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Q74882: MASM MUL Operation Accepts Only One Operand

Article: Q74882
Product(s): Microsoft Macro Assembler
Version(s): MS-DOS:5.01a,5.1,6.0
Operating System(s): 
Keyword(s): 
Last Modified: 04-MAY-2001

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The information in this article applies to:

- Microsoft Macro Assembler (MASM), versions 5.1, 5.01a, 6.0 
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SUMMARY
=======

The assembly language multiplication instruction MUL accepts only one operand.
The second operand is implied to be either the AX or the AL register depending
on whether an 8-bit multiplication or 16-bit multiplication is being performed.

If a second operand is specified, the Microsoft Macro Assembler (MASM) version
6.0 will generate the following error:

  error A2008: syntax error : ,

MASM versions 5.1 and 5.1a generate the following warning:

  warning A4001: Extra characters on line

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

The sample code below can be used to illustrate this situation. Assembling the
code with MASM version 5.1, 5.1a, or 6.0 will result in one of the above
errors.

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

  ; Assemble options needed: none

      .MODEL small
      .CODE
      mul ah, 10
      END

Additional query words: kbinf 5.10 5.10a 6.00 6.00a 6.00b

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Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM600
Version           : MS-DOS:5.01a,5.1,6.0

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