Chapter 10 Writing Assembler Control Statements
188 Identifier Definement
10.3.2 #undef
Syntax
#undef identifier
Functional description
This directive deletes an identifier defined by a #define directive. The effective range of an identifier is
from the line following #define until the line before #undef.
To redefine the replacement string of an identifier, redefine it with #define after performing an #undef.
Coding rules
The identifier for an #undef directive must be the same string as the identifier for the corresponding
#define directive. The string is case sensitive.
Usage example
A source file that uses #undef is shown below.
#define data1 0x11
#define data2 0x22
_CODE section CODE, PUBLIC, 2
mov data1, D0
mov data2, D1
#undef data1
mov data1, D0
#undef data2
#define data1 0x33
#define data2 0x44
mov data1, D0
mov data2, D1
end
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