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System Control Coprocessor
ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 4-27
ID013010 Non-Confidential, Unrestricted Access
To access the Instruction Set Attributes Register 0, read CP15 with:
MRC p15, 0, <Rd>, c0, c2, 0 ; Read Instruction Set Attributes Register 0
c0, Instruction Set Attributes Register 1, ISAR1
The Instruction Set Attributes Register 1 provides information about the instruction set that the
processor supports beyond the basic set.
The Instruction Set Attributes Register 1 is:
• a read-only register
• accessible in Privileged mode only.
Figure 4-20 shows the bit arrangement for Instruction Set Attributes Register 1.
Figure 4-20 Instruction Set Attributes Register 1 format
[11:8] Bitfield instructions Indicates support for bitfield instructions.
0x1
, the processor supports bitfield instructions,
BFC
,
BFI
,
SBFX
, and
UBFX
.
[7:4] Bit counting instructions Indicates support for bit counting instructions.
0x1
, the processor supports
CLZ
.
[3:0] Atomic instructions Indicates support for atomic load and store instructions.
0x1
, the processor supports
SWP
and
SWPB
.
Table 4-14 Instruction Set Attributes Register 0 bit functions (continued)
Bits Field Function
31 28 27 24 23 20 19 16 15 12 11 8 7 4 3 0
Jazelle instructions
Interworking instructions
Immediate instructions
ITE instructions
Extend instructions
Exception 2 instructions
Exception 1 instructions
Endian instructions