constraints
This register is accessible as follows:
EL0 EL1
(NS)
EL1
(S)
EL2 EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
RO
RO
RO
RO
RO
Configurations
ID_ISAR3_EL1 is architecturally mapped to AArch32 register ID_ISAR3. See
B1.77 Instruction Set Attribute Register 3
.
Attributes
ID_ISAR3_EL1 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 B2-33 ID_ISAR3_EL1 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.
SynchPrim, [15:12]
Indicates the implemented Synchronization Primitive instructions:
0x2
• The
LDREX
and
STREX
instructions.
• The
CLREX
,
LDREXB
,
STREXB
, and
STREXH
instructions.
• The
LDREXD
and
STREXD
instructions.
SVC, [11:8]
B2 AArch64 system registers
B2.60 AArch32 Instruction Set Attribute Register 3, EL1
100236_0100_00_en
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B2-461
Non-Confidential
Summary of Contents for Cortex-A35
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