Q84744: Conditionally Assembling the END Directive

Article: Q84744
Product(s): Microsoft Macro Assembler
Version(s): MS-DOS:5.x,6.0,6.0a,6.0b
Operating System(s): 
Keyword(s): 
Last Modified: 06-MAY-2001

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The information in this article applies to:

- Microsoft Macro Assembler (MASM), versions 5.x, 6.0, 6.0a, 6.0b 
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SUMMARY
=======

Sometimes it is helpful to conditionally have a starting label specified with
the END directive; for example, to use preprocessor directives to specify
various END directives:

  IFDEF xyz
    END start_label
  ELSE
    END
  ENDIF

Note, however, that this approach will not work. As soon as MASM encounters the
first END directive it will stop assembling. The assembler stops regardless of
whether or not the END directive is inside a preprocessor block. This is the
expected behavior for the assembler.

A method that can be used to accomplish this task involves using a conditionally
defined text equate with the END directive. The following sample code
demonstrates this method:

Sample Code
-----------

  ; Assemble options needed: /Dxyz

  .MODEL small

  .STACK 4096

  .CODE
  start_label:
    mov ax, 4C00h
    int 21h

  IFDEF xyz
    end_label EQU <start_label>
  ELSE
    end_label EQU <>
  ENDIF

  END end_label

Additional query words: kbinf 6.00 6.00a 6.00b

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Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM600 kbMASM600a kbMASM600b
Version           : MS-DOS:5.x,6.0,6.0a,6.0b

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