## ALP Programming Guide and Reference

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### IFxx (Begin Primary Conditional Block)

You can use each IFxx conditional directive with the ELSExx, ELSE and ENDIF directives to provide the statements to be considered for conditional assembly. ALP assembles the statements following the IFxx directive only if this condition is true.

Syntax

    IFxx   operand
        .
        .
        .
    [ ELSEIFxx ]   ( optional )
        .
        .
        .
    [ ELSE ]   ( optional )
        .
        .
        .
    ENDIF

Remarks

The following directives are members of the IFxx family:

IF
IFB
IFDEF
IFDIF
IFDIFI
IFE
IFIDN
IFIDNI
IFNB
IFNDEF
IF1
IF2

You can nest the conditional directives to any level. They are not limited to use within a macro. The assembler must know any operand to a conditional on pass one to avoid errors and incorrect evaluation.