4
Chapter 1 Fundamentals of Computer Design
packaging, power, and cooling. Optimizing the design requires familiarity with a
very wide range of technologies, from compilers and operating systems to logic
design and packaging.
In the past, the term
computer architecture
often referred only to instruction
set design. Other aspects of computer design were called
implementation,
often
insinuating that implementation is uninteresting or less challenging. The authors
believe this view is not only incorrect, but is even responsible for mistakes in the
design of new instruction sets. The architect’s or designer’s job is much more
than instruction set design, and the technical hurdles in the other aspects of the
project are certainly as challenging as those encountered in doing instruction set
design. This is particularly true at the present when the differences among in-
struction sets are small (see Appendix C).
In this book the term
instruction set architecture
refers to the actual programmer-
visible instruction set. The instruction set architecture serves as the boundary be-
tween the software and hardware, and that topic is the focus of Chapter 2. The im-
plementation of a machine has two components: organization and hardware. The
term
organization
includes the high-level aspects of a computer’s design, such as
the memory system, the bus structure, and the internal CPU (central processing
unit—where arithmetic, logic, branching, and data transfer are implemented)
design. For example, two machines with the same instruction set architecture but
different organizations are the SPARCstation-2 and SPARCstation-20.
Hardware
is used to refer to the specifics of a machine. This would include the detailed
logic design and the packaging technology of the machine. Often a line of ma-
chines contains machines with identical instruction set architectures and nearly
identical organizations, but they differ in the detailed hardware implementation.
For example, two versions of the Silicon Graphics Indy differ in clock rate and in
detailed cache structure. In this book the word
architecture
is intended to cover
all three aspects of computer design—instruction set architecture, organization,
and hardware.
Computer architects must design a computer to meet functional requirements
as well as price and performance goals. Often, they also have to determine what
the functional requirements are, and this can be a major task. The requirements
may be specific features, inspired by the market. Application software often
drives the choice of certain functional requirements by determining how the ma-
chine will be used. If a large body of software exists for a certain instruction set
architecture, the architect may decide that a new machine should implement an
existing instruction set. The presence of a large market for a particular class of
applications might encourage the designers to incorporate requirements that
would make the machine competitive in that market. Figure 1.2 summarizes
some requirements that need to be considered in designing a new machine. Many
of these requirements and features will be examined in depth in later chapters.
Once a set of functional requirements has been established, the architect must
try to optimize the design. Which design choices are optimal depends, of course,
on the choice of metrics. The most common metrics involve cost and perfor-
5星 · 超过95%的资源 需积分: 34 47 浏览量
2007-07-06
13:26:39
上传
评论 3
收藏 4.82MB PDF 举报 
- 1
- 2
- 3
- 4
前往页