SPECULATIVE EXECUTION FOLLOWING A STATE TRANSITION INSTRUCTION

摘要

An apparatus and a method are described, the apparatus comprising: processing circuitry adapted to execute instructions from an instruction stream comprising a state transition instruction followed by a further instruction, wherein the processing circuitry is responsive to the state transition instruction to change a security state of the processing circuitry; issue circuitry adapted to issue the further instruction to be speculatively executed prior to the state transition instruction being completed, the further instruction having a requirement in respect of the security state; and completion circuitry adapted to perform a completion operation on the further instruction comprising checking whether the requirement in respect of the security state is met.