Invalidates all Branch records in the Branch Record Buffer.
This instruction is present only when FEAT_BRBE is implemented. Otherwise, direct accesses to BRB IALL are UNDEFINED.
BRB IALL is a 64-bit System instruction.
This instruction has no applicable fields.
The value in the register specified by <Xt> is ignored.
Rt should be encoded as 0b11111. If the Rt field is not set to 0b11111, it is CONSTRAINED UNPREDICTABLE whether:
The instruction is UNDEFINED.
The instruction behaves as if the Rt field is set to 0b11111.
Accesses to this instruction use the following encodings in the System instruction encoding space:
BRB IALL
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b01 | 0b001 | 0b0111 | 0b0010 | 0b100 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGITR_EL2.nBRBIALL == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else BRB_IALL(); elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else BRB_IALL(); elsif PSTATE.EL == EL3 then BRB_IALL();