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Q26270: FIX: Relational Operators with MOV May Evaluate Incorrectly

Article: Q26270
Product(s): Microsoft Macro Assembler
Version(s): 5.0,5.1,5.1a
Operating System(s): 
Keyword(s): 
Last Modified: 06-MAY-2001

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

- Microsoft Macro Assembler (MASM), versions 5.0, 5.1, 5.1a 
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SYMPTOMS
========

In the Microsoft Macro Assembler (MASM) versions 5.0, 5.1, and 5.1a, some of the
relational operators evaluate to the wrong value when used with a MOV
instruction.

STATUS
======

Microsoft has confirmed this to be a problem in MASM versions 5.0, 5.1, and
5.1a. This problem was corrected in MASM version 6.0.

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

The following listing-file sections are examples of this problem. It is
important to note that FFFF=true, and 0000=false. It is also important to note
that when FFFFh is used with the GT, GE, LE, and LT operators, it is interpreted
as the largest positive number, not as -1.

Sample Listing File
-------------------

1                                .MODEL SMALL
2                                .CODE
3 0000  B8 0000                  MOV AX, 0FFFFH GT -1
4 0003  B8 FFFF                  MOV AX, 0FFFFH LE -1
5                                END
*******************************************************

1                                .386
2                                .MODEL SMALL
3                                .CODE
4 0000  66| B8 FFFF              MOV AX, -1  GE  0FFFFFFFFH
5 0004  66| B8 FFFF              MOV AX, 0FFFFFFFFH  LE  -1
6 0008  66| B8 0000              MOV AX, 0FFFFFFFFH  GT  -1
7 000C  66| B8 0000              MOV AX, -1  LT  0FFFFFFFFH
8                                END

Additional query words: 5.00 5.10 5.10a 6.00 buglist5.00 buglist5.10 buglist5.10a fixlist6.00

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM500 kbMASM510a
Version           : :5.0,5.1,5.1a
Solution Type     : kbfix

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

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