Method and system for propagating exception status in data registers and for detecting exceptions from speculative operations with non-speculative operations

摘要

A method for supporting speculative execution includes designating operations as speculative or non-speculative, and then deferring exceptions generated by speculative operations while immediately reporting exceptions by non-speculative operations. If a speculative operation uses a result of a speculative operation that has generated an exception, the exception is propagated. Deferred exceptions are detected and reported using a check operation either incorporated into a non- speculative operation or inserted as a separate check operation. A system for supporting speculative execution includes a functional unit for recognizing a speculative operation and deferring any exceptions generated by such an operation. The functional unit may defer an exception by storing information indicating an error has occurred in the register file. To check for deferred exceptions, the functional unit then reads the register file. If an exception is detected, then the exception is processed and one or more of the speculative operation are re-executed (in a non-speculative mode) where necessary to process the exception.