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Q39373: FIX: Warning A4057 Generated Instead of Error A2019

Article: Q39373
Product(s): Microsoft Macro Assembler
Version(s): 5.1
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), version 5.1 
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SYMPTOMS
========

The code below is correctly flagged as an error in the Microsoft Macro Assembler
(MASM) versions 5.0, 6.0, 6.0a, 6.0b, but MASM 5.1 generates a warning and
incorrect code.

The following is the error generated by MASM 5.0

  A2019: Wrong type of register

Macro Assembler Version 5.1 fails to generate an error on the MOV instruction
using the 8-bit registers (AH, BH, CH, DH, AL, BL, CL, DL) with segment
registers (CS, DS, ES, SS). Instead, the following warning is generated

  A4057: Illegal size for operand

The code generated is also in error. Each of the (8-bit) byte registers maps to
the set (SP, DI, BP, SI, AX, BX, CX, DX).

The following is the error generated by MASM 6.0

  A2024: invalid operand size for instruction

STATUS
======

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

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

The following sample code demonstrates the problem:

Sample Code:
------------

  ;Assemble options needed: none

  _TEXT   segment word public 'CODE'
        ; instruction in source     Generated code shown in listing
          mov     ds, ah          ; mov   ds, sp
          mov     ds, bh          ; mov   ds, di
          mov     ds, ch          ; mov   ds, bp
          mov     ds, dh          ; mov   ds, si

          mov     ds, al          ; mov   ds, ax
          mov     ds, bl          ; mov   ds, bx
          mov     ds, cl          ; mov   ds, cx
          mov     ds, dl          ; mov   ds, dx

          mov     ah, 4ch
          int     21h
  _TEXT   ends
          end

Additional query words: 5.10 buglist5.10 fixlist6.00

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

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

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