0b11
Full access.
If Advanced SIMD and floating-point are not implemented, this field is
RES0
.
The Advanced SIMD and floating-point features controlled by these fields are:
• Floating-point instructions.
• Advanced SIMD instructions, both integer and floating-point.
• Advanced SIMD and floating-point registers D0-D31 and their views as S0-S31 and Q0-
Q15.
• FPSCR, FPSID, MVFR0, MVFR1, MVFR2, FPEXC system registers.
If the cp11 and cp10 fields are set to different values, the behavior is the same as if both fields
were set to the value of cp10, in all respects other than the value read back by explicitly reading
cp11.
cp10, [21:20]
Defines the access rights for CP10, that control the Advanced SIMD and floating-point features.
Possible values of the fields are:
0b00
Access denied. Any attempt to access Advanced SIMD and floating-point registers or
instructions generates an Undefined Instruction exception. This is the reset value.
0b01
Access at EL1 only. Any attempt to access Advanced SIMD and floating-point registers
or instructions from software executing at EL0 generates an Undefined Instruction
exception.
0b10
Reserved.
0b11
Full access.
If Advanced SIMD and floating-point are not implemented, this bit is
RES0
.
The Advanced SIMD and floating-point features controlled by these fields are:
• Floating-point instructions.
• Advanced SIMD instructions, both integer and floating-point.
• Advanced SIMD and floating-point registers D0-D31 and their views as S0-S31 and Q0-
Q15.
• FPSCR, FPSID, MVFR0, MVFR1, MVFR2, FPEXC system registers.
[19:0]
Reserved,
RES0
.
To access the CPACR:
MRC p15,0,<Rt>,c1,c0,2 ; Read CPACR into Rt
MCR p15,0,<Rt>,c1,c0,2 ; Write Rt to CPACR
Register access is encoded as follows:
Table B1-35 CPACR access encoding
coproc opc1 CRn CRm opc2
1111
000
0001 0000 010
B1 AArch32 system registers
B1.41 Architectural Feature Access Control Register
100236_0100_00_en
Copyright © 2015–2017, 2019 Arm Limited or its affiliates. All rights
reserved.
B1-207
Non-Confidential
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