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CP15DMB, Data Memory Barrier System instruction
The CP15DMB characteristics are:
Purpose
Performs a Data Memory Barrier.
Arm deprecates any use of this System instruction, and strongly recommends that software use the DMB instruction instead.
Configuration
This instruction is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to CP15DMB are UNDEFINED.
Attributes
CP15DMB is a 32-bit System instruction.
Field descriptions
This instruction has no applicable fields.
The value in the register specified by <Rt> is ignored.
Executing the CP15DMB instruction
Accesses to this instruction use the following encodings:
MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
| coproc | opc1 | CRn | CRm | opc2 |
|---|---|---|---|---|
| 0b1111 | 0b000 | 0b0111 | 0b1010 | 0b101 |
if PSTATE.EL == EL0 then
if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && SCTLR_EL1.CP15BEN == '0' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCTLR_EL2.CP15BEN == '0' then
UNDEFINED;
elsif ELUsingAArch32(EL1) && SCTLR.CP15BEN == '0' then
UNDEFINED;
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T7 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T7 == '1' then
AArch32.TakeHypTrapException(0x03);
else
CP15DMB();
elsif PSTATE.EL == EL1 then
if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T7 == '1' then
AArch64.AArch32SystemAccessTrap(EL2, 0x03);
elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T7 == '1' then
AArch32.TakeHypTrapException(0x03);
elsif SCTLR.CP15BEN == '0' then
UNDEFINED;
else
CP15DMB();
elsif PSTATE.EL == EL2 then
if HSCTLR.CP15BEN == '0' then
UNDEFINED;
else
CP15DMB();
elsif PSTATE.EL == EL3 then
if SCTLR.CP15BEN == '0' then
UNDEFINED;
else
CP15DMB();