Computers as Components, 2nd Edition

236 CHAPTER 5 Program Design and Analysis

aptr

4 bytes

field1

field2

struct {

int field1;

char field2;

} mystruct;

struct mystruct a, *aptr 5 &a;

FIGURE 5.15

C structure layout and access.

5.5 PROGRAM OPTIMIZATION

Now that we understand something about how programs are created,we can start to

understand how to optimize programs. If we want to write programs in a high-level

language, then we need to understand how to optimize them without rewriting

them in assembly language. This first requires creating the proper source code that

causes the compiler to do what we want. Hopefully, the compiler can optimize our

program by recognizing features of the code and