AN3350 datasheet(73/185 Pages) STMICROELECTRONICS

73 / 185 page

AN3350

Working with the assembler

Doc ID 018512 Rev 2

73/185

Searches are retroactive — when files with the same name reside in the path, then the file

chosen for inclusion is taken from the path's most recently added directory, unless the file's

absolute name is provided. You can explicitly add more directories to the path from within

the code by using #path directory or a command line option. All path additions made by

a file during its processing are deleted upon file completion. System files are similarly

searched in the 'system path'. The path begins from the directory containing the etpu_bins

tool.

You are responsible for avoiding repeated inclusion of files. This can be achieved by defining

a distinct macro in the included file and testing for its definition.

Example: the following code can be used to prevent multiple inclusion of the file 'foo.def':

#ifndef(FOO_DEF)

#define FOO_DEF

; actual content of file 'foo.def'

#endif // FOO_DEF //

#path

The directive '#path {directory}' adds directories to the include search path. Enclose

the directory name in double quotes. To add a directory to the system path, enclose the

directory name in angled brackets.

Note:

As this directive seriously limits portability of source code, its use is not generally

recommended. It is usually preferable to update the path using the IDE or from the

command line.

10.6.3

Preprocessor operations

Most operations begin with the modulo character ('%'). This section lists all preprocessor

directives and operators. Nested operator behavior, however, is not defined.

%defined

The '%defined' operator checks the definition of single-line macros: %defined (MACRO)

will evaluate to true (the integer one) if a single-line macro called 'MACRO' exists, otherwise

it will evaluate to zero. To test whether or not a macro has been defined, the result of the

above noted operation can be negated (e.g., '#if !%defined(MACRO)').

when testing definition of a single macro inside an #if condition, the shorter notation (#ifdef /

#ifndef) is preferred

%mac

The '%mac' operator checks for the existence of multi-line macros.

AN3350 Datasheet(PDF) 73 Page - STMicroelectronics