B1.75
Instruction Set Attribute Register 1
The ID_ISAR1 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_ISAR2, ID_ISAR3, ID_ISAR4 and ID_ISAR5. See:
•
B1.74 Instruction Set Attribute Register 0
•
B1.76 Instruction Set Attribute Register 2
•
B1.77 Instruction Set Attribute Register 3
•
B1.78 Instruction Set Attribute Register 4
•
B1.79 Instruction Set Attribute Register 5
Configurations
ID_ISAR1 is architecturally mapped to AArch64 register ID_ISAR1_EL1. See
Instruction Set Attribute Register 1, EL1
.
There is one copy of this register that is used in both Secure and Non-secure states.
Attributes
ID_ISAR1 is a 32-bit register.
31
28 27
24 23
20 19
16 15
12 11
8 7
4 3
0
Jazelle
Interwork
Immediate
IfThen
Extend
Except_AR
Except
Endian
Figure B1-30 ID_ISAR1 bit assignments
Jazelle, [31:28]
Indicates the implemented Jazelle state instructions:
0x1
The
BXJ
instruction, and the J bit in the PSR.
Interwork, [27:24]
Indicates the implemented Interworking instructions:
0x3
• The
BX
instruction, and the T bit in the PSR.
• The
BLX
instruction. The PC loads have
BX
-like behavior.
• Data-processing instructions in the A32 instruction set with the PC as the
destination and the S bit clear, have
BX
-like behavior.
Immediate, [23:20]
Indicates the implemented data-processing instructions with long immediates:
B1 AArch32 system registers
B1.75 Instruction Set Attribute Register 1
100236_0100_00_en
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B1-271
Non-Confidential
Summary of Contents for Cortex-A35
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