DOCUMENT:Q74532  04-MAY-2001  [masm]
TITLE   :FIX: Near Call Between Segments Within a Group May Fail
PRODUCT :Microsoft Macro Assembler
PROD/VER:MS-DOS:6.0
OPER/SYS:
KEYWORDS:

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

 - Microsoft Macro Assembler (MASM), version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

The Microsoft Macro Assembler (MASM) version 6.0 may generate incorrect code
when a near call is made to a procedure in another segment. When a call is made
from an offset greater that 0FDh in the calling segment to a procedure declared
in the same source file, the call is made to an incorrect offset.

RESOLUTION
==========

To work around this problem, code the procedure in another module and declare it
as external in the problem module.

STATUS
======

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

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

The sample program below illustrates this problem. It defines two segments that
are defined in the same group. Calls are being made from different offsets in
the file. All calls after offset 0FDh are made to incorrect addresses rather
than being set up as relocatable calls.

The following is incorrect code generated for the procedure called Generic:

    00F8                           Generic proc    near
    00F8  E8 0000 R                        call    Simple
    00FB  E8 0000 R                        call    Simple
    00FE  E8 11B2                          call    Simple
    0101  E8 5200                          call    Simple
    0104  E8 11B2                          call    Simple
    0107  E8 11B2                          call    Simple
    010A  E8 0854                          call    Simple
    010D                           Generic endp

The correct code that should be generated would appear as follows:

    00F8                           Generic proc    near
    00F8  E8 0000 R                        call    Simple
    00FB  E8 0000 R                        call    Simple
    00FE  E8 0000 R                        call    Simple
    0101  E8 0000 R                        call    Simple
    0104  E8 0000 R                        call    Simple
    0107  E8 0000 R                        call    Simple
    010A  E8 0000 R                        call    Simple
    010D                           Generic endp

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

   ; Assemble options needed: none
   ;

   CGroup  group   Init, Code

   ASSUME CS:CGroup

   Code    segment para public 'CODE'

   Simple  proc    near
           ret
   Simple  endp

   Code    ends

   Init    segment para public 'CODE'
           ORG     0F8h

   Generic proc    near
           call    Simple
           call    Simple
           call    Simple
           call    Simple
           call    Simple
           call    Simple
           call    Simple
   Generic endp

   Init    ends

   END

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

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM600
Version           : MS-DOS:6.0
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.