User:Dcshapiro/Instruction set extension
The instruction set of some processors can be extended with additional instructions called Instruction Set Extensions (ISE)[1]. Adding ISEs to a processor allows the designer to trade chip area for throughput, hopefully resulting in a speedup. ISEs are often composed of parallel and/or chained sequences of operations which are known to be commonly found in some specific application which the designer is targeting. Companies such as Altera and Tensilica provide processors which can be extended with ISEs (e.g. NIOS-II and Xtensa). For more information on this sort of processor extensibility see application-specific instruction-set processor.