Patent ID: 11698789

Abstract:
Restoring speculative history used for making speculative predictions for instructions processed in a processor. The processor can be configured to speculatively predict an outcome of a condition or predicate of a conditional control instruction before its condition is fully evaluated in execution. Predictions are made by the processor based on a history that is updated based on outcomes of past predictions. If a conditional control instruction is mispredicted in execution, the processor can perform a misprediction recovery by stalling the instruction pipeline, flushing younger instructions in the instruction pipeline back to the mispredicted conditional control instruction, and then re-fetching instructions in the correct instruction flow path for execution. The processor can be configured to restore entries of the speculative history associated with younger control independent (CI) conditional control instructions, so that younger fetched instructions that follow non-re-fetched CI instructions in misprediction recovery will use a more accurate speculative history.