METHOD FOR SECURE, SIMPLE, AND FAST SPECULATIVE EXECUTION

A method of verifying authenticity of a speculative control-flow instruction is disclosed which includes receiving a new speculative source-destination pair (PAIR), checking the PAIR against one or more memory tables each having memory source-destination pairs associated with previous combinations of source-destination pairs that have successfully cleared as non-speculative source-destination pairs, if the PAIR exists in the one or more memory tables, fetching the instruction associated with the destination, if the PAIR does not exist in the one or more memory tables i) waiting until speculation of the source has cleared as being non-speculative or one or more program counter clock cycles later, ii) updating the one or more memory tables, wherein the updating is associated with inclusion of the PAIR as a new authentic pair, and iii) fetching the non-speculative destination, and if the speculation of the source does not clear as non-speculative, then the source is nullified.