Chapter 10 Writing Assembler Control Statements
Conditional Assembly 193
10.4.2 #if, #ifn
Syntax
Syntax for #if Syntax for #ifn
#if expression #ifn expression
block1 block1
[#else [#else
block2] block2]
#endif #endif
Functional description
#if
If the value of expression is not 0, block1 will be assembled. If it is 0 and an #else directive has been
coded, block2 will be assembled.
#ifn
If the value of expression is 0, block1 will be assembled. If it is not 0 and an #else directive has been
coded, block2 will be assembled.
Coding rules
These directives can be used within macro definitions and wherever machine language instructions can
be coded.