DOCUMENT:Q77078  06-MAY-2001  [masm]
TITLE   :FIX: Whitespace Character Must Precede DUP Operator
PRODUCT :Microsoft Macro Assembler
PROD/VER:MS-DOS:6.0,6.0a,6.0b
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Macro Assembler (MASM), versions 6.0, 6.0a, 6.0b 
-------------------------------------------------------------------------------

SYMPTOMS
========

When using the DUP operator in the Microsoft Macro Assembler (MASM), you must
place a whitespace character before the DUP operator if using the "?" operator.
If no whitespace is present, no error message is produced by the assembler, and
incorrect code will be generated. The assembler will generate one data item for
the specified type, initialized to the value of the repeat size for the DUP
operator.

RESOLUTION
==========

To work around the problem, place a space between the repeat size and the DUP
operator. Initializing the variable will cause a syntax error to be generated.

STATUS
======

Microsoft has confirmed this to be a problem in MASM version 6.0, 6.0a, and
6.0b. This problem was corrected in MASM for MS-DOS version 6.1.

MORE INFORMATION
================

The code example below generates a listing file that shows the size generated
for the respective DUP statements. It can be seen that the first DUP operation
generates 4 data bytes; however, the second generates 1 data byte initialized to
4.

The assembler has problems parsing this statement because the DUP operator begins
with a letter (d), which is a valid radix suffix.

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

   ; Assemble options needed: /Fl

   .MODEL small
   .STACK 4096

   .DATA
   a       DB 4 DUP(0)
   size_a  DB SIZEOF a
   b       DB 4DUP(?)
   size_b  DB SIZEOF b

   .CODE
   start:
      mov ax, 4C00H
      int 21H      ; Terminate Process
   END start

Additional query words: 6.00 6.00a 6.00b buglist6.00 buglist6.00a buglist6.00b fixlist6.10

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM600 kbMASM600a kbMASM600b
Version           : MS-DOS:6.0,6.0a,6.0b
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.