12.4 Opportunities and Challenges

In the decade leading up to 2000, the computer industry engaged in a sort of arms race over the potential of subword (multimedia) instructions. These were added in one degree or another to each manufacturer's general-purpose microarchitecture (e.g., sparingly for Alpha but more abundantly for UltraSPARC). Much has been written about opportunities, challenges, and cautions brought about by such modifications of computer architectures.

Contrary to what someone without experience in digital circuit design might speculate, the addition of the MAX-2 selection of instructions for subword parallelism in PA-RISC 2.0 architecture consumed remarkably little area on a processor chip, as Lee has noted.

Applications ranging from "edutainment" to computationally intensive scientific software can be accelerated substantially by subword instructions. For example, De Sutter et al. reported that a speedup of 45% on an UltraSPARC system was attained when the inner loops of a positron emission tomography image reconstruction algorithm were transformed to use subword parallelism.

The references section lists an article by university and industry authors (Conte et al.) that gives an overview and a closing challenge to academics to help develop compiler techniques that better utilize new hardware capabilities.