BPIALL Branch Predictor Invalidate All when FEAT_AA32EL1 is implemented Invalidate all entries from branch predictors. Cache In an implementation where the branch predictors are architecturally invisible, this instruction can execute as a NOP. BPIALL is a 32-bit System instruction. The PE ignores the value of <Rt>. Software does not have to write a value to this register before issuing this instruction. When HCR.FB is 1, at Non-secure EL1 this instruction executes as a BPIALLIS. MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>} if !IsFeatureImplemented(FEAT_AA32EL1) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); 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 EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HCR().FB == '1' then BPIALLIS(); else BPIALL(); end; elsif PSTATE.EL == EL2 then BPIALL(); elsif PSTATE.EL == EL3 then BPIALL(); end; 2026-03-26 20:27:25 2026-03_rel