A speculative execution computing apparatus and method

One embodiment of the invention recovers return address stack (RAS) content and restores alignment of a RAS top-of-stack (TOS) pointer for occurrences of mispredictions due to speculative operation, out-of-order instruction processing, and exception handling. In at least one embodiment of the invention, an apparatus includes a speculative execution processor pipeline, a first structure for maintaining return addresses relative to instruction flow at a first stage of the pipeline, at least a second structure for maintaining return addresses relative to instruction flow at a second stage of the pipeline. The second stage of the pipeline is deeper in the pipeline than the first stage. The apparatus includes circuitry operable to reproduce at least return addresses from the second structure to the first structure.