Summary

This chapter built upon the preceding chapters, which presented the basic aspects of computer architecture and architectural variations addressing domain-specific requirements. We focused here on extensions commonly implemented at the processor instruction set level to provide additional system capabilities beyond generic computing requirements.

You should now have a good understanding of privileged processor modes and how they are used in multiprocessing and multiuser contexts, the concepts of floating-point processors and instruction sets, techniques for power management in battery-powered devices, and processor features intended to enhance system security.

This background has prepared us for the next chapter, in which we will, the most popular processor architectures and instruction sets currently used in personal computing, business computing, and in smart portable devices. These architectures are the x86, the x64, and the 32-bit and 64-bit variants of ARM.