Texas Instruments MSP50C614 User Manual

Page 342

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C– – Compiler

5-42

5.9.4

C– – Directives

C– – has a limited number of directives and some additional directives not
found in ANSI C compilers. The following directives are recognized by the
compiler.

5.9.4.1

#define

This directive is used to introduce 2 types of macros, in typical C fashion:

Without Arguments:
defines a replacement string for a given string

Example:

#define PI 3.1415926535

Every occurrence of the token PI will henceforth be replaced with the string
3.1415926535.

If there is no replacement string, the given string is deemed

defined: this can

be used in conjunction with the #ifdef / #ifndef directives. It is also possible
to

undefine a macro with the #undefine directive.

With Arguments:
The macro name must be immediately followed by a pair of parenthesis,
which introduces the arguments. This is completely compatible with the usual
C definition.

Example:
#define modulo(i,j) (i%j)

Every occurrence of the word modulo followed by an expression in
parentheses will be replaced by (i%j), where i is the first argument in the
parenthesis, and j the second argument. modulo((a*b),c) will thus be replaced
by ((a*b)%c).

5.9.4.2

#undefine

The string following this directive is removed from the list of macros. There is
no warning if the string is not found in the macro list.

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