System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-38
ID021414
Non-Confidential
Configurations
ID_AA64PFR0_EL1 is architecturally mapped to external register
ID_AA64PFR0_EL1.
Attributes
ID_AA64PFR0_EL1 is a 64-bit register.
Figure 4-17
shows the ID_AA64PFR0_EL1 bit assignments.
Figure 4-17 ID_AA64PFR0_EL1 bit assignments
Table 4-45
shows the ID_AA64PFR0_EL1 bit assignments.
To access the ID_AA64PFR0_EL1:
MRS <Xt>, ID_AA64PFR0_EL1 ; Read ID_AA64PFR0_EL1 into Xt
Register access is encoded as follows:
63
0
RES
0
4 3
8 7
12 11
16 15
EL3
handling
EL2
handling
EL1
handling
EL0
handling
AdvSIMD
FP
20 19
24 23
GIC
28 27
Table 4-45 ID_AA64PFR0_EL1 bit assignments
Bits
Name
Function
[63:28]
-
Reserved,
RES
0.
[27:24]
GIC
GIC CPU interface:
0x0
GIC CPU interface is disabled.
0x1
GIC CPU interface is implemented.
[23:20]
FP
a
Floating-point. The possible values are:
0x0
Floating-point is implemented.
0xF
Floating-point is not implemented.
[19:16]
AdvSIMD
a
Advanced SIMD. The possible values are:
0x0
Advanced SIMD is implemented.
0xF
Advanced SIMD is not implemented.
[15:12]
EL3 handling
EL3 exception handling:
0x2
Instructions can be executed at EL3 in AArch64 or AArch32 state.
[11:8]
EL2 handling
EL2 exception handling:
0x2
Instructions can be executed at EL2 in AArch64 or AArch32 state.
[7:4]
EL1 handling
EL1 exception handling. The possible values are:
0x2
Instructions can be executed at EL1 in AArch64 or AArch32 state.
[3:0]
EL0 handling
EL0 exception handling. The possible values are:
0x2
Instructions can be executed at EL0 in AArch64 or AArch32 state.
a. The FP and AdvSIMD both take the same value, as both must be implemented, or neither.
Table 4-46 ID_AA64PFR0_EL1 access encoding
op0
op1
CRn
CRm
op2
11
000
0000
0100
000