Performs a Data Synchronization Barrier.
Arm deprecates any use of this System instruction, and strongly recommends that software use the DSB instruction instead.
This instruction is present only when FEAT_AA32 is implemented. Otherwise, direct accesses to CP15DSB are UNDEFINED.
CP15DSB is a 32-bit System instruction.
This instruction has no applicable fields.
The value in the register specified by <Rt> is ignored.
Accesses to this instruction use the following encodings in the System instruction encoding space:
| coproc | opc1 | CRn | CRm | opc2 |
|---|---|---|---|---|
| 0b1111 | 0b000 | 0b0111 | 0b1010 | 0b100 |
if !IsFeatureImplemented(FEAT_AA32) then UNDEFINED; elsif PSTATE.EL == EL0 then if IsFeatureImplemented(FEAT_AA64EL1) && !ELUsingAArch32(EL1) && !ELIsInHost(EL0) && SCTLR_EL1.CP15BEN == '0' then UNDEFINED; elsif ELIsInHost(EL0) && SCTLR_EL2.CP15BEN == '0' then UNDEFINED; elsif IsFeatureImplemented(FEAT_AA32EL1) && ELUsingAArch32(EL1) && SCTLR.CP15BEN == '0' then UNDEFINED; elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && !ELIsInHost(EL0) && HSTR_EL2.T7 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HSTR.T7 == '1' then AArch32.TakeHypTrapException(0x03); else CP15DSB(); elsif PSTATE.EL == EL1 then if EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && HSTR_EL2.T7 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HSTR.T7 == '1' then AArch32.TakeHypTrapException(0x03); elsif SCTLR.CP15BEN == '0' then UNDEFINED; else CP15DSB(); elsif PSTATE.EL == EL2 then if HSCTLR.CP15BEN == '0' then UNDEFINED; else CP15DSB(); elsif PSTATE.EL == EL3 then if SCTLR.CP15BEN == '0' then UNDEFINED; else CP15DSB();