This invention prevents illegal memory address faults on speculative data
loads. Circular addressing of the address pointer limits memory access to
a range of addresses including all addresses used by the address pointer
and not including any invalid addresses. The invention uses circular
addressing hardware, if available on the data processor. If not
available, this invention simulates circular addressing. This invention
permits loads to be issued earlier than if predication were used and
allows already predicated loads to be speculated without the overhead of
a compound predicate. This invention can be used on processors without
hardware supporting speculation.