- Purpose
- Provides information on the exception handling of
the processor in AArch64 state.
- Usage constraints
The accessibility to the ID_AA64PFR0_EL1 by Exception
level is:
EL0 |
EL1(NS) |
EL1(S) |
EL2 |
EL3(SCR.NS = 1) |
EL3(SCR.NS = 0) |
- |
RO |
RO |
RO |
RO |
RO |
The external debug accessibility to ID_AA64PFR0_EL1[63:32]
and ID_AA64PFR0_EL1[31:0] by condition code is:
Off |
DLK |
OSLK |
EDAD |
SLK |
Default |
- |
- |
- |
- |
- |
RO |
- Configurations
The ID_AA64PFR0 is architecturally mapped as follows:
- [63:32] to external ID_AA64PFR0[63:32]
register.
- [31:0] to external ID_AA64PFR0[31:0] register.
- Attributes
- See the register summary in Table 4-1 AArch64 identification registers.
The following figure shows the
ID_AA64PFR0_EL1 bit assignments.
Figure 4-17 ID_AA64PFR0_EL1 bit assignments
The following table shows the ID_AA64PFR0_EL1
bit assignments.
Table 4-32 ID_AA64PFR0_EL1 bit assignments
Bits |
Name |
Function |
[63:28] |
- |
Reserved, RES0. |
[27:24] |
GIC system registers |
Indicates support for the GIC System
register interface. The possible values are:
0x0
| No GIC System registers are supported. This is the reset
value when GICCDISABLE is tied HIGH. |
0x1
| GICv3 System registers are supported. This is the reset
value when GICCDISABLE is tied LOW. |
|
[23:20] |
AdvSIMD |
Returns 0x0 to indicate support
for Advanced SIMD. |
[19:16] |
FP |
Returns 0x0 to indicate support
for Floating-point. |
[15:12] |
EL3 |
Returns 0x2 to indicate EL3 supports AArch64 state
or AArch32 state. |
[11:8] |
EL2 |
Returns 0x2 to indicate EL2 supports AArch64 state
or AArch32 state. |
[7:4] |
EL1 |
Returns 0x2 to indicate EL1 supports AArch64 state
or AArch32 state. |
[3:0] |
EL0 |
Returns 0x2 to indicate EL0 supports AArch64 state
or AArch32 state. |
To access the ID_AA64PFR0_EL1 in AArch64 state, read the register
with:
MRS <Xt>, ID_AA64PFR0_EL1; Read AArch64 Processor Feature Register 0
The ID_AA64PFR0[31:0] can be accessed through the memory-mapped
interface and the external debug interface, offset 0xD20
.
The ID_AA64PFR0[63:32] can be accessed through the memory-mapped
interface and the external debug interface, offset 0xD24
.