Conditionally Assembling the END Directive (84744)

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