AMAIR0

When using the Long-descriptor format translation tables for stage 1 translations, provides IMPLEMENTATION DEFINED memory attributes for the memory regions specified by MAIR0.

Configuration

AArch32 System register AMAIR0 bits [31:0] are architecturally mapped to AArch64 System register AMAIR_EL1[31:0].

This register is present only when EL1 is capable of using AArch32. Otherwise, direct accesses to AMAIR0 are UNDEFINED.

Attributes

Field descriptions

This register is RES0 in the following cases:

When an implementation does not provide any IMPLEMENTATION DEFINED memory attributes.
When the Long-descriptor translation table format is not used.

If EL3 is implemented and is using AArch32:

AMAIR0(S) gives the value for memory accesses from Secure state.
AMAIR0(NS) gives the value for memory accesses from Non-secure states other than Hyp mode.

Any IMPLEMENTATION DEFINED memory attributes are additional qualifiers for the memory locations and must not change the architected behavior specified by MAIR0 and MAIR1.

In a typical implementation, AMAIR0 and AMAIR1 split into eight one-byte fields, corresponding to the MAIRn.Attr<n> fields, but the architecture does not require them to do so.

IMPLEMENTATION DEFINED, bits [31:0]

Accessing AMAIR0

Accesses to this register use the following encodings in the System register encoding space:

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc	opc1	CRn	CRm	opc2
0b1111	0b000	0b1010	0b0011	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T10 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T10 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TRVM == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TRVM == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then R[t] = AMAIR0_NS; else R[t] = AMAIR0; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then R[t] = AMAIR0_NS; else R[t] = AMAIR0; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then R[t] = AMAIR0_S; else R[t] = AMAIR0_NS;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc	opc1	CRn	CRm	opc2
0b1111	0b000	0b1010	0b0011	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T10 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T10 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TVM == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TVM == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then AMAIR0_NS = R[t]; else AMAIR0 = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then AMAIR0_NS = R[t]; else AMAIR0 = R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' && CP15SDISABLE == Signal_High then UNDEFINED; elsif SCR.NS == '0' && CP15SDISABLE2 == Signal_High then UNDEFINED; else if SCR.NS == '0' then AMAIR0_S = R[t]; else AMAIR0_NS = R[t];

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IMPLEMENTATION DEFINED

AMAIR0, Auxiliary Memory Attribute Indirection Register 0