Abstract: All pointer-based accesses require first that the value contained in a pointer register to be read and then that value be used as an address to the appropriate region in random access memory (RAM). As implemented today, this requires two memory read access cycles, each of which takes at least one clock cycle and therefore this implementation does not allow single cycle operation. In accordance with an embodiment of the invention, when an access is performed to pointer memory to read the contents of a pointer, it is the shadow memory that is actually read and that returns the pointer value. Since the shadow memory is made up of pointer registers, a read access involves multiplexing out of appropriate data for the pointer address from these pointer registers to form a target pointer address.

Abstract: A first tag is assigned to a branch instruction. Dependent on the type of branch instruction, a second tag is assigned to an instruction in the branch delay slot of the branch instruction. The second tag may equal the first tag if the branch delay slot is unconditional for that branch, and may equal a different tag if the branch delay slot is conditional for the branch. If the branch is mispredicted, the first tag is broadcast to pipeline stages that may have speculative instructions, and the first tag is compared to tags in the pipeline stages. If the tag in a pipeline stage matches the first tag, the instruction is not cancelled. If the tag mismatches, the instruction is cancelled.