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Q119872: PRB: Error A2032 Using Indexed Addressing

Article: Q119872
Product(s): Microsoft Macro Assembler
Version(s): 6.0,6.0a,6.0b,6.1,6.11,6.1a
Operating System(s): 
Keyword(s): 
Last Modified: 06-MAY-2001

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

- Microsoft Macro Assembler (MASM), versions 6.0, 6.0a, 6.0b, 6.1, 6.1a, 6.11 
-------------------------------------------------------------------------------

SYMPTOMS
========

Assembling a line of code that performs indexed addressing, such as the
following:

  mov dx,mylabel-2[bx]

produces the following error:

  error A2032: invalid use of register

The same line of code assembles without error under MASM version 5.1.

CAUSE
=====

The index operator '[]' is now at the very top of the MASM operator precedence
list, while the binary "+" and "-" operators are in the lower half. So, for
example, if the expression

  2 - 3[bx]

is no longer equivalent to

  2 - 3 + bx

but rather to

  2 - (3 + bx) ; or 2 - 3 - bx

then it is the "- bx" that is causing the A2032 error.

RESOLUTION
==========

Assemble using the OPTION M510 directive, the /Zm switch (which implies the
OPTION M510), or use one of the following syntaxes:

  mov dx, (mylabel-2)[bx]
  mov dx, mylabel-2+[bx]
  mov dx, mylabel[bx]-2

NOTE: The OPTION M510 is used for compilation with maximum MASM version 5.10
compatibility.

Additional query words: 6.00 6.00a 6.00b 6.10 6.10a

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM600 kbMASM610 kbMASM611 kbMASM610a kbMASM600a kbMASM600b
Version           : :6.0,6.0a,6.0b,6.1,6.11,6.1a

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

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