Zilog Z8F0130 - Manual (Page 348)

Using the Macro Assembler UM013037-1212
324
Zilog Developer Studio II – Z8 Encore!
User Manual
•
The syntax of the structured assembly block must conform to the requirements speci-
fied in the
Structured Assembly Inputs section on page 319.
•
The .$IF and .$ENDIF directives must be properly balanced, that is, there must be
exactly one .$ENDIF directive for each .$IF directive, and the .$IF directive must
precede its corresponding .$ENDIF directive.
•
The .$REPEAT and .$UNTIL directives must be properly balanced, that is, there must
be exactly one .$UNTIL directive for each .$REPEAT directive, and the .$REPEAT
directive must precede its corresponding .$UNTIL directive.
•
The .$WHILE and .$WEND directives must be properly balanced, that is, there must be
exactly one .$WEND directive for each .$WHILE directive, and the .$WHILE directive
must precede its corresponding .$WEND directive.
•
The structured assembly block must be completely specified with a single assembly
unit. An assembly unit is a single source file or a single macro definition.
Sequence of Operations
The following sequences of operations are performed in processing structured assembly
test directives:
•
.$IF Sequence of Operations – see page 324
•
.$REPEAT Sequence of Operations – see page 325
•
.$WHILE Sequence of Operations – see page 325
.$IF Sequence of Operations
The following sequence of operations is performed in processing the .$IF structured
assembly test directives:
1. The assembler generates object code to evaluate the conditions specified on the .$IF
directive and on any optional .$ELSEIF directives. If the condition is true at execu-
tion time, the object code generated from the statements associated with the .$IF
directive are executed.
2. If the condition specified on the .$IF directive is false at execution-time, the assem-
bler-generated object code successively evaluates the conditions specified on the
.$ELSEIF directives, if there are any, until a true condition is evaluated. On evaluat-
ing a true .$ELSEIF condition, the object code generated from the statements associ-
ated with the .$ELSEIF directive are executed.
3. If all conditions on the .$IF and .$ELSEIF directives are false at execution-time, and
an .$ELSE directive is present, the object code generated from the statements associ-
ated with the .$ELSE directive are executed.
4. If no tested condition is true, and if no .$ELSE directive is specified, no statements in
the structured assembly block are executed.