ID_AFR0, Auxiliary Feature Register 0

The ID_AFR0 characteristics are:

Purpose

Provides information about the IMPLEMENTATION DEFINED features of the PE in AArch32 state.

Must be interpreted with the Main ID Register, MIDR.

For general information about the interpretation of the ID registers see 'Principles of the ID scheme for fields in ID registers'.

Configuration

AArch32 System register ID_AFR0 bits [31:0] are architecturally mapped to AArch64 System register ID_AFR0_EL1[31:0] .

This register is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to ID_AFR0 are UNDEFINED.

Attributes

ID_AFR0 is a 32-bit register.

Field descriptions

The ID_AFR0 bit assignments are:

Bits [31:16]

Reserved, RES0.

IMPLEMENTATION DEFINED, bits [15:12]

IMPLEMENTATION DEFINED.

IMPLEMENTATION DEFINED, bits [11:8]

IMPLEMENTATION DEFINED.

IMPLEMENTATION DEFINED, bits [7:4]

IMPLEMENTATION DEFINED.

IMPLEMENTATION DEFINED, bits [3:0]

IMPLEMENTATION DEFINED.

if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T0 == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T0 == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TID3 == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TID3 == '1' then
        AArch32.TakeHypTrapException(0x03);
    else
        return ID_AFR0;
elsif PSTATE.EL == EL2 then
    return ID_AFR0;
elsif PSTATE.EL == EL3 then
    return ID_AFR0;