Integer performance Improving integer performance is one of tougher task in comparison to improving floating-point and multimedia performance. First way of improving performance is reduce various penalties. Reducing branch penalty is very important. There will be helpful other techniques, in addition to very effective branch prediction mechanism included in Alpha 21264 for reducing branch penalties. One of obvious candidates is predicated instruction execution.
Alpha supports only conditional move to reduce branch penalty.
Still remain memory operations and subprogram calls, for which conditional move only is not adequate. However, increased number of instructions and memory resources is penalty. This instruction just adds tag into micro-operation stored into reorder buffer. Next issue is branch prepare instruction. Sometimes branch is hard predictable even by dynamic branch prediction.