Q67760: FIX: Bad Object File Generated with MASM 5.1 and 5.1a

Article: Q67760
Product(s): Microsoft Macro Assembler
Version(s): 5.1,5.1a
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 5.1, 5.1a 
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SYMPTOMS
========

The following mixed-language program does not assemble properly under the
Microsoft Macro Assembler (MASM) version 5.1 and 5.1a.

CAUSE
=====

The assembler does not generate the correct .OBJ record for the linker to
resolve the reference properly. When the .EXE is built, the _test variable is
located in the NULL segment instead of the _DATA segment; therefore, instead of
the residing 1 byte apart, they are actually 42h bytes apart.

RESOLUTION
==========

Removing the ASSUME statements from the assembly code eliminates the problem.
These ASSUME statements are not necessary.

STATUS
======

Microsoft has confirmed this to be a problem in MASM versions 5.1 and 5.1a. This
problem was corrected in MASM version 6.0.

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

Sample Code #1
--------------

  ; Assemble options needed: none

          .model small, c

          .data
         ASSUME ds: nothing
  PUBLIC xxx
  xxx    DB 1
         ASSUME ds: @data
  PUBLIC yyy
  yyy    DB 2

         .code
  PUBLIC func
  func   PROC
         MOV ax, OFFSET yyy
         SUB ax, OFFSET xxx
         RET
  func   ENDP

         END

Sample Code #2
--------------

  /* Compile options needed: none
  */ 

  #include <stdio.h>
  extern char xxx;
  extern char yyy;

  void main ()
  {
     printf( "C distance of yyy - xxx = %X\n", &yyy - &xxx );
     printf( "MASM distance of yyy - xxx = %X\n", func () );
  }

Additional query words: 5.10 5.10a 6.00 buglist5.10 buglist5.10a fixlist6.00

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM510a
Version           : :5.1,5.1a
Solution Type     : kbfix

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

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