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DOCUMENT:Q32811  04-MAY-2001  [masm]
TITLE   :FIX: Wrong Opcode For Far Call from USE16 Seg to USE32 Seg
PRODUCT :Microsoft Macro Assembler
PROD/VER::5.1
OPER/SYS:
KEYWORDS:

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

 - Microsoft Macro Assembler (MASM), version 5.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

MASM will generate both an address-size and operand-size override for a far call
from a USE16 segment to a USE32 segment. Only the operand-size override is
necessary.

STATUS
======

Microsoft has confirmed this to be a problem in Version 5.10. This problem was
corrected in MASM version 5.10a.

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

The address-size prefix is 67h and the operand-size prefix is 66h.

The following sample code demonstrates the problem:

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

   ;Assemble options needed: none

      .386

      s32 SEGMENT USE32
      assume cs:@CurSeg
         p   PROC
         p   ENDP
      s32    ENDS

      s16 segment USE16
      assume cs:@CurSeg
             CALL   far ptr p
      s16    ENDS

             END

   The opcode generated for the far call by MASM 5.1 is as follows

      67| 66| 9A 00000000

   The correct opcode (generated by MASM 5.10a) is as follows

          66| 9A 00000000

Additional query words: 5.10 buglist5.10 fixlist5.10a

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

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

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Copyright Microsoft Corporation 2001.
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