Itanium® Architecture for Programmers: Understanding 64-Bit Processors and EPIC Principles

2.1. Computer Structures

Nearly all microcomputers share the same overall structure, consisting of three essential components that are visible to the assembly language programmer:

• the central processing unit (the CPU), which contains local storage registers, a data manipulation unit that performs arithmetic and logic operations, and essential control circuitry;

• the high-speed primary memory, which holds both instructions and data; and

• the peripheral input and output devices (the I/O system), which enable interaction with humans or with other devices.

These components must be interconnected in some fashion, as indicated schematically in Figure 2-1. In a typical implementation of any architecture, the interconnections take the form of a bus, or several ...