Abstract: When a processor executes a memory operation instruction by means of data dependence speculative execution, a speculative execution result history table which stores history information concerning success/failure results of the speculative execution of memory operation instructions of the past is referred to and thereby whether the speculative execution will succeed or fail is predicted. In the prediction, the target address of the memory operation instruction is converted by a hash function circuit into an entry number of the speculative execution result history table (allowing the existence of aliases), and an entry of the table designated by the entry number is referred to. If the prediction is “success”, the memory operation instruction is executed in out-of-order execution speculatively (with regard to data dependence relationship between the instructions).

Abstract: A circuit selectively extracts bits from different locations from a source register and loads them in logical order in one side of a destination register. The register is divided into subsets. All of the transfer bits in each subset are arranged on one side and in logical order. These subsets are paired. The bits from one pair are shifted by an amount equal to the non-transfer bits from the other pair and then combined with the bits from the other pair to form a new group of bits that are on one side and are in logical order. The process of shifting bits of one of a pair of groups and combining with the other of the pair continues until all of the transfer bits from the source register are in one group on one side and in logical order.

Abstract: A system, method and apparatus is provided that splits a microprocessor load instruction into two (2) parts, a speculative load instruction and a check speculative load instruction. The speculative load instruction can be moved ahead in the instruction stream by the compiler as soon as the address and result registers are available. This is true even when the data to be loaded is not actually required. This speculative load instruction will not cause a fault in the memory if the access is invalid, i.e. the load misses and a token bit is set. The check speculative load instruction will cause the speculative load instruction to be retried in the event the token bit was set equal to one. In this manner, the latency associated with branching to an interrupt routine will be eliminated a significant amount of the time. It is very possible that the reasons for invalidating the speculative load operation are no longer present (e.g. page in memory is not present) and the load will be allowed to complete.