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BPIALL, Branch Predictor Invalidate All

The BPIALL characteristics are:

Purpose

Invalidate all entries from branch predictors.

Configuration

In an implementation where the branch predictors are architecturally invisible, this instruction can execute as a NOP.

Attributes

BPIALL is a 32-bit System instruction.

Field descriptions

BPIALL ignores the value in the register specified by the instruction encoding. Software does not have to write a value to the register before issuing this instruction.

Executing the BPIALL 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.

Accesses to this instruction use the following encodings:

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

coprocopc1CRnCRmopc2
0b11110b0000b01110b01010b110
if PSTATE.EL == EL0 then
    UNDEFINED;
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 EL2Enabled() && ELUsingAArch32(EL2) && HCR.FB == '1' then
        BPIALLIS();
    else
        BPIALL();
elsif PSTATE.EL == EL2 then
    BPIALL();
elsif PSTATE.EL == EL3 then
    BPIALL();
              


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