Motorola HC12 Manuale Utente

User’s Manual

MCUez HC12 Assembler

174

Assembler Directives

MOTOROLA

Syntax:

IF

<condition>

 [<assembly language statements>]

[

ELSE

]

 [<assembly language statements>]

ENDIF

Description:

If <condition> is true, the statements between

IF

 and the

corresponding

ELSE

 directive generate code.

If <condition> is false, the statements between

ELSE

 and the

corresponding

ENDIF

 directive generate code. Nesting of

conditional blocks is allowed. The maximum level of nesting is
limited by the available memory at assembly time.

Example:

This is an example of using conditional assembly directives:

Try: EQU 0

     IF  Try != 0

       LDD   #1023

     ELSE

       LDD   #0

     ENDIF

The value of

Try

 determines the instruction that generates

code. As shown, the

LDD #1023

instruction generates code.

Changing the operand of the

equ

directive to 1 causes the

LDD #0

instruction to generate code instead.

The following shows the listing provided by the assembler for
these lines of code:

       0000 0001   Try:  EQU   0

       0000 0001         IF  Try != 0

                               ELSE

 000000 CC 0000            LDD #0

                         ENDIF