MVFR2_EL1, AArch32 Media and VFP Feature Register 2

The MVFR2_EL1 characteristics are:

Purpose

Describes the features provided by the AArch32 Advanced SIMD and Floating-point implementation.

Must be interpreted with MVFR0_EL1 and MVFR1_EL1.

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

Configuration

AArch64 System register MVFR2_EL1 bits [31:0] are architecturally mapped to AArch32 System register MVFR2[31:0] .

In an implementation where at least one Exception level supports execution in AArch32 state, but there is no support for Advanced SIMD and floating-point operation, this register is RAZ.

Attributes

MVFR2_EL1 is a 64-bit register.

Field descriptions

The MVFR2_EL1 bit assignments are:

When AArch32 is supported at any Exception level:

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
RES0
RES0																								FPMisc				SIMDMisc

Bits [63:8]

Reserved, RES0.

FPMisc, bits [7:4]

Indicates whether the floating-point implementation provides support for miscellaneous VFP features.

All other values are reserved.

In Armv8-A, the permitted values are 0b0000 and 0b0100.

SIMDMisc, bits [3:0]

Indicates whether the Advanced SIMD implementation provides support for miscellaneous Advanced SIMD features.

All other values are reserved.

In Armv8-A, the permitted values are 0b0000 and 0b0011.

Otherwise:

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
UNKNOWN
UNKNOWN
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0

Bits [63:0]

Reserved, UNKNOWN.

if PSTATE.EL == EL0 then
    if IsFeatureImplemented("FEAT_IDST") then
        if EL2Enabled() && HCR_EL2.TGE == '1' then
            AArch64.SystemAccessTrap(EL2, 0x18);
        else
            AArch64.SystemAccessTrap(EL1, 0x18);
    else
        UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && HCR_EL2.TID3 == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        return MVFR2_EL1;
elsif PSTATE.EL == EL2 then
    return MVFR2_EL1;
elsif PSTATE.EL == EL3 then
    return MVFR2_EL1;