Dynamically Exploiting Narrow Width Operands to Improve Processor Power and Performance
In general-purpose microprocessors, recent trends have pushed towards 64-bit word widths, primarily to accommodate the large addressing needs of some programs. Many integer problems, however, rarely need the full 64-bit dynamic range these CPUs provide. In fact, another recent instruction set trend has been increased support for sub-word operations (that is, manipulating data in quantities less than the full word size). In particular, most major processor families have introduced "Multimedia" instruction set extensions that operate in parallel on several sub-word quantities in the same ALU.