Barcode Reader User Manual

Glossary

B-3

Glossary

pragma: Preprocessor directive that provides directions to the compiler

about how to treat a particular statement.

protected-mode programs: 32-bit extended DOS programs. These

programs require an extended memory manager and run on 80386,

80486, and Pentium based PCs only. Protected-mode programs can use

all available RAM on a computer up to 64M bytes.

real-mode: 16-bit native DOS mode. This mode limits the available memory

to 640K bytes. Calls to DOS may involve switching from protected to real

mode.

DOS real-mode tools are no longer supported by the TMS470R1x

code generation tools.

shell program: A utility that lets you compile, assemble, and optionally link

in one step. The shell runs one or more source modules through the com-

piler (including the parser, optimizer, and code generator), the assem-

bler, and the linker.

structure: A collection of one or more variables grouped together under a

single name.

swap file: The file where virtual memory (secondary memory) is allocated

on the hard disk.

veneer: A sequence of instructions that serves as an alternate entry point

into a routine if a state change is required.

virtual memory: The ability of a program to use more memory than a

computer actually has available as RAM. This is accomplished by using

a swap file on disk to augment RAM. When RAM is not sufficient, part of

the program is swapped out to a disk file until it is needed again. The

combination of the swap file and available RAM is the virtual memory.

The TMS470R1x tools use the DOS/4GW memory extender to provide

virtual-memory management (VMM). This memory extender is not pro-

vided as an executable file but is embedded in several of the tools

shipped by TI. Contact technical support for more information.