Computers as Components, 2nd Edition

248 CHAPTER 5 Program Design and Analysis

Code

CPU

Interpreter

OS

FIGURE 5.21

Structure of a program interpretation system.

some abstract machine langua ge. As illustrated in Figure 5.21, the interpreter sits

between the program and the machine. It translates one statement of the program

at a time. The interpreter may or may not generate an explicit piece of code to

represent the statement. Because the interpreter translates only a very small piece

of the program at any given time, a small amount of memor y is used to hold inter-

mediate representations of the program. In many cases, a Forth program plus the

Forth interpreter are smaller than the equivalent ...