ID_AA64PFR1_EL1, AArch64 Processor Feature Register 1, EL1
The ID_AA64PFR1_EL1 provides additional information about implemented core features in AArch64.
Bit field descriptions
ID_AA64PFR1_EL1 is a 64-bit register, and is part of the Identification registers functional group.
This register is Read Only.
Figure B2-47 ID_AA64PFR1_EL1 bit assignments
- RES0, [63:8]
- SSBS, [7:4]
PSTATE.SSBS. The possible values are:
AArch64 provides the PSTATE.SSBS mechanism to mark regions that are Speculative Store Bypassing Safe (SSBS), but does not implement the MSR/MRS instructions to directly read and write the PSTATE.SSBS field.
- RES0, [3:0]
ID_AA64PFR1_EL1 is architecturally mapped to External register EDPFR.
Bit fields and details that are not provided in this description are architecturally defined. See the Arm® Architecture Reference Manual Armv8, for Armv8-A architecture profile.